A method for preparing polyaluminum chloride composite material by using polyaluminum chloride water treatment agent waste residue

Abstract

The application relates to the technical field of water purification material preparation, in particular to a method for preparing a polyaluminum chloride composite material by using polyaluminum chloride water treatment agent waste residue. The method for preparing the polyaluminum chloride composite material by using the polyaluminum chloride water treatment agent waste residue comprises the following steps: solid-liquid separation, drying, grinding, calcination and grinding and screening of a solid-liquid mixture containing polyaluminum chloride water treatment agent waste residue to obtain pretreated residue powder; acid treatment and concentration of an aluminum-rich filtrate, and then alkali treatment to obtain an aluminumate-rich filtrate; mixing the aluminumate-rich filtrate with an aluminum source, and then performing a hydrochloric acid aqueous solution polymerization reaction to obtain an aqueous solution containing polyaluminum chloride; mixing the aqueous solution containing polyaluminum chloride with cationic polyacrylamide, and then performing vacuum filtration, vacuum drying and grinding and screening to obtain a finished product. The application carries out secondary development and utilization of aluminum-containing waste residue generated in a sewage treatment process, extracts aluminum resources in the aluminum-containing waste residue to produce a polyaluminum chloride composite material, improves resource utilization rate and meets a sustainable green development trend.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of water purification material preparation, in particular to a method for preparing a polyaluminum chloride composite material from polyaluminum chloride water treatment agent waste residues. BACKGROUND

[0002] At present, in the process of treating domestic sewage, the domestic sewage sequentially passes through an anaerobic tank, an acid adjusting tank, a Fenton oxidation tank, an alkali adjusting tank, a DTCR tank, a flocculation and sedimentation tank and a sedimentation tank. The lack of oxygen tank is a biochemical system in which the dissolved oxygen is controlled between 0.2-0.5 mg / l, mainly plays a role in removing nitrate nitrogen through denitrification, and removes part of BOD. The acid adjusting tank adjusts the pH value of the water to be treated, so that the water is acidic, and the quality of the Fenton reagent in the Fenton oxidation tank is ensured, that is, the ferrous ions in the Fenton reagent do not precipitate with hydroxyl ions. The Fenton reagent in the Fenton oxidation tank can effectively oxidize and remove organic pollutants in the water body which are difficult to be degraded biologically or are difficult to be removed by general chemical oxidation, thereby reducing the BOD content. The DTCR tank is a water tank containing heavy metal heavy trapping agent, which is used for adsorbing heavy metal ions in the water body, and can capture and adsorb free heavy metal ions in the water body. The flocculation and sedimentation tank is a water tank containing polyaluminum chloride coagulant, which adsorbs, agglomerates and precipitates particulate matter and suspended matter in the water body, so that the water body enters the sedimentation tank, and the heavy metal heavy trapping agent adsorbing the heavy metal ions in the water body, part of the insoluble organic wastewater, flocculent iron hydroxide, polyaluminum chloride and other suspended matter and particulate impurities are aggregated and then separated and removed, so as to obtain preliminary purified water. The obtained preliminary purified water flows into the MBR tank and then flows into the MBR water production tank for storage and reuse.

[0003] The waste residues in the sedimentation tank in the sewage system not only include polyaluminum chloride aggregated suspended matter, but also include heavy metal heavy trapping agent of heavy metal ions, part of insoluble organic wastewater, flocculent iron hydroxide and particulate impurities. At present, the waste residues generated by the sedimentation tank are generally treated as waste together with the sludge in the anaerobic tank, which not only causes the cost of sewage treatment to rise, but also causes secondary pollution, which is not conducive to sustainable development. In order to solve the above problems, the applicant provides a method for preparing a polyaluminum chloride composite material from polyaluminum chloride water treatment agent waste residues for the first time in the industry. SUMMARY

[0004] In order to solve the problems existing in the prior art, the application provides a method for preparing a polyaluminum chloride composite material from polyaluminum chloride water treatment agent waste residues, which develops and utilizes the aluminum-containing waste residues again, improves the resource utilization rate, and meets the trend of sustainable development.

[0005] The method for preparing a polyaluminum chloride composite material from polyaluminum chloride water treatment agent waste residues provided by the application is realized through the following technical scheme:

[0006] A method for preparing polyaluminum chloride composite materials using waste residue from polyaluminum chloride water treatment agents includes the following steps:

[0007] Step 1: The solid-liquid mixture containing polyaluminum chloride water treatment agent waste residue is placed in a solid-liquid separator for solid-liquid separation treatment. The resulting wastewater is fed into the sewage pipe, and the resulting solid is dried, crushed, and screened to obtain slag powder particles with a particle size of <50 mesh.

[0008] Step 2: The obtained slag powder particles are calcined at 400-650℃ for 1-3 hours, and then ground and sieved to obtain 300-800 mesh pretreated slag powder;

[0009] Step 3: Mix 10 parts of the pretreated slag powder obtained in Step 2 with 40-100 parts of tap water evenly, maintain at 80-200 rpm, add 0.1-0.5 mol / L hydrochloric acid aqueous solution, adjust the pH value to 2.8-3.5, and continue stirring at 80-200 rpm for 4-8 hours. Let stand for 12-24 hours, filter and take the supernatant for the next step of treatment. After solid-liquid separation treatment, the obtained solid waste is sent into the sewage pipe, and the obtained solid is dried, crushed and used as cement admixture.

[0010] Step 4: At a speed of 80-200 rpm, add 0.1-0.5 mol / L sodium hydroxide aqueous solution to the supernatant obtained in Step 3, adjust the pH value to 12-13, raise the temperature to 80-98℃ and maintain it for 5-15 minutes, cool it to room temperature, let it stand for 6-12 hours, filter and take the supernatant for the next step of processing, the resulting solid-liquid mixture rich in metal impurities is subjected to solid-liquid separation treatment, the resulting wastewater is sent into the sewage pipeline, and the resulting solid waste residue rich in heavy metals is dried, crushed, screened and recycled.

[0011] Step 5: At least an aluminum source is added to the supernatant obtained in Step 4. The aluminum source is bauxite and / or calcium aluminate powder. The mass ratio of the aluminum source to the supernatant is 100:(5-20). At 80-200 rpm, 0.4-1.2 mol / L hydrochloric acid aqueous solution is added. After the pH value is 3.6-4.0, the temperature is raised to 75-90℃ to carry out the polymerization reaction to obtain an aqueous solution containing polyaluminum chloride.

