Preparation method of polyaluminum chloride-based composite sewage treatment agent

Abstract

The application discloses a preparation method of a polyaluminum chloride-based composite sewage treatment agent, which is prepared from the following raw materials in parts by weight: 20-35 parts of polyaluminum chloride, 5-12 parts of slow-release microbial bacteria, 3-6 parts of modified activated carbon, 4-8 parts of modified attapulgite, 0.5-1.2 parts of cocamide propyl betaine and 2-5 parts of polyacrylamide. The preparation method comprises the following steps: uniformly mixing the polyaluminum chloride and the cocamide propyl betaine, then adding the modified activated carbon, the modified attapulgite and the polyacrylamide, uniformly stirring again, then adding the slow-release microbial bacteria, and finally stirring and drying to obtain the polyaluminum chloride-based composite sewage treatment agent. The polyaluminum chloride-based composite sewage treatment agent prepared by the method has the advantages of high efficiency in short time for removing nitrogen, phosphorus and heavy metals, good slow-release effect and good performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage material preparation, and particularly relates to a preparation method of a polyaluminum chloride-based composite sewage treatment agent. BACKGROUND

[0002] With the acceleration of global industrialization and urbanization, the amount of sewage discharge has increased dramatically, and water pollution has become a serious challenge to human health, ecological balance and sustainable development. The discharge of industrial and domestic sewage, excessive nitrogen and phosphorus indicators, and heavy metal pollution due to its concealment are still major problems, and there is a potential risk. Correspondingly, abnormal nitrogen and phosphorus indicators can easily cause water eutrophication and blue-green algae outbreak, and heavy metal pollution can directly harm human health. Therefore, water treatment is still an important and arduous task.

[0003] In existing research, there have been many reports on water treatment agents. According to the technical type, they can be divided into biological treatment technology, chemical oxidation treatment technology and physical treatment technology. The biological treatment technology mainly uses microorganisms to metabolize in aerobic or anaerobic, anaerobic environment to biodegrade and assimilate organic pollutants in water, effectively removing biodegradable organic matter, ammonia nitrogen, total phosphorus, nitrite and iron and manganese pollutants in water. Chemical oxidation technology is to use the oxidizing property of chemical oxidants to oxidize the pollutants in the polluted water to lose electrons, reduce the stability of organic matter and the interaction between them, and then oxidize and decompose them (such as potassium permanganate, chlorine, etc.), and gather into colloidal particles through the Tyndall effect, so as to achieve the purpose of degrading and removing pollutants. Physical treatment technology includes membrane separation technology, adsorption method, etc. In existing technology, there have been many application reports. For example, patent document CN108017129A provides a composite sewage treatment agent, which is prepared from the following raw materials by weight percentage: polyaluminum chloride 20-35wt%, polyferric chloride 15-20wt%, modified bentonite 10-20wt%, silica gel 10-15wt%, acrylic ester adhesive 3-5wt%, and the balance is modified zero-valent iron; It has the functions of decolorization, flocculation, COD and BOD removal, and the decolorization rate is extremely high, but the treatment of nitrogen, phosphorus and heavy metals needs to be improved, and the treatment does not have long-term effect.

[0004] For example, patent document CN102409035A provides a micro-ecological slow-release bacterial agent, which is a Bacillus subtilis microcapsule product, which mainly relies on microbial bacteria treatment, and has single effect.

[0005] For example, patent document CN115286063A provides a sewage treatment agent based on polyaluminum chloride, which is made from the following raw material components in parts by weight: polyaluminum chloride 40-70 parts, mineral powder 5-15 parts, dispersing agent 3-8 parts, absorbent 3-6 parts, shell ash 5-10 parts, crosslinking agent 3-5 parts, bactericide 3-5 parts; the mineral powder is a mixed mineral powder of sepiolite powder and leca stone powder mixed in a mass ratio of 1:1; the shell ash is a mixture of rice husk ash and millet skin ash in a mass ratio of 1:1. In the above scheme, polyaluminum chloride is used as the main active ingredient, and the mixed mineral powder of sepiolite powder and leca stone powder mixed in a mass ratio of 1:1 is added to significantly reduce the COD of sewage, and the mixture of rice husk ash and millet skin ash in a mass ratio of 1:1 is added to significantly reduce the SS in the sewage. However, its treatment effect still needs to be further improved.

[0006] Therefore, the present application hopes to provide a preparation method of a polyaluminum chloride-based composite sewage treatment agent. SUMMARY

[0007] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of a polyaluminum chloride-based composite sewage treatment agent, which has good short-time high-efficiency removal of nitrogen, phosphorus and heavy metals, good slow-release effect and good performance.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0009] Firstly, the present application provides a polyaluminum chloride-based composite sewage treatment agent, which is prepared from the following raw materials in parts by weight: 20-35 parts of polyaluminum chloride, 5-12 parts of slow-release microbial bacteria, 3-6 parts of modified activated carbon, 4-8 parts of modified attapulgite, 0.5-1.2 parts of cocamide propyl betaine, and 2-5 parts of polyacrylamide.

[0010] As a preferred technical scheme of the present application, the preparation of the modified activated carbon comprises the following steps:

[0011] S11, adding activated carbon to nitric acid and performing ultrasonic treatment under heating conditions, then washing and drying the treated activated carbon to obtain pre-modified activated carbon;

[0012] S12, adding the pre-modified activated carbon obtained in step S11 to water, then adding urea, stirring uniformly, and performing heating treatment, then drying and high-temperature treatment after the treatment is completed to obtain first modified activated carbon;

[0013] S13, adding the first modified activated carbon obtained in step S12 to ferric nitrate solution, stirring uniformly, then filtering and drying, and then performing calcination treatment under nitrogen protection, and the modified activated carbon is obtained after the treatment is completed.

[0014] As a preferred technical scheme of the present application, in step S11, the concentration of nitric acid is 4-6 mol / L, the heating temperature is 35-45 DEG C, the ultrasonic treatment power is 50-100 W, and the ultrasonic treatment time is 1-4 h; the amount ratio of activated carbon to nitric acid is 1 g:8-15 mL;

[0015] In step S12, the mass ratio of pre-modified activated carbon, water and urea is 1:10-20:0.8-1.2; the heating treatment temperature is 35-55 DEG C, and the treatment time is 12-36 h; the high-temperature treatment is carried out under nitrogen protection, the treatment temperature is 550-650 DEG C, and the treatment time is 1-4 h;

[0016] In step S13, the concentration of ferric nitrate solution is 5-10 wt%, the amount ratio of primary modified activated carbon to ferric nitrate solution is 1 g:15-30 mL, the calcination treatment temperature is 500-580 DEG C, and the treatment time is 1-4 h.

