High-efficiency aluminum sulfate treating agent with catalysis-flocculation synergy

Abstract

The application discloses a kind of catalysis-flocculation synergistic high-efficiency aluminium sulfate treating agent, belong to wastewater treatment technical field.The high-efficiency aluminium sulfate treating agent includes the following components: composite catalysis-flocculation material, aluminium sulfate, solve the problem that traditional single flocculant is limited in efficiency, narrow in scope in wastewater treatment;Through the synergistic effect of organic and inorganic flocculants, and introduce the composite material with photocatalytic and flocculation performance, effectively improve the removal efficiency of suspended solids, heavy metal ions and organic matter in water, realize the collaborative management of various pollutants;The treating agent preparation process is simple, process condition is mild, cost is lower, with good environmental and economic benefits, suitable for industrial wastewater, municipal sewage and complex water purification treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect. Background Technology

[0002] With the acceleration of industrialization and urbanization, water pollution has become increasingly prominent, especially the spread of urban sewage, industrial wastewater, and pollution sources, posing a serious threat to the environment and human health. Common water pollutants include suspended solids, heavy metals, and organic matter. Among these, flocculation, as an economical and efficient water treatment technology, plays an important role in removing suspended particles and some dissolved pollutants from water bodies. Aluminum sulfate, as a representative of inorganic flocculants, is widely used in water supply and drainage treatment due to its low preparation cost, convenient addition, and good flocculation effect.

[0003] Although aluminum sulfate flocculants are widely used in water treatment, they also have some drawbacks in application. These include the slow hydrolysis reaction of aluminum sulfate in low-temperature or high-turbidity water, which leads to a decrease in flocculation efficiency; and the difficulty of completely removing dissolved organic matter and some recalcitrant pollutants by relying solely on physical adsorption and charge neutralization.

[0004] To overcome the shortcomings of traditional flocculants, the "catalytic-flocculation synergistic treatment" technology has gradually become a research hotspot in recent years. This approach introduces catalytically active components into the flocculation system to promote reactions such as the oxidative decomposition and structural transformation of pollutants, thereby enhancing the encapsulation and adsorption of pollutants by the flocs. The synergistic effect of the catalytic reaction and the flocculation process can significantly improve the removal rate of complex components such as organic pollutants and heavy metal ions by aluminum sulfate flocculants, while simultaneously inhibiting the formation of byproducts and reducing treatment costs.

[0005] Chinese patent document CN106915810A discloses a high-efficiency composite flocculant, its preparation method, and its application, belonging to the field of water treatment. Specifically, it relates to a high-efficiency composite flocculant for treating papermaking wastewater, composed of aluminum sulfate, polyacrylamide, and polyvinyl alcohol-modified chitosan. This high-efficiency composite flocculant shows significant effects in treating high-COD papermaking wastewater, with treatment effects superior to existing conventional flocculants for all indicators in the wastewater. The COD removal rate reaches over 85%, and the turbidity and BOD removal rates are both over 78%. The light transmittance of the treated wastewater reaches over 85%. This patent uses aluminum sulfate, polyacrylamide, and polyvinyl alcohol-modified chitosan in combination. The polyacrylamide used is difficult to completely degrade after use, leaving residues in the environment and causing secondary pollution problems. These residues may have long-term negative impacts on water bodies and soil, thereby threatening ecosystem health and human quality of life. Summary of the Invention

[0006] The main objective of this invention is to propose a highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect, which has good flocculation and degradation effects on suspended solids and organic matter in wastewater.

[0007] To achieve the above objectives, this invention proposes a highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect, comprising the following components in parts by weight: 8-10 parts of composite catalytic-flocculation material and 10-20 parts of aluminum sulfate.

[0008] Preferably, the preparation method of the composite catalytic-flocculation material is as follows:

[0009] (1) Mix carbon nitride precursor, ammonium bicarbonate and water, stir to dissolve, remove most of the solvent by vacuum evaporation, and then calcine to obtain porous carbon nitride material; mix bentonite with porous carbon nitride material, add anhydrous ethanol and stir thoroughly to mix evenly, then add zinc chloride aqueous solution, and adjust the pH value to 8-10 with sodium hydroxide aqueous solution, then carry out hydrothermal reaction in high pressure reactor, centrifuge, collect solids, wash, dry and grind to obtain composite catalytic material;

[0010] (2) The composite catalytic material was dispersed in an ethanol aqueous solution, KH550 was added, and the mixture was heated to react, thus obtaining the surface-treated composite catalytic material;

[0011] (3) The surface-treated composite catalytic material was dispersed in N,N-dimethylformamide, 4-hydroxy-3-methoxycinnamoaldehyde was added, and the reaction was heated. After the reaction was completed, the mixture was filtered, and the solid product was dispersed in anhydrous ethanol. Dimethyl diallyl ammonium chloride and ammonium persulfate were added, and the mixture was stirred. After the reaction was completed, the solid was collected by filtration. The solid was washed and dried to obtain the composite catalytic-flocculation material.