[0012] Step 6: Add at least 1-3 wt% cationic polyacrylamide to the aqueous solution containing polyaluminum chloride, stir at 100-400 rpm for 1-3 hours, mature for 6-8 hours, filter under reduced pressure, vacuum dry the resulting solid powder, grind and sieve to obtain the polyaluminum chloride composite material.

[0013] The application carries out secondary development and utilization on the aluminum-containing waste residue generated in the sewage treatment process, extracts aluminum resources in the aluminum-containing waste residue to produce polyaluminum chloride composite materials, improves resource utilization rate, and meets the sustainable green development trend.

[0014] Further, in step three, 10 parts of the pretreated residue obtained in step two are uniformly mixed with 60-80 parts of tap water, 0.3-0.5 mol / L hydrochloric acid aqueous solution is added under the condition of maintaining 120-160 rpm, the pH value is adjusted to 3.2-3.5, then the stirring is continued for 5-6 h under the condition of maintaining 120-160 rpm, and the upper clear liquid is obtained by filtration after standing for 18-24 h, and the upper clear liquid is subjected to the next step.

[0015] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved.

[0016] Further, in step four, 0.3-0.5 mol / L sodium hydroxide aqueous solution is added to the upper clear liquid obtained in step three under the condition of 120-160 rpm, the pH value is adjusted to 12.4-12.8, then the temperature is raised to 80-85°C for 10-15 min, and after the temperature is lowered to room temperature, the upper clear liquid is obtained by filtration after standing for 10-12 h, and the upper clear liquid is subjected to the next step.

[0017] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved.

[0018] Further, in step five, at least an aluminum source is added to the upper clear liquid obtained in step four, the aluminum source is bauxite and / or calcium aluminate powder, the mass ratio of the aluminum source to the upper clear liquid is 100:(8-12), 0.8-1.0 mol / L hydrochloric acid aqueous solution is added under the condition of 160-200 rpm, the pH value is 3.6-3.8, then the temperature is raised to 80-85°C for polymerization to obtain a water solution containing polyaluminum chloride.

[0019] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved.

[0020] Further, in step five, an aluminum source and a titanium source are added to the upper clear liquid obtained in step four, the aluminum source is bauxite and / or calcium aluminate powder, the titanium source is 0.05-0.2 mol / L titanium tetrachloride aqueous solution, the mass ratio of the aluminum source to the upper clear liquid is 100:(8-12), the mass ratio of the titanium tetrachloride aqueous solution to the upper clear liquid is 100:(1-3), 0.8-1.0 mol / L hydrochloric acid aqueous solution is added under the condition of 160-200 rpm, the pH value is 3.6-3.8, then the temperature is raised to 80-85°C for polymerization to obtain a water solution containing polyaluminum chloride.

[0021] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved, and the prepared polyaluminum chloride composite material flocculation performance can be improved.

[0022] Further, in the step six, at least 1-3wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at a speed of 240-320 rpm for 2-3 h, aged for 6-8 h, and the obtained solid powder is subjected to vacuum drying treatment, the vacuum drying temperature is 60-90℃, the air pressure is 0.01-0.1 Pa, the vacuum drying time is 6-8 h, and the obtained solid material is mixed with 0.1-0.5wt% of active silicon acid, ground and sieved to obtain polyaluminum chloride composite material with a particle size of 200-500 mesh.

[0023] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved.

[0024] Further, in the step six, at least 1-3wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at a speed of 240-320 rpm for 2-3 h, aged for 6-8 h, and the obtained solid powder is subjected to vacuum drying treatment, the vacuum drying temperature is 60-90℃, the air pressure is 0.01-0.1 Pa, the vacuum drying time is 6-8 h, and the obtained solid material is mixed with 0.1-0.5wt% of active silicon acid, ground and sieved to obtain polyaluminum chloride composite material with a particle size of 200-500 mesh.

[0025] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved, and the prepared polyaluminum chloride composite material flocculation performance can be improved.

[0026] Further, in the step six, at least 1-3wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at a speed of 240-320 rpm for 2-3 h, aged for 6-8 h, and the obtained solid powder is subjected to vacuum drying treatment, the vacuum drying temperature is 60-90℃, the air pressure is 0.01-0.1 Pa, the vacuum drying time is 6-8 h, and the obtained solid material is mixed with 0.1-0.5wt% of active silicon acid, ground and sieved to obtain polyaluminum chloride composite material with a particle size of 200-500 mesh.

[0027] Further, the step six, at least 1-3wt% of cationic polyacrylamide is added into the aqueous solution containing polyaluminum chloride, stirring at 240-320rpm for 2-3h, aging for 6-8h, then adding 0.5-2wt% of monatomic modified synergistic coagulant, ultrasonic dispersion for 100-120min at ultrasonic frequency of 34-60kHz and ultrasonic power of 600-1200W, aging for 8-12h, vacuum filtration of the obtained solid powder, vacuum drying treatment at vacuum drying temperature of 60-90℃, air pressure of 0.01-0.1Pa, vacuum drying time of 6-8h, grinding and sieving to obtain polyaluminum chloride composite material with particle size of 200-500mesh.

[0028] Further, the monatomic modified synergistic coagulant comprises an inorganic carrier and a metal monatomic, the metal monatomic is anchored in the defect site on the surface of the inorganic carrier in the form of a monatomic; the inorganic carrier is at least one of mixed crystal titanium dioxide, halloysite, diatomite, kaolin, graphene, carbon nanotube; the metal monatomic is at least one of Al, Fe, Cu, Co, Ce, Ag.

[0029] By adopting the above technical scheme, the overall production efficiency and product quality stability can be improved, the flocculation performance of the prepared polyaluminum chloride composite material can be improved, and the polyaluminum chloride composite material is also endowed with excellent antibacterial and algicidal properties.

[0030] In summary, the present application has the following advantages:

[0031] 1. The present application develops and utilizes the aluminum-containing waste residue generated in the sewage treatment process, extracts aluminum resources from the aluminum-containing waste residue for the production of polyaluminum chloride composite material, improves the resource utilization rate, and meets the sustainable green development trend.

