CN115818810A - Composite polyaluminium chloride water treatment agent and preparation method thereof - Google Patents

Abstract

The invention discloses a composite polyaluminium chloride water treatment agent and a preparation method thereof, belonging to the technical field of water treatment agent preparation, and the preparation steps are as follows: placing a polyaluminium chloride solution into a reaction kettle, adding KH-570 coupling agent hydrolysate, uniformly stirring, adjusting the pH to 10 by using 0.1mol/L sodium hydroxide solution, stirring for reaction for 4-6h, then adding modified octavinyl-POSS, modified chitosan and a compound emulsifier, stirring, slowly dropwise adding ammonium persulfate under the protection of nitrogen, sealing the reaction kettle, and stirring for reaction for 3-4h at the temperature of 60-65 ℃ to obtain the compound polyaluminium chloride water treatment agent.

Description

Composite polyaluminum chloride water treatment agent and preparation method thereof

technical field

The invention belongs to the technical field of preparation of water treatment agents, and in particular relates to a composite polyaluminum chloride water treatment agent and a preparation method thereof.

Background technique

Polyaluminum chloride water treatment agent, that is, polyaluminum chloride water purifying agent, abbreviated as PAC, has a molecular formula of [Al ₂ (OH _{) n} Cl _6-n ] _m , and is a cationic polyhydric and multinuclear complex. Inorganic macromolecule flocculant, also known as basic aluminum chloride or coagulant, the appearance of solid product is light yellow.

At present, polyaluminum chloride is widely used in water treatment and sludge dehydration treatment. Compared with traditional aluminum salt flocculants, it has a wide range of water quality, low price, good effect on low-temperature and low-turbidity water treatment, and is easy to settle and pollute. Mud dehydration and other advantages, but its shape, degree of polymerization and the corresponding coagulation and flocculation effect are still inferior to organic polymer flocculants, its molecular weight and the ability to adsorb and bridge colloidal substances are much worse than organic polymer flocculants, due to the lack of heavy metals The ion-coordinated chelating group has poor removal efficiency for heavy metal ions, and single polyaluminium chloride often increases the solubility of aluminum ions in water during water treatment, and excessive aluminum ion concentration in water will cause Human health problems such as dementia.

In view of the above problems, compound polyaluminum chloride water treatment agents are often used to improve the purification performance of polyaluminum chloride. For example, Chinese patent CN109231387B discloses a straw/polyaluminum chloride composite water treatment material and its preparation method. A liquid phase method is adopted to prepare aluminum chloride powder with fly ash as a raw material, and then compound the aluminum chloride powder with rice straw to obtain a composite material with good water treatment effect. The material has a high specific surface area and good adsorption and flocculation ability, but the straw and polyaluminum chloride are only combined through hydrogen bonding, and the interaction between the two is weak, resulting in the composite material being resistant to shear during water treatment. The cutting ability is poor, the flocculation is easily broken, and the small flocs can enter the filtered water through the filter layer, resulting in poor treatment effect. Therefore, it is necessary to improve a composite polyaluminum chloride water treatment agent with higher performance.

Contents of the invention

The object of the present invention is to provide a kind of composite polyaluminum chloride water treatment agent and preparation method thereof, to solve the problems in the background technology.

The purpose of the present invention can be achieved through the following technical solutions:

The preparation method of composite polyaluminum chloride water treatment agent comprises the following steps:

Put the polyaluminum chloride solution in the reaction kettle, add KH-570 coupling agent hydrolyzate and stir evenly, adjust the pH to 10 with 0.1mol/L sodium hydroxide solution, stir for 4-6h, and then add the modified eight Vinyl-POSS, modified chitosan and compound emulsifier, stirred for 20-30min, under the protection of nitrogen, slowly added ammonium persulfate dropwise, sealed the reaction vessel, stirred for 3-4h at 60-65°C, and the reaction ended Finally, the product was precipitated with ethanol, washed with acetone, and then dried at 50°C to constant weight to obtain a composite polyaluminum chloride water treatment agent.

Further, the KH-570 coupling agent hydrolyzate is obtained through the following steps:

The silane coupling agent KH-570 was adjusted to pH 3-4 with 5 wt% hydrochloric acid solution, and hydrolyzed for 12 hours to obtain the KH-570 coupling agent hydrolyzate.

