KR100237313B1 - Water treatment agent for heavy metal removal using chitin xanthate or chitosan xanthate and water treatment method - Google Patents

Abstract

The present invention reacts chitin or chitosan of the following structural formula (I) with carbon disulfide (CS ₂ ) in a 0.01 to 10N base solution, and the product is separated by filtration, and the separated product is washed with distilled water and unreacted. Removing the substance, and drying the washed product in the air or in the oven, and a method for producing a heavy metal removal water treatment agent and the adsorptive power to the heavy metal produced by the above-described method is improved and useful minerals to the human body A water treatment agent for heavy metal removal that does not remove:

Wherein R is COCH ₃ or H, chitin for COCH ₃ and chitosan for H.

Description

Water treatment agent for heavy metal removal using chitin xanthate or chitosan xanthate and water treatment method

1 is a graph showing the amount of lead adsorption of chitin xanthate over time according to an embodiment of the present invention.

2 is a graph showing the amount of lead adsorption of chitosan xanthate over time according to an embodiment of the present invention.

[Field of Invention]

The present invention relates to a water treatment agent for removing heavy metals using chitin xantate or chitosan xantate and a water treatment method thereof. More specifically, the present invention relates to a water treatment agent for removing heavy metals using chitin xanthate or chitosan xantate in which xanthation of chitin or chitosan is performed using a base and carbon disulfide (CS ₂ ), and a water treatment method using the same.

Background of the Invention and Prior Art

Conventional methods of chemical precipitation, ion exchange resins and separation membranes have been used to remove heavy metals in river water, groundwater and wastewater. However, in the chemical precipitation method, the sludge generated after the treatment may act as a secondary pollutant, and the method using the ion exchange resin and the membrane has a disadvantage in that the treatment cost is high and the mineral metal useful for the human body is also adsorbed.

Recently, in order to solve the problems of the conventional treatment technology, development of biosorbents using biomass such as microorganisms, algae, and organism-derived polymers has been developed.

Cellulose and starch, which has a similar molecular structure to chitin in biomass, has been used for a long time in comparison with chitin. The use of chitin so far is such that chitosan, a deacetylate of chitin, is used as a flocculant in water treatment agents.

However, recently, chitin and chitosan have been actively developed for the use of medical materials and food materials, and research into water treatment agents for the removal of heavy metals has also been actively conducted. U.S. Patent No. 4,992,180 describes a method for removing heavy metals such as copper, cadmium and mercury using chitosan. However, chitin and chitosan have the disadvantage that the removal rate for heavy metals is not high.

Adsorption of heavy metals by biomass is achieved by the role of various ion-exchanging and chelating ligands in the polymers of living organisms. The adsorption capacity of the functional group in the biological polymer is weak, but the adsorption capacity can be improved by transforming the hydroxy group present in a large fraction into another functional group having a high affinity for heavy metals.

Accordingly, the present inventors have developed a water treatment agent for removing heavy metals and a water treatment method using the same by replacing a hydroxy group in a biological polymer with a xanthate group having a high complex-forming ability to heavy metals, and functioning as a coagulant and removing heavy metals. Reached.

[Purpose of invention]

An object of the present invention is to provide a chitin xanthate or chitosan xanthate capable of adsorbing and removing heavy metals at the same time as a conventional flocculant by introducing a xanthate group into chitin or chitosan.

Another object of the present invention is to provide a water treatment agent having improved adsorption capacity to heavy metals by using chitin xantate or chitosan xantate.

Still another object of the present invention is to provide a water treatment method for selectively removing only heavy metal components without removing mineral metal by using chitin xanthate or chitosan xantate as a water treatment agent.

The above and other objects of the present invention can be achieved by the present invention described below.

[Summary of invention]

The present invention reacts chitin or chitosan of the following structural formula (I) with carbon disulfide (CS ₂ ) in a 0.01-10 N base solution, and the product is isolated by filtration, and the separated product is washed with distilled water and unreacted. Removing the substance, and drying the washed product in the air or in the oven, and a method for producing a heavy metal removal water treatment agent and the adsorptive power to the heavy metal produced by the above-described method is improved and useful minerals to the human body A water treatment agent for heavy metal removal that does not remove:

Wherein R is COCH ₃ or H, and if R is COCH ₃ it is chitin and H is chitosan.