[0012] Preferably, in step S1, the carbon nitride precursor is at least one of cyanamide, dicyandiamide, urea, and thiourea; the mass ratio of the carbon nitride precursor to ammonium bicarbonate is 2-4:3-5; the calcination temperature is 400-800℃, and the calcination time is 2-4h; the mass ratio of bentonite, porous carbon nitride material, and zinc chloride aqueous solution is 10-15:5-8:20-30; the concentration of the zinc chloride aqueous solution is 25-30wt%; and the hydrothermal reaction temperature is 150-200℃, and the reaction time is 10-20h.

[0013] Preferably, in step S2, the mass ratio of the composite catalyst material to KH550 is 10-15:3-5; the heating temperature is 40-60℃, and the heating time is 4-6h.

[0014] Preferably, in step S3, the mass ratio of the modified composite material, 4-hydroxy-3-methoxycinnamaldehyde, and dimethyldiallylammonium chloride is 8-12:3-5:6-10; the heating temperature is 30-50℃, and the heating time is 3-5h; the stirring reaction temperature is 20-30℃, and the reaction time is 15-18h.

[0015] The composite catalytic-flocculation material of the present invention uses a composite catalytic material as a substrate, and then performs surface treatment with KH550 to introduce amino groups onto its surface. The amino groups then react with 4-hydroxy-3-methoxycinnamaldehyde to generate Schiff bases and introduce double bonds. Finally, dimethyl diallyl ammonium chloride undergoes a polymerization reaction with carbon-carbon double bonds under the action of ammonium persulfate to graft the cationic compound dimethyl diallyl ammonium chloride onto the surface of the composite catalytic material, thus obtaining the composite catalytic-flocculation material.

[0016] The present invention also discloses a method for preparing the highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect, comprising the following steps: mixing composite catalytic-flocculation material and aluminum sulfate evenly to obtain the highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention provides a highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect and its preparation method, solving the problems of limited efficiency and narrow applicability of traditional single flocculants in wastewater treatment. Through the synergistic effect of organic and inorganic flocculants and the introduction of composite materials with photocatalytic and flocculation properties, the removal efficiency of suspended solids, heavy metal ions and organic matter in water is effectively improved, achieving synergistic treatment of multiple pollutants. The preparation process of this treatment agent is simple, the process conditions are mild, and the cost is low, with good environmental and economic benefits. It is suitable for the purification and treatment of industrial wastewater, urban sewage and complex water bodies.

[0019] 2. The composite catalytic-flocculation material of the present invention uses a composite catalytic material as a substrate. The composite catalytic material is prepared by introducing nano-sized zinc oxide into porous carbon nitride material to form a highly hybrid nanocomposite system, and uniformly loading it onto a bentonite matrix. This not only significantly increases the specific surface area of ​​the composite material, but also broadens the material's response range to visible light. The composite catalytic-flocculation material can not only generate a large number of active free radicals under light conditions to promote the decomposition of organic pollutants, but also achieve efficient adsorption and flocculation of pollutants through surface active groups, significantly improving the removal capacity of organic matter and heavy metal ions in water.

[0020] 3. The Schiff base, hydroxyl, and imidazole groups in the composite catalytic-flocculation material of this invention provide numerous adsorption and coordination sites, enabling coordination with metal ions in wastewater and thus removing them. Furthermore, the positive charge in the cationic flocculant neutralizes the negative charge on the surface of the colloidal particles, reducing electrostatic repulsion between particles and promoting particle aggregation. On the other hand, the cationic compound dimethyl diallyl ammonium chloride can simultaneously adsorb onto multiple particle surfaces, connecting them through bridging to form larger flocs, facilitating sedimentation and separation, thereby achieving flocculation. Compared to ordinary physical mixing, the connection between 4-hydroxy-3-methoxycinnamonaldehyde, dimethyl diallyl ammonium chloride, and the composite catalytic material is more robust, making the highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect less prone to loss with water flow in continuous flow systems, thus improving material utilization. Detailed Implementation

[0021] To avoid unnecessary details, unless otherwise specified, all items used in the following examples are commercially available products, and all methods used are conventional methods unless otherwise specified.

