CN120189906A

CN120189906A - Preparation method and application of high-efficiency granular clay adsorbent for deolefination/denitrification

Info

Publication number: CN120189906A
Application number: CN202510068637.2A
Authority: CN
Inventors: 朱永林; 朱卓钦; 刘建国
Original assignee: Hangzhou Yongsheng Catalyst Co ltd
Current assignee: Hangzhou Yongsheng Catalyst Co ltd
Priority date: 2025-01-16
Filing date: 2025-01-16
Publication date: 2025-06-24
Anticipated expiration: 2045-01-16
Also published as: CN120189906B

Abstract

The invention provides a preparation method and application of an efficient granular clay adsorbent for removing olefins/denitrification, which comprises the steps of carrying out organic intercalation modification treatment on activated clay by adopting hexadecyl trimethyl ammonium bromide and caprolactam to obtain intercalation modified clay, carrying out surface hydrophobic modification treatment on the intercalation modified clay by adopting a silane coupling agent to obtain composite modified clay, adding magnesium chloride into clay dispersion liquid to obtain an intermediate solution, adding sodium hydroxide into the intermediate solution, mixing and stirring, heating to react, and obtaining the efficient granular clay adsorbent after the reaction is finished. According to the invention, through hydrothermal synthesis reaction of magnesium chloride and sodium hydroxide, nano magnesium oxide is synthesized on the surface and between layers of the composite modified clay, more new gaps are formed through stacking of the nano magnesium oxide, and the high-efficiency granular clay adsorbent with high specific surface area and high porosity is obtained.

Description

Preparation method and application of efficient granular clay adsorbent for removing olefins/denitrification

Technical Field

The invention belongs to the technical field of petrochemical industry, and relates to a preparation method and application of an efficient granular clay adsorbent for removing olefins and denitrification.

Background

Clay is a natural multifunctional clay mineral, its main component is montmorillonite, and contains small quantity of quartz, feldspar and other impurities. Clay exhibits excellent adsorption, ion exchange and catalytic properties due to its unique layered structure and large specific surface area. Clay plays an irreplaceable role in various fields of petrochemical industry, environmental protection, daily chemicals and the like. Particularly, in the oil refining process, the clay is used as an adsorbent, so that impurities in the oil can be effectively removed, and the purity and quality of the product are improved.

In the field of deolefination, clay applications have focused mainly on the refining of aromatic hydrocarbons and the treatment of reformate. Aromatic hydrocarbons are important raw materials in petrochemical industry, but the production process of the aromatic hydrocarbons is often accompanied with the generation of impurities such as olefin and the like. These impurities not only affect the purity of the aromatic hydrocarbon, but may also adversely affect subsequent processing. Conventionally, clay adsorption has been used to effectively remove these olefinic impurities and improve the purity of aromatic hydrocarbons. However, with the increasing demand for oil quality, the use of conventional clay adsorbents in the field of dealkenation presents a number of challenges. First, clay has a limited adsorption capacity, and it is difficult to meet the demand for mass production of high-purity aromatic hydrocarbons. Secondly, the clay is easy to reach adsorption saturation in the use process, so that the use period is short, and the frequent replacement of the adsorbent not only increases the production cost, but also influences the production efficiency. In addition, clay is susceptible to deactivation under severe operating conditions such as high temperature or high pressure, limiting its use in certain specific processes.

Besides the dealkenation, clay also has certain application in the field of denitrification. In oil products, basic nitrides are one of the important factors affecting the quality and stability of the oil product. Through the adsorption of clay, the nitrides can be effectively removed, and the quality of oil products is improved. However, the use of clay in the denitrification field also faces a number of limitations. On the one hand, the denitrification capability of the clay is relatively weak, the adsorption capacity is small, and the requirement of high denitrification rate is difficult to meet. On the other hand, the disposal problem of spent bleaching clay is also becoming increasingly prominent. The waste clay contains a large amount of harmful substances, and if the waste clay is improperly treated, serious pollution to the environment is caused.

Disclosure of Invention

Aiming at the defects existing in the prior art, the invention aims to provide a preparation method and application of an efficient granular clay adsorbent for removing olefin and denitrification, according to the invention, the bentonite raw ore is treated by the specific acidulant, so that the activation effect of bentonite is effectively improved, and a solid foundation is laid for subsequent modification treatment. The organic intercalation modification of activated clay by adopting hexadecyl trimethyl ammonium bromide and caprolactam further enhances the interlayer structure and adsorption performance of the activated clay, and the surface hydrophobic modification of the activated clay by utilizing a silane coupling agent ensures that the activated clay has good hydrophobic performance and improves the affinity with olefin while maintaining the high-efficiency adsorption capacity. Finally, synthesizing nano magnesium oxide on the surface and the interlayer of the composite modified clay through hydrothermal synthesis reaction of magnesium chloride and sodium hydroxide, and stacking the nano magnesium oxide to form more new pores to finally obtain the high-efficiency granular clay adsorbent with high activity and large aperture.

To achieve the purpose, the invention adopts the following technical scheme:

In a first aspect, the present invention provides a process for the preparation of a high efficiency particulate clay adsorbent for dealkenation/denitrification, the process comprising:

(I) Mixing concentrated hydrochloric acid, concentrated sulfuric acid, oxalic acid and deionized water to obtain an acidulant, crushing and sieving raw bentonite ores to obtain bentonite powder, and mixing the bentonite powder with deionized water to obtain bentonite slurry; uniformly mixing the bentonite slurry, the acidulant and sodium chloride to obtain a raw material mixture, heating and activating the raw material mixture to obtain an activated product, and rinsing, centrifuging, drying and crushing the activated product to obtain activated clay;

(II) performing organic intercalation modification treatment on the activated clay obtained in the step (I) by adopting cetyl trimethyl ammonium bromide and caprolactam to obtain intercalation modified clay;

(III) dispersing the composite modified clay obtained in the step (II) in deionized water to obtain clay dispersion liquid, adding magnesium chloride into the clay dispersion liquid, mixing, stirring and heating to obtain intermediate solution, adding sodium hydroxide into the intermediate solution, mixing, stirring and heating to react, and filtering, washing, extruding, shaping, drying, calcining, crushing and screening after the reaction is finished to obtain the efficient granular clay adsorbent.

According to the invention, the bentonite raw ore is treated by the specific acidulant, so that the activation effect of bentonite is effectively improved, and a solid foundation is laid for subsequent modification treatment. The organic intercalation modification of activated clay by adopting hexadecyl trimethyl ammonium bromide and caprolactam further enhances the interlayer structure and adsorption performance of the activated clay, and the surface hydrophobic modification of the activated clay by utilizing a silane coupling agent ensures that the activated clay has good hydrophobic performance and improves the affinity with olefin while maintaining the high-efficiency adsorption capacity. Finally, synthesizing nano magnesium oxide on the surface and the interlayer of the composite modified clay through hydrothermal synthesis reaction of magnesium chloride and sodium hydroxide, and stacking the nano magnesium oxide to form more new pores to finally obtain the high-efficiency granular clay adsorbent with high activity and large aperture.

According to the invention, mixed acid liquid consisting of concentrated hydrochloric acid, concentrated sulfuric acid and oxalic acid is adopted to carry out acid activation treatment on bentonite, so that the deolefination and denitrification capacities of activated clay can be remarkably improved, on one hand, in the acidification process, some non-adsorptive impurities, soluble impurities and mineral substances in the bentonite can be dissolved in a liquid phase system after being decomposed by acid, so that partial lattices of the bentonite are destroyed, the inter-crystal face distance is increased, pore channels of the bentonite are opened, the pore diameter is increased, the adsorption sites are increased, and the physical adsorption capacity of the activated clay on olefin and nitrogen is improved. On the other hand, in the aspect of de-olefine, the surface of activated clay after acid activation treatment has a large number of acid sites, so that olefine can be subjected to alkylation and condensation polymerization reaction, thereby being effectively removed, in the aspect of denitrification, when bentonite is activated by mixed acid, hydrogen ions replace exchangeable metal ions, rich acid centers are formed on the surface, the basicity of basic nitride morpholine is that nitrogen atoms of the basic nitride morpholine contain unshared electron pairs and can be combined with protons to form positively charged ions, and when morpholine with stronger basicity is adsorbed on the surface of activated clay, the acid centers of the activated clay can be subjected to neutralization reaction with the nitrogen atoms of morpholine to form corresponding amine salts and deposit on the surface of activated clay, thereby achieving the aim of denitrification.

The activated clay obtained after acidification has hydrophilicity, poor affinity to organic matters, and the interlayer structure of the activated clay is not completely opened, so that the adsorption capacity to olefin and nitrogen is weak. In order to improve affinity and adsorption capacity of the activated clay and fully utilize huge specific surface area, the invention adopts hexadecyl trimethyl ammonium bromide and caprolactam to carry out composite intercalation modification treatment on the activated clay, and after carrying out ion exchange on organic cations of hexadecyl trimethyl ammonium bromide and inorganic cations among activated clay layers, cations are partially attached to activated clay sheets and organic parts are remained among the layers, so that the interlayer spacing of the activated clay is increased, the structure is more loose, the porosity is higher, and partial sheet stripping occurs.