Further, the mass fraction of polyaluminum chloride solution is 10-20%, the dosage of KH-570 is 8-10% of the mass of polyaluminum chloride, and the mass ratio of polyaluminum chloride, octavinyl-POSS and modified chitosan 100:20-23:3-10, the amount of compound emulsifier is 1% of the mass sum of octavinyl-POSS and modified chitosan, and the amount of ammonium persulfate is octavinyl-POSS and modified chitosan 0.6-0.7% of mass sum.

Further, the preparation steps of modified octavinyl-POSS are as follows:

Step S11, mix octavinyl-POSS, mercaptoethylamine, benzoin dimethyl ether and DMF, irradiate with ultraviolet light with a wavelength of 365nm for 1-2h, and remove DMF by rotary evaporation to obtain bifunctional POSS, octavinyl-POSS, mercaptoethyl The dosage ratio of amine, benzoin dimethyl ether and DMF is 3mmol: 12mmol: 20mg: 40-50mL;

Step S12, mix the bifunctional POSS and dimethyl sulfoxide, stir to dissolve, add dibutyltin dilaurate dropwise, then add 4-carboxyphenyl isothiocyanate, stir for 5-10min, and stir for 4h at 50°C , lowered to room temperature and reacted for 48 hours. After the reaction, dimethyl sulfoxide was distilled off under reduced pressure to obtain modified octavinyl-POSS, bifunctional POSS, dimethyl sulfoxide, dibutyltin dilaurate and 4-carboxybenzene The dosage ratio of isothiocyanate is 10.5-11.3g: 80-100mL: 0.3g: 7.3-8.5g.

Using octavinyl-POSS and mercaptoethylamine as raw materials, controlling the amount ratio between raw materials, through mercapto-ene click reaction, to obtain bifunctional POSS containing active amino groups and unsaturated double bonds, and then using active amino groups and 4-carboxybenzene The isothiocyanate reaction of base isothiocyanate can obtain POSS containing thiourea structure, carboxyl group, benzene ring and unsaturated double bond, that is, modified octavinyl-POSS.

Further, the preparation steps of modified chitosan are as follows:

Step S21, add allyl chloride, triethanolamine and deionized water into the flask, seal the bottle mouth with a rubber stopper and adhesive tape, heat to 40°C, and react with magnetic stirring for 24 hours, then remove the deionized water and unreacted alkenes by rotary evaporation Propyl chloride, obtain trihydroxy allyl quaternary ammonium salt compound;

Step S22, disperse chitosan and phthalic anhydride in DMF, under the protection of nitrogen, heat up to 120°C, stir for 8h, then cool to room temperature, pour the reaction product into ice water, stir for 20-30min, filter , the filter cake is washed 3-5 times with methanol, freeze-dried to obtain amino-protected chitosan;

Step S23, put pyridine in a flask, add amino-protected chitosan at 0°C, stir to dissolve, slowly add thionyl chloride, under nitrogen protection, stir at 80°C for 0.5h, cool to room temperature and pour into ice water , filtered after stirring, and the filter cake was vacuum-dried to obtain an intermediate product; put tetrahydrofuran in a flask, add trihydroxyallyl quaternary ammonium compound at 0°C, stir evenly, add NaH, under nitrogen protection, stir at 60°C for 1h and cool to 0°C, add the intermediate product, stir for 0.5h, and stir at 60°C for 12h. After the reaction is over, pour the reaction product into methanol, filter, and freeze-dry the filter cake to obtain quaternary ammonium salt etherified chitosan;

Step S24, dissolving quaternary ammonium salt etherified chitosan in N-methyl-2-pyrrolidone, then adding hydrazine hydrate solution with a concentration of 4 mol/L, and reacting at 100°C for 4-6 hours under the protection of argon, and the reaction is completed After rotary steaming to remove the water in the reaction solution, the rotary steamed product was placed in absolute ethanol for precipitation and centrifugation, and the obtained solid was washed with absolute ethanol, then placed in a dialysis bag for dialysis for 2 days, and freeze-dried to obtain modified chitosan .