[0017] As a preferred technical scheme of the present application, the preparation of the slow-release microbial bacteria comprises the following steps:

[0018] S21, titanium dioxide is added into anhydrous ethanol, stirred and uniformly dispersed, then KH550 is added, and then refluxed under heating; then filtered, washed and dried to obtain a pretreated carrier;

[0019] S22, after coffee acid is dissolved in PBS buffer, then 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide are added, activated under stirring, then the pretreated carrier obtained in step S21 is added, and reacted under heating and stirring; after the reaction is completed, filtered, washed and dried to obtain a modified carrier;

[0020] S23, the mixed bacteria are added into the modified carrier obtained in step S22, then sodium alginate solution is added after stirring, then calcium chloride solution is slowly added after stirring again, and then freeze-dried to obtain slow-release microbial bacteria.

[0021] As a preferred technical scheme of the present application, in step S21, the amount ratio of titanium dioxide, anhydrous ethanol and KH550 is 1 g:5-10 mL:1-3 mL;

[0022] The reflux reaction temperature is 80-85 DEG C, and the reaction time is 8-16 h.

[0023] As a preferred technical scheme of the present application, in step S22, the amount ratio of coffee acid and PBS buffer is 1 mg:0.5-1 mL;

[0024] The mass ratio of the coffee acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxy succinimide, and the pretreated carrier is 1:0.8-1.2:0.3-0.5:1.5-2.5;

[0025] The activation temperature is 4 DEG C, and the activation time is 20-50 min;

[0026] The heating and stirring temperature is 40-55 DEG C, and the reaction time under heating and stirring is 3-6 h.

[0027] As a preferred technical solution of the present application, in step S23, the total number of viable bacteria of the mixed bacteria is not less than 1x10 10 CFU / g; the mixed bacteria are obtained by mixing nitrifying bacteria, Pseudomonas mendocina, and Bacillus subtilis at a viable bacteria number of 1:1:1.2;

[0028] The mass concentration of the sodium alginate solution is 1.5-3%, and the mass concentration of the calcium chloride solution is 5-10%.

[0029] The mass ratio of the modified carrier and the sodium alginate is 1:0.45-0.65.

[0030] As a preferred technical solution of the present application, the preparation of the modified palygorskite includes the following steps:

[0031] S31, the palygorskite is added into a hydrochloric acid solution, and is stirred under heating, after the treatment, the pretreated palygorskite is obtained through filtration, washing, and drying treatment;

[0032] S32, boric acid is added into anhydrous ethanol, and after stirring, a boric acid ethanol solution is obtained and is prepared for use; the pretreated palygorskite obtained in step S31 is added into the boric acid ethanol solution, and is stirred under heating, after the treatment, the modified palygorskite is obtained through filtration, washing, and drying treatment.

[0033] As a preferred technical solution of the present application, in step S31, the concentration of the hydrochloric acid solution is 5-10 wt%, and the dosage ratio of the palygorskite and the hydrochloric acid solution is 1 g:5-10 mL; the heating temperature is 40-55 DEG C, and the stirring treatment time is 1-4 h;

[0034] In step S32, the concentration of the boric acid ethanol solution is 0.05-0.1 g / mL; the dosage ratio of the pretreated palygorskite and the boric acid ethanol solution is 1 g:10-15 mL; the heating temperature is 55-70 DEG C, and the stirring treatment time is 5-20 min.

[0035] Secondly, the application further provides a preparation method of the polyaluminum chloride-based composite sewage treatment agent, comprising the following steps: uniformly mixing polyaluminum chloride and cocamide propyl betaine, then adding modified activated carbon, modified attapulgite and polyacrylamide, uniformly stirring again, then adding slow-release microbial bacteria, and finally stirring and drying to obtain the polyaluminum chloride-based composite sewage treatment agent.

[0036] Compared with the prior art, the application has the following beneficial effects:

[0037] The polyaluminum chloride-based composite sewage treatment agent provided by the application uses polyaluminum chloride as a main raw material, and is combined with modified activated carbon, modified attapulgite and slow-release microbial bacteria, so that the prepared water treatment agent has good effects of removing nitrogen, phosphorus and heavy metals, and good slow-release effect.

[0038] The activated carbon used in the polyaluminum chloride-based composite sewage treatment agent is a kind of good water treatment agent, and the activated carbon is modified in the application to further improve the treatment effect. Specifically, in the application, the activated carbon is first subjected to ultrasonic acid treatment, which is beneficial to further increase the specific surface area and increase the active groups, and is beneficial to the subsequent modification of urea and the loading of ferric nitrate; the urea modification is beneficial to improving the hydrophilicity of the activated carbon and improving the sewage treatment effect of the activated carbon; meanwhile, the introduction of nitrogen is beneficial to further improving the subsequent iron adsorption and improving the loading effect of iron; the ferric nitrate modified activated carbon is a relatively common modified material, and based on the ultrasonic acid treatment and nitrogen modification of the activated carbon, the sewage treatment effect of the activated carbon after iron modification can be effectively improved. The various modification steps of the activated carbon in the application cooperate with each other, so that the sewage treatment capacity of the modified activated carbon is greatly improved.

[0039] The slow-release microbial bacteria used in the polyaluminum chloride-based composite sewage treatment agent has a microcapsule structure, which ensures the long-acting property of sewage treatment. Specifically, in order to improve the use effect of the microbial bacteria, the modified carrier is used to adsorb and fix the microbial bacteria in the application, and then calcium chloride is used to solidify sodium alginate to form a wall material; the carrier is mainly titanium dioxide, which has a certain microbial adsorption property, and the adhesion effect of the complex microbial population is further improved by treating the carrier with KH550 and coffee acid in the application; the use of KH550 is beneficial to introducing an amino group, which can react with a carboxyl group in coffee acid under the activation of 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide; in addition, the introduced phenolic hydroxyl group (biomimetic adhesion interface) can improve the adsorption effect of the microbial bacteria, and the antioxidant property of coffee acid itself can reduce the oxidative stress of the microbial population to the external system, improve the adsorption strength, activity and action time of the microbial bacteria.