Detailed Description of the Invention

The present invention reacts chitin or chitosan of the following structural formula (I) with carbon disulfide (CS ₂ ) in a 0.01-10 N base solution, and the product is isolated by filtration, and the separated product is washed with distilled water and unreacted. Removing the substance, and drying the washed product in the air or in the oven, and a method for producing a heavy metal removal water treatment agent and the adsorptive power to the heavy metal produced by the above-described method is improved and useful minerals to the human body A water treatment agent for heavy metal removal that does not remove:

Wherein R is COCH ₃ or H, and if R is COCH ₃ it is chitin and H is chitosan.

The water treatment agent of the present invention does not remove minerals useful to the human body while increasing the adsorption power to heavy metals by sequencing the hydroxyl group of chitin or chitosan, which is a linear polymer of the structural formula (I), with a base and carbon disulfide (CS ₂ ). Water treatment agent for heavy metal removal.

As the base, NaOH, KOH, or Ca (OH ₂ ) may be used, and in the reaction, the base is used at a concentration of 0.01-10N and preferably at a concentration of 0.1-3N.

The carbon disulfide is used in 1 to 50% by volume of the reaction solution to perform the residual reaction and is preferably used in 5 to 20% by volume.

In the water treatment agent of the present invention, chitin or chitosan is added to a base solution and stirred at room temperature, and the carbon disulfide solution is added to the stirred solution to react at room temperature for 12 hours or at 60 ° C for 3 hours. As the reaction proceeds, the color turns orange. The reactants produced by the reaction are separated by filtration, washed several times with distilled water to remove unreacted additives and then dried to obtain chitin-xanthate or chitosan-xanthate.

Chitin xanthate or chitosan xanthate according to the present invention can perform the function of removing the existing flocculant and heavy metal adsorption at the same time. In addition, the water treatment agent using chitin xanthate or chitosan xanthate of the present invention can be used in continuous processes such as batch processes, columns, and water purifiers in sewage, wastewater and water treatment.

The invention will be further elucidated by the following examples which are set forth only for the purpose of illustrating the invention and are not intended to limit the scope of the invention.

EXAMPLE

Example 1 Reaction of Chitin

20 g of chitin was added to 200 mL of a 1.0N NaOH solution, followed by stirring at room temperature for 1 hour. 20 ml of CS ₂ solution was added and reacted at room temperature for 12 hours.

After the reaction, the reaction product was separated by filtration, washed several times with distilled water to remove unreacted additives, and dried in air to obtain chitin xantate.

Example 2 Xantation Reaction of Chitosan

20 g of chitosan was added to 200 mL of a 1.0N NaOH solution, followed by stirring at room temperature for 1 hour. 20 ml of CS ₂ solution was added and reacted at room temperature for 12 hours.

After the reaction, the reaction product was separated by filtration, washed several times with distilled water to remove unreacted additives, and dried in air to obtain chitosan xantate.

[Confirmation test of residual reaction]

Chitin used as a reactant in Example 1, chitosan used as a reactant in Example 2, chitin xantate produced in Example 1 and chitosan xantate produced in Example 2 to confirm the xantion reaction Elemental analysis of the content of sulfur (S) was investigated. The analytical results are shown in Table 1 below.

TABLE 1

Note) N.D: Detection limit of non-detectable sulfur element is 0.1%.

[Lead adsorption test]

In each Erlenmeyer flask containing 100 ml of an initial lead concentration of 200 ppm, 100 mg of chitin or chitosan and chitin xanthate produced in Example 1 or chitosan xanthate produced in Example 2 were added, and the mixture was stirred at 25 ° C. The lead adsorption experiment was carried out while stirring at 250 rpm. 1 ml of sample was taken from the state of adsorption equilibrium, and the supernatant was taken by centrifugation. The residual lead concentration was measured by using an atomic absorption spectrometer by diluting the supernatant by 20 times.