First, allyl chloride and triethanolamine are used as raw materials to obtain trihydroxyallyl quaternary ammonium compound through quaternization reaction, and then phthalic anhydride is used to protect the active amino groups on the chitosan molecular chain, and then dichloro The sulfoxide causes the hydroxyl group of the chitosan molecular chain to obtain chlorinated chitosan (intermediate product), and then uses the chlorinated chitosan to react with trihydroxyallyl quaternary ammonium salt compound to eliminate HCl, and the trihydroxyallyl group The quaternary ammonium salt compound is grafted on the chitosan molecular chain through the ether bond, and finally the quaternary ammonium salt etherification chitosan removes the amino protecting group in the hydrazine hydrate solution to obtain an active amino group, a quaternary ammonium salt structure, and an unsaturated bis Compared with introducing functional compounds into chitosan molecular chain through acylation reaction or esterification reaction, the modified chitosan with ether bond has higher stability and good acid and alkali resistance, which can ensure the modification of chitosan molecule stability.

Further, the dosage ratio of allyl chloride, triethanolamine and deionized water in step S21 is 0.1 mol: 0.11 mol: 150-200 mL.

Further, the dosage ratio of chitosan, phthalic anhydride and DMF in step S22 is 4.5-4.8g: 13.32g: 200mL.

Further, the dosage ratio of pyridine, amino-protected chitosan, thionyl chloride, tetrahydrofuran, trihydroxyallyl quaternary ammonium compound and NaH in step S23 is 100mL: 2g: 0.5mL: 50-60mL: 2.3-2.5 g: 1g.

Further, the dosage ratio of the quaternary ammonium salt etherified chitosan, N-methyl-2-pyrrolidone and hydrazine hydrate solution in step S24 is 2.5-3.0 g: 100 mL: 100 mL.

Further, the compound emulsifier is composed of anionic emulsifier and nonionic emulsifier according to the mass ratio of 0.5-3:1, and the anionic emulsifier is selected from sodium lauryl sulfate, sodium dodecylbenzenesulfonate, fat One of alcohol ether sodium sulfate and sodium secondary alkyl sulfonate; the nonionic emulsifier is selected from one of Tween 80, Span 80, alkylphenol polyoxyethylene ether, and fatty alcohol polyoxyethylene ether.

The composite polyaluminum chloride water treatment agent is prepared by the above preparation method.

Beneficial effects of the present invention:

The invention provides a composite polyaluminum chloride water treatment agent, which uses polyaluminum chloride as a base material, uses KH-570 coupling agent to pre-treat it, and then utilizes KH-570 coupling agent unsaturated double bond and modified Polymerize the unsaturated double bonds of the permanent octavinyl-POSS and modified chitosan, and KH-570 builds a "molecular bridge" between the inorganic hydroxyl polyaluminum chloride and the organic polymer, so that the polyaluminum chloride and the modified Permanent octavinyl-POSS and modified chitosan are connected by chemical bonds, and the obtained composite polyaluminum chloride has more stable performance, larger surface area, and a spatial network structure inside, which has better properties than the branched structure. Flocculation of small particles and bridging adsorption properties, therefore, the use of composite polyaluminum chloride as a water treatment agent not only has strong adsorption capacity, but also forms stable flocs.

The present invention introduces modified octavinyl-POSS into composite polyaluminum chloride, which not only acts together with modified chitosan to form a spatial network structure on the surface of polyaluminum chloride, but also introduces a porous cage siloxane structure, It is beneficial to interact with inorganic heavy metal ions and organic pollutants in water, combined with the thiourea structure, benzene ring, and active carboxyl group in the modified octavinyl-POSS molecule, it can interact with inorganic heavy metal ions through coordination and π-π adsorption Interact with organic pollutants to improve the adsorption and removal effect.

The present invention introduces modified chitosan into composite polyaluminum chloride, not only utilizes the abundant amino groups and hydroxyl groups in chitosan molecules, but also absorbs organic pollutants, metal ions and protein molecules through adsorption and coordination, and through active The coordination between amino groups and aluminum ions can overcome the danger of polyaluminum chloride releasing aluminum ions and causing the excessive solubility of aluminum ions in the water body, and there is a quaternary ammonium salt structure in the modified chitosan in the present invention, which can Attracts pollutants by electrostatic interaction.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Example 1

This embodiment provides a modified octavinyl-POSS, the preparation steps are as follows:

Step S11, mixing 3 mmol of octavinyl-POSS, 12 mmol of mercaptoethylamine, 20 mg of benzoin dimethyl ether and 40 mL of DMF, irradiating with ultraviolet light with a wavelength of 365 nm for 1 h, and removing DMF by rotary evaporation to obtain bifunctional POSS;

Step S12, mix 10.5g of bifunctional POSS and 80mL of dimethyl sulfoxide, stir to dissolve, add dropwise 0.3g of dibutyltin dilaurate, then add 7.3g of 4-carboxyphenyl isothiocyanate, stir for 5min, 50 The reaction was stirred at ℃ for 4 hours, then lowered to room temperature and reacted for 48 hours. After the reaction, dimethyl sulfoxide was distilled off under reduced pressure to obtain modified octavinyl-POSS.