[0040] The polyaluminum chloride-based composite sewage treatment agent provided by the application uses palygorskite that is simply acid-treated and modified by boric acid, and the boric acid modification can form acid sites to improve the adsorption effect of water pollutants, and can also reduce the surface energy of the palygorskite to improve the compatibility of the palygorskite with other substances and promote the efficient compounding of the sewage treatment agent system.

[0041] The polyaluminum chloride-based composite sewage treatment agent provided by the application uses modified activated carbon, modified palygorskite and slow-release microbial bacteria, which can work together to achieve the best sewage treatment effect, specifically, the nitrogen substances adsorbed by the palygorskite are oxidized to nitrate by nitrobacteria, and the nitrogen substances adsorbed by the activated carbon are reduced to nitrogen by Pseudomonas mendocina; the macromolecules can be decomposed into small molecules by the photolysis of titanium dioxide, and the Bacillus subtilis can directly degrade and metabolize to avoid the accumulation of products; the activated carbon modified by nitrogen can act as an electron mediator, and the added Fe promotes the electron transfer between the microorganisms and promotes nitrification and denitrification; and the coffee acid introduced by the titanium dioxide can effectively shield the inhibition of heavy metals in the sewage on the microorganisms and improve the action time of the microbial flora. In summary, the above-mentioned substances work together to achieve very good sewage treatment effect.

[0042] In summary, the application can achieve very good treatment effect in 5 minutes by the synergistic use of the substances, and can efficiently treat ammonium ions, phosphate ions and heavy metals at the same time; and due to the use of slow-release microbial bacteria, long-term treatment effect can be achieved, so the application is suitable for both rapid sewage treatment and long-term treatment of flowing water bodies. DETAILED DESCRIPTION

[0043] The embodiments of the application are described in detail below, all of which are exemplary and are intended to explain the application, and cannot be understood as a limitation of the application.

[0044] In the embodiments of the application, the activated carbon is purchased from Chengde Tianyuan Activated Carbon Co., Ltd., and the particle size is about 150 μm;

[0045] The polyaluminum chloride is purchased from Shenzhen Qingyuan Water Purification Equipment Co., Ltd.;

[0046] The palygorskite is purchased from Junda Palygorskite Co., Ltd.;

[0047] The polyacrylamide is purchased from the National Pharmaceutical Group Chemical Reagent Co., Ltd.;

[0048] The nitrobacteria are Vibrio nitrificans, which are purchased from Beijing Bao Wei Biological Technology Co., Ltd.;

[0049] The Pseudomonas mendocina is purchased from Beijing Bao Wei Biological Technology Co., Ltd.;

[0050] Bacillus subtilis was purchased from Beijing Bao Bo Wei Biotechnology Co., Ltd.

[0051] 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, CAS number 1892-57-5, English abbreviation EDC;

[0052] N-hydroxysuccinimide, CAS number 6066-82-6, English abbreviation NHS.

[0053] It should be particularly pointed out that the parts mentioned in the following examples are all weight parts without special instructions, and the specific weights mentioned are only examples, which can be enlarged in proportion according to the needs in actual production.

[0054] Example 1

[0055] A polyaluminum chloride-based composite sewage treatment agent is prepared from the following raw materials by mass: 30 g of polyaluminum chloride, 8 g of slow-release microbial bacteria, 4 g of modified activated carbon, 5.5 g of modified attapulgite, 0.65 g of cocamide propyl betaine, and 2.5 g of polyacrylamide.

[0056] The preparation of the modified activated carbon comprises the following steps:

[0057] S11, according to the dosage ratio of 1 g:10 mL, the activated carbon is added to 5 mol / L nitric acid, and ultrasonic treatment (80 W, 2 h) is carried out under heating conditions (40℃), after the treatment, after washing and drying treatment, the pre-modified activated carbon is obtained;

[0058] S12, the pre-modified activated carbon obtained in step S11 is added to water, and then urea is added, and after stirring, heating treatment (40℃, 16h) is carried out, after the treatment, after drying and high temperature treatment (nitrogen protection, 600℃, 1.5h), the first modified activated carbon is obtained; wherein the mass ratio of pre-modified activated carbon, water and urea is 1:15:1;

[0059] S13, according to the dosage ratio of 1 g:20 mL, the first modified activated carbon obtained in step S12 is added to 8wt% iron nitrate solution, after stirring, filtration and drying treatment, and then calcination treatment (520℃, 2h) is carried out under nitrogen protection, after the treatment, the modified activated carbon is obtained.

[0060] The preparation of the slow-release microbial bacteria comprises the following steps:

[0061] S21, titanium dioxide is added to anhydrous ethanol, stirred and dispersed uniformly, then KH550 is added, and then reflux reaction (85℃, 10h) is carried out under heating conditions; then after filtration, washing and drying treatment, the pretreated carrier is obtained; wherein the dosage ratio of titanium dioxide, anhydrous ethanol and KH550 is 1 g:6 mL:2 mL.

[0062] S22, according to 1mg:0.8mL, after the caffeic acid is dissolved in PBS buffer, then 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide are added, and activation is carried out under stirring conditions (4℃, 30min), then the pretreated carrier obtained in step S21 is added, and reaction is carried out under heating and stirring conditions (45℃, 4h); after the reaction is completed, filtration, washing and drying treatment are carried out, and a modified carrier is obtained; wherein the mass ratio of caffeic acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxysuccinimide and pretreated carrier is 1:1:0.4:2;

[0063] S23, mixed bacteria (total viable bacteria number is 1×10 10 CFU / g, obtained by mixing nitrifying bacteria, Pseudomonas mendocina and Bacillus subtilis according to viable bacteria number 1:1:1.2) are added to the modified carrier obtained in step S22, 2wt% sodium alginate solution is added after stirring, and 8wt% calcium chloride solution is slowly added after stirring again, and then freeze-drying treatment is carried out, to obtain slow-release microbial bacteria; wherein the mass ratio of modified carrier and sodium alginate is 1:0.55.

[0064] Preparation of the modified attapulgite includes the following steps:

[0065] S31, according to the dosage ratio of 1g:8mL, attapulgite is added to 8wt% hydrochloric acid solution, and stirring treatment is carried out under heating conditions (45℃, 3h); after the treatment is completed, filtration, washing and drying treatment are carried out, to obtain pretreated attapulgite;

[0066] S32, boric acid is added to anhydrous ethanol, and stirring is carried out, to obtain boric acid ethanol solution (concentration is 0.08m / mL), which is used for standby; according to the dosage ratio of 1g:12mL, the pretreated attapulgite obtained in step S31 is added to the boric acid ethanol solution, and stirring treatment is carried out under heating conditions (60℃, 15min); after the treatment is completed, filtration, washing and drying treatment are carried out, to obtain modified attapulgite.