As a result of measuring lead adsorption, chitin was 20 mg / g, chitin xanthate was 64 mg / g, chitosan was 20 mg / g, and chitosan xantate was 190 mg / g.

Example 3: Preparation of Chitin Xantate in 0.1 N NaOH

Chitin xantate was prepared in the same manner as in Example 1 in 0.1 N NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

Example 4 Preparation of Chitin Xanthate in 0.5 N NaOH

Chitin xantate was prepared in the same manner as in Example 1 in 0.5 N NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

Example 5 Preparation of Chitin Xanthate in 1.0 N NaOH

Chitin xantate was prepared in the same manner as in Example 1 in 1.0 N of NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

Example 6 Preparation of Chitin Xanthate in 2.0 N NaOH

Chitin xantate was prepared in the same manner as in Example 1 in 2.0 N of NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

Example 7 Preparation of Chitosan Xantate in 0.1 N NaOH

Chitinic acid xanthate was prepared in the same manner as in Example 1 in 0.1 N NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

Example 8 Preparation of Chitosan Xantate in 0.5 N NaOH

Chitinic acid xanthate was prepared in the same manner as in Example 1 in 0.5 N NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

Example 9 Preparation of Chitosan Xantate in 1.0 N NaOH

Chitosan xantate was prepared in the same manner as in Example 2 in 1.0 N of NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

In Example 1 and Examples 3 to 6, the chitin that was not shunted was obtained by reacting at a concentration of 0.5 N NaOH or higher while the maximum lead concentration of 200 ppm to 55 ppm (adsorbed amount: 55 mg / g) was removed. Chitin xantate was adsorbed and removed over 103ppm of lead. As shown in FIG. 1, the adsorption amount in the adsorption equilibrium was about 123 ppm (adsorption amount: 123 mg / g) of lead removed from chitin xanthate obtained from 0.5 N NaOH, and the amount of lead adsorption increased by 2 times. Chitin xanthate was 144 ppm (adsorbed amount: 144 mg / g mg) lead was removed, the lead adsorption amount was 2.6 times improved. As a result of measuring the adsorption rate after 10 minutes to determine the adsorption rate, the initial adsorption rate was similar to 80% for chitin, whereas 71% to 81% for chitin xantate showed similar results. .

The results of the lead adsorption performance evaluation experiment with chitosan xanthate obtained at the concentrations of 0.1, 0.5, 1.0 and 2.0 N NaOH in Examples 7 to 10 are as shown in FIG.

In Example 2, chitosan was absorbed and removed by 45 ppm of lead at adsorption equilibrium, whereas chitosan xanthate obtained in 0.5 N NaOH of Example 6 was found to adsorb and remove about 174 ppm of lead. . The lead adsorption removal rate was 58% in chitosan after 10 minutes, while chitosan xantate was slightly increased to 60-80%.

Example 10 Preparation of Chitosan Xantate in 2.0 N NaOH

Chitinic acid xanthate was prepared in the same manner as in Example 2 in 2.0 N of NaOH. The lead adsorption test was conducted by the method presented above, and sampled after 10 minutes, 30 minutes, 1 hour and 3 hours. The results of the lead adsorption capacity evaluation experiment are shown in FIG.

In the case of chitin which was not treated in Examples 1 and 3 to 6, up to 55 ppm (adsorption amount: 55 mg / g chitin) of lead was removed from the initial lead concentration of 200 ppm while reacting in NaOH of 0.5 N or more concentration. The chitin xanthate obtained by the adsorption was adsorbed and removed at 103 ppm or more. In FIG. 1, the adsorption amount at the adsorption equilibrium showed that the chitin xanthate obtained from 0.5 N NaOH was 123 ppm (adsorption amount: 123 mg / g chitin xanthate), and lead adsorption amount was doubled. At 2.0 N NaOH As for the obtained chitin xantate, the lead of 144 ppm (adsorbed amount: 144 mg / g chitin xantate) was removed, and the lead adsorption amount improved 2.6 times. Lead adsorption removal after 10 minutes to determine the adsorption rate was 80% compared to the final in the case of chitin, while 71% to 81% in the case of chitin xanthate showed similar results to the initial adsorption rate.