However, the modified activated clay by adopting cetyl trimethyl ammonium bromide has high cost, and the modified activated clay has poor compatibility with olefin, so that an intercalation structure is difficult to form. Therefore, on the basis of adopting cetyl trimethyl ammonium bromide to carry out organic intercalation modification, caprolactam is added to carry out composite modification on activated clay, and the interlayer spacing of the intercalation modified clay obtained after the cetyl trimethyl ammonium bromide/caprolactam composite intercalation modification is obviously improved, because after the cetyl trimethyl ammonium bromide and the activated clay are subjected to cation exchange, on one hand, the interlayer spacing of the activated clay is enlarged to a certain extent, and sufficient adsorption space is provided for the entering of subsequent caprolactam; on the other hand, the interlayer microenvironment of the activated clay is changed from hydrophilicity to lipophilicity through the intercalation modification of the cetyl trimethyl ammonium bromide, the caprolactam is favorably adsorbed to the interlayer of the activated clay under the environment, and the C=O group of the caprolactam adsorbed to the interlayer of the activated clay and the-OH group of the bentonite are easy to form hydrogen bonds, so that caprolactam molecules are introduced into the interlayer of the activated clay, and the interlayer spacing of the activated clay is further enlarged.

The organic intercalation modification is carried out on the activated clay by adopting cetyl trimethyl ammonium bromide and caprolactam, and the activated clay enters the activated clay layers through ion exchange and chemical bond action to realize intercalation modification, but the modification mode can only modify the interlayer of the activated clay, can improve the interlayer spacing of the activated clay, provides a certain space for adsorbing olefin and nitrogen, but the surface modification effect on the activated clay is insufficient only through intercalation modification treatment, so that the surface hydrophobicity of the activated clay cannot be obviously improved, thereby influencing the compatibility between the activated clay and an organic phase, and leading to insufficient affinity of the activated clay to olefin. Therefore, after intercalation modification is carried out on the activated clay, the surface of the intercalation modified clay is further subjected to hydrophobic modification treatment by adopting a silane coupling agent, the silane coupling agent is a substance with two functional groups with different chemical properties, namely a non-hydrolytic group and a hydrolytic group, silanol generated by hydrolysis can react with hydroxyl groups on the surface of the intercalation modified clay so as to be grafted on the surface of the intercalation modified clay, and meanwhile, silanol grafted on the surface of the intercalation modified clay is mutually associated to form a hydrophobic membrane with a reticular structure and covers the surface of the intercalation modified clay, the hydrophilicity of the composite modified clay obtained after modification by the silane coupling agent is changed into hydrophobicity, and the affinity, expansibility and dispersibility of the composite modified clay in an organic phase are improved, so that the composite modified clay can be better applied to olefin removal/denitrification in an organic system.

The magnesium hydroxide is generated through the hydrothermal synthesis reaction of magnesium chloride and sodium hydroxide, then the magnesium hydroxide is used as a precursor, and magnesium oxide particles are loaded on the surface and the interlayer of the composite modified clay in situ after high-temperature calcination, so that the efficient particle clay adsorbent provided by the invention is finally obtained. Compared with the composite modified clay, the specific surface area of the efficient particle clay adsorbent loaded with the magnesium oxide particles is reduced (the specific surface area of the composite modified clay is about 91-100 m ²/g, and the specific surface area of the efficient particle clay adsorbent is about 30-40 m ²/g), because the magnesium oxide particles are inserted between layers of the composite modified clay, channels and surface pores between the layers are blocked, and the specific surface area of the composite modified clay is reduced. However, at the same time, the pore volume and the pore diameter of the efficient particle clay adsorbent loaded with the magnesia particles are remarkably increased (the pore volume of the composite modified clay is about 0.1-0.15 cc/g, the pore diameter is about 3.5-4 nm, the pore volume of the efficient particle clay adsorbent is about 0.35-0.4 cc/g, and the pore diameter is about 35-40 nm), because the magnesium hydroxide deposited on the surface of the composite modified clay is decomposed into magnesia through high-temperature calcination, and in the high-temperature calcination process, by-products volatilize and escape, including physically adsorbed and chemically adsorbed water molecules, carbon dioxide and the like, the space originally occupied by the products forms a pore channel structure, so that a certain number of micropores are generated inside and on the surface of the magnesia, and in addition, as the calcination is continuously carried out, the magnesia loaded on the surface of the composite modified clay is continuously generated and stacked to form a large amount of mesoporous structures, so that the pore volume and the pore diameter of the finally obtained efficient particle clay adsorbent are remarkably increased, and adsorption sites are remarkably increased.

In the step (I), the concentrated hydrochloric acid is slowly added into deionized water and uniformly mixed to obtain diluted hydrochloric acid, then the concentrated sulfuric acid is slowly added into the diluted hydrochloric acid to obtain mixed acid solution, and finally oxalic acid is added into the mixed acid solution and uniformly mixed to obtain the acidulant.

In some alternative examples, the mass fraction of the concentrated hydrochloric acid is 35-37 wt%, such as 35wt%, 35.2wt%, 35.4wt%, 35.6wt%, 35.8wt%, 36wt%, 36.2wt%, 36.4wt%, 36.6wt%, 36.8wt%, or 37wt%, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the mass fraction of the concentrated sulfuric acid is 95-98 wt%, for example, 95wt%, 95.5wt%, 96wt%, 96.5wt%, 97wt%, 97.5wt%, or 98wt%, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the volume ratio of the concentrated hydrochloric acid to the concentrated sulfuric acid to the deionized water is 1 (1.4-1.6): (35-40), for example, 1:1.4:35、1:1.42:35.5、1:1.44:36、1:1.46:36.5、1:1.48:37、1:1.5:37.5、1:1.52:38、1:1.5:38.5、1:1.56:39、1:1.58:39.5 or 1:1.6:40, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The invention particularly limits the volume ratio of (1.4-1.6) of the concentrated hydrochloric acid to (35-40), and the hydrogen ion concentration ionized by the sulfuric acid is too high, so that the crystal layer structure of the bentonite is damaged, and the aluminum ions and magnesium ions in the interlayer part of the bentonite are dissolved out by the hydrogen ions, thereby collapsing the framework of the bentonite and damaging the octahedron. The concentration of hydrogen ions ionized by hydrochloric acid is relatively low, and the activation effect in the acid modification process is inferior to that of mixed acid. The concentration of hydrogen ions ionized by mixed acid consisting of hydrochloric acid, sulfuric acid and oxalic acid is moderate, and indissolvable salts can be generated by adding oxalic acid and calcium ions and magnesium ions, so that the replacement of calcium ions and magnesium ions between bentonite layers is facilitated, and the activation effect is best.

In some alternative examples, the mass fraction of oxalic acid in the acidulant is 5-10wt%, such as 5.0wt%, 5.5wt%, 6.0wt%, 6.5wt%, 7.0wt%, 7.5wt%, 8.0wt%, 8.5wt%, 9.0wt%, 9.5wt% or 10.0wt%, but not limited to the recited values, and other non-recited values in the range of values are equally applicable.

In a preferred embodiment of the present invention, in the step (I), the particle size of the bentonite powder is 100 to 200 mesh, for example, 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh, 150 mesh, 160 mesh, 170 mesh, 180 mesh, 190 mesh or 200 mesh, but the present invention is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable.

In some alternative examples, the bentonite powder and deionized water are mixed according to a mass ratio of (0.6-0.7): 1 to obtain the bentonite slurry, for example, 0.6:1, 0.61:1, 0.62:1, 0.63:1, 0.64:1, 0.65:1, 0.66:1, 0.67:1, 0.68:1, 0.69:1 or 0.7:1, but not limited to the listed values, and other non-listed values in the range of values are equally applicable.

In some alternative examples, the mass ratio of bentonite slurry, the acidulant and sodium chloride is 1 (0.6-0.7): (0.08-0.1), for example, 1:0.6:0.08、1:0.61:0.082、1:0.62:0.084、1:0.63:0.086、1:0.64:0.088、1:0.65:0.09、1:0.66:0.092、1:0.67:0.094、1:0.68:0.096、1:0.69:0.098 or 1:0.7:0.1, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The invention particularly limits the mass ratio of bentonite slurry, an acidulant and sodium chloride to 1 (0.6-0.7): (0.08-0.1), and when the dosage of the acidulant is lower than the lower limit of the range defined by the invention, the replacement of calcium ions by hydrogen ions is incomplete, and the quality of the finally obtained activated clay is poor. With the increase of the dosage of the acidifier, the concentration of the hydrogen ions is increased, and the activity degree of the activated clay obtained after the acid activation is rapidly increased, which shows that calcium ions and magnesium ions among bentonite layers are fully replaced by the hydrogen ions, and the bentonite layers are acidified and modified into the high-efficiency activated clay with larger specific surface area and stronger adsorptivity. When the dosage of the acidulant exceeds the upper limit of the range defined by the invention, the concentration of hydrogen ions is too high, so that aluminum ions in the tetrahedral structure of bentonite are also exchanged and dissolved out, the framework structure of bentonite is destroyed, and the activity of the finally obtained activated clay is obviously reduced.