[0032] 2. The preparation method of the present application is relatively simple, and the implementation operation difficulty is relatively low, which is convenient for industrial production.

[0033] 3. The polyaluminum chloride composite material prepared by the present application adds a monatomic modified synergistic coagulant, which can not only improve the flocculation performance of the prepared polyaluminum chloride composite material, but also endow the polyaluminum chloride composite material with excellent antibacterial and algicidal properties. DETAILED DESCRIPTION

[0034] In order to further understand the present application, the preferred embodiments of the present application are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present application, and are not limitations of the claims. Those skilled in the art can refer to the content herein to appropriately improve the process parameters.

[0035] It is specifically intended that all the various alternatives and modifications that can be incorporated with the principles of the present application and fall within the scope of the application are to be considered as included within the scope of the present application. The methods and applications of the present application have been described by way of preferred embodiments, and it will be apparent to those skilled in the art that changes and modifications can be made within the scope of the present application which falls within the principles, spirit and scope of the application, and which result in equivalent methods and applications of the present application. Although the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the disclosed subject matter.

[0036] As used herein, the terms "comprises," "comprising," "includes," "including," or "characterized by" are used synonymously to mean that the named element is included or characterized by the element, and are not intended to exclude additional, unrecited elements or method steps, whether or not the additional, unrecited elements or method steps are specifically disclosed. "Comprises" is a broadening term and is used in its open-ended sense that does not exclude additional, unrecited elements or method steps.

[0037] Preparation Example

[0038] Preparation Example 1: Preparation of monatomic modified synergistic coagulant aid is as follows: S1. The concentration of 8 g / L of ferric nitrate, 8 g / L of cerium nitrate, 8 g / L of cobalt nitrate and mixed crystal titanium dioxide (nanometer titanium dioxide (J25) of Xuancheng Crystal and Environmental Protection New Material Technology, average particle size 15±5 nm, specific surface area 60-120 m3 / g) are mixed uniformly, the ratio of the content of metallic iron in ferric nitrate, the content of cerium in cerium nitrate, and the content of cobalt in cobalt nitrate is 1:1:1, the mass ratio of the sum of the content of metallic iron in ferric nitrate and the content of cerium in cerium nitrate to the mixed crystal titanium dioxide is 1:20, the obtained mixed solution is first subjected to ultrasonic dispersion treatment for 60 min, the ultrasonic power is 800 W, the ultrasonic frequency is 44 kHz, and then it is subjected to magnetic stirring aging for 24 h at 200 rpm, to obtain a precursor mixed solution; S2. The obtained precursor mixed solution is heated to remove the solvent, and the obtained solid is placed in a planetary ball mill to mill at 80 rpm for 30 min to obtain a solid powder; S3. The solid powder obtained in S1.2 is placed in a 5% hydrogen-argon mixed gas atmosphere (hydrogen-argon volume ratio = 1:19), heated to 350°C at a rate of 15°C / min, and held for 1 h, then heated to 650°C at a rate of 25°C / min and held for 2 h, and then naturally cooled to room temperature. The obtained solid powder is placed in a planetary ball mill and milled at 60 rpm for 40 min to obtain the finished product.

[0039] Preparation Example 2: The preparation method of the single-atom modified synergistic coagulant aid is as follows: S1. Mix 8 g / L of aluminum nitrate, 8 g / L of silver nitrate, and 8 g / L of iron nitrate with halloysite nanotubes uniformly, the ratio of the content of metallic aluminum in the aluminum nitrate, the content of silver in the silver nitrate, and the content of iron in the iron nitrate is 1:1:1, and the mass ratio of the sum of the content of metallic aluminum in the aluminum nitrate, the content of silver in the silver nitrate, and the content of iron in the iron nitrate to the halloysite nanotubes is 1:20, the obtained mixed solution is first subjected to ultrasonic dispersion treatment for 60 min, the ultrasonic power is 800 W, and the ultrasonic frequency is 44 kHz, and then the obtained mixed solution is subjected to magnetic stirring aging at 200 rpm for 24 h, to obtain a precursor mixed solution; S2. The obtained precursor mixed solution is heated to remove the solvent, and the obtained solid is placed in a planetary ball mill and subjected to ball milling at 80 rpm for 30 min, to obtain a solid powder; S3. The obtained solid powder in S1.2 is placed in a 6vt% (hydrogen to argon volume ratio = 3:50) hydrogen-argon mixed gas atmosphere, heated to 300°C at 15°C / min, and kept for 1 h, then heated to 550°C at 25°C / min, and kept for 2 h, naturally cooled to room temperature, and then placed in a planetary ball mill and subjected to ball milling at 60 rpm for 40 min, to obtain a finished product.

[0040] Preparation Example 3: The preparation method of the single-atom modified synergistic coagulant aid is as follows: S1. Mix 8 g / L of cerium nitrate, 8 g / L of iron nitrate, and 8 g / L of copper nitrate with carboxylated graphene (carboxylated graphene TNRGOC, thickness: 0.55-3.74 nm, diameter: 0.5-3 μm, layer number: <10 layers, oxygen content: >10 wt%, Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences) uniformly, the ratio of the content of metallic cerium in the cerium nitrate, the content of iron in the iron nitrate, and the content of copper in the copper nitrate is 1:1:1, and the mass ratio of the sum of the content of metallic cerium in the cerium nitrate, the content of iron in the iron nitrate, and the content of copper in the copper nitrate to the carboxylated graphene is 1:20, the obtained mixed solution is first subjected to ultrasonic dispersion treatment for 60 min, the ultrasonic power is 800 W, and the ultrasonic frequency is 44 kHz, and then the obtained mixed solution is subjected to magnetic stirring aging at 200 rpm for 24 h, to obtain a precursor mixed solution; S2. The obtained precursor mixed solution is heated to remove the solvent, and the obtained solid is placed in a planetary ball mill and subjected to ball milling at 80 rpm for 30 min, to obtain a solid powder; S3. The obtained solid powder in S1.2 is placed in a 5vt% (hydrogen to argon volume ratio = 1:19) hydrogen-argon mixed gas atmosphere, heated to 320°C at 15°C / min, and kept for 1 h, then heated to 640°C at 25°C / min, and kept for 2 h, naturally cooled to room temperature, and then placed in a planetary ball mill and subjected to ball milling at 60 rpm for 40 min, to obtain a finished product.