[0022] The sources of some of the raw materials used in this invention are as follows:

[0023] Bentonite, 200-260 mesh, purchased from Qingdao Ruihexiang Refractory Materials Co., Ltd.

[0024] Example 1

[0025] A method for preparing a highly efficient aluminum sulfate treatment agent with synergistic catalytic and flocculation effects includes the following steps:

[0026] (1) Mix 30g dicyandiamide, 40g ammonium bicarbonate and 100mL water, stir to dissolve, remove 80% of the solvent by vacuum evaporation, and then calcine in a muffle furnace at 550℃ for 3h to obtain porous carbon nitride material; mix 24g bentonite with 14g porous carbon nitride material, add 200mL anhydrous ethanol and stir thoroughly to mix evenly, then add 500g 28wt% zinc chloride aqueous solution, and adjust the pH value to 9 with 1mol / L sodium hydroxide aqueous solution, and then carry out hydrothermal reaction in a high-pressure reactor at 180℃ for 12h. After the reaction is completed, cool, centrifuge, collect the solid, wash, dry and grind to obtain composite catalytic material;

[0027] (2) Disperse 23g of composite catalyst material in 200mL of 50wt% ethanol aqueous solution, add 7.8g of KH550, heat at 50℃ for 5h, filter after the reaction is completed, collect the solid product, wash and dry to obtain surface-treated composite catalyst material;

[0028] (3) 10g of surface-treated composite catalyst material was dispersed in 200mL of N,N-dimethylformamide, 4.5g of 4-hydroxy-3-methoxycinnamoaldehyde was added, and the reaction was heated at 40℃ for 4h. After the reaction was completed, the mixture was filtered, and the solid product was dispersed in 200mL of anhydrous ethanol. 8g of dimethyl diallyl ammonium chloride and 0.8g of ammonium persulfate were added, and the mixture was stirred at 25℃ for 16h. After the reaction was completed, the solid was collected by filtration, and the solid was washed and dried to obtain the composite catalyst-flocculation material.

[0029] (4) Mix 9g of composite catalytic-flocculation material and 15g of aluminum sulfate evenly to obtain the highly efficient aluminum sulfate treatment agent with the synergistic effect of catalysis-flocculation.

[0030] Example 2

[0031] A method for preparing a highly efficient aluminum sulfate treatment agent with synergistic catalytic and flocculation effects includes the following steps:

[0032] (1) Mix 20g dicyandiamide, 30g ammonium bicarbonate and 100mL water, stir to dissolve, remove 80% of the solvent by vacuum evaporation, and then calcine in a muffle furnace at 550℃ for 3h to obtain porous carbon nitride material; mix 20g bentonite with 10g porous carbon nitride material, add 200mL anhydrous ethanol and stir thoroughly to mix evenly, then add 400g 25wt% zinc chloride aqueous solution, and adjust the pH value to 8 with 1mol / L sodium hydroxide aqueous solution, and then carry out hydrothermal reaction in a high-pressure reactor at 180℃ for 12h. After the reaction is completed, cool, centrifuge, collect the solid, wash, dry and grind to obtain composite catalytic material;

[0033] (2) Disperse 20g of composite catalyst material in 200mL of 50wt% ethanol aqueous solution, add 6g of KH550, heat at 40℃ for 6h, filter after the reaction is completed, collect the solid product, wash and dry to obtain surface-treated composite catalyst material;

[0034] (3) Disperse 8g of surface-treated composite catalyst material in 200mL of N,N-dimethylformamide, add 3g of 4-hydroxy-3-methoxycinnamoaldehyde, heat at 30℃ for 5h, filter after the reaction is complete, disperse the solid product in 200mL of anhydrous ethanol, add 6g of dimethyl diallyl ammonium chloride and 0.6g of ammonium persulfate, stir at 20℃ for 18h, filter after the reaction is complete, collect the solid material, wash and dry the solid material to obtain composite catalyst-flocculation material;

[0035] (4) Mix 8g of composite catalytic-flocculation material and 10g of aluminum sulfate evenly to obtain the highly efficient aluminum sulfate treatment agent with the synergistic effect of catalysis-flocculation.