In some alternative examples, the operation of heat activation includes:

And heating the raw material mixture to a first activation temperature and preserving heat, continuously heating to a second activation temperature and preserving heat after the heat preservation is finished, and cooling to room temperature after the heat preservation is finished to obtain the activation product.

In some alternative examples, the first activation temperature is 80 to 90 ℃, for example, 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃, or 90 ℃, but the present invention is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the first activation temperature is maintained for 2-3 h, for example, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the second activation temperature is 100 to 110 ℃, for example, 100 ℃, 101 ℃, 102 ℃, 103 ℃, 104 ℃, 105 ℃, 106 ℃, 107 ℃, 108 ℃, 109 ℃ or 110 ℃, but the second activation temperature is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the second activation temperature is kept for 2-3 h, for example, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, deionized water is used to rinse the activated product until the pH of the activated product reaches 4 to 5, which may be, for example, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5.0, although not limited to the recited values, other non-recited values within the range are equally applicable.

In some alternative examples, the rotational speed of the centrifugation is 3000 to 4000rpm, for example, 3000rpm, 3100rpm, 3200rpm, 3300rpm, 3400rpm, 3500rpm, 3600rpm, 3700rpm, 3800rpm, 3900rpm or 4000rpm, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the centrifugation time is 5-10 min, for example, 5.0min, 5.5min, 6.0min, 6.5min, 7.0min, 7.5min, 8.0min, 8.5min, 9.0min, 9.5min or 10.0min, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

As a preferred embodiment of the present invention, in the step (II), the operation steps of the organic intercalation modification treatment include:

dispersing the activated clay in deionized water to obtain clay suspension, sequentially adding cetyltrimethylammonium bromide and caprolactam into the clay suspension under the conditions of continuous stirring and water bath heating to react, centrifuging after the reaction is finished, and washing and drying precipitate obtained after the centrifugation to obtain the intercalation modified clay.

In a preferred embodiment of the present invention, the mass fraction of activated clay in the clay suspension is 2 to 5wt%, and may be, for example, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt%, or 5.0wt%, but is not limited to the recited values, and other non-recited values within the range are equally applicable.

In some alternative examples, the mass ratio of activated clay to cetyltrimethylammonium bromide in the clay suspension is 1 (0.3-0.5), such as 1:0.3, 1:0.32, 1:0.34, 1:0.36, 1:0.38, 1:0.4, 1:0.42, 1:0.44, 1:0.46, 1:0.48 or 1:0.5, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The invention particularly limits the mass ratio of activated clay to cetyltrimethylammonium bromide to 1 (0.3-0.5), and the interlayer spacing of the finally obtained intercalation modified clay is in a change trend of increasing and then decreasing along with the increase of the dosage of the cetyltrimethylammonium bromide, and when the mass ratio of the activated clay to the cetyltrimethylammonium bromide is in the numerical range defined by the invention, the larger interlayer spacing can be obtained, and the higher intercalation efficiency can be realized. When the amount of cetyltrimethylammonium bromide used is less than the lower limit of the range defined in the present invention, the interlayer cations of activated clay cannot be completely exchanged by cetyltrimethylammonium bromide chains, resulting in a smaller interlayer spacing of the intercalated modified clay, thereby affecting the adsorption capacity for olefins and nitrogen. When the dosage of the cetyl trimethyl ammonium bromide exceeds the upper limit of the range defined by the invention, excessive organic chains are easily accumulated in the interlayer edge area of the activated clay, so that the exchange channels of the organic chains and interlayer cations are blocked, steric hindrance is generated on the cetyl trimethyl ammonium bromide molecular chains which do not enter the interlayer, so that only a small part of the cetyl trimethyl ammonium bromide molecular chains can successfully enter the interlayer of the activated clay, and most of the cetyl trimethyl ammonium bromide molecular chains cannot successfully enter the interlayer of the activated clay, but are simply adsorbed on the surface of the activated clay, and the interlayer spacing of the activated clay is prevented from being continuously increased, so that the interlayer spacing of the activated clay cannot be continuously enlarged and the intercalation efficiency is lower by continuously increasing the dosage of the cetyl trimethyl ammonium bromide.

In some alternative examples, the mass ratio of the cetyltrimethylammonium bromide to the caprolactam is (2-3): 1, for example, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1 or 3.0:1, but not limited to the recited values, and other non-recited values within the range are equally applicable.

The invention is particularly limited to the case that the mass ratio of the cetyl trimethyl ammonium bromide to the caprolactam is (2-3): 1, and when the cetyl trimethyl ammonium bromide and the caprolactam are in the range, the interlayer spacing of the obtained intercalated modified clay is maximum, because the caprolactam reacts with sodium ions between activated clay layers to open loops to generate amide ions, thereby entering the activated clay layers, and increasing the interlayer spacing of the activated clay. When the dosage of caprolactam is lower than the lower limit of the range defined by the invention, enough caprolactam does not participate in the reaction, the caprolactam entering the activated clay layers is too little, the activated clay cannot be effectively intercalated and modified, and the interlayer spacing of the activated clay is limited in improvement degree. When the dosage of caprolactam exceeds the upper limit of the range defined by the invention, the caprolactam can react with lattice sites to destroy the lattice sites between activated clay layers, so that the cetyltrimethylammonium bromide which enters the activated clay layers and has completed cation exchange loses bonding sites and finally falls off from the activated clay layers, and in addition, the caprolactam can preferentially enter the activated clay layers because of high solubility of the caprolactam in water and the hydroxyl and hydrogen ions between the activated clay layers and at the edge are easy to form amide ions, so that the caprolactam which preferentially enters the activated clay layers can generate a certain blocking effect on the cetyltrimethylammonium bromide which does not enter the activated clay layers, and the intercalation modifying effect of the cetyltrimethylammonium bromide is influenced.

In some alternative examples, the temperature of the water bath heating is 70-80 ℃, such as 70 ℃, 71 ℃, 72 ℃, 73 ℃, 74 ℃, 75 ℃, 76 ℃, 77 ℃, 78 ℃, 79 ℃ or 80 ℃, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, after adding cetyltrimethylammonium bromide to the clay suspension, mixing and stirring are continued for 10-20 min under water bath heating, and then caprolactam is added, for example, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min or 20min, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, after adding caprolactam, mixing and stirring under water bath heating conditions are continued for 3-4 hours, for example, 3.0 hours, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours or 4.0 hours, but not limited to the listed values, and other non-listed values in the range of values are equally applicable.

In some alternative examples, the rotational speed of the centrifuge is 7000 to 8000rpm, for example 7000rpm, 7100rpm, 7200rpm, 7300rpm, 7400rpm, 7500rpm, 7600rpm, 7700rpm, 7800rpm, 7900rpm or 8000rpm, but not limited to the recited values, and other non-recited values within the range are equally applicable.

In some alternative examples, the centrifugation time is 10-20 min, for example, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min or 20min, but not limited to the recited values, and other non-recited values within the range are also applicable.

As a preferred embodiment of the present invention, in the step (II), the operation step of the surface hydrophobic modification treatment includes:

And uniformly mixing the silane coupling agent and the ethanol water solution to obtain a coupling agent solution, adding the intercalation modified clay into the coupling agent solution, mixing, stirring and heating to react, and filtering, washing and drying after the reaction is finished to obtain the composite modified clay.

As a preferred technical scheme of the invention, the volume ratio of the ethanol to the deionized water in the ethanol aqueous solution is (4-5): 1, for example, it may be 4.0:1, 4.1:1, 4.2:1, 4.3:1, 4.4:1, 4.5:1, 4.6:1, 4.7:1, 4.8:1, 4.9:1 or 5.0:1, but not limited to the recited values, and other non-recited values in the range of values are equally applicable.

In some alternative examples, the mass fraction of the silane coupling agent in the coupling agent solution is 1-5wt%, for example, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt% or 5.0wt%, but not limited to the recited values, and other non-recited values in the range of values are equally applicable.

In some alternative examples, the mass ratio of the silane coupling agent in the coupling agent solution to the intercalation-modified clay is (0.02-0.05): 1, for example, 0.02:1, 0.025:1, 0.03:1, 0.035:1, 0.04:1, 0.045:1, or 0.05:1, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The invention is particularly limited in that the mass ratio of the silane coupling agent to the intercalation modified clay is (0.02-0.05): 1, and the hydrophobicity of the finally obtained composite modified clay is in a change trend of increasing and then decreasing with the increase of the use amount of the silane coupling agent, because the silane coupling agent cannot completely react with the intercalation modified clay when the use amount of the silane coupling agent is lower than the lower limit of the range defined by the invention, and the number of the silane coupling agent grafted on the surface of the intercalation modified clay is continuously increased with the increase of the use amount of the silane coupling agent, thereby improving the surface hydrophobicity of the intercalation modified clay and further improving the affinity between the intercalation modified clay and olefin. When the usage amount of the silane coupling agent reaches the upper limit of the range defined by the invention, the silane coupling agent exactly reacts with all hydroxyl groups on the surface of the intercalation modified clay, so that an ordered silane coupling agent monomolecular layer is grafted on the surface of the intercalation modified clay, and the intercalation modified clay has the highest hydrophobicity and the best affinity with olefin. When the dosage of the silane coupling agent exceeds the upper limit of the range defined by the invention, the silane coupling agent is excessively hydrolyzed to form silanol, and the silanol is accumulated on the surface of the intercalation modified clay to form a silanol multi-molecular layer, so that the surface hydrophobicity of the intercalation modified clay is reduced, the affinity between the intercalation modified clay and olefin is further influenced, and the removal rate of the olefin is influenced.