[0041] Embodiment

[0042] A method for preparing a polyaluminum chloride composite material from polyaluminum chloride water treatment agent waste residue, comprising the following steps:

[0043] Step one, the solid-liquid mixture containing polyaluminum chloride water treatment agent waste residue is placed in a solid-liquid separator for solid-liquid separation treatment, the obtained sewage is input into a sewage pipeline, and the obtained solid is dried, broken, and sieved to obtain residue powder particles with a particle size of < 50 μm;

[0044] Step two, the obtained residue powder particles are calcined at 400-650°C for 1-3h, and are ground and sieved to obtain pretreated residue powder with a particle size of 300-800 μm;

[0045] Step three, 10 parts of the pretreated residue powder obtained in step two are uniformly mixed with 40-100 parts of tap water, 0.1-0.5 mol / L hydrochloric acid aqueous solution is added under the condition of maintaining 80-200 rpm, the pH value is adjusted to 2.8-3.5, and then stirring is continued for 4-8h under the condition of maintaining 80-200 rpm, and then standing for 12-24h, the upper clear liquid is taken by filtration for the next step treatment, and the obtained solid-liquid waste residue is subjected to solid-liquid separation treatment, the obtained sewage is input into a sewage pipeline, and the obtained solid is dried, broken, and used as a cement admixture;

[0046] Preferably, in step three, 10 parts of the pretreated residue powder obtained in step two are uniformly mixed with 60-80 parts of tap water, 0.3-0.5 mol / L hydrochloric acid aqueous solution is added under the condition of maintaining 120-160 rpm, the pH value is adjusted to 3.2-3.5, and then stirring is continued for 5-6h under the condition of maintaining 120-160 rpm, and then standing for 18-24h, the upper clear liquid is taken by filtration for the next step treatment;

[0047] Step four, 0.1-0.5 mol / L sodium hydroxide aqueous solution is added to the upper clear liquid obtained in step three under the condition of maintaining 80-200 rpm, the pH value is adjusted to 12-13, then the temperature is raised to 80-98°C for 5-15 min, then the temperature is lowered to room temperature, then standing for 6-12h, the upper clear liquid is taken by filtration for the next step treatment, and the obtained solid-liquid mixture rich in metal impurities is subjected to solid-liquid separation treatment, the obtained sewage is input into a sewage pipeline, and the obtained solid waste residue rich in heavy metals is dried, broken, and sieved for recycling;

[0048] Preferably, in step four, 0.3-0.5 mol / L sodium hydroxide aqueous solution is added to the upper clear liquid obtained in step three under the condition of maintaining 120-160 rpm, the pH value is adjusted to 12.4-12.8, then the temperature is raised to 80-85°C for 10-15 min, then the temperature is lowered to room temperature, then standing for 10-12h, the upper clear liquid is taken by filtration for the next step treatment;

[0049] Step five, at least adding aluminum source into the supernatant obtained in step three, the aluminum source is bauxite and / or calcium aluminate powder, the mass ratio of aluminum source and supernatant is 100:(5-20), adding 0.4-1.2 mol / L hydrochloric acid aqueous solution under 80-200 rpm, after the pH value is 3.6-4.0, heating to 75-90℃ for polymerization reaction to obtain a water solution containing polyaluminum chloride;

[0050] Preferably, step five, adding aluminum source into the supernatant obtained in step four, the aluminum source is bauxite and / or calcium aluminate powder, the mass ratio of aluminum source and supernatant is 100:(8-12), adding 0.8-1.0 mol / L hydrochloric acid aqueous solution under 160-200 rpm, after the pH value is 3.6-3.8, heating to 80-85℃ for polymerization reaction to obtain a water solution containing polyaluminum chloride;

[0051] Preferably, step five, adding aluminum source and titanium source into the supernatant obtained in step four, the aluminum source is bauxite and / or calcium aluminate powder, the titanium source is 0.05-0.2 mol / L titanium tetrachloride aqueous solution, the mass ratio of aluminum source and supernatant is 100:(8-12), the mass ratio of titanium tetrachloride aqueous solution and supernatant is 100:(1-3), adding 0.8-1.0 mol / L hydrochloric acid aqueous solution under 160-200 rpm, after the pH value is 3.6-3.8, heating to 80-85℃ for polymerization reaction to obtain a water solution containing polyaluminum chloride;

[0052] Step six, adding at least 1-3 wt% cationic polyacrylamide into the water solution containing polyaluminum chloride, stirring at 100-400 rpm for 1-3 h, aging for 6-8 h, vacuum drying the solid powder obtained by pressure filtration, grinding and screening to obtain polyaluminum chloride composite material;

[0053] Preferably, step six, adding at least 1-3 wt% cationic polyacrylamide into the water solution containing polyaluminum chloride, stirring at 240-320 rpm for 2-3 h, aging for 6-8 h, vacuum drying the solid powder obtained by pressure filtration, the vacuum drying temperature is 60-90℃, the air pressure is 0.01-0.1 Pa, the vacuum drying time is 6-8 h, grinding and screening to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0054] Preferably, in step six, at least 1-3 wt% of cationic polyacrylamide is added to an aqueous solution containing polyaluminum chloride, stirred at 240-320 rpm for 2-3 hours, matured for 6-8 hours, and the resulting solid powder is vacuum dried at a temperature of 60-90℃, a pressure of 0.01-0.1 Pa, and a drying time of 6-8 hours. 0.1-0.5 wt% of active silicic acid is mixed into the resulting solid, and the mixture is ground and sieved to obtain a polyaluminum chloride composite material with a particle size of 200-500 mesh.

[0055] Preferably, in step six, at least 1-3 wt% cationic polyacrylamide is added to an aqueous solution containing polyaluminum chloride, stirred at 240-320 rpm for 2-3 hours, and matured for 6-8 hours. Then, 0.5-2 wt% of a single-atom modified synergistic coagulant is added, ultrasonically dispersed for 1-2 hours, and matured for 8-12 hours. The solid powder obtained by vacuum filtration is then vacuum dried at a temperature of 60-90℃, a pressure of 0.01-0.1 Pa, and a drying time of 6-8 hours. After grinding and sieving, a polyaluminum chloride composite material with a particle size of 200-500 mesh is obtained. The single-atom modified synergistic coagulant includes an inorganic carrier and metal single atoms, with the metal single atoms anchored to defect sites on the surface of the inorganic carrier in the form of single atoms. The inorganic carrier is at least one of mixed-crystal titanium dioxide, halloysite, diatomaceous earth, kaolin, graphene, and carbon nanotubes; the metal single atom is at least one of Al, Fe, Cu, Co, Ce, and Ag.