[0067] In the embodiment, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, which includes the following steps: polyaluminum chloride and cocamide propyl betaine are uniformly mixed, then modified activated carbon, modified attapulgite and polyacrylamide are added, stirring is carried out again, then slow-release microbial bacteria are added, and finally stirring and drying treatment are carried out, to obtain the product.

[0068] Example 2

[0069] A polyaluminum chloride-based composite sewage treatment agent is prepared from the following raw materials by mass: 30 g of polyaluminum chloride, 7.5 g of slow-release microbial bacteria, 4.5 g of modified activated carbon, 5 g of modified attapulgite, 0.6 g of cocamide propyl betaine, and 2.2 g of polyacrylamide.

[0070] The preparation of the modified activated carbon comprises the following steps:

[0071] S11, the activated carbon is added to 5 mol / L nitric acid at a dosage ratio of 1 g:10 mL, and ultrasonic treatment (80 W, 1.5 h) is performed under heating conditions (40℃); after the treatment is completed, the pre-modified activated carbon is obtained by washing and drying treatment;

[0072] S12, the pre-modified activated carbon obtained in step S11 is added to water, and then urea is added; after stirring, heating treatment (45℃, 12 h) is performed; after the treatment is completed, the modified activated carbon is obtained by drying and high-temperature treatment (nitrogen protection, 600℃, 1 h); the mass ratio of the pre-modified activated carbon, water and urea is 1:12:1;

[0073] S13, the modified activated carbon obtained in step S12 is added to an 8wt% iron nitrate solution at a dosage ratio of 1 g:20 mL; after stirring, the modified activated carbon is obtained by filtering, drying treatment, and then calcination treatment (530℃, 1.5 h) under nitrogen protection.

[0074] The preparation of the slow-release microbial bacteria comprises the following steps:

[0075] S21, titanium dioxide is added to anhydrous ethanol, and stirred to disperse uniformly; then KH550 is added, and reflux reaction (85℃, 10 h) is performed under heating conditions; then the pretreated carrier is obtained by filtering, washing and drying treatment; the dosage ratio of titanium dioxide, anhydrous ethanol and KH550 is 1 g:7 mL:2 mL;

[0076] S22, coffee acid is dissolved in PBS buffer at a dosage ratio of 1 mg:0.75 mL; then 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide are added; activation is performed under stirring conditions (4℃, 25 min); then the pretreated carrier obtained in step S21 is added; reaction is performed under heating and stirring conditions (45℃, 4 h); after the reaction is completed, the modified carrier is obtained by filtering, washing and drying treatment; the mass ratio of coffee acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxysuccinimide and the pretreated carrier is 1:1:0.4:2;

[0077] S23, the mixed bacteria (total number of viable bacteria is 1×10 10CFU / g, obtained by mixing nitrifying bacillus, Pseudomonas mendocina and Bacillus subtilis at a ratio of 1:1:1.2 by viable cell number) is added to the modified carrier obtained in step S22, stirred, and then 2wt% sodium alginate solution is added, stirred again, and then 8wt% calcium chloride solution is slowly added, and after freezing and drying treatment, a slow-release microbial bacteria is obtained; wherein the mass ratio of the modified carrier and sodium alginate is 1:0.6.

[0078] The preparation of the modified attapulgite includes the following steps:

[0079] S31, attapulgite is added to 7wt% hydrochloric acid solution at a dosage ratio of 1g:8mL, and stirred under heating conditions (45℃, 3h), after treatment, filter, wash and dry to obtain pretreated attapulgite;

[0080] S32, boric acid is added to anhydrous ethanol, stirred to obtain a boric acid ethanol solution (concentration of 0.08m / mL), and used as needed; pretreated attapulgite obtained in step S31 is added to the boric acid ethanol solution at a dosage ratio of 1g:12mL, and stirred under heating conditions (60℃, 10min), after treatment, filter, wash and dry to obtain modified attapulgite.

[0081] In this embodiment, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, which includes the following steps: polyaluminum chloride and cocamide propyl betaine are uniformly mixed, then modified activated carbon, modified attapulgite, and polyacrylamide are added, stirred again, then slow-release microbial bacteria is added, and finally stirred and dried to obtain the product.

[0082] Example 3

[0083] A polyaluminum chloride-based composite sewage treatment agent is prepared from the following raw materials by mass: 30g polyaluminum chloride, 8.5g slow-release microbial bacteria, 3.5g modified activated carbon, 6g modified attapulgite, 0.6g cocamide propyl betaine, and 2g polyacrylamide.

[0084] The preparation of the modified activated carbon includes the following steps:

[0085] S11, activated carbon is added to 5.5mol / L nitric acid at a dosage ratio of 1g:12mL, and ultrasonic treatment (100W, 1h) is carried out under heating conditions (40℃), after treatment, washed and dried to obtain pretreated activated carbon;

[0086] S12, the pre-modified activated carbon obtained in step S11 is added to water, then urea is added, and after stirring, heating treatment (45℃, 12h) is performed, and after the treatment is completed, drying and high-temperature treatment (nitrogen protection, 600℃, 1.5h) are performed, to obtain a first modified activated carbon; wherein the mass ratio of the pre-modified activated carbon, water and urea is 1:15:1;

[0087] S13, the first modified activated carbon obtained in step S12 is added to a 9wt% iron nitrate solution according to the amount ratio of 1g:18mL, and after stirring, filtration and drying treatment, calcination treatment (520℃, 2h) is performed under nitrogen protection, and after the treatment is completed, the modified activated carbon is obtained.