In some alternative examples, the reaction temperature of the intercalation-modifying clay and the coupling agent solution is 70-80 ℃, such as 70 ℃,71 ℃, 72 ℃, 73 ℃, 74 ℃, 75 ℃, 76 ℃, 77 ℃, 78 ℃, 79 ℃, or 80 ℃, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the reaction time between the intercalation-modified clay and the coupling agent solution is 3-5 h, for example, 3.0h, 3.2h, 3.4h, 3.6h, 3.8h, 4.0h, 4.2h, 4.4h, 4.6h, 4.8h or 5.0h, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In a preferred embodiment of the present invention, in the step (III), the mass fraction of the composite modified clay in the clay dispersion liquid is 2 to 5wt%, and may be, for example, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt%, or 5.0wt%, but not limited to the above-mentioned values, and other values not shown in the above-mentioned value range are equally applicable.

In some optional examples, the mass ratio of the composite modified clay to the magnesium chloride in the clay dispersion is 1 (0.5-0.6), for example, may be 1:0.5, 1:0.51, 1:0.52, 1:0.53, 1:0.54, 1:0.55, 1:0.56, 1:0.57, 1:0.58, 1:0.59 or 1:0.6, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

According to the invention, the magnesium oxide particles are synthesized in situ on the surface and the interlayer of the composite modified clay by a hydrothermal synthesis method, so that the specific surface area of the composite modified clay is greatly increased, the finally obtained efficient granular clay adsorbent has proper mesoporous quantity, and the removal effect of olefin and nitrogen is improved. The invention particularly limits that the mass ratio of the composite modified clay to the magnesium chloride in the clay dispersion liquid is 1 (0.5-0.6), and the specific surface area of the finally obtained high-efficiency granular clay adsorbent is in a change trend of increasing and then decreasing along with the increase of the magnesium chloride dosage in the hydrothermal synthesis process. This is because magnesium hydroxide flocculent precipitate is formed when magnesium chloride and sodium hydroxide are used as reaction raw materials for hydrothermal reaction, and magnesium oxide is formed after calcining the magnesium hydroxide flocculent precipitate. After adding a proper amount of magnesium chloride, obtaining a proper amount of nano magnesium oxide after reaction and calcination, wherein the proper amount of nano magnesium oxide can be uniformly distributed on the surface and the interlayer of the composite modified clay and stacked with each other to form more new pores, thereby improving the porosity of the composite modified clay. When the amount of magnesium chloride exceeds the upper limit of the range defined by the invention, the generated magnesium hydroxide flocculent precipitate is excessive, so that the surface pores of the composite modified clay are covered by excessive magnesium hydroxide, the magnesium hydroxide can be decomposed into nano magnesium oxide in the calcining process, the nano magnesium oxide is easy to agglomerate due to higher surface energy, and the surface pores of the composite modified clay are blocked by the agglomerated magnesium oxide, so that the porosity is reduced.

In some alternative examples, the clay dispersion and magnesium chloride are mixed and stirred for 1-2 h, for example, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2.0h, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the clay dispersion and magnesium chloride may be heated to a temperature of 50-60 ℃ during mixing, such as 50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃ or 60 ℃, but are not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the molar ratio of magnesium ions of magnesium chloride to hydroxide ions of sodium hydroxide in the intermediate solution is (0.5-0.7): 1, for example, may be 0.5:1, 0.52:1, 0.54:1, 0.56:1, 0.58:1, 0.6:1, 0.62:1, 0.64:1, 0.66:1, 0.68:1 or 0.7:1, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the intermediate solution and sodium hydroxide are mixed and stirred for 6-8 h, for example, 6.0h, 6.2h, 6.4h, 6.6h, 6.8h, 7.0h, 7.2h, 7.4h, 7.6h, 7.8h or 8.0h, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In some alternative examples, the heating temperature of the intermediate solution and the sodium hydroxide during mixing and stirring is 80-90 ℃, for example, 80 ℃, 81 ℃, 82 ℃, 83 ℃, 84 ℃, 85 ℃, 86 ℃, 87 ℃, 88 ℃, 89 ℃ or 90 ℃, but not limited to the recited values, and other non-recited values in the range of the values are equally applicable.

In some alternative examples, the temperature rising rate of the calcination is 10 to 20 ℃ per minute, for example, 10 ℃ per minute, 11 ℃ per minute, 12 ℃ per minute, 13 ℃ per minute, 14 ℃ per minute, 15 ℃ per minute, 16 ℃ per minute, 17 ℃ per minute, 18 ℃ per minute, 19 ℃ per minute, or 20 ℃ per minute, but not limited to the recited values, and other non-recited values in the range of values are equally applicable.

In some alternative examples, the calcination temperature is 440-460 ℃, such as 440 ℃, 442 ℃, 444 ℃, 446 ℃, 448 ℃, 450 ℃, 452 ℃, 454 ℃, 456 ℃, 458 ℃, or 460 ℃, but the calcination temperature is not limited to the recited values, and other non-recited values within the range are equally applicable.

The invention is particularly limited in that the calcination temperature is 440-460 ℃, magnesium hydroxide cannot be fully decomposed when the calcination temperature is lower than 440 ℃, and the generated magnesium oxide is easy to agglomerate when the calcination temperature is higher than 460 ℃, so that the porosity of the high-efficiency particle clay adsorbent is reduced, and the number of effective adsorption sites is reduced.

In some alternative examples, the calcination time is 2-3 h, for example, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3.0h, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

In a second aspect, the invention provides an application of the efficient granular clay adsorbent for removing olefin and nitrogen, which is prepared by adopting the preparation method in the first aspect, and is used in the fields of olefin removal and nitrogen removal.

Compared with the prior art, the invention has the beneficial effects that:

Drawings

FIG. 1 is a flow chart of the process for preparing the efficient granular clay adsorbent for removing olefins/denitrification provided in examples 1-5 of the present invention;

FIG. 2 is a schematic structural diagram of a de-olefination evaluation device used in the present invention;

wherein, the device comprises a 1-raw material tank, a 2-feed pump, a 3-reactor, a 4-cooler and a 5-product collecting tank;

FIG. 3 is an XRD pattern of bentonite, activated clay prepared in example 1 of the present invention, and composite modified clay;

FIG. 4 is an infrared spectrum of bentonite and activated clay prepared in example 1 of the present invention;

FIG. 5 is a scanning electron microscope image of example 1 of the present invention, wherein FIG. 5 (a) is a scanning electron microscope image of bentonite powder used in example 1 of the present invention, FIG. 5 (b) is a scanning electron microscope image of activated clay prepared in example 1 of the present invention, FIG. 5 (c) is a scanning electron microscope image of composite modified clay prepared in example 1 of the present invention, FIG. 5 (d) is a scanning electron microscope image of a high-efficiency particulate clay adsorbent prepared in example 1 of the present invention at a low magnification, and FIG. 5 (e) is a scanning electron microscope image of a high-efficiency particulate clay adsorbent prepared in example 1 of the present invention at a high magnification;

FIG. 6 shows XRD patterns of activated clay and highly efficient granular clay adsorbent prepared in example 1 of the present invention.

Detailed Description

The technical scheme of the application is described in detail below with reference to specific embodiments and attached drawings. The examples described herein are specific embodiments of the present application for illustrating the concepts of the application, and are intended to be illustrative and exemplary and are not to be construed as limiting the scope of the embodiments and the application. In addition to the embodiments described herein, those skilled in the art can adopt other obvious solutions based on the disclosure of the claims and the specification thereof, including those adopting any obvious substitutions and modifications to the embodiments described herein.

The chemical reagents adopted in the specific implementation mode of the invention are all commercial products, and the information of the model, the specification, the manufacturer and the like is as follows:

concentrated hydrochloric acid, analytically pure, purchased from the metallocene chemical reagent plant in the Tianjin city;

concentrated sulfuric acid, analytically pure, purchased from the metallocene chemical reagent plant in Tianjin;

oxalic acid, analytically pure, purchased from Shandong new materials Co., ltd;

Sodium chloride, R21092-500ml, available from Shanghai Yuan Yes Biotechnology Co., ltd;

Cetyl trimethyl ammonium bromide S15001-100g, purchased from Shanghai Seiyaka Biotech Co., ltd;

Caprolactam S70056-100g, available from Shanghai Seiyaka Biotechnology Co., ltd;

Silane coupling agent KH550, S15028-500ml, purchased from Shanghai Seiya Biotechnology Co., ltd;

silane coupling agent KH560, S15029-500ml, purchased from Shanghai Seiya Biotechnology Co., ltd;

absolute ethyl alcohol, analytically pure, purchased from south Beijing chemical reagents, inc.;

Analytically pure magnesium chloride, available from fomes (Tianjin) chemical reagent limited;

sodium hydroxide, analytically pure, purchased from fomes chemical company, ltd.