Example 2

This embodiment provides a modified octavinyl-POSS, the preparation steps are as follows:

Step S11, mixing 3 mmol of octavinyl-POSS, 12 mmol of mercaptoethylamine, 20 mg of benzoin dimethyl ether and 50 mL of DMF, irradiating with ultraviolet light with a wavelength of 365 nm for 2 hours, and removing DMF by rotary evaporation to obtain bifunctional POSS;

Step S12, mix 11.3g of bifunctional POSS and 100mL dimethyl sulfoxide, stir to dissolve, add dropwise 0.3g of dibutyltin dilaurate, then add 8.5g of 4-carboxyphenyl isothiocyanate, stir for 10min, 50 The reaction was stirred at ℃ for 4 hours, then lowered to room temperature and reacted for 48 hours. After the reaction, dimethyl sulfoxide was distilled off under reduced pressure to obtain modified octavinyl-POSS.

Comparative example 1

This comparative example is octavinyl-POSS.

Example 3

A modified chitosan, the preparation steps are as follows:

Step S21, add 0.1mol allyl chloride, 0.11mol triethanolamine and 150mL deionized water into the flask, seal the bottle mouth with a rubber stopper and adhesive tape, heat to 40°C, and react with magnetic stirring for 24 hours, then remove the deionized water and The unreacted allyl chloride obtains the trihydroxy allyl quaternary ammonium salt compound;

Step S22, disperse 4.5g chitosan and 13.32g phthalic anhydride in 200mL DMF, under the protection of nitrogen, heat up to 120°C, stir and react for 8h, then cool to room temperature, pour the reaction product into ice water, stir 20, filter, the filter cake is washed 3 times with methanol, and freeze-dried to obtain amino-protected chitosan;

Step S23: Put 100 mL of pyridine in a flask, add 2 g of amino-protected chitosan at 0°C, stir to dissolve, then slowly add 0.5 mL of thionyl chloride, under nitrogen protection, stir at 80°C for 0.5 h, and cool to room temperature Pour into ice water, stir and filter, and vacuum-dry the filter cake to obtain an intermediate product; put 50mL tetrahydrofuran in a flask, add 2.3g trihydroxyallyl quaternary ammonium compound at 0°C, stir well, add 1g NaH, nitrogen Under protection, stir at 60°C for 1h and cool to 0°C, add the intermediate product, stir for 0.5h, and stir at 60°C for 12h. After the reaction, pour the reaction product into methanol, filter, freeze-dry the filter cake, and obtain the quaternary ammonium salt Chitosan;

Step S24, dissolving 2.5g of quaternary ammonium salt etherified chitosan in 100mL of N-methyl-2-pyrrolidone, then adding 100mL of hydrazine hydrate solution with a concentration of 4mol/L, and reacting at 100°C for 4h under the protection of argon, After the reaction was completed, the water in the reaction solution was removed by rotary evaporation, and the rotary steamed product was placed in absolute ethanol to precipitate and centrifuged, and the obtained solid was washed with absolute ethanol, then placed in a dialysis bag for dialysis for 2 days, and freeze-dried to obtain a modified shell polysaccharides.

Example 4

A modified chitosan, the preparation steps are as follows:

Step S21, add 0.1mol allyl chloride, 0.11mol triethanolamine and 200mL deionized water into the flask, seal the bottle mouth with a rubber stopper and adhesive tape, heat to 40°C, and react with magnetic stirring for 24 hours, then remove the deionized water and The unreacted allyl chloride obtains the trihydroxy allyl quaternary ammonium salt compound;

Step S22, disperse 4.8g chitosan and 13.32g phthalic anhydride in 200mL DMF, under the protection of nitrogen, heat up to 120°C, stir for 8h, then cool to room temperature, pour the reaction product into ice water, stir 30min, filter, the filter cake is washed 5 times with methanol, and freeze-dried to obtain amino-protected chitosan;