[0056] More preferably, in step six, at least 1-3 wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240-320 rpm for 2-3 hours, and matured for 6-8 hours. Then, 0.5-2 wt% of single-atom modified synergist is added, and ultrasonic dispersion is performed at an ultrasonic frequency of 34-60 kHz and an ultrasonic power of 600-1200 W for 100-120 minutes, followed by maturation for 8-12 hours. The solid powder obtained by vacuum filtration is then vacuum dried at a temperature of 60-90℃, a pressure of 0.01-0.1 Pa, and a drying time of 6-8 hours. The resulting polyaluminum chloride composite material with a particle size of 200-500 mesh is obtained by grinding and sieving.

[0057] Example 1: The specific steps of the method for preparing polyaluminum chloride composite material using waste residue from polyaluminum chloride water treatment agent are as follows:

[0058] Step 1: The solid-liquid mixture containing polyaluminum chloride water treatment agent waste residue is placed in a solid-liquid separator for solid-liquid separation. The resulting wastewater is fed into the sewage pipe. The resulting solid is dried until the moisture content is less than 5%, and then placed in a cement crusher for crushing. The resulting granules are screened using a 50-mesh sieve. The screened material is slag powder with a particle size of <50 mesh.

[0059] Step two, the residue powder with particle size < 50 μm obtained in step one was calcined in a rotary large cement rotary kiln at a temperature of 460℃ for 3h, and the obtained solid powder was ground in a conical ball mill. The obtained ground powder was sieved through 300 mesh and 500 mesh sieves, respectively, to obtain 300-500 mesh pretreated residue powder.

[0060] Step three, 10 parts of the pretreated residue powder obtained in step two and 70 parts of tap water were mixed uniformly at 150 rpm for 30 min. Then, 0.35 mol / L hydrochloric acid aqueous solution was added, and the pH value of the system was adjusted to 3.4-3.5. The stirring was continued at 150 rpm for 5.5 h, and then the system was left to stand for 18.5 h. The upper clear liquid was filtered and used for the next step. The solid-liquid mixture was separated, and the obtained sewage was discharged into the sewage pipe. The obtained solid waste was dried, crushed, and used as a cement admixture.

[0061] Step four, 0.35 mol / L sodium hydroxide aqueous solution was added to the upper clear liquid obtained in step three at a stirring speed of 150 rpm. The pH value of the system was adjusted to 12.7-12.8, and then the system was heated to 85℃ for 10 min. After the system was cooled to room temperature, it was left to stand for 10.0 h. The upper clear liquid was filtered and used for the next step. The obtained solid-liquid mixture rich in heavy metals was separated, and the obtained sewage was discharged into the sewage pipe. The obtained solid waste rich in heavy metals was dried, crushed, and sieved for recycling.

[0062] Step five, bauxite was added to the upper clear liquid obtained in step four at a mass ratio of 10:1, and 0.80 mol / L hydrochloric acid aqueous solution was added at a stirring speed of 160 rpm. The pH value of the system was adjusted to 3.6-3.7, and then the system was heated to 80℃ for 8 h. After the system was left to stand for 12 h, the upper clear liquid was obtained, which was a water solution containing polyaluminum chloride.

[0063] Step six, 2 wt% cationic polyacrylamide was added to the water solution containing polyaluminum chloride, and the system was stirred at a stirring speed of 240 rpm for 150 min and left to stand for 8.0 h. The obtained solid powder was vacuum dried at a temperature of 85℃ and an air pressure of 0.01-0.1 Pa for 6.0 h. The obtained polyaluminum chloride composite material was ground and sieved to obtain a product with a particle size of 325 mesh. The product index of the obtained polyaluminum chloride composite material was as follows: appearance: light yellow powder; Al2O3 content: 29.8%; salt base: 56.4%; water-insoluble content: 1.24%; pH value (1.0% aqueous solution): 3.8; and Fe2O3 content: 1.08%.

[0064] Example 2 differs from Example 1 in that in Step 5, the bauxite and 0.1 mol / L titanium tetrachloride aqueous solution obtained in Step 4 are mixed at a mass ratio of 10:1 and 100:2, respectively, and 0.80 mol / L hydrochloric acid aqueous solution is added at a rotation speed of 160 rpm until the pH value reaches 3.6-3.7, and then the mixture is heated to 80°C and polymerized for 8 h, and then aged for 12 h, and the supernatant is taken as the aqueous solution containing polymeric titanium chloride aluminum.

[0065] Example 3 differs from Example 1 in that in Step 6, 2 wt% cationic polyacrylamide is added to the aqueous solution containing polymeric aluminum chloride, stirred at a rotation speed of 240 rpm for 150 min, aged for 8.0 h, and the obtained solid powder is subjected to vacuum drying treatment at a temperature of 85°C and an air pressure of 0.01-0.1 Pa for 6.0 h, and then 0.2 wt% active silicic acid is mixed with the obtained solid, ground and sieved to obtain polymeric aluminum chloride composite material with a particle size of 200-500 mesh.

[0066] Example 4 differs from Example 2 in that in Step 6, 2 wt% cationic polyacrylamide is added to the aqueous solution containing polymeric titanium chloride aluminum, stirred at a rotation speed of 240 rpm for 150 min, aged for 8.0 h, and the obtained solid powder is subjected to vacuum drying treatment at a temperature of 85°C and an air pressure of 0.01-0.1 Pa for 6.0 h, and then 0.2 wt% active silicic acid is mixed with the obtained solid, ground and sieved to obtain polymeric aluminum chloride composite material with a particle size of 200-500 mesh.

