Nano-modified high-efficiency flocculant aluminum chloride water treatment agent and its preparation method

Abstract

This invention discloses a nano-modified high-efficiency flocculant aluminum chloride water treatment agent and its preparation method, belonging to the field of wastewater treatment technology. The nano-modified high-efficiency flocculant aluminum chloride water treatment agent comprises modified montmorillonite and polyaluminum chloride in a mass ratio of 1-3:1-3. By modifying the montmorillonite and compounding it with polyaluminum chloride, the flocculation performance of the water treatment agent is significantly improved. This water treatment agent not only greatly enhances the adsorption, capture, and sedimentation efficiency of various pollutants such as suspended solids, colloidal substances, and heavy metals in water, achieving a higher water purification effect, but also possesses high stability and dispersibility, maintaining high efficiency under different water quality conditions. Compared with traditional polyaluminum chloride flocculants, this product has a lower dosage, faster floc formation speed, and better sedimentation performance, facilitating subsequent solid-liquid separation and treatment, thus improving the overall economy and environmental friendliness of the water treatment process.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a nano-modified high-efficiency flocculant aluminum chloride water treatment agent and its preparation method. Background Technology

[0002] Polyaluminum chloride (PAC), as an important inorganic polymeric flocculant, has become one of the most widely used flocculants due to its advantages over traditional aluminum salts (such as aluminum sulfate), including a higher positive charge, stronger adsorption and bridging ability, a wider suitable pH range, larger and faster-settling flocs, lower dosage, less corrosiveness, and significant effectiveness in treating low-temperature and low-turbidity water. The general chemical formula of PAC is typically represented as [Al₂(OH)₂]. n Cl 6-n ] m Polyaluminum chloride (PAC) is a cationic inorganic polymeric flocculant with polyhydroxy and polynuclear complexes. Its flocculation effect mainly depends on the distribution of aluminum ions, especially the content of polynuclear hydroxy complexes such as Al13 and Al30 with high polymerization degree. Although polyaluminum chloride has achieved significant results in water treatment, the flocculation effect of traditional PAC is sometimes not ideal for some complex wastewater, slightly polluted water sources, and low-temperature, low-turbidity water. At the same time, the removal rate of heavy metal ions is not high. When treating wastewater with high turbidity or high organic matter content, the dosage of PAC is relatively large, which increases the treatment cost and sludge production.

[0003] Chinese patent document CN116969535A discloses a wastewater treatment agent containing polyaluminum chloride and its preparation method. The preparation method of the wastewater treatment agent containing polyaluminum chloride consists of the following steps: primary treatment, secondary treatment, and formulation; the primary treatment consists of the following steps: premixing, plasma modification, and cationic modification. The wastewater treatment agent containing polyaluminum chloride of the present invention can achieve good wastewater treatment effect in low water temperature environments. The wastewater treatment agent containing polyaluminum chloride has good dispersion effect in low temperature water and high wastewater treatment efficiency. At the same time, it can effectively improve the adaptability and treatment effect of the wastewater treatment agent to acidic or alkaline wastewater, and can maintain good wastewater treatment effect and efficiency in acidic or alkaline wastewater. The functional carrier of this patent is activated carbon and nano-silica. Although plasma and surface cationic modification have been carried out, the types and densities of functional groups are limited, which cannot achieve efficient removal of organic pollutants and heavy metal ions, thus leading to the defect of further improving its flocculation effect. Summary of the Invention

[0004] The main objective of this invention is to propose a nano-modified high-efficiency flocculating aluminum chloride water treatment agent and its preparation method. The water treatment agent combines the characteristics of inorganic and organic flocculants. By blending modified montmorillonite with polyaluminum chloride, the high specific surface area of ​​the modified montmorillonite provides a good carrier for polyaluminum chloride. During the flocculation process, the modified montmorillonite and polyaluminum chloride synergistically form a spatial network structure, enhancing the capture and agglomeration sedimentation rate of particles. The large number of active groups on the surface of the modified montmorillonite can interact with pollutants in multiple ways, achieving the capture of inorganic suspended solids, organic matter, and heavy metals.

[0005] To achieve the above objectives, this invention proposes a nano-modified high-efficiency flocculant aluminum chloride water treatment agent, comprising modified montmorillonite and polyaluminum chloride in a mass ratio of 1-3:1-3.

[0006] Preferably, the preparation method of the modified montmorillonite includes the following steps: 1) Dissolve xanthan gum in hot water, add epichlorohydrin and polyethyleneimine, heat to react, cool and filter, freeze-dry the solid to obtain pretreated xanthan gum; 2) Disperse montmorillonite in a mixed solution of ethanol and water, add γ-glycidoxypropyltrimethoxysilane, stir the reaction, filter, collect the solid, wash and dry to obtain epoxy montmorillonite; 3) Disperse epoxy montmorillonite in water, add pretreated xanthan gum, heat and react for a period of time, filter, collect the solid and add it to N,N-dimethylformamide, then add 1-(carboxymethyl)-3-methylimidazolium chloride, 3-thiophene malonic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide, reflux, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0007] Preferably, in step 1), the mass ratio of xanthan gum, epichlorohydrin, and polyethyleneimine is 12-18:5-8:10-15; the heating reaction temperature is 80-95℃, and the reaction time is 2-4h.

[0008] Xanthan gum is a natural organic polymeric flocculant containing multiple active hydroxyl groups in its molecular structure. Under the action of epichlorohydrin, the polyamino compound polyethyleneimine is grafted onto xanthan gum, which increases the cation density and the number of active groups on the xanthan gum molecular chain, enhances the bridging effect and adsorption capacity with pollutants, improves the flocculation performance of xanthan gum on the one hand, and is beneficial to subsequent reactions on the other hand.

[0009] Preferably, in step 2), the mass ratio of montmorillonite to γ-glycidoxypropyltrimethoxysilane is 15-24:4-8; the stirring reaction temperature is 40-60℃, and the reaction time is 3-5h.

[0010] By surface-treating montmorillonite with γ-glycidoxypropyltrimethoxysilane, epoxy groups are introduced onto its surface, which avoids the aggregation of montmorillonite and also facilitates its reaction with pretreated xanthan gum.

[0011] Preferably, in step 3), the mass ratio of epoxy montmorillonite, pretreated xanthan gum, 1-(carboxymethyl)-3-methylimidazolium chloride, and 3-thiophene malonic acid is 6-10:2-3:1-2:1.2-2.2; the heating reaction temperature is 50-80℃, and the reaction time is 5-7h; the concentration of EDC in the EDC / NHS aqueous solution is 30-40mM / L, and the concentration of NHS is 40-50mM / L; the reflux reaction temperature is 50-60℃, and the reaction time is 6-8h.

[0012] In this step, the epoxy groups on the epoxy-based montmorillonite react with the hydroxyl and amino groups on the pretreated xanthan gum, combining the pretreated xanthan gum with montmorillonite to form a stable organic-inorganic hybrid material. This material possesses high specific surface area, structural stability, and multifunctional surface activity, which not only enhances the adsorption capacity of organic pollutants but also synergistically captures inorganic suspended solids and heavy metals. It then reacts with 1-(carboxymethyl)-3-methylimidazolium chloride and 3-thiophene malonic acid under EDC / NHS aqueous solution activation, grafting 1-(carboxymethyl)-3