Step S23: Put 100 mL of pyridine in a flask, add 2 g of amino-protected chitosan at 0°C, stir to dissolve, then slowly add 0.5 mL of thionyl chloride, under nitrogen protection, stir at 80°C for 0.5 h, and cool to room temperature Pour into ice water, stir and filter, and vacuum-dry the filter cake to obtain an intermediate product; put 60mL tetrahydrofuran in a flask, add 2.5g trihydroxyallyl quaternary ammonium compound at 0°C, stir well, add 1g NaH, nitrogen Under protection, stir at 60°C for 1h and cool to 0°C, add the intermediate product, stir for 0.5h, and stir at 60°C for 12h. After the reaction, pour the reaction product into methanol, filter, freeze-dry the filter cake, and obtain the quaternary ammonium salt Chitosan;

Step S24, dissolving 3.0 g of quaternary ammonium salt etherified chitosan in 100 mL of N-methyl-2-pyrrolidone, then adding 100 mL of hydrazine hydrate solution with a concentration of 4 mol/L, and reacting at 100° C. for 6 h under argon protection, After the reaction was completed, the water in the reaction solution was removed by rotary evaporation, and the rotary steamed product was placed in absolute ethanol to precipitate and centrifuged, and the obtained solid was washed with absolute ethanol, then placed in a dialysis bag for dialysis for 2 days, and freeze-dried to obtain a modified shell polysaccharides.

Comparative example 2

This comparative example is the trihydroxy allyl quaternary ammonium salt compound prepared in step S21 of Example 3.

Example 5

A preparation method of composite polyaluminum chloride water treatment agent, comprising the following steps:

Use 5wt% hydrochloric acid solution to adjust the pH of the silane coupling agent KH-570 to 3, and hydrolyze it for 12 hours to obtain the hydrolyzed solution of the KH-570 coupling agent, put the polyaluminum chloride solution with a mass fraction of 10% in the reaction kettle, and add KH After stirring the hydrolyzate of -570 coupling agent evenly, adjust the pH to 10 with 0.1mol/L sodium hydroxide solution, stir and react for 4 hours, then add the modified octavinyl-POSS of Example 1 and the modified shell of Example 3 Stir the polysaccharide and compound emulsifier for 20 minutes, slowly add ammonium persulfate dropwise under the protection of nitrogen, seal the reaction vessel, and stir for 3 hours at 60°C. After the reaction, the product is precipitated with ethanol, washed with acetone, and then placed in C and dried to constant weight to obtain a composite polyaluminum chloride water treatment agent.

Among them, the amount of KH-570 is 8% of the mass of polyaluminum chloride, the mass ratio of polyaluminum chloride, octavinyl-POSS and modified chitosan is 100:20:3, and the amount of compound emulsifier is octavinyl -1% of POSS and modified chitosan quality sum, ammonium persulfate consumption is 0.6% of octavinyl-POSS and modified chitosan quality sum

Wherein, the compound emulsifier is composed of sodium lauryl sulfate and Tween 80 in a mass ratio of 0.5:1.

Example 6

A preparation method of composite polyaluminum chloride water treatment agent, comprising the following steps:

Use 5wt% hydrochloric acid solution to adjust the pH of the silane coupling agent KH-570 to 4, hydrolyze it for 12 hours to obtain the hydrolyzate of the KH-570 coupling agent, put the polyaluminum chloride solution with a mass fraction of 15% in the reaction kettle, add KH After stirring the hydrolyzate of -570 coupling agent evenly, adjust the pH to 10 with 0.1mol/L sodium hydroxide solution, stir and react for 5 hours, then add the modified octavinyl-POSS of Example 1 and the modified shell of Example 4 Stir the polysaccharide and compound emulsifier for 20 minutes, slowly add ammonium persulfate dropwise under the protection of nitrogen, seal the reaction vessel, and stir for 3.5 hours at 64°C. After the reaction, the product is precipitated with ethanol, washed with acetone, and placed in Dry at 50°C to constant weight to obtain a composite polyaluminum chloride water treatment agent.

Among them, the amount of KH-570 is 9% of the mass of polyaluminum chloride, the mass ratio of polyaluminum chloride, octavinyl-POSS and modified chitosan is 100:22:6, and the amount of compound emulsifier is octavinyl 1% of the mass sum of -POSS and modified chitosan, and the amount of ammonium persulfate is 0.6% of the mass sum of octavinyl-POSS and modified chitosan.