[0067] Example 5 differs from Example 1 in that in Step 6, 2 wt% cationic polyacrylamide is added to the aqueous solution containing polymeric aluminum chloride, stirred at a rotation speed of 240 rpm for 150 min, aged for 8.0 h, and then 0.5 wt% monatomic modified synergistic coagulant aid prepared in Preparation Example 1 is added, and ultrasonic dispersion is performed at an ultrasonic frequency of 44 kHz and an ultrasonic power of 1000 W for 120 min, and then aged for 12 h, and the obtained solid powder is subjected to vacuum drying treatment at a temperature of 85°C and an air pressure of 0.01-0.1 Pa for 6.0 h, and then ground and sieved to obtain polymeric aluminum chloride composite material with a particle size of 200-500 mesh.

[0068] Example 6 differs from Example 1 in that in Step VI, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240 rpm for 150 min, aged for 8.0 h, then 0.5wt% of the monatomic modified synergistic coagulant aid of Preparation Example 1 is added, ultrasonically dispersed at ultrasonic frequency of 44 kHz and ultrasonic power of 1000 W for 120 min, aged for 12 h, the solid powder obtained is vacuum dried, the vacuum drying temperature is 85°C, the air pressure is controlled at 0.01-0.1 Pa, the vacuum drying time is 6.0 h, 0.2wt% of active silicic acid is mixed into the solid product, ground and sieved to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0069] Example 7 differs from Example 1 in that in Step VI, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240 rpm for 150 min, aged for 8.0 h, then 1.0wt% of the monatomic modified synergistic coagulant aid of Preparation Example 1 is added, ultrasonically dispersed at ultrasonic frequency of 44 kHz and ultrasonic power of 1000 W for 120 min, aged for 12 h, the solid powder obtained is vacuum dried, the vacuum drying temperature is 85°C, the air pressure is controlled at 0.01-0.1 Pa, the vacuum drying time is 6.0 h, 0.2wt% of active silicic acid is mixed into the solid product, ground and sieved to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0070] Example 8 differs from Example 1 in that in Step VI, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240 rpm for 150 min, aged for 8.0 h, then 2wt% of the monatomic modified synergistic coagulant aid of Preparation Example 1 is added, ultrasonically dispersed at ultrasonic frequency of 44 kHz and ultrasonic power of 1000 W for 120 min, aged for 12 h, the solid powder obtained is vacuum dried, the vacuum drying temperature is 85°C, the air pressure is controlled at 0.01-0.1 Pa, the vacuum drying time is 6.0 h, 0.2wt% of active silicic acid is mixed into the solid product, ground and sieved to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0071] Example 9 differs from Example 1 in that in Step VI, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240 rpm for 150 min, aged for 8.0 h, then 1wt% of the monatomic modified synergistic coagulant in Preparation Example 2 is added, ultrasonically dispersed at ultrasonic frequency of 44 kHz and ultrasonic power of 1000 W for 120 min, aged for 12 h, the solid powder obtained is vacuum dried, the vacuum drying temperature is 85°C, the air pressure is controlled at 0.01-0.1 Pa, the vacuum drying time is 6.0 h, 0.2wt% of active silicic acid is mixed into the solid product, ground and sieved to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0072] Example 10 differs from Example 1 in that in Step VI, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240 rpm for 150 min, aged for 8.0 h, then 1wt% of the monatomic modified synergistic coagulant in Preparation Example 3 is added, ultrasonically dispersed at ultrasonic frequency of 44 kHz and ultrasonic power of 1000 W for 120 min, aged for 12 h, the solid powder obtained is vacuum dried, the vacuum drying temperature is 85°C, the air pressure is controlled at 0.01-0.1 Pa, the vacuum drying time is 6.0 h, 0.2wt% of active silicic acid is mixed into the solid product, ground and sieved to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0073] Example 11 differs from Example 2 in that in Step VI, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum titanium chloride, stirred at 240 rpm for 150 min, aged for 8 h, then 1wt% of the monatomic modified synergistic coagulant in Preparation Example 1 is added, ultrasonically dispersed at ultrasonic frequency of 44 kHz and ultrasonic power of 1000 W for 120 min, aged for 12 h, the solid powder obtained is vacuum dried, the vacuum drying temperature is 85°C, the air pressure is controlled at 0.01-0.1 Pa, the vacuum drying time is 6.0 h, ground and sieved to obtain polyaluminum titanium chloride composite material with particle size of 200-500 mesh.

[0074] Example 12 differs from Example 2 in that in Step six, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirring at 240rpm for 150min, aging for 8.0h, then adding 0.5wt% of the monatomic modified synergistic coagulant in Preparation Example 1, 0.3wt% of the monatomic modified synergistic coagulant in Preparation Example 2, 0.2wt% of the monatomic modified synergistic coagulant in Preparation Example 3, ultrasonic dispersion at 44kHz, 1000W for 120min, then aging for 12h, vacuum drying the obtained solid powder, vacuum drying temperature 85℃, air pressure controlled at 0.01-0.1Pa, vacuum drying time 6.0h, mixing 0.3wt% of active silicic acid in the obtained solid, grinding and sieving to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0075] Comparative Example 1 differs from Example 1 in that the method for preparing polyaluminum chloride composite material from polyaluminum chloride water treatment agent waste residue is as follows.

[0076] Step one, the solid-liquid mixture containing polyaluminum chloride water treatment agent waste residue is placed in a solid-liquid separator for solid-liquid separation treatment, the obtained wastewater is input into the sewage pipe, the obtained solid is dried to a water content of less than 5%, then placed in a cement crusher for crushing treatment, the obtained granules are sieved using a 50 mesh sieve, the sieve residue is the residue powder with particle size <50 mesh, which is placed in a conical ball mill for grinding treatment, then sieved using a 300 mesh and a 500 mesh sieve to obtain residue powder with particle size of 300-500 mesh;

[0077] Step two, 10 parts of the residue powder obtained in Step one is mixed with 70 parts of tap water at 150rpm for 30min, then 0.35mol / L hydrochloric acid aqueous solution is added, the pH value of the system is adjusted to 3.4-3.5, then stirring is continued at 150rpm for 5.5h, and the system is left to stand for 18.5h, the upper clear liquid is filtered for next step, the obtained solid-liquid waste residue is subjected to solid-liquid separation treatment, the obtained wastewater is input into the sewage pipe, and the separated solid is dried and crushed for use as cement admixture;