[0036] Example 3

[0037] A method for preparing a highly efficient aluminum sulfate treatment agent with synergistic catalytic and flocculation effects includes the following steps:

[0038] (1) Mix 40g dicyandiamide, 50g ammonium bicarbonate and 200mL water, stir to dissolve, remove 80% of the solvent by vacuum evaporation, and then calcine in a muffle furnace at 550℃ for 3h to obtain porous carbon nitride material; mix 30g bentonite with 16g porous carbon nitride material, add 200mL anhydrous ethanol and stir thoroughly to mix evenly, then add 600g 30wt% zinc chloride aqueous solution, and adjust the pH value to 10 with 1mol / L sodium hydroxide aqueous solution, and then carry out hydrothermal reaction in a high-pressure reactor at 180℃ for 12h. After the reaction is completed, cool, centrifuge, collect the solid, wash, dry and grind to obtain composite catalytic material;

[0039] (2) Disperse 30g of composite catalyst material in 200mL of 50wt% ethanol aqueous solution, add 10g of KH550, heat at 60℃ for 4h, filter after the reaction is completed, collect the solid product, wash and dry to obtain surface-treated composite catalyst material;

[0040] (3) 12g of surface-treated composite catalyst material was dispersed in 200mL of N,N-dimethylformamide, 5g of 4-hydroxy-3-methoxycinnamoaldehyde was added, and the reaction was heated at 50℃ for 3h. After the reaction was completed, the mixture was filtered, and the solid product was dispersed in 200mL of anhydrous ethanol. 10g of dimethyl diallyl ammonium chloride and 1g of ammonium persulfate were added, and the mixture was stirred at 30℃ for 15h. After the reaction was completed, the solid was collected by filtration, and the solid was washed and dried to obtain the composite catalyst-flocculation material.

[0041] (4) Mix 10g of composite catalytic-flocculation material and 20g of aluminum sulfate evenly to obtain the highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect.

[0042] Comparative Example 1

[0043] A method for preparing a highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect is similar to that in Example 1, except that polydimethyldiallyl ammonium chloride is not grafted onto it. Specifically, it includes the following steps:

[0044] (1) Mix 30g dicyandiamide, 40g ammonium bicarbonate and 100mL water, stir to dissolve, remove 80% of the solvent by vacuum evaporation, and then calcine in a muffle furnace at 550℃ for 3h to obtain porous carbon nitride material; mix 24g bentonite with 14g porous carbon nitride material, add 200mL anhydrous ethanol and stir thoroughly to mix evenly, then add 500g 28wt% zinc chloride aqueous solution, and adjust the pH value to 9 with 1mol / L sodium hydroxide aqueous solution, and then carry out hydrothermal reaction in a high-pressure reactor at 180℃ for 12h. After the reaction is completed, cool, centrifuge, collect the solid, wash, dry and grind to obtain composite catalytic material;

[0045] (2) Disperse 23g of composite catalyst material in 200mL of 50wt% ethanol aqueous solution, add 7.8g of KH550, heat at 50℃ for 5h, filter after the reaction is completed, collect the solid product, wash and dry to obtain surface-treated composite catalyst material;

[0046] (3) Disperse 10g of surface-treated composite catalyst material in 200mL of N,N-dimethylformamide, add 4.5g of 4-hydroxy-3-methoxycinnamoaldehyde, heat at 40℃ for 4h, filter after the reaction is completed, wash and dry the solid product to obtain composite catalyst-flocculation material;

[0047] (4) Mix 9g of composite catalytic-flocculation material and 15g of aluminum sulfate evenly to obtain the highly efficient aluminum sulfate treatment agent with the synergistic effect of catalysis-flocculation.

[0048] Comparative Example 2

[0049] A method for preparing a highly efficient aluminum sulfate treatment agent is similar to that in Example 1, except that the composite catalyst-flocculation material is a mixture of a composite catalyst material and dimethyl diallyl ammonium chloride, comprising the following steps:

[0050] (1) Mix 30g dicyandiamide, 40g ammonium bicarbonate and 100mL water, stir to dissolve, remove 80% of the solvent by vacuum evaporation, and then calcine in a muffle furnace at 550℃ for 3h to obtain porous carbon nitride material; mix 24g bentonite with 14g porous carbon nitride material, add 200mL anhydrous ethanol and stir thoroughly to mix evenly, then add 500g 28wt% zinc chloride aqueous solution, and adjust the pH value to 9 with 1mol / L sodium hydroxide aqueous solution, and then carry out hydrothermal reaction in a high-pressure reactor at 180℃ for 12h. After the reaction is completed, cool, centrifuge, collect the solid, wash, dry and grind to obtain composite catalytic material;

[0051] (2) 23g of composite catalyst material was dispersed in 200mL of 50wt% ethanol aqueous solution, 7.8g of KH550 was added, and the reaction was heated at 50℃ for 5h. After the reaction was completed, the mixture was filtered, the solid product was collected, washed and dried to obtain the surface-treated composite catalyst material.