Wherein, the compound emulsifier is composed of sodium dodecylbenzenesulfonate and Span 80 in a mass ratio of 1:1.

Example 7

A preparation method of composite polyaluminum chloride water treatment agent, comprising the following steps:

The silane coupling agent KH-570 was adjusted to pH 4 with 5wt% hydrochloric acid solution, hydrolyzed for 12 hours to obtain the KH-570 coupling agent hydrolyzate, and the polyaluminum chloride solution with a mass fraction of 20% was placed in the reaction kettle, and KH-570 was added After stirring the hydrolyzate of -570 coupling agent evenly, adjust the pH to 10 with 0.1mol/L sodium hydroxide solution, stir and react for 6h, then add the modified octavinyl-POSS of Example 2 and the modified shell of Example 4 Stir the polysaccharide and compound emulsifier for 30 minutes, slowly add ammonium persulfate dropwise under the protection of nitrogen, seal the reaction vessel, and stir for 4 hours at 65°C. After the reaction, the product is precipitated with ethanol, washed with acetone, and then placed in 50 C and dried to constant weight to obtain a composite polyaluminum chloride water treatment agent.

Among them, the amount of KH-570 is 10% of the mass of polyaluminum chloride, the mass ratio of polyaluminum chloride, octavinyl-POSS and modified chitosan is 100:23:10, and the amount of compound emulsifier is octavinyl 1% of the mass sum of -POSS and modified chitosan, and the amount of ammonium persulfate is 0.7% of the mass sum of octavinyl-POSS and modified chitosan.

Wherein, the compound emulsifier is composed of sodium dodecylbenzenesulfonate and fatty alcohol polyoxyethylene ether in a mass ratio of 3:1.

Comparative example 3

Compared with Example 5, the modified octavinyl-POSS in Example 5 was replaced with the substance in Comparative Example 1, and the rest of the raw materials and preparation process were the same as in Example 5.

Comparative example 4

Compared with Example 5, the modified chitosan in Example 5 was made into the material in Comparative Example 2, and the rest of the raw materials and preparation process were the same as in Example 5.

The compound polyaluminum chloride prepared by embodiment 5-7 and comparative example 3-4 is carried out performance test, and test item is as follows:

Collect the production wastewater of a certain company. The content of each substance in the wastewater is as follows: methylene blue 55.8mg/L, Cu ²⁺ 50.3mg/mL, COD 312.9mg/mL;

(1) Aluminum ion dissolution performance test:

The composite polyaluminium chloride of embodiment and comparative example is added in the waste water that is contained in the collection of 500mL Erlenmeyer flask (addition amount is 0.5g/L), shakes 5min, leaves standstill 30min, takes supernatant and measures aluminum ion residue quantity;

(2) Purification ability:

The composite polyaluminum chloride of embodiment and comparative example is added in the waste water that is contained in the collection of 500mL Erlenmeyer flask (addition amount is 0.5g/L), vibrate 5min, stand still 30min, take supernatant liquid test treated liquid Medium methylene blue content, COD content, Cu ²⁺ content, and calculate methylene blue removal rate, COD removal rate, Cu ²⁺ removal rate;

The test results are shown in Table 1:

Table 1

project Example 5 Example 6 Example 7 Comparative example 3 Comparative example 4 Residual amount of aluminum ion (mg/L) 1.2 1.1 0.9 1.7 2.4 Methylene blue removal rate (%) 96.4 96.9 97.8 95.9 94.2 COD removal rate (%) 88.1 88.7 89.2 87.1 84.2 Cu²⁺ removal rate (%) 95.3 95.9 96.5 91.4 88.3

As can be seen from Table 1, compared with Comparative Examples 3-4, the composite polyaluminum chloride prepared in Example 5-7 has low residual aluminum ions after waste water treatment, and has a low effect on polluting dyes, COD, metal ions The removal rate is high, and it has a high purification effect.

It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or order between them. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications and substitutions can be made to these embodiments without departing from the principle and spirit of the present invention. and modifications, the scope of the invention is defined by the appended claims and their equivalents.