[0078] Step three, 0.35mol / L sodium hydroxide aqueous solution is added to the upper clear liquid obtained in Step three at 150rpm, the pH value of the system is adjusted to 12.7-12.8, then the system is heated to 85℃ for 10min, cooled to room temperature, left to stand for 10.0h, the upper clear liquid is filtered for next step, and the obtained solid-liquid mixture rich in metal impurities is subjected to solid-liquid separation treatment, the obtained wastewater is input into the sewage pipe, and the separated solid waste residue rich in heavy metals is dried, crushed and sieved for recycling;

[0079] Step four, the bauxite in the supernatant obtained in step four, the mass ratio of the supernatant and the bauxite is 10:1, 0.80 mol / L hydrochloric acid aqueous solution is added under the rotation speed of 160 rpm, the pH value is 3.6-3.7, and then the polymerization reaction is carried out at 80℃ for 8 h, and the supernatant is obtained after standing for 12 h, which is a polyaluminum chloride-containing aqueous solution;

[0080] Step five, the polyaluminum chloride-containing aqueous solution is stirred at the rotation speed of 240 rpm for 150 min, and is aged for 8.0 h, the solid powder obtained by reduced pressure filtration is subjected to vacuum drying treatment, the vacuum drying temperature is 85℃, the air pressure is controlled to be 0.01-0.1 Pa, the vacuum drying time is 6.0 h, and the polyaluminum chloride composite material with a particle size of 325 mesh is obtained by grinding and screening.

[0081] The difference between Comparative Example 2 and Comparative Example 1 lies in that: in step five, 2wt% of cationic polyacrylamide is added to the polyaluminum chloride-containing aqueous solution, which is stirred at the rotation speed of 240 rpm for 150 min, and is aged for 8.0 h, and the solid powder obtained by reduced pressure filtration is subjected to vacuum drying treatment, the vacuum drying temperature is 85℃, the air pressure is controlled to be 0.01-0.1 Pa, the vacuum drying time is 6.0 h, and the polyaluminum chloride composite material with a particle size of 325 mesh is obtained by grinding and screening.

[0082] The difference between Comparative Example 3 and Example 5 lies in that: in step six, 2wt% of cationic polyacrylamide is added to the polyaluminum chloride-containing aqueous solution, which is stirred at the rotation speed of 240 rpm for 150 min, and is aged for 8.0 h, then 0.5wt% of mixed crystal titanium dioxide is added, ultrasonic dispersion is carried out at the ultrasonic frequency of 44 kHz and the ultrasonic power of 1000 W for 120 min, and then the solid powder obtained by reduced pressure filtration is subjected to vacuum drying treatment, the vacuum drying temperature is 85℃, the air pressure is controlled to be 0.01-0.1 Pa, the vacuum drying time is 6.0 h, and the polyaluminum chloride composite material with a particle size of 200-500 mesh is obtained by grinding and screening.

[0083] The difference between Comparative Example 4 and Example 5 lies in that: in step six, 2wt% of cationic polyacrylamide is added to the polyaluminum chloride-containing aqueous solution, which is stirred at the rotation speed of 240 rpm for 150 min, and is aged for 8.0 h, then 0.5wt% of halloysite nanotubes is added, ultrasonic dispersion is carried out at the ultrasonic frequency of 44 kHz and the ultrasonic power of 1000 W for 120 min, and then the solid powder obtained by reduced pressure filtration is subjected to vacuum drying treatment, the vacuum drying temperature is 85℃, the air pressure is controlled to be 0.01-0.1 Pa, the vacuum drying time is 6.0 h, and the polyaluminum chloride composite material with a particle size of 200-500 mesh is obtained by grinding and screening.

[0084] Comparative Example 5 differs from Example 5 in that in Step 6, 2wt% of cationic polyacrylamide is added to the aqueous solution containing polyaluminum chloride, stirred at 240rpm for 150min, aged for 8.0h, then 0.5wt% of graphene is added, ultrasonic dispersed at ultrasonic frequency of 44kHz and ultrasonic power of 1000W for 120min, aged for 12h, the obtained solid powder is vacuum dried at 85℃, the gas pressure is controlled at 0.01-0.1Pa, the vacuum drying time is 6.0h, ground and sieved to obtain polyaluminum chloride composite material with particle size of 200-500 mesh.

[0085] Comparative Example 6 is a polyaluminum chloride water purification composite material composed of polyaluminum chloride and cationic polyacrylamide flocculant in a mass ratio of 3:1.

[0086] Performance test: The simulated wastewater is prepared by using kaolin, KH2PO4 and tap water, the mass concentration of KH2PO4 is 4.4mg / L, the turbidity is about 42.0NTU, and the pH value is 7.88. In the flocculation beaker test, 500mL of the target water sample is added to the beaker, 15g of the polyaluminum chloride water purification composite material is added thereto under rapid stirring (300r / min), then rapid stirring (300r / min) is carried out for 1min, slow stirring (70r / min) is carried out for 15min, and standing and sedimentation is carried out for 30min, the turbidity and TP concentration are measured at 2-3cm below the liquid surface, and the turbidity removal rate and phosphorus removal rate of the polyaluminum chloride water purification composite material are calculated. The domestic wastewater in a certain sewage plant is selected, the humic acid concentration is preferably 32-35mg / L, the polyaluminum chloride water purification composite material in Examples 1-30 and Comparative Examples 1-8 is added at 15g / L, stirred at 250rpm for 15s, stirred at 150rpm for 8min, and stirred at 60rpm for 18min, the humic acid concentration is tested, and the humic acid removal rate is calculated. The algae-containing river water has a turbidity of 41.4NTU and a Chl-a content of 63.6μg / L. The treatment method is as follows: the algae-containing raw water is pumped to the coagulation reaction chamber by using a self-priming centrifugal pump, the polyaluminum chloride water purification composite material in Examples 1-30 and Comparative Examples 1-8 is added to the coagulation reaction chamber, the contact chamber is fully contacted with the dissolved air water, and then enters the separation chamber for separation, and the Chl-a content is tested, i.e. the algae removal rate.

[0087] Table 1 is a test parameter table of the polyaluminum chloride composite material in Examples 1-12 and Comparative Examples 1-5

[0088]

[0089] It can be seen from the combination of Example 1 and Comparative Examples 1-2 and Table 1 that the polyaluminum chloride composite material obtained by the preparation method in the present application has good flocculation performance, which is comparable to the performance of commercially available cationic polyacrylamide / polyaluminum chloride water purification composite material.

