CN103191684B - Preparation method and application of polymeric phosphato aluminum iron chloride coagulant - Google Patents

Abstract

The invention discloses a preparation method and application of a polyphosphorus aluminum ferric chloride flocculant under the condition of microwave radiation. The present invention uses polyaluminum chloride and FeCl ₃ 6H ₂ O as main raw materials, dissolves them in water, mixes them uniformly, then adds disodium hydrogen phosphate solution to adjust the molar ratio of phosphorus to aluminum iron, puts them into a microwave reactor for radiation , heating to make it polymerize under microwave conditions, then take it out from the microwave reactor, add NaOH solution under water bath conditions to adjust the degree of alkalinity and continue the reaction for a period of time, and finally obtain polyaluminum ferric chloride phosphorus after aging at room temperature. The invention can be widely used in the treatment of source water, production wastewater and domestic sewage, and its function is better than ordinary polyaluminum chloride and polyferric chloride. In water supply treatment, the polyaluminum chloride ferric phosphorus of the present invention can effectively reduce the turbidity and UV ₂₅₄ of the water body; in domestic sewage and industrial waste water, the polyaluminum chloride ferric phosphorus of the present invention can effectively reduce turbidity, COD, Total phosphorus has a good removal effect.

Description

A kind of preparation method and application of polyphosphorus aluminum iron chloride flocculant

technical field

The invention belongs to the technical field of chemical engineering and environmental protection engineering, and in particular relates to the preparation and application of a polyphosphorus aluminum chloride ferric flocculant under the condition of microwave radiation.

Background technique

In the field of water treatment technology, flocculation is one of the most important treatment steps. It has the advantages of simple process, low treatment cost and good treatment effect, and is widely used in water treatment.

Polyaluminum ferric chloride is a high-efficiency inorganic polymer flocculant developed in recent years. Because it has the advantages of polyaluminum chloride and polyferric chloride at the same time, and it is used in water treatment, the water color The chromaticity is much lower than that after treatment with polyferric chloride and polyferric sulfate, and the residual amount of aluminum is lower than that after treatment with polyaluminum chloride. At the same time, the polyaluminum chloride ferric phosphorus has a high degree of polymerization, so it can well exert the ability of adsorption bridging and netting and sweeping. It can be widely used in industrial wastewater treatment, domestic sewage treatment, and the treatment of source water in water supply plants.

Over the years, the preparation process of polyaluminum ferric chloride has gradually matured, but there are many synthetic routes, and the traditional synthetic process still has room for improvement, such as: longer synthesis time and higher energy consumption. In the current country, energy conservation and emission reduction are strongly advocated. Under the current situation, it is an urgent problem for researchers in this field to choose a method for preparing polyaluminum ferric chloride with low energy consumption. Microwave, as a new type of high-tech, has the advantages of simple operation, fast heating, short initiation time, high efficiency and energy saving, meets the requirements of the national environmental protection strategy, and has potentially broad application prospects.

Contents of the invention

One of the objectives of the present invention is to provide a polyphosphorus chloride with short synthesis time, stable performance and good water treatment effect in view of the shortcomings of the existing water treatment technology in the preparation of polyphosphorus aluminum iron chloride flocculant, such as long reaction time and high application cost. The preparation method of aluminum iron flocculant.

The preparation method of polyphosphorus aluminum iron chloride flocculant of the present invention comprises the steps:

(1) At room temperature, put a certain amount of liquid polyaluminum chloride or solid polyaluminum chloride aqueous solution and FeCl ₃ aqueous solution in a container, and stir for 3 to 15 minutes, then add Na ₂ HPO ₄ ·2H ₂ O aqueous solution, Continue to stir for 3 to 15 minutes to make it evenly mixed;

(2) Place the container containing the mixed solution in step (1) in the microwave reactor, turn on the microwave, and raise the temperature rapidly to the reaction temperature of 40-120°C under the condition of 20-100W microwave radiation, and then control the microwave power at 20~60W, keep the reaction temperature constant, react for 3~15min;

(3) Take out the container after the reaction in the microwave reactor, and then place it in a water bath at 30-60°C, add a certain amount of NaOH solution to adjust the degree of alkalinity, and continue the reaction for 2-24 hours;

(4) After the reaction is completed, the product is matured at room temperature for 2 to 24 hours to obtain a reddish brown polyaluminum chloride ferric chloride flocculant.

Specifically, in step (1), the Al/Fe molar ratio is controlled between 0.1 and 8.0; the P/(Al+Fe) molar ratio is controlled between 0.1 and 0.6.

In step (3), the degree of alkalization is controlled between 0.1 and 0.6.

The second object of the present invention is to provide the application of polyaluminum phosphorus chloride iron flocculant prepared by the above method, that is, for the removal of turbidity and UV ₂₅₄ in feed water treatment, and for domestic sewage and production wastewater to reduce turbidity in water bodies , COD and total phosphorus.

Compared with the prior art, the beneficial effects of the present invention are reflected in the following points:

(1) The preparation method of the present invention adopts a microwave radiation polymerization process. Microwaves can promote the polymerization reaction, and the temperature of the reaction system rises quickly, which can significantly shorten the synthesis time.