[0088] The preparation of the slow-release microbial bacteria includes the following steps:

[0089] S21, titanium dioxide is added to anhydrous ethanol, stirred and dispersed uniformly, then KH550 is added, and then reflux reaction is performed under heating conditions (85℃, 10h); and then filtration, washing and drying treatment are performed, to obtain a pretreated carrier; wherein the amount ratio of titanium dioxide, anhydrous ethanol and KH550 is 1g:6mL:2mL;

[0090] S22, according to 1mg:0.8mL, coffee acid is dissolved in PBS buffer, then 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide are added, and activation is performed under stirring conditions (4℃, 30min), then the pretreated carrier obtained in step S21 is added, and reaction is performed under heating and stirring conditions (45℃, 4h); after the reaction is completed, filtration, washing and drying treatment are performed, to obtain a modified carrier; wherein the mass ratio of coffee acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxysuccinimide and the pretreated carrier is 1:1:0.4:2;

[0091] S23, mixed bacteria (total viable bacteria number is 1×10 10 CFU / g, obtained by mixing nitrifying bacteria, Pseudomonas mendocina and Bacillus subtilis according to the viable bacteria number of 1:1:1.2) are added to the modified carrier obtained in step S22, 2wt% sodium alginate solution is added after stirring, 8wt% calcium chloride solution is slowly added after stirring again, and then freeze-drying treatment is performed, to obtain slow-release microbial bacteria; wherein the mass ratio of the modified carrier and sodium alginate is 1:0.55.

[0092] The preparation of the modified attapulgite includes the following steps:

[0093] S31, add attapulgite to 8wt% hydrochloric acid solution according to the dosage ratio of 1g:8mL, stir under heating condition (45℃, 3h), after treatment, filter, wash, dry to get pretreated attapulgite;

[0094] S32, add boric acid to anhydrous ethanol, stir to get boric acid ethanol solution (concentration of 0.07m / mL), ready for use; add pretreated attapulgite obtained in step S31 to the boric acid ethanol solution according to the dosage ratio of 1g:10mL, stir under heating condition (65℃, 12min), after treatment, filter, wash, dry to get modified attapulgite.

[0095] In the embodiment, a preparation method of the polyaluminum chloride-based composite sewage treatment agent is also provided, which comprises the following steps: uniformly mixing polyaluminum chloride and cocamide propyl betaine, then adding modified activated carbon, modified attapulgite, and polyacrylamide, uniformly stirring again, then adding slow-release microbial bacteria, and finally stirring and drying to obtain the polyaluminum chloride-based composite sewage treatment agent.

[0096] Comparative Example 1

[0097] Comparative Example 1 is the same as Example 1 except that step S12 is omitted. Specifically, in the comparative example, a polyaluminum chloride-based composite sewage treatment agent is provided, which is prepared from the following raw materials by mass: 30g polyaluminum chloride, 8g slow-release microbial bacteria, 4g modified activated carbon, 5.5g modified attapulgite, 0.65g cocamide propyl betaine, and 2.5g polyacrylamide.

[0098] The preparation of the modified activated carbon comprises the following steps:

[0099] S11, add activated carbon to 5mol / L nitric acid according to the dosage ratio of 1g:10mL, and perform ultrasonic treatment (80W, 2h) under heating condition (40℃), after treatment, wash and dry to obtain pretreated activated carbon;

[0100] S12, add the pretreated activated carbon obtained in step S12 to 8wt% ferric nitrate solution according to the dosage ratio of 1g:20mL, stir uniformly, then filter and dry, and then perform calcination treatment (520℃, 2h) under nitrogen protection, after treatment, obtain modified activated carbon.

[0101] The preparation of the slow-release microbial bacteria comprises the following steps:

[0102] S21, add titanium dioxide into anhydrous ethanol, stir to disperse uniformly, then add KH550, and then reflux under heating conditions (85℃, 10h); then filter, wash, and dry to obtain a pretreated carrier; wherein the amount ratio of titanium dioxide, anhydrous ethanol, and KH550 is 1g:6mL:2mL;

[0103] S22, according to 1mg:0.8mL, dissolve caffeic acid in PBS buffer, then add 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide, activate under stirring conditions (4℃, 30min), then add the pretreated carrier obtained in step S21, and react under heating and stirring conditions (45℃, 4h); after the reaction is completed, filter, wash, and dry to obtain a modified carrier; wherein the mass ratio of caffeic acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxysuccinimide, and the pretreated carrier is 1:1:0.4:2;

[0104] S23, add mixed bacteria (total viable bacteria number is 1×10 10 CFU / g, obtained by mixing nitrifying bacteria, Pseudomonas mendocina, and Bacillus subtilis according to a viable bacteria number of 1:1:1.2) into the modified carrier obtained in step S22, stir, then add 2wt% sodium alginate solution, stir again, then slowly add 8wt% calcium chloride solution, and then freeze-dry to obtain a slow-release microbial bacteria; wherein the mass ratio of the modified carrier and sodium alginate is 1:0.55.

[0105] Preparation of the modified attapulgite includes the following steps:

[0106] S31, according to the amount ratio of 1g:8mL, add attapulgite into 8wt% hydrochloric acid solution, stir under heating conditions (45℃, 3h), after the treatment is completed, filter, wash, and dry to obtain pretreated attapulgite;

[0107] S32, add boric acid into anhydrous ethanol, stir to obtain a boric acid ethanol solution (concentration is 0.08m / mL), and reserve; according to the amount ratio of 1g:12mL, add the pretreated attapulgite obtained in step S31 into the boric acid ethanol solution, stir under heating conditions (60℃, 15min), after the treatment is completed, filter, wash, and dry to obtain modified attapulgite.

[0108] In the present comparative example, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, including the following steps: uniformly mix polyaluminum chloride and cocamide propyl betaine, then add modified activated carbon, modified attapulgite, and polyacrylamide, stir again, then add slow-release microbial bacteria, and finally stir and dry to obtain.

[0109] Comparative Example 2

[0110] Comparative Example 2 is the same as Example 1 except that step S22 is omitted. Specifically, in the present comparative example, a polyaluminum chloride-based composite sewage treatment agent is prepared from the following raw materials by mass: 30 g of polyaluminum chloride, 8 g of slow-release microbial bacteria, 4 g of modified activated carbon, 5.5 g of modified attapulgite, 0.65 g of cocamide propyl betaine, and 2.5 g of polyacrylamide.

[0111] The preparation of the modified activated carbon comprises the following steps:

[0112] S11, under heating conditions (40°C), the activated carbon is added to 5 mol / L nitric acid and ultrasonically treated (80W, 2h). After treatment, the pre-modified activated carbon is obtained by washing and drying.

[0113] S12, the pre-modified activated carbon obtained in step S11 is added to water, and then urea is added. After stirring, the mixture is heated (40°C, 16h). After treatment, the first modified activated carbon is obtained by drying and high-temperature treatment (nitrogen protection, 600°C, 1.5h). The mass ratio of the pre-modified activated carbon, water, and urea is 1:15:1.