Example 1

The embodiment provides a preparation method of an efficient granular clay adsorbent for olefin removal/denitrification, as shown in fig. 1, which specifically comprises the following steps:

(1) Slowly adding 35wt% of concentrated hydrochloric acid into deionized water, uniformly mixing to obtain dilute hydrochloric acid, slowly adding 98wt% of concentrated sulfuric acid into the dilute hydrochloric acid, uniformly mixing to obtain mixed acid solution, and finally adding oxalic acid into the mixed acid solution, uniformly mixing to obtain an acidulant, wherein the mass percentage of oxalic acid in the acidulant is 5wt%;

Crushing and sieving bentonite raw ore to obtain bentonite powder with the particle size of 100 meshes, mixing the bentonite powder with deionized water according to the mass ratio of 0.6:1 to obtain bentonite slurry, uniformly mixing the bentonite slurry, an acidulant and sodium chloride according to the mass ratio of 1:0.6:0.08 to obtain a raw material mixture, heating the raw material mixture to 80 ℃, preserving heat for 3 hours, continuously heating to 100 ℃ after the heat preservation is finished, preserving heat for 3 hours, cooling to room temperature after the heat preservation is finished, and obtaining an activated product;

(2) Dispersing activated clay obtained in the step (1) in deionized water to obtain clay suspension with the mass fraction of 2wt%, adding cetyltrimethylammonium bromide into the clay suspension under the conditions of continuous stirring and water bath heating at 70 ℃, adding cetyltrimethylammonium bromide with the mass ratio of 1:0.3 into the clay suspension, mixing and stirring for 20min under the water bath heating at 70 ℃, then adding caprolactam with the mass ratio of 2:1 into the clay suspension, mixing and stirring for 4h under the water bath heating at 70 ℃ to react, centrifuging for 20min at the rotating speed of 7000rpm after the reaction is finished, and washing and drying the precipitate obtained after centrifugation to obtain intercalation modified clay;

Uniformly mixing ethanol and deionized water according to a volume ratio of 4:1 to obtain an ethanol aqueous solution, uniformly mixing a silane coupling agent and the ethanol aqueous solution to obtain a coupling agent solution with a mass fraction of 1wt%, adding intercalation modified clay into the coupling agent solution, mixing and stirring the silane coupling agent and the intercalation modified clay for 5 hours under a heating condition of 70 ℃ to react, and filtering, washing and drying after the reaction is finished to obtain composite modified clay;

(3) Dispersing the composite modified clay obtained in the step (2) in deionized water to obtain clay dispersion liquid with the mass fraction of 2wt%, adding magnesium chloride into the clay dispersion liquid, mixing and stirring for 2 hours under the heating condition of 50 ℃ to obtain an intermediate solution, adding sodium hydroxide into the intermediate solution, mixing and stirring for 8 hours under the heating condition of 80 ℃ to react, filtering, washing, extruding strips, shaping and drying after the reaction is finished, heating the dried reaction product to 440 ℃ at the heating rate of 10 ℃ per min, preserving heat for 3 hours, completing the calcination treatment, and crushing and screening the clay after the calcination is finished to obtain the efficient particle adsorbent.

FIG. 3 shows XRD patterns of bentonite, activated clay prepared in example 1 of the invention and composite modified clay, wherein bentonite shows strong diffraction peaks at 2θ=7.00 degrees, the interlayer spacing of bentonite can be calculated to be 1.048nm by using Bragg equation, wherein n is 1, and λ is 0.15406nm, activated clay shows strong diffraction peaks at 2θ=7.96 degrees, activated clay shows strong diffraction at 2θ=6.48 degrees, and composite modified clay shows strong diffraction at 2θ=6.48 degrees. It can be seen that the interlayer spacing of the activated clay obtained after the acid activation treatment is significantly increased compared to the bentonite which has not been subjected to the modification treatment, because hydrogen ions in the acid replace metal cations in the bentonite during the acid activation of the bentonite, so that the bentonite undergoes interlayer ion exchange, and the interlayer spacing of the bentonite is further increased. Compared with activated clay, the interlayer spacing of the composite modified clay obtained through organic intercalation modification and silane coupling agent surface modification is further increased, the specific surface area is increased, active sites are increased, and the adsorption performance of the composite modified clay is improved.

FIG. 4 is an infrared spectrum of bentonite and activated clay prepared in example 1 of the present invention, and it can be seen by comparing the tensile and flexural vibration absorption peaks corresponding to the hydroxyl groups of water molecules in the bentonite crystal structure at 1653cm ^-1, and the tensile vibration absorption peaks, si-O-Si flexural vibration absorption peak and O-Si-O asymmetric tensile vibration absorption peak corresponding to 1043cm ^-1、471cm^-1 and 823cm ^-1, respectively. The infrared curves of bentonite and activated clay differ in that the activated clay has an increased peak intensity at the high frequency region 3628cm ^-1 due to O-H stretching vibrations, which suggests that during the acid activation treatment exchangeable cations are replaced by protons, increasing the number of hydroxyl groups available for further functionalization. In addition, the band intensities of the tensile vibration absorption peak of Si-O and the flexural vibration absorption peak of Si-O-Si at 1043cm ^-1 and 471cm ^-1 were decreased, and the band intensity of the asymmetric tensile vibration absorption peak of O-Si-O at 823cm ^-1 was enhanced, which indicates that the texture of active white clay was changed and the active site was increased due to the change in the Si environment caused by the acid corrosion after the acid activation treatment.

Fig. 5 (a), 5 (b), 5 (c) and 5 (d) are scanning electron microscope images of bentonite powder used in this example, activated clay prepared in this example, composite modified clay and efficient granular clay adsorbent, respectively, and as can be seen from comparison of fig. 5 (a) and 5 (b), the activated clay has better particle dispersibility, larger specific surface area and higher porosity, and overall presents loose and regular granular agglomerates, as compared with the bentonite powder. As can be seen from fig. 5 (c), the porosity of the composite modified clay is higher, the particle size dispersion is more uniform, the structure is more loose, the lamellar structure is obviously reduced, the interlayer spacing is larger, and a large number of voids are generated. As can be seen from fig. 5 (d) and fig. 5 (e), the surface of the efficient granular clay adsorbent can see magnesium oxide in a hexagonal plate structure, and the magnesium oxide is accumulated to generate more pores, so that a mesoporous structure is formed.

Fig. 6 shows XRD patterns of the activated clay and the high-efficiency granular clay adsorbent prepared in this example, and it can be seen from the figure that, compared with the activated clay, the high-efficiency granular clay adsorbent has two stronger diffraction peaks at 2θ=42.9° and 62.2 ° respectively corresponding to (200) crystal planes and (220) crystal planes, and positions of the two diffraction peaks are consistent with a standard magnesium oxide spectrum, which indicates that the high-efficiency granular clay adsorbent prepared in the invention is successfully loaded with magnesium oxide. In addition, the XRD diffraction peak of the high-efficiency particle clay adsorbent is remarkably widened and sharp, which indicates that the loaded magnesium oxide particles have small particle size and good crystallinity.

Example 2

(1) Slowly adding concentrated hydrochloric acid with the mass fraction of 35.5wt% into deionized water, uniformly mixing to obtain diluted hydrochloric acid, slowly adding concentrated sulfuric acid with the mass fraction of 97wt% into the diluted hydrochloric acid, wherein the volume ratio of the concentrated hydrochloric acid to the concentrated sulfuric acid to the deionized water is 1:1.45:36, uniformly mixing to obtain mixed acid solution, and finally adding oxalic acid into the mixed acid solution, uniformly mixing to obtain an acidulant, wherein the mass fraction of oxalic acid in the acidulant is 6wt%;

Crushing and sieving bentonite raw ore to obtain bentonite powder with the particle size of 120 meshes, mixing the bentonite powder with deionized water according to the mass ratio of 0.62:1 to obtain bentonite slurry, uniformly mixing the bentonite slurry, an acidulant and sodium chloride according to the mass ratio of 1:0.62:0.085 to obtain a raw material mixture, heating the raw material mixture to 82 ℃ and preserving heat for 2.8 hours, continuously heating to 102 ℃ and preserving heat for 2.8 hours after the heat preservation is finished, and cooling to room temperature after the heat preservation is finished to obtain an activated product;

(2) Dispersing activated clay obtained in the step (1) in deionized water to obtain clay suspension with the mass fraction of 3wt%, adding cetyltrimethylammonium bromide into the clay suspension under the conditions of continuous stirring and water bath heating at 72 ℃, adding cetyltrimethylammonium bromide with the mass ratio of 1:0.35, mixing and stirring for 18min under the water bath heating at 72 ℃, then adding caprolactam with the mass ratio of 2.2:1, adding caprolactam, continuing mixing and stirring for 3.8h under the water bath heating at 72 ℃ to react, centrifuging for 18min at the rotating speed of 7200rpm after the reaction is finished, and washing and drying precipitate obtained after centrifugation to obtain intercalation modified clay;