[0090] It can be seen from the combination of Examples 1-12 and Comparative Examples 1-5 and Table 1 that the addition of active silicic acid has a positive effect on the comprehensive performance of the polyaluminum chloride composite material.

[0091] It can be seen from the combination of Example 1 and Example 2 and Table 1 that the polyaluminum chloride composite material prepared using the polyaluminum titanium chloride filtrate has relatively optimal comprehensive performance.

[0092] It can be seen from the combination of Example 1, Examples 5-12 and Comparative Examples 3-5 and Table 1 that the addition of single-atom modified synergistic coagulant can improve the flocculation performance of the polyaluminum chloride composite material, while also imparting good antibacterial and algae removal performance.

[0093] It can be seen from the combination of Example 2, 12 and Comparative Examples 3-5 and Table 1 that the use of the single-atom modified synergistic coagulant in Preparation Examples 1-3, i.e., the use of a mixture of the three, can improve the flocculation performance and antibacterial and algae removal performance of the polyaluminum chloride composite material.

[0094] In summary, the present application conducts secondary development and utilization of aluminum-containing waste residues generated during the wastewater treatment process, extracts aluminum resources from the aluminum-containing waste residues for the production of polyaluminum chloride composite materials, improves resource utilization, and conforms to the sustainable green development trend.

[0095] The specific embodiments are merely an explanation of the present application and are not a limitation of the present application. Those skilled in the art can make modifications to the embodiments without creative contribution after reading the present specification, as long as the modifications are within the scope of the claims of the present application and are protected by the patent law.

Claims

1. A method for preparing polyaluminum chloride composite materials using waste residue from polyaluminum chloride water treatment agents, characterized in that: Includes the following steps: Step 1: The solid-liquid mixture containing polyaluminum chloride water treatment agent waste residue is placed in a solid-liquid separator for solid-liquid separation treatment. The resulting wastewater is fed into the sewage pipe, and the resulting solid is dried, crushed, and screened to obtain slag powder particles with a particle size of <50 mesh. Step 2: The obtained slag powder particles are calcined at 400-650℃ for 1-3 hours, and then ground and sieved to obtain 300-800 mesh pretreated slag powder; Step 3: Mix 10 parts of the pretreated slag powder obtained in Step 2 with 40-100 parts of tap water evenly, maintain at 80-200 rpm, add 0.1-0.5 mol / L hydrochloric acid aqueous solution, adjust the pH value to 2.8-3.5, and continue stirring at 80-200 rpm for 4-8 hours. Let stand for 12-24 hours, filter and take the supernatant for the next step of treatment. After solid-liquid separation treatment, the obtained solid waste is sent into the sewage pipe, and the obtained solid is dried, crushed and used as cement admixture. Step 4: At a speed of 80-200 rpm, add 0.1-0.5 mol / L sodium hydroxide aqueous solution to the supernatant obtained in Step 3, adjust the pH value to 12-13, raise the temperature to 80-98℃ and maintain it for 5-15 minutes, cool it to room temperature, let it stand for 6-12 hours, filter and take the supernatant for the next step of processing, the resulting solid-liquid mixture rich in metal impurities is subjected to solid-liquid separation treatment, the resulting wastewater is sent into the sewage pipeline, and the resulting solid waste residue rich in heavy metals is dried, crushed, screened and recycled. Step 5: Add an aluminum source and a titanium source to the supernatant obtained in Step 4. The aluminum source is bauxite and / or calcium aluminate powder, and the titanium source is a 0.05-0.2 mol / L titanium tetrachloride aqueous solution. The mass ratio of the aluminum source to the supernatant is 100:(8-12), and the mass ratio of the titanium tetrachloride aqueous solution to the supernatant is 100:(1-3). Add a 0.8-1.0 mol / L hydrochloric acid aqueous solution at 160-200 rpm. After the pH value is 3.6-3.8, raise the temperature to 80-85℃ to carry out the polymerization reaction to obtain an aqueous solution containing polyaluminum chloride. Step 6: Add at least 1-3 wt% cationic polyacrylamide to the aqueous solution containing polyaluminum chloride, stir at 240-320 rpm for 2-3 hours, and mature for 6-8 hours. Then add 0.5-2 wt% single-atom modified synergist, ultrasonically disperse for 1-2 hours, and mature for 8-12 hours. Filter the resulting solid powder under reduced pressure and vacuum dry at 60-90℃, 0.01-0.1 Pa, and for 6-8 hours. Mix 0.1... -0.5wt% active silica is ground and sieved to obtain a polyaluminum chloride composite material with a particle size of 200-500 mesh; the single-atom modified and synergistic coagulant includes an inorganic carrier and a metal single atom, wherein the metal single atom is anchored in the form of a single atom at the defect site on the surface of the inorganic carrier; the inorganic carrier is at least one of mixed crystal form titanium dioxide, halloysite, diatomite, kaolin, graphene, and carbon nanotubes; the metal single atom is at least one of Al, Fe, Cu, Co, Ce, and Ag.

2. The method for preparing polyaluminum chloride composite material using waste residue from polyaluminum chloride water treatment agent according to claim 1, characterized in that: In step three, 10 parts of the pretreated residue powder obtained in step two are mixed evenly with 60-80 parts of tap water. The mixture is stirred at 120-160 rpm, and 0.3-0.5 mol / L hydrochloric acid aqueous solution is added. The pH value is adjusted to 3.2-3.5, and the mixture is stirred at 120-160 rpm for 5-6 hours. The mixture is then allowed to stand for 18-24 hours, and the supernatant is filtered for further processing.

3. The method for preparing polyaluminum chloride composite materials using waste residue from polyaluminum chloride water treatment agents according to claim 1, characterized in that: In step four, at a speed of 120-160 rpm, add 0.3-0.5 mol / L sodium hydroxide aqueous solution to the supernatant obtained in step three, adjust the pH value to 12.4-12.8, raise the temperature to 80-85℃ and maintain it for 10-15 min, cool it to room temperature, let it stand for 10-12 h, filter and take the supernatant for the next step of processing.

4. The method for preparing polyaluminum chloride composite materials using waste residue from polyaluminum chloride water treatment agents according to claim 1, characterized in that: In step six, ultrasonic dispersion is performed for 100-120 minutes at an ultrasonic frequency of 34-60kHz and an ultrasonic power of 600-1200W.

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