[0114] S13, according to the dosage ratio of 1g:20mL, the first modified activated carbon obtained in step S12 is added to an 8wt% iron nitrate solution. After stirring, the mixture is filtered, dried, and then calcined under nitrogen protection (520°C, 2h). The modified activated carbon is obtained after treatment.

[0115] The preparation of the slow-release microbial bacteria comprises the following steps:

[0116] S21, titanium dioxide is added to anhydrous ethanol, stirred and dispersed uniformly, and then KH550 is added. After refluxing under heating conditions (85°C, 10h), the pretreated carrier is obtained by filtering, washing, and drying. The dosage ratio of titanium dioxide, anhydrous ethanol, and KH550 is 1g:6mL:2mL.

[0117] S22, mixed bacteria (total viable bacteria number is 1×10 10 CFU / g, obtained by mixing nitrifying bacteria, Pseudomonas mendocina, and Bacillus subtilis at a viable bacteria number of 1:1:1.2) are added to the pretreated carrier obtained in step S21. After stirring, 2wt% sodium alginate solution is added, and then 8wt% calcium chloride solution is slowly added. After freeze-drying, the slow-release microbial bacteria are obtained. The mass ratio of the pretreated carrier and sodium alginate is 1:0.55.

[0118] The preparation of the modified attapulgite includes the following steps:

[0119] S31, attapulgite is added to an 8wt% hydrochloric acid solution in a ratio of 1g:8mL, and stirred under heating conditions (45℃, 3h). After the treatment is completed, the pretreated attapulgite is obtained by filtration, washing, and drying treatment;

[0120] S32, boric acid is added to anhydrous ethanol, and stirred to obtain a boric acid ethanol solution (concentration of 0.08m / mL) for standby use. The pretreated attapulgite obtained in step S31 is added to the boric acid ethanol solution in a ratio of 1g:12mL, and stirred under heating conditions (60℃, 15min). After the treatment is completed, the modified attapulgite is obtained by filtration, washing, and drying treatment.

[0121] In the present comparative example, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, which includes the following steps: polyaluminum chloride and cocamide propyl betaine are uniformly mixed, and then modified activated carbon, modified attapulgite, and polyacrylamide are added. After being stirred again, slow-release microbial bacteria are added. Finally, after stirring and drying treatment, the polyaluminum chloride-based composite sewage treatment agent is obtained.

[0122] Comparative Example 3

[0123] Compared with Example 1, step S32 is omitted in Comparative Example 3, and the rest are the same. Specifically, in the present comparative example, a polyaluminum chloride-based composite sewage treatment agent is provided, which is prepared from the following raw materials by mass: 30g polyaluminum chloride, 8g slow-release microbial bacteria, 4g modified activated carbon, 5.5g modified attapulgite, 0.65g cocamide propyl betaine, and 2.5g polyacrylamide.

[0124] The preparation of the modified activated carbon includes the following steps:

[0125] S11, activated carbon is added to 5mol / L nitric acid in a ratio of 1g:10mL, and ultrasonic treatment (80W, 2h) is performed under heating conditions (40℃). After the treatment is completed, the pretreated activated carbon is obtained by washing and drying treatment;

[0126] S12, the pretreated activated carbon obtained in step S11 is added to water, and then urea is added. After being stirred uniformly, heating treatment (40℃, 16h) is performed. After the treatment is completed, the first modified activated carbon is obtained by drying and high-temperature treatment (nitrogen protection, 600℃, 1.5h). The mass ratio of the pretreated activated carbon, water, and urea is 1:15:1;

[0127] S13, according to the amount ratio 1g:20mL, the primary modified activated carbon obtained in step S12 is added into 8wt% iron nitrate solution, after stirring uniformly, it is filtered, dried and treated, then it is calcined under nitrogen protection (520℃, 2h), after the treatment is completed, the modified activated carbon is obtained.

[0128] The preparation of the slow-release microbial bacteria includes the following steps:

[0129] S21, the titanium dioxide is added into anhydrous ethanol, after stirring and dispersing uniformly, the KH550 is added, then the reflux reaction is carried out under heating condition (85℃, 10h), then it is filtered, washed and dried to obtain the pretreated carrier; wherein the amount ratio of the titanium dioxide, the anhydrous ethanol and the KH550 is 1g:6mL:2mL;

[0130] S22, according to the amount ratio 1mg:0.8mL, the caffeic acid is dissolved in PBS buffer, then the 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and the N-hydroxysuccinimide are added, the activation is carried out under stirring condition (4℃, 30min), then the pretreated carrier obtained in step S21 is added, the reaction is carried out under heating and stirring condition (45℃, 4h), after the reaction is completed, it is filtered, washed and dried to obtain the modified carrier; wherein the mass ratio of the caffeic acid, the 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, the N-hydroxysuccinimide and the pretreated carrier is 1:1:0.4:2;

[0131] S23, the mixed bacteria (the total number of viable bacteria is 1×10 10 CFU / g, which is obtained by mixing the nitrifying bacteria, the Pseudomonas mendocina and the Bacillus subtilis according to the number of viable bacteria 1:1:1.2) is added into the modified carrier obtained in step S22, then the 2wt% sodium alginate solution is added after stirring, the 8wt% calcium chloride solution is slowly added after stirring uniformly, then it is freeze-dried to obtain the slow-release microbial bacteria; wherein the mass ratio of the modified carrier and the sodium alginate is 1:0.55.

[0132] The preparation of the modified attapulgite includes the following steps:

[0133] S31, according to the amount ratio 1g:8mL, the attapulgite is added into 8wt% hydrochloric acid solution, it is stirred and treated under heating condition (45℃, 3h), after the treatment is completed, it is filtered, washed and dried to obtain the modified attapulgite;

[0134] In the present comparative example, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, which comprises the following steps: uniformly mixing polyaluminum chloride and cocamide propyl betaine, then adding modified activated carbon, modified attapulgite, and polyacrylamide, uniformly stirring again, then adding slow-release microbial bacteria, and finally stirring, drying, and processing to obtain the product.

[0135] Comparative Example 4

[0136] In the present comparative example, a polyaluminum chloride-based composite sewage treatment agent is provided, which is prepared from the following raw materials by mass: 30 g of polyaluminum chloride, 8 g of slow-release microbial bacteria, 5.5 g of modified attapulgite, 0.65 g of cocamide propyl betaine, and 2.5 g of polyacrylamide.