Uniformly mixing ethanol and deionized water according to a volume ratio of 4.2:1 to obtain an ethanol aqueous solution, uniformly mixing a silane coupling agent and the ethanol aqueous solution to obtain a coupling agent solution with a mass fraction of 2wt%, adding intercalation modified clay into the coupling agent solution, mixing and stirring the silane coupling agent and the intercalation modified clay for 4.5 hours under a heating condition of 72 ℃ to react, and filtering, washing and drying after the reaction is finished to obtain composite modified clay;

(3) Dispersing the composite modified clay obtained in the step (2) in deionized water to obtain clay dispersion liquid with the mass fraction of 3wt%, adding magnesium chloride into the clay dispersion liquid, mixing and stirring for 1.8 hours under the heating condition of 52 ℃ to obtain an intermediate solution, adding sodium hydroxide into the intermediate solution, mixing and stirring for 7.5 hours under the heating condition of 82 ℃ to react, filtering, washing, extruding and drying after the reaction is finished, heating the dried reaction product to 445 ℃ at the heating rate of 12 ℃ per min, preserving heat for 2.8 hours, completing the calcination treatment, and crushing and screening after the calcination is finished to obtain the efficient granular clay adsorbent.

Example 3

(1) Slowly adding 36wt% of concentrated hydrochloric acid into deionized water, uniformly mixing to obtain diluted hydrochloric acid, slowly adding 96wt% of concentrated sulfuric acid into the diluted hydrochloric acid, uniformly mixing the concentrated hydrochloric acid, the concentrated sulfuric acid and the deionized water to obtain mixed acid solution, and finally adding oxalic acid into the mixed acid solution, uniformly mixing to obtain an acidulant, wherein the mass percentage of oxalic acid in the acidulant is 7wt%;

Crushing and sieving bentonite raw ore to obtain bentonite powder with the particle size of 150 meshes, mixing the bentonite powder with deionized water according to the mass ratio of 0.65:1 to obtain bentonite slurry, uniformly mixing the bentonite slurry, an acidulant and sodium chloride according to the mass ratio of 1:0.65:0.09 to obtain a raw material mixture, heating the raw material mixture to 85 ℃, preserving heat for 2.5 hours, continuously heating to 105 ℃ after the heat preservation is finished, preserving heat for 2.5 hours, and cooling to room temperature after the heat preservation is finished to obtain an activated product;

(2) Dispersing activated clay obtained in the step (1) in deionized water to obtain clay suspension with the mass fraction of 4wt%, adding cetyltrimethylammonium bromide into the clay suspension under the conditions of continuous stirring and 75 ℃ water bath heating, wherein the mass ratio of the activated clay to the cetyltrimethylammonium bromide is 1:0.4, adding the cetyltrimethylammonium bromide, mixing and stirring for 15min under the 75 ℃ water bath heating condition, then adding caprolactam, the mass ratio of the cetyltrimethylammonium bromide to the caprolactam is 2.5:1, adding caprolactam, continuing mixing and stirring for 3.5h under the 75 ℃ water bath heating condition to react, centrifuging for 15min at the 7500rpm rotating speed after the reaction is finished, and washing and drying precipitate obtained after centrifugation to obtain intercalation modified clay;

Uniformly mixing ethanol and deionized water according to a volume ratio of 4.5:1 to obtain an ethanol aqueous solution, uniformly mixing a silane coupling agent and the ethanol aqueous solution to obtain a coupling agent solution with a mass fraction of 3wt%, adding intercalation modified clay into the coupling agent solution, mixing and stirring the silane coupling agent and the intercalation modified clay for 4 hours under a heating condition of 75 ℃ to react, and filtering, washing and drying after the reaction is finished to obtain composite modified clay;

(3) Dispersing the composite modified clay obtained in the step (2) in deionized water to obtain clay dispersion liquid with the mass fraction of 3wt%, adding magnesium chloride into the clay dispersion liquid, mixing and stirring for 1.5 hours under the heating condition of 55 ℃ to obtain an intermediate solution, adding sodium hydroxide into the intermediate solution, mixing and stirring for 7 hours under the heating condition of 85 ℃ to react, filtering, washing, extruding and drying after the reaction is finished, heating the dried reaction product to 450 ℃ at the temperature rising rate of 15 ℃ per min, preserving heat for 2.5 hours, completing the calcination treatment, and crushing and screening after the calcination is finished to obtain the efficient granular clay adsorbent.

Example 4

(1) Slowly adding 36.5wt% of concentrated hydrochloric acid into deionized water, uniformly mixing to obtain diluted hydrochloric acid, slowly adding 96wt% of concentrated sulfuric acid into the diluted hydrochloric acid, uniformly mixing the concentrated hydrochloric acid, the concentrated sulfuric acid and the deionized water to obtain mixed acid solution, and finally adding oxalic acid into the mixed acid solution, uniformly mixing to obtain an acidulant, wherein the mass fraction of oxalic acid in the acidulant is 8wt%;

Crushing and sieving bentonite raw ore to obtain bentonite powder with the particle size of 180 meshes, mixing the bentonite powder with deionized water according to the mass ratio of 0.68:1 to obtain bentonite slurry, uniformly mixing the bentonite slurry, an acidulant and sodium chloride according to the mass ratio of 1:0.68:0.095 to obtain a raw material mixture, heating the raw material mixture to 88 ℃ and preserving heat for 2.2 hours, continuously heating to 108 ℃ and preserving heat for 2.2 hours after the heat preservation is finished, and cooling to room temperature after the heat preservation is finished to obtain an activated product;

(2) Dispersing activated clay obtained in the step (1) in deionized water to obtain clay suspension with the mass fraction of 4wt%, adding cetyltrimethylammonium bromide into the clay suspension under the conditions of continuous stirring and water bath heating at 78 ℃, adding cetyltrimethylammonium bromide with the mass ratio of 1:0.45, mixing and stirring for 12min under the water bath heating at 78 ℃, then adding caprolactam with the mass ratio of 2.8:1, adding caprolactam, continuing mixing and stirring for 3.2h under the water bath heating at 78 ℃ to react, centrifuging for 12min at the rotating speed of 7800rpm after the reaction is finished, and washing and drying precipitate obtained after centrifugation to obtain intercalation modified clay;

Uniformly mixing ethanol and deionized water according to a volume ratio of 4.8:1 to obtain an ethanol aqueous solution, uniformly mixing a silane coupling agent and the ethanol aqueous solution to obtain a coupling agent solution with a mass fraction of 4wt%, adding intercalation modified clay into the coupling agent solution, mixing and stirring the silane coupling agent and the intercalation modified clay for 3.5 hours under a heating condition of 78 ℃ to react, and filtering, washing and drying after the reaction is finished to obtain composite modified clay;

(3) Dispersing the composite modified clay obtained in the step (2) in deionized water to obtain clay dispersion liquid with the mass fraction of 4wt%, adding magnesium chloride into the clay dispersion liquid, mixing and stirring for 1.2 hours under the heating condition of 58 ℃ to obtain an intermediate solution, adding sodium hydroxide into the intermediate solution, mixing and stirring for 6.5 hours under the heating condition of 88 ℃ to react, filtering, washing, extruding and drying after the reaction is finished, heating the dried reaction product to 455 ℃ at the heating rate of 18 ℃ per min, preserving the heat for 2.2 hours, completing the calcination treatment, and crushing and screening after the calcination is finished to obtain the efficient granular clay adsorbent.

Example 5

(1) Slowly adding concentrated hydrochloric acid with the mass fraction of 37wt% into deionized water, uniformly mixing to obtain diluted hydrochloric acid, slowly adding concentrated sulfuric acid with the mass fraction of 95wt% into the diluted hydrochloric acid, wherein the volume ratio of the concentrated hydrochloric acid to the concentrated sulfuric acid to the deionized water is 1:1.6:40, uniformly mixing to obtain mixed acid solution, and finally adding oxalic acid into the mixed acid solution, uniformly mixing to obtain an acidulant, wherein the mass fraction of oxalic acid in the acidulant is 10wt%;

Crushing and sieving bentonite raw ore to obtain bentonite powder with the particle size of 200 meshes, mixing the bentonite powder with deionized water according to the mass ratio of 0.7:1 to obtain bentonite slurry, uniformly mixing the bentonite slurry, an acidulant and sodium chloride according to the mass ratio of 1:0.7:0.1 to obtain a raw material mixture, heating the raw material mixture to 90 ℃ and preserving heat for 2 hours, continuously heating to 110 ℃ and preserving heat for 2 hours after the heat preservation is finished, and cooling to room temperature after the heat preservation is finished to obtain an activated product;