[0052] (3) Mix 10g of surface-treated composite catalyst material, 4.5g of 4-hydroxy-3-methoxycinnamonaldehyde and 8g of dimethyl diallyl ammonium chloride evenly to obtain composite catalyst-flocculation material;

[0053] (4) Mix 9g of composite catalytic-flocculation material and 15g of aluminum sulfate evenly to obtain the high-efficiency aluminum sulfate treatment agent.

[0054] Performance testing

[0055] Using dyeing and printing wastewater from a certain factory as the subject, the high-efficiency aluminum sulfate treatment agent prepared in Examples 1-3 and Comparative Examples 1-2 was used to conduct flocculation effect tests on the wastewater. The tests were conducted simultaneously in five sedimentation tanks. The dosage of the high-efficiency aluminum sulfate treatment agent was 1 g / L. After stirring, the mixture was allowed to stand for 1 hour and then irradiated under ultraviolet light for 3 hours. The chemical oxygen demand (COD), suspended solids (SS), decolorization rate, and heavy metal ion removal rate of the wastewater before and after the addition of the flocculant were measured. The COD was determined according to HJ828-2017 "Determination of Chemical Oxygen Demand in Water - Dichromate Method", and the SS was determined according to GB11901-1989 "Determination of Suspended Solids in Water - Gravimetric Method". The decolorization rate was determined by ultraviolet-visible spectrophotometry. The test results are shown in Table 1.

[0056] Table 1. Flocculation performance test results of high-efficiency aluminum sulfate treatment agent

[0057]

[0058] As can be seen from the experimental results in Table 1, the highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect prepared in this invention has a good wastewater treatment effect.

[0059] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A highly efficient aluminum sulfate treatment agent with synergistic catalytic-flocculation effect, characterized in that, The composition includes the following components in parts by weight: 8-10 parts of composite catalytic-flocculation material, and 10-20 parts of aluminum sulfate; The preparation method of the composite catalytic-flocculation material is as follows: S1. Mix carbon nitride precursor, ammonium bicarbonate, and water, stir to dissolve, remove most of the solvent by vacuum distillation, and then calcine to obtain porous carbon nitride material; mix bentonite with porous carbon nitride material, add anhydrous ethanol and stir thoroughly to mix evenly, then add zinc chloride aqueous solution, and adjust the pH value to 8-10 with sodium hydroxide aqueous solution, then carry out hydrothermal reaction in high pressure reactor, centrifuge, collect solids, wash, dry, and grind to obtain composite catalytic material; S2. Disperse the composite catalytic material in an aqueous ethanol solution, add KH550, and heat to react to obtain the surface-treated composite catalytic material; S3. Disperse the surface-treated composite catalytic material in N,N-dimethylformamide, add 4-hydroxy-3-methoxycinnamic aldehyde, heat to react, filter after the reaction is complete, disperse the solid product in anhydrous ethanol, add dimethyl diallyl ammonium chloride and ammonium persulfate, stir to react, filter to collect the solid after the reaction is complete, wash and dry the solid to obtain the composite catalytic-flocculation material.

2. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The carbon nitride precursor in S1 is at least one of cyanamide, dicyandiamide, urea, and thiourea.

3. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The mass ratio of carbon nitride precursor to ammonium bicarbonate in S1 is 2-4:3-5.

4. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The mass ratio of bentonite, porous carbon nitride material, and zinc chloride aqueous solution in S1 is 10-15:5-8:20-30; the concentration of zinc chloride aqueous solution is 25-30 wt%.

5. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The hydrothermal reaction temperature is 150-200℃, and the reaction time is 10-20h.

6. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The mass ratio of the composite catalyst material and KH550 in S2 is 10-15:3-5; the heating temperature is 40-60℃ and the heating time is 4-6h.

7. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The mass ratio of the modified composite material, 4-hydroxy-3-methoxycinnamaldehyde, and dimethyl diallyl ammonium chloride in S3 is 8-12:3-5:6-10.

8. The high-efficiency aluminum sulfate treatment agent according to claim 1, characterized in that: The heating temperature in S3 is 30-50℃, and the heating time is 3-5h; the stirring reaction temperature is 20-30℃, and the reaction time is 15-18h.

9. A method for preparing the high-efficiency aluminum sulfate treatment agent according to any one of claims 1-8, characterized in that: A highly efficient aluminum sulfate treatment agent with synergistic catalytic and flocculation effects is obtained by uniformly mixing composite catalytic-flocculation materials and aluminum sulfate.

Images