[0137] The preparation of the slow-release microbial bacteria comprises the following steps:

[0138] S21. Adding titanium dioxide to anhydrous ethanol, uniformly stirring and dispersing, then adding KH550, and then refluxing under heating conditions (85°C, 10h); then filtering, washing, and drying to obtain a pretreated carrier; wherein the amount ratio of titanium dioxide, anhydrous ethanol, and KH550 is 1g:6mL:2mL;

[0139] S22. Dissolving caffeic acid in PBS buffer according to 1mg:0.8mL, then adding 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide, activating under stirring conditions (4°C, 30min), then adding the pretreated carrier obtained in step S21, and reacting under heating and stirring conditions (45°C, 4h); after the reaction, filtering, washing, and drying to obtain a modified carrier; wherein the mass ratio of caffeic acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxysuccinimide, and the pretreated carrier is 1:1:0.4:2;

[0140] S23. Adding mixed bacteria (total viable bacteria number is 1×10 10 CFU / g, obtained by mixing nitrifying bacteria, Pseudomonas mendocina, and Bacillus subtilis according to a viable bacteria number of 1:1:1.2) to the modified carrier obtained in step S22, then adding 2wt% sodium alginate solution, stirring again, then slowly adding 8wt% calcium chloride solution, and finally freeze-drying to obtain slow-release microbial bacteria; wherein the mass ratio of the modified carrier and sodium alginate is 1:0.55.

[0141] The preparation of the modified attapulgite comprises the following steps:

[0142] S31, add attapulgite to 8wt% hydrochloric acid solution according to the dosage ratio of 1g:8mL, stir under heating condition (45℃, 3h), after treatment, filter, wash and dry to obtain pretreated attapulgite;

[0143] S32, add boric acid to anhydrous ethanol, stir to obtain boric acid ethanol solution (concentration of 0.08m / mL), and reserve; add the pretreated attapulgite obtained in step S31 to the boric acid ethanol solution according to the dosage ratio of 1g:12mL, stir under heating condition (60℃, 15min), after treatment, filter, wash and dry to obtain modified attapulgite.

[0144] In the present comparative example, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, which comprises the following steps: uniformly mix polyaluminum chloride and cocamide propyl betaine, then add modified attapulgite and polyacrylamide, uniformly stir again, then add slow-release microbial bacteria, and finally stir and dry to obtain the product.

[0145] Comparative Example 5

[0146] Compared with Example 1, the use of modified attapulgite is directly omitted in Comparative Example 5, and the rest is the same. Specifically, a polyaluminum chloride-based composite sewage treatment agent is provided in the present comparative example, which is prepared from the following raw materials by mass: 30g polyaluminum chloride, 8g slow-release microbial bacteria, 4g modified activated carbon, 0.65g cocamide propyl betaine, and 2.5g polyacrylamide.

[0147] The preparation of the modified activated carbon comprises the following steps:

[0148] S11, add activated carbon to 5mol / L nitric acid according to the dosage ratio of 1g:10mL, and perform ultrasonic treatment (80W, 2h) under heating condition (40℃), after treatment, wash and dry to obtain pretreated activated carbon;

[0149] S12, add the pretreated activated carbon obtained in step S11 to water, then add urea, stir uniformly, and then perform heating treatment (40℃, 16h), after treatment, perform drying and high-temperature treatment (nitrogen protection, 600℃, 1.5h) to obtain first modified activated carbon; wherein the mass ratio of pretreated activated carbon, water and urea is 1:15:1;

[0150] S13, add the first modified activated carbon obtained in step S12 to 8wt% ferric nitrate solution according to the dosage ratio of 1g:20mL, stir uniformly, then filter and dry, and then perform calcination treatment (520℃, 2h) under nitrogen protection, after treatment, obtain modified activated carbon.

[0151] The preparation of the slow-release microbial bacteria includes the following steps:

[0152] S21, titanium dioxide is added to anhydrous ethanol, stirred and uniformly dispersed, then KH550 is added, followed by reflux reaction under heating conditions (85℃, 10h); then, the pretreated carrier is obtained through filtration, washing and drying treatment; wherein, the amount ratio of titanium dioxide, anhydrous ethanol and KH550 is 1g:6mL:2mL;

[0153] S22, according to 1mg:0.8mL, the coffee acid is dissolved in PBS buffer, then 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide and N-hydroxysuccinimide are added, activated under stirring conditions (4℃, 30min), then the pretreated carrier obtained in step S21 is added, and the reaction is carried out under heating and stirring conditions (45℃, 4h); after the reaction is completed, the modified carrier is obtained through filtration, washing and drying treatment; wherein, the mass ratio of coffee acid, 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide, N-hydroxysuccinimide and pretreated carrier is 1:1:0.4:2;

[0154] S23, the mixed bacteria (total viable bacteria number is 1×10 10 CFU / g, obtained by mixing nitrifying bacteria, Pseudomonas mendocina and Bacillus subtilis according to the viable bacteria number 1:1:1.2) are added to the modified carrier obtained in step S22, then 2wt% sodium alginate solution is added, stirred again, then 8wt% calcium chloride solution is slowly added, and finally freeze-dried to obtain the slow-release microbial bacteria; wherein, the mass ratio of modified carrier and sodium alginate is 1:0.55.

[0155] In the present comparative example, a preparation method of the above-mentioned polyaluminum chloride-based composite sewage treatment agent is also provided, which includes the following steps: polyaluminum chloride and cocamide propyl betaine are uniformly mixed, then modified activated carbon and polyacrylamide are added, stirred again, then slow-release microbial bacteria are added, and finally stirred and dried to obtain the polyaluminum chloride-based composite sewage treatment agent.

[0156] The polyaluminum chloride-based composite sewage treatment agents prepared in Example 1 and Comparative Examples 1-5 are subjected to performance test, and the specific method is as follows: K2Cr2O7 is added to pure tap water to make the Cr 6+The concentration of the simulated wastewater is 100 mg / L; ammonium chloride is added so that the concentration of ammonium ions is 40 mg / L; potassium dihydrogen phosphate is added so that the concentration of phosphate ions is 40 mg / L, and after stirring, the simulated wastewater is prepared. Then, an equal amount of the simulated wastewater is taken, and 0.15 g / L of the polyaluminum chloride-based composite sewage treatment agent prepared in Example 1 and Comparative Examples 1-5 is added, respectively, and stirred at a speed of 40 rpm for 5 min, and each test group is kept under the same conditions. Then, samples are taken immediately to measure the content of phosphate ions, ammonium ions and Cr 6+ The removal rate of the above substances is calculated; after stopping stirring, the content of the above substances is detected again when the standing time reaches 12 h. The content of phosphate ions, ammonium ions and Cr 6+ The detection is performed by using a spectrophotometer, and the detection method is common and can be detected by using the general method in the prior art, which is not described here. The test results are shown in Table 1.