(2) Dispersing activated clay obtained in the step (1) in deionized water to obtain clay suspension with the mass fraction of 5wt%, adding cetyltrimethylammonium bromide into the clay suspension under the conditions of continuous stirring and water bath heating at 80 ℃, adding cetyltrimethylammonium bromide with the mass ratio of 1:0.5 into the clay suspension, mixing and stirring for 10min under the water bath heating at 80 ℃, then adding caprolactam with the mass ratio of 3:1 into the clay suspension, mixing and stirring for 3h under the water bath heating at 80 ℃ to react, centrifuging for 10min at the rotating speed of 8000rpm after the reaction is finished, and washing and drying the precipitate obtained after centrifugation to obtain intercalation modified clay;

Uniformly mixing ethanol and deionized water according to a volume ratio of 5:1 to obtain an ethanol aqueous solution, uniformly mixing a silane coupling agent and the ethanol aqueous solution to obtain a coupling agent solution with a mass fraction of 5wt%, adding intercalation modified clay into the coupling agent solution, mixing and stirring the silane coupling agent and the intercalation modified clay for 3 hours under a heating condition of 80 ℃ to react, and filtering, washing and drying after the reaction is finished to obtain composite modified clay;

(3) Dispersing the composite modified clay obtained in the step (2) in deionized water to obtain clay dispersion liquid with the mass fraction of 5wt%, adding magnesium chloride into the clay dispersion liquid, mixing and stirring for 1h under the heating condition of 60 ℃ to obtain an intermediate solution, adding sodium hydroxide into the intermediate solution, mixing and stirring for 6h under the heating condition of 90 ℃ to react, filtering, washing, extruding strips, shaping and drying after the reaction is finished, heating the dried reaction product to 460 ℃ at the heating rate of 20 ℃ per min, preserving heat for 2h, completing the calcination treatment, and crushing and screening the clay after the calcination is finished to obtain the efficient particle adsorbent.

Comparative example 1

The comparative example provides a preparation method of efficient granular clay adsorbent for removing olefin and denitrification, which is different from the preparation method of the embodiment 1 in that concentrated hydrochloric acid is omitted in the preparation process of the acidulant, concentrated sulfuric acid is slowly added into deionized water, diluted sulfuric acid is obtained after uniform mixing, oxalic acid is added into the diluted sulfuric acid, the acidulant is obtained after uniform mixing, and other process parameters and operation steps are identical to those of the embodiment 1.

Comparative example 2

The comparative example provides a preparation method of efficient granular clay adsorbent for removing olefin and denitrification, which is different from the preparation method of the embodiment 1 in that concentrated sulfuric acid is omitted in the preparation process of the acidulant, concentrated hydrochloric acid is slowly added into deionized water, diluted hydrochloric acid is obtained after uniform mixing, oxalic acid is added into the diluted hydrochloric acid, the acidulant is obtained after uniform mixing, and other process parameters and operation steps are identical to those of the embodiment 1.

Comparative example 3

The comparative example provides a preparation method of efficient granular clay adsorbent for removing olefin and denitrification, which is different from example 1 in that oxalic acid is omitted in the preparation process of acidulant, concentrated hydrochloric acid is slowly added into deionized water, diluted hydrochloric acid is obtained after uniform mixing, then concentrated sulfuric acid is slowly added into the diluted hydrochloric acid, acidulant is obtained after uniform mixing, and other technological parameters and operation steps are identical to those of example 1.

Comparative example 4

The comparative example provides a process for preparing a highly efficient granular clay adsorbent for dealkenation/denitrification, which is different from example 1 in that the mass ratio of activated clay to cetyltrimethylammonium bromide in clay suspension is adjusted to 1:0.2, and other process parameters and operation steps are exactly the same as example 1.

Comparative example 5

The comparative example provides a process for preparing a highly efficient granular clay adsorbent for dealkenation/denitrification, which is different from example 1 in that the mass ratio of activated clay to cetyltrimethylammonium bromide in clay suspension is adjusted to 1:0.6, and other process parameters and operation steps are exactly the same as example 1.

Comparative example 6

This comparative example provides a process for the preparation of a highly effective granular clay adsorbent for de-olefination/denitrification, which differs from example 1 in that the mass ratio of cetyltrimethylammonium bromide to caprolactam is adjusted to 1.5:1, and other process parameters and operating procedures are exactly the same as example 1.

Comparative example 7

This comparative example provides a process for the preparation of a highly effective granular clay adsorbent for de-olefination/denitrification, which differs from example 1 in that the mass ratio of cetyltrimethylammonium bromide to caprolactam is adjusted to 3.5:1, and other process parameters and operating procedures are exactly the same as example 1.

Comparative example 8

The comparative example provides a preparation method of a high-efficiency granular clay adsorbent for removing olefins/denitrification, which is different from example 1 in that the mass ratio of composite modified clay to magnesium chloride in clay dispersion liquid is adjusted to be 1:0.3, and other process parameters and operation steps are identical to those of example 1.

Comparative example 9

The comparative example provides a preparation method of a high-efficiency granular clay adsorbent for removing olefins/denitrification, which is different from example 1 in that the mass ratio of composite modified clay to magnesium chloride in clay dispersion liquid is adjusted to be 1:0.8, and other process parameters and operation steps are identical to those of example 1.

The activity, pore diameter, denitrification rate and olefin removal rate of the high-efficiency granular clay adsorbents prepared in examples 1 to 5 and comparative examples 1 to 9 were tested as follows:

(1) Activity test:

the activity is an important measure of the adsorption performance of activated clay, and is generally expressed by the volume (mL) of NaOH standard solution [ c (naoh=1.000 mol/L ] consumed for neutralizing 1000g of clay sample.

The activity of the efficient granular clay adsorbents prepared in examples 1 to 5 and comparative examples 1 to 9 is measured by referring to the industry standard HG/T2569-2007 activated clay.

(2) Pore size testing:

And (3) analyzing and detecting the aperture of the sample by adopting a full-automatic gas adsorption analyzer, degassing for 7 hours under the vacuum condition of 150 ℃ before testing, and then testing the nitrogen adsorption-desorption performance.

(3) And (3) denitrification rate test:

the denitrification activity evaluation raw material is aromatic raffinate oil provided by a petrochemical company, and the nitrogen content is 12.51 mug/g.

The denitrification evaluation device is a tubular fixed bed reaction device, an electric heating temperature control system is arranged outside the reaction device, 100g of adsorbent is filled in a catalyst bed layer of the reaction device, aromatic raffinate oil is pumped to 0.8MPa after being metered and enters a preheater at a certain airspeed, the aromatic raffinate oil enters the adsorbent bed layer after being heated to 40 ℃, a raffinate oil product after denitrification refining enters a low-pressure tank after being cooled, and the refined product is sampled and analyzed at regular time, wherein the nitrogen content in the refined product is more than 0.5 mu g/g as a solid adsorbent deactivation standard.

The total nitrogen content in the raw materials and the products adopts SH/T0657-2007 method for measuring oxidation combustion and chemiluminescence of trace nitrogen in liquid petroleum hydrocarbon, and the denitrification rate is calculated through the total nitrogen content in the raw materials and the total nitrogen content in the products.

(4) Olefin removal rate test:

The olefin removal activity evaluation raw material was reformate provided by a petrochemical company, and the bromine index was 670mgBr/100g.

The deolefination evaluation device is shown in fig. 2, and comprises a raw material tank 1, a feed pump 2, a reactor 3, a cooler 4 and a product collection tank 5, wherein the reactor 3 is divided into an upper section, a middle section and a lower section, a certain amount of 20-40 mesh quartz sand is respectively filled in the upper section and the lower section, the middle section is a constant temperature section, 5mL of adsorbent is filled in and is hammered into a solid state by a hammer, the evaluation condition is that the temperature is 170 ℃, the pressure is 1MPa, the volume airspeed is 10h ^-1, sampling is carried out once every 2h, the bromine index of the raw material and the product is measured by adopting the national standard GB/T5177-2017 industrial linear alkylbenzene, the smaller the bromine index of the aromatic hydrocarbon deolefination product is, the lower the olefin content is, and the better the deolefination effect of the adsorbent is shown.

The olefin removal rate of the aromatic hydrocarbon product was calculated using the formula:

the test results are shown in Table 1.

TABLE 1 results of Performance test of highly efficient granular clay adsorbents prepared in examples 1 to 5 and comparative examples 1 to 9

The test data provided in table 1 shows that the high-efficiency granular clay adsorbent prepared by the invention has higher activity and larger pore diameter, so that the high-efficiency granular clay adsorbent has good removal rate in the fields of olefin removal and denitrification. The test result shows that the activity of the high-efficiency granular clay adsorbent prepared by the invention exceeds 215mmol/100g, which shows that the high-efficiency granular clay adsorbent has extremely strong adsorption activity and reaction capacity, so that the adsorbent can more effectively interact with target substances (such as nitrides and olefins), thereby improving the adsorption efficiency and the removal rate. In addition, the average pore diameter of the high-efficiency granular clay adsorbent prepared by the method exceeds 36nm, and the large pore diameter is not only beneficial to rapid diffusion and transmission of adsorbates (such as nitrogen and olefin molecules), but also provides more adsorption sites, so that the adsorption capacity and the adsorption rate are enhanced. Under the combined action of high activity and large pore diameter, the denitrification rate of the high-efficiency granular clay adsorbent prepared by the invention in a denitrification activity evaluation test is up to more than 95%, and the olefin removal rate in a de-olefination activity evaluation test is up to more than 90%, which fully proves the remarkable advantages of the clay adsorbent prepared by the invention in de-olefination and denitrification.