Claims (9)

1. The preparation method of the compound polyaluminium chloride water treatment agent is characterized by comprising the following steps:

firstly, mixing bifunctional POSS and dimethyl sulfoxide, stirring and dissolving, then dropwise adding dibutyltin dilaurate, then adding 4-carboxyphenyl isothiocyanate, stirring, reacting for 4 hours at 50 ℃, cooling to room temperature, and reacting for 48 hours to obtain modified octavinyl-POSS;

and secondly, adding the KH-570 coupling agent hydrolysate into the polyaluminium chloride solution, stirring uniformly, adjusting the pH to 10 by using 0.1mol/L sodium hydroxide solution, stirring for reacting for 4-6h, then adding the modified octavinyl-POSS, the modified chitosan and the compound emulsifier, stirring, dropwise adding ammonium persulfate under the protection of nitrogen, and stirring for reacting for 3-4h at the temperature of 60-65 ℃ to obtain the compound polyaluminium chloride water treatment agent.

2. The method for preparing the composite polyaluminum chloride water treatment agent according to claim 1, wherein the ratio of the amount of bifunctional POSS, dimethyl sulfoxide, dibutyltin dilaurate and 4-carboxyphenyl isothiocyanate is 10.5-11.3g:80-100mL:0.3g:7.3-8.5g.

3. The preparation method of the composite polyaluminum chloride water treatment agent according to claim 1, wherein the KH-570 coupling agent hydrolysate is obtained by the following steps:

adjusting pH of KH-570 with 5wt% hydrochloric acid solution to 3-4, and hydrolyzing for 12 hr to obtain KH-570 coupling agent hydrolysate.

4. The preparation method of the compound polyaluminium chloride water treatment agent according to claim 1, wherein the mass ratio of the polyaluminium chloride to the octavinyl-POSS to the modified chitosan is 100:20-23:3 to 10 percent, and the dosage of the ammonium persulfate is 0.6 to 0.7 percent of the sum of the mass of the octavinyl-POSS and the mass of the modified chitosan.

5. The preparation method of the compound polyaluminium chloride water treatment agent as claimed in claim 1, wherein the mass fraction of the polyaluminium chloride solution is 10-20%, and the amount of KH-570 is 8-10% of the mass of the polyaluminium chloride.

6. The preparation method of the composite polyaluminum chloride water treatment agent according to claim 1, wherein the bifunctional POSS is prepared by the following steps:

mixing octavinyl-POSS, mercaptoethylamine, benzoin dimethyl ether and DMF, and irradiating the mixture for 1 to 2 hours by ultraviolet light with the wavelength of 365nm to obtain the bifunctional POSS.

7. The preparation method of the compound polyaluminium chloride water treatment agent according to claim 1, wherein the modified chitosan is prepared by the following steps:

step S21, mixing allyl chloride, triethanolamine and deionized water, and stirring and reacting for 24 hours at 40 ℃ to obtain a trihydroxy allyl quaternary ammonium salt compound;

s22, dispersing chitosan and phthalic anhydride in DMF, and stirring and reacting for 8 hours at 120 ℃ under the protection of nitrogen to obtain amino-protected chitosan;

s23, putting pyridine into a flask, adding amino protective polysaccharide at 0 ℃, stirring and dissolving, slowly adding thionyl chloride, and stirring and reacting at 80 ℃ for 0.5h under the protection of nitrogen to obtain an intermediate product; placing tetrahydrofuran in a flask, adding trihydroxy allyl quaternary ammonium salt compound at 0 ℃, uniformly stirring, adding NaH, stirring at 60 ℃ for 1h under the protection of nitrogen, cooling to 0 ℃, adding an intermediate product, stirring for 0.5h, and stirring at 60 ℃ for 12h to obtain quaternary ammonium salt etherified chitosan;

and S24, dissolving quaternary ammonium salt etherified chitosan in N-methyl-2-pyrrolidone, adding a hydrazine hydrate solution with the concentration of 4mol/L, and reacting for 4-6 hours at 100 ℃ under the protection of argon to obtain the modified chitosan.

8. The preparation method of the composite polyaluminum chloride water treatment agent according to claim 7, wherein in step S23, the dosage ratio of the pyridine, the amino-protective chitosan, thionyl chloride, tetrahydrofuran, the trihydroxyallyl quaternary ammonium compound and NaH is 100mL:2g:0.5mL:50-60mL:2.3-2.5g:1g of the total weight of the composition.

9. The composite polyaluminum chloride water treatment agent is characterized by being prepared by the preparation method of any one of claims 1 to 8.