[0157] Table 1: Removal rate of each substance

[0158]

[0159] As can be seen from Table 1, the polyaluminum chloride-based composite sewage treatment agent prepared in the present application can achieve very good treatment effect within 5 min, can simultaneously and efficiently remove ammonium ions, phosphate ions and Cr 6+ , and meets the requirements of high-level sewage treatment and discharge; at the same time, from the comparison of the treatment results of 12 h and 5 min, it can be seen that with the increase of the treatment time, the slow-release bacteria gradually play a role and can also achieve better treatment effect, and is suitable for long-acting treatment requirements of flowing water bodies.

[0160] The basic principles, main features and advantages of the present application are shown and described. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A polyaluminum chloride-based composite wastewater treatment agent, characterized in that, It is prepared by weight from the following raw materials: 20-35 parts polyaluminum chloride, 5-12 parts slow-release microbial bacteria, 3-6 parts modified activated carbon, 4-8 parts modified attapulgite, 0.5-1.2 parts cocamidopropyl betaine, and 2-5 parts polyacrylamide. The preparation of the modified activated carbon includes the following steps: S11. Add activated carbon to nitric acid and perform ultrasonic treatment under heating conditions. After treatment, wash and dry to obtain pre-modified activated carbon. S12. Add the pre-modified activated carbon obtained in step S11 to water, then add urea, stir evenly and heat it. After the treatment is completed, dry and high temperature treatment to obtain primary modified activated carbon. S13. Add the modified activated carbon obtained in step S12 to the ferric nitrate solution, stir evenly, filter and dry, and then calcine under nitrogen protection. After the treatment is completed, the modified activated carbon is obtained. The preparation of the slow-release microbial strain includes the following steps: S21. Add titanium dioxide to anhydrous ethanol, stir to disperse evenly, then add KH550, and then reflux under heating conditions; then filter, wash and dry to obtain the pretreated carrier; S22. After dissolving caffeic acid in PBS buffer, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide are added and activated under stirring. Then, the pretreated carrier obtained in step S21 is added and the reaction is carried out under heating and stirring. After the reaction is completed, the modified carrier is obtained by filtration, washing and drying. S23. Add the mixed bacteria to the modified carrier obtained in step S22, stir, then add sodium alginate solution, stir again until uniform, then slowly add calcium chloride solution, and then freeze-dry to obtain slow-release microbial bacteria; the mixed bacteria are obtained by mixing nitrifying bacteria, Pseudomonas mendoza and Bacillus subtilis at a viable count of 1:1:1.

2. The preparation of modified attapulgite includes the following steps: S31. Add attapulgite to hydrochloric acid solution, stir under heating conditions, and after treatment, filter, wash and dry to obtain pretreated attapulgite. S32. Add boric acid to anhydrous ethanol and stir to obtain a boric acid ethanol solution for later use. Add the pretreated attapulgite obtained in step S31 to the boric acid ethanol solution and stir under heating conditions. After the treatment is completed, filter, wash and dry to obtain modified attapulgite.

2. The polyaluminum chloride-based composite wastewater treatment agent according to claim 1, characterized in that, In step S11, the concentration of nitric acid is 4~6 mol / L, the heating temperature is 35~45℃, the ultrasonic treatment power is 50~100W, and the ultrasonic treatment time is 1~4h; the ratio of activated carbon to nitric acid is 1g:8~15mL. In step S12, the mass ratio of pre-modified activated carbon, water, and urea is 1:10~20:0.8~1.2; the heating treatment temperature is 35~55℃, and the treatment time is 12~36h; the high-temperature treatment is carried out under nitrogen protection, with a treatment temperature of 550~650℃ and a treatment time of 1~4h. In step S13, the concentration of the ferric nitrate solution is 5-10 wt%, the ratio of the amount of primary modified activated carbon to ferric nitrate solution is 1 g: 15-30 mL, the calcination temperature is 500-580℃, and the treatment time is 1-4 h.

3. The polyaluminum chloride-based composite wastewater treatment agent according to claim 1, characterized in that, In step S21, the ratio of titanium dioxide, anhydrous ethanol, and KH550 is 1g: 5~10mL: 1~3mL; The reflux reaction temperature is 80~85℃, and the reaction time is 8~16h.

4. The polyaluminum chloride-based composite wastewater treatment agent according to claim 1, characterized in that, In step S22, the ratio of caffeic acid to PBS buffer is 1 mg: 0.5~1 mL; The mass ratio of caffeic acid, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, N-hydroxysuccinimide, and pretreatment carrier is 1:0.8~1.2:0.3~0.5:1.5~2.5; The activation temperature is 4℃, and the activation time is 20~50min; The heating and stirring temperature is 40~55℃, and the reaction time under heating and stirring is 3~6h.

5. The polyaluminum chloride-based composite wastewater treatment agent according to claim 1, characterized in that, In step S23, the total viable count of the mixed bacteria is not less than 1×10⁻⁶. 10 CFU / g; the mass concentration of sodium alginate solution is 1.5~3%, and the mass concentration of calcium chloride solution is 5~10%; The mass ratio of the modified carrier to sodium alginate is 1:0.45~0.

65.

6. The polyaluminum chloride-based composite wastewater treatment agent according to claim 1, characterized in that, In step S31, the concentration of hydrochloric acid solution is 5~10wt%, the ratio of attapulgite to hydrochloric acid solution is 1g:5~10mL; the heating temperature is 40~55℃, and the stirring treatment time is 1~4h. In step S32, the concentration of boric acid ethanol solution is 0.05~0.1g / mL; the ratio of pretreated attapulgite to boric acid ethanol solution is 1g:10~15mL; the heating temperature is 55~70℃; and the stirring time is 5~20min.

7. A method for preparing the polyaluminum chloride-based composite wastewater treatment agent according to any one of claims 1 to 6, characterized in that, The process includes the following steps: mixing polyaluminum chloride and cocamidopropyl betaine evenly, then adding modified activated carbon, modified attapulgite, and polyacrylamide, stirring evenly again, then adding slow-release microorganisms, and finally stirring and drying to obtain the final product.

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