As can be seen from the test data of example 1, comparative example 2 and comparative example 3, the denitrification rate and the olefin removal rate of comparative example 1, comparative example 2 and comparative example 3 are lower than those of example 1, because hydrochloric acid is omitted from the acidulant of comparative example 1, sulfuric acid is omitted from the acidulant of comparative example 2, and oxalic acid is omitted from the acidulant of comparative example 3, which indicates that the activity and the pore diameter of activated clay can be effectively improved by acidifying bentonite with a mixed acid solution composed of hydrochloric acid, sulfuric acid and oxalic acid, thereby greatly improving the adsorption capacity of the efficient granular clay adsorbent.

As can be seen from the test data of example 1, comparative example 4 and comparative example 5, the denitrification rate and the olefin removal rate of comparative example 4 and comparative example 5 are lower than those of example 1, because the amount of cetyltrimethylammonium bromide in comparative example 4 is too low, the amount of cetyltrimethylammonium bromide in comparative example 5 is too high, and the amount of cetyltrimethylammonium bromide directly affects the intercalation modifying effect on activated clay, thereby affecting the adsorption capacity of the efficient granular clay adsorbent.

As can be seen from the test data of example 1, comparative example 6 and comparative example 7, the denitrification rate and the olefin removal rate of comparative example 6 and comparative example 7 are lower than those of example 1, because the amount of cetyltrimethylammonium bromide in comparative example 6 is too low and the amount of caprolactam is relatively high, and the amount of cetyltrimethylammonium bromide in comparative example 7 is too high and the amount of caprolactam is relatively low. The proportion of hexadecyl trimethyl ammonium bromide and caprolactam can directly influence the intercalation modification effect of activated clay, thereby influencing the adsorption capacity of the efficient granular clay adsorbent.

As can be seen from the test data of example 1, comparative example 8 and comparative example 9, the denitrification rate and olefin removal rate of comparative example 8 and comparative example 9 are lower than those of example 1, because the magnesium chloride used in comparative example 8 is too low to result in less magnesium oxide being finally produced and not to effectively increase the pore diameter of the efficient granular clay adsorbent, and the magnesium chloride used in comparative example 9 is too high to result in the occurrence of agglomeration due to the excessive magnesium oxide being produced and also to affect the pore diameter of the efficient granular clay adsorbent, and finally the adsorption capacity of the efficient granular clay adsorbent is lowered.

The applicant declares that the above is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be apparent to those skilled in the art that any changes or substitutions that are easily conceivable within the technical scope of the present invention disclosed by the present invention fall within the scope of the present invention and the disclosure.

Claims

1. A method for preparing a highly efficient granular clay adsorbent for deolefination/denitrification, characterized in that the preparation method comprises:

(I) mixing concentrated hydrochloric acid, concentrated sulfuric acid, oxalic acid and deionized water to obtain an acidifier, crushing and sieving bentonite ore to obtain bentonite powder, mixing the bentonite powder with deionized water to obtain bentonite slurry; uniformly mixing the bentonite slurry, the acidifier and sodium chloride to obtain a raw material mixture, heating and activating the raw material mixture to obtain an activated product, rinsing, centrifuging, drying and crushing the activated product to obtain activated clay;

(II) using hexadecyltrimethylammonium bromide and caprolactam to carry out organic intercalation modification treatment on the activated clay obtained in step (I) to obtain intercalation modified clay; then, using a silane coupling agent to carry out surface hydrophobic modification treatment on the intercalation modified clay to obtain composite modified clay;

(III) dispersing the composite modified clay obtained in step (II) in deionized water to obtain a clay dispersion; adding magnesium chloride to the clay dispersion, mixing, stirring and heating to obtain an intermediate solution; adding sodium hydroxide to the intermediate solution, mixing, stirring and heating to react, filtering, washing, extruding, drying, calcining and crushing and screening after the reaction is completed to obtain the high-efficiency granular clay adsorbent.

2. The preparation method according to claim 1, characterized in that in step (I), when preparing the acidulant, the concentrated hydrochloric acid is first slowly added to deionized water, and the mixture is mixed to obtain dilute hydrochloric acid; then concentrated sulfuric acid is slowly added to the dilute hydrochloric acid to obtain a mixed acid solution; finally, oxalic acid is added to the mixed acid solution, and the mixture is mixed to obtain the acidulant.

3. The preparation method according to claim 2, characterized in that the mass fraction of the concentrated hydrochloric acid is 35-37wt%;

The mass fraction of the concentrated sulfuric acid is 95-98wt%;

The volume ratio of the concentrated hydrochloric acid, the concentrated sulfuric acid and the deionized water is 1:(1.4-1.6):(35-40);

The mass fraction of oxalic acid in the acidulant is 5-10wt%.

4. The preparation method according to claim 1, characterized in that in step (I), the particle size of the bentonite powder is 100-200 mesh;

The bentonite powder and deionized water are mixed in a mass ratio of (0.6-0.7):1 to obtain the bentonite slurry;

The mass ratio of the bentonite slurry, the acidulant and sodium chloride is 1:(0.6-0.7):(0.08-0.1);

The heating activation operation steps include:

The raw material mixture is heated to a first activation temperature and kept warm, and then the temperature is further raised to a second activation temperature and kept warm after the insulation is completed, and then the temperature is cooled to room temperature after the insulation is completed to obtain the activated product;

The first activation temperature is 80-90°C;

Keeping the temperature at the first activation temperature for 2 to 3 hours;

The second activation temperature is 100-110°C;

Keeping the temperature at the second activation temperature for 2 to 3 hours;

The activated product is rinsed with deionized water until the pH value of the activated product reaches 4-5;

The centrifugal speed is 3000-4000 rpm;

The centrifugation time is 5 to 10 minutes.

5. The preparation method according to claim 1, characterized in that in step (II), the operation steps of the organic intercalation modification treatment include:

The activated clay is dispersed in deionized water to obtain a clay suspension; under continuous stirring and water bath heating conditions, hexadecyltrimethylammonium bromide and caprolactam are sequentially added to the clay suspension to react, and after the reaction is completed, centrifugation is performed, and the precipitate obtained after centrifugation is washed and dried to obtain the intercalated modified clay.

6. The preparation method according to claim 5, characterized in that the mass fraction of the activated clay in the clay suspension is 2-5wt%;

The mass ratio of activated clay to hexadecyltrimethylammonium bromide in the clay suspension is 1:(0.3-0.5);

The mass ratio of the hexadecyltrimethylammonium bromide to the caprolactam is (2-3):1;

The water bath heating temperature is 70-80°C;

After adding hexadecyltrimethylammonium bromide to the clay suspension, continue mixing and stirring under water bath heating conditions for 10 to 20 minutes, and then add caprolactam;

After adding caprolactam, continue mixing and stirring under heating in a water bath for 3 to 4 hours;

The centrifugal speed is 7000-8000 rpm;

The centrifugation time is 10 to 20 minutes.

7. The preparation method according to claim 1, characterized in that in step (II), the surface hydrophobic modification treatment comprises:

The silane coupling agent and the ethanol aqueous solution are uniformly mixed to obtain a coupling agent solution, the intercalated modified clay is added to the coupling agent solution, mixed and stirred and heated to react, and after the reaction is completed, filtered, washed and dried to obtain the composite modified clay.

8. The preparation method according to claim 7, characterized in that the volume ratio of ethanol to deionized water in the ethanol aqueous solution is (4-5):1;

The mass fraction of the silane coupling agent in the coupling agent solution is 1-5wt%;

The mass ratio of the silane coupling agent in the coupling agent solution to the intercalation modified clay is (0.02-0.05):1;

The reaction temperature of the intercalation modified clay and the coupling agent solution is 70-80°C;

The reaction time of the intercalated modified clay and the coupling agent solution is 3 to 5 hours.

9. The preparation method according to claim 1, characterized in that, in step (III), the mass fraction of the composite modified clay in the clay dispersion is 2-5wt%;

The mass ratio of the composite modified clay to magnesium chloride in the clay dispersion is 1:(0.5-0.6);

The mixing time of the clay dispersion and magnesium chloride is 1 to 2 hours;

The heating temperature of the clay dispersion and magnesium chloride during mixing and stirring is 50-60°C;

The molar ratio of magnesium ions of magnesium chloride to hydroxide ions of sodium hydroxide in the intermediate solution is (0.5-0.7):1;

The mixing time of the intermediate solution and the sodium hydroxide is 6 to 8 hours;

The heating temperature of the intermediate solution and sodium hydroxide during mixing and stirring is 80-90°C;

The heating rate of the calcination is 10-20°C/min;

The calcination temperature is 440-460°C;

The calcination time is 2 to 3 hours.

10. An application of a high-efficiency granular clay adsorbent for deolefination/denitrification prepared by the preparation method according to any one of claims 1 to 9, characterized in that the high-efficiency granular clay adsorbent is used in the fields of deolefination and denitrification.