(2) Under the condition of microwave radiation, it can overcome the disadvantage of uneven heating in the process of heating the aqueous solution, and the properties of the reactants are more stable and not easy to deteriorate.

(3) The flocculant prepared by the method of the present invention has a wide range of uses, can be widely used in water supply treatment and wastewater treatment, and has the characteristics of good treatment effect and fast settling speed of flocs.

Detailed ways

The present invention will be further described in detail below in conjunction with specific experimental examples.

Example 1:

(1) At room temperature, take 6 parts by volume of 2mol/L PAC (polyaluminum chloride) aqueous solution and 4 parts by volume of 2mol/L FeCl ₃ aqueous solution in a container, stir for 3 minutes, and then add 2mol/L Na ₂ HPO _4. 2H ₂ O aqueous solution, adjust the molar ratio P/(Al+Fe) of phosphorus to aluminum and iron to 0.2, and continue to stir for 10 minutes to make it evenly mixed;

(2) Place the container in a microwave reactor, turn on the microwave, and rapidly raise the temperature to a reaction temperature of 60°C under 100W microwave radiation conditions, then reduce the microwave power to 40W, and control the reaction temperature at 60°C for 8 minutes of polymerization;

(3) After taking the container out of the microwave reactor, add 4mL of 2mol/L NaOH solution in a water bath at 50°C to adjust the degree of alkalinity, and continue the reaction for 4h;

(4) After the reaction is completed, mature the product at room temperature for 8 hours;

(5) The polyaluminum iron chloride with a reddish-brown liquid appearance and a degree of alkalinity of 0.42 was prepared.

Example 2:

(1) At room temperature, take 5 volume parts of 2mol/L PAC (polyaluminum chloride) aqueous solution and 4 volume parts of 3mol/L FeCl ₃ aqueous solution in a container, stir for 3min, then add 2mol/L Na ₂ HPO _4. 2H ₂ O aqueous solution, adjust the molar ratio P/(Al+Fe) of phosphorus to aluminum and iron to 0.3, and continue to stir for 10 minutes to make it evenly mixed;

(2) Place the container in a microwave reactor, turn on the microwave, and rapidly raise the temperature to a reaction temperature of 60°C under 100W microwave radiation conditions, then reduce the microwave power to 40W, and control the reaction temperature at 50°C for 10 minutes of polymerization;

(3) After taking the container out of the microwave reactor, add 4mL of 2mol/L NaOH solution in a water bath at 60°C to adjust the degree of alkalinity, and continue the reaction for 4h;

(4) After the reaction is completed, mature the product at room temperature for 10 hours;

(5) Prepare polyaluminum iron chloride with a reddish-brown liquid appearance and an alkalization degree of 0.51.

The embodiment that product of the present invention is applied to water treatment:

The products PPFAC (polyphosphorus aluminum ferric chloride flocculant), industrial PFC, and industrial PAC of Example 1 and Example 2 of the present invention are used for the removal of domestic sewage turbidity and COD, and the coagulation effect is shown in Table 1:

Table 1

COD removal rate (%) Turbidity removal rate (%) Example 1 product 83.4 97.6 Example 2 product 89.2 93.9 Industrial PFC 68.6 74.3 Industrial PAC 73.1 82.6

As can be seen from Table 1, the polyphosphorus aluminum iron chloride flocculant prepared by the method of the present invention has a significantly higher removal rate of domestic sewage turbidity and COD than industrial PFC and industrial PAC.

Claims (3)

1. a preparation method for poly-phosphorus aluminum ferric chloride flocculant, is characterized in that comprising the steps:

(1) under room temperature, by a certain amount of liquid aluminium polychloride or the solid polyaluminium chloride aqueous solution and FeCl ₃the aqueous solution is placed in container, and stirs 3 ~ 15min, then adds Na ₂hPO ₄2H ₂the aqueous solution of O, continues stirring 3 ~ 15min and makes it mix;

(2) container step (1) being equipped with mixed solution is placed in the middle of microwave reactor, open microwave, under 20 ~ 100W microwave condition, make temperature rise to rapidly reaction temperature 40 ~ 120 DEG C, then microwave power is made to control at 20 ~ 60W, keep reaction temperature certain, reaction 3 ~ 15min;

(3) after completion of the reaction container is taken out in microwave reactor, then under being placed in 30 ~ 60 DEG C of water bath condition, adding a certain amount of NaOH solution and regulate basicity, continue reaction 2 ~ 24h;

(4) after having reacted, by product slaking 2 ~ 24h at normal temperatures, the poly-phosphorus aluminum ferric chloride flocculant of rufous is obtained.

2. gather the preparation method of phosphorus aluminum ferric chloride flocculant according to claim 1, it is characterized in that: in step (1), Al/Fe mol ratio controls between 0.1 ~ 8.0; P/ (Al+Fe) mol ratio controls between 0.1 ~ 0.6.

3. gather the preparation method of phosphorus aluminum ferric chloride flocculant according to claim 1, it is characterized in that: in step (3), basicity controls between 0.1 ~ 0.6.