In Examples 7 to 10, the results of the lead adsorption capacity evaluation experiment with chitosan xantate obtained in NaOH at 0.1, 0.5, 1.0 and 2.0 N concentrations are shown in FIG. The chitosan of Example 2 was 174 ppm of adsorption xanthate obtained from 0.5 N NaOH of Example 6, compared to 45 ppm (adsorption amount: 45 mg / g) of lead at an adsorption equilibrium at an initial lead concentration of 200 ppm. 174mg / g) of lead was removed by adsorption, which is a 3.9-fold increase in lead adsorption. After 10 minutes, the adsorption removal rate of lead increased chitosan by 58% and chitosan xantate slightly increased to 60 ~ 80%.

[Examples 11-15: Lead adsorption test of chitin xanthate according to pH]

In order to determine the effect of pH on the lead adsorption of chitin xanthate, each of them was placed in a Erlenmeyer flask containing distilled water and adjusted to a desired pH with 1.0 N HCl solution. A high concentration of lead solution was injected into each flask to make a final lead concentration of 200 ppm, and stirred at 250 rpm in a 25 ° C stirrer. Lead adsorption experiment was carried out by the method described above and the results are shown in Table 2.

[Examples 16-20: Lead adsorption test of chitosan xantate according to pH]

A lead adsorption test was conducted in the same manner as in Examples 11 to 15 except that chitosan xantate was used, and the results are shown in Table 2.

TABLE 2

Example 21 Lead Adsorption Test of Chitosan Xantate in the Presence of Highly Concentrated Mineral Metals

When the adsorption was removed using chitin xantate, the initial lead concentration was 200ppm and the effect of lead adsorption on the mineral metal Na ⁺ and Mg2 ⁺ ion of 1,000ppm was investigated. Lead adsorption was carried out in the same manner as above. As a result, the concentration of lead remaining after 3 hours of adsorption was 141 ppm and 130 ppm, respectively, similar to 152 ppm in the absence of mineral metal.

Example 22 Lead Adsorption Test of Chitosan Xantate in the Presence of Highly Concentrated Mineral Metals

When adsorption was removed using chitosan xantate, the initial lead concentration was 200ppm and the effect of lead adsorption on the mineral metal Na ⁺ and Mg2 ⁺ ions at 1,000ppm was examined. Lead adsorption was carried out in the same manner as above. As a result, the concentration of lead remaining after 3 hours of adsorption was 20 ppm and 34 ppm of lead remaining after 3 hours, even when Na ⁺ and Mg ²⁺ were present, compared to 25 ppm of lead without mineral metal.

Therefore, it can be seen that the adsorption capacity and selectivity of chitin xanthate or chitosan xanthate to lead are maintained even in the presence of high concentrations of Na ⁺ and Mg ²⁺ ions.

Simple modifications and variations of the present invention can be readily made by those skilled in the art, and all such variations or modifications can be regarded as belonging to the scope of the present invention.

Claims (6)

A water treatment agent for removing heavy metals, comprising a chitin xantate or chitosan xantate prepared by introducing a xanthate group into chitin or chitosan of the following structural formula (I):

Wherein R is COCH ₃ or H, chitin if R is COCH ₃ and chitosan if R is H. Reacting chitin or chitosan of the following structural formula (I) with carbon disulfide (CS ₂ ) in a base solution of 0.01-10 N; Filtering off the product; Washing the separated product with distilled water to remove unreacted material; And drying the washed product in air or in an oven; Method for producing a water treatment agent for removing heavy metals, characterized in that consisting of:

Wherein R is COCH ₃ or H, chitin if R is COCH ₃ and chitosan if R is H. The method of claim 2, wherein the base is NaOH, KOH, or Ca (OH) ₂ . The method of claim 2, wherein the carbon disulfide (CS ₂ ) is used in an amount of 1 to 50% by volume of the reaction solution. The water treatment method for removing heavy metals according to claim 1, wherein the water treatment agent is used as a water treatment agent in a batch or continuous water treatment process. The water treatment method for removing heavy metals according to claim 1, wherein the water treatment agent is used as a filter filler of a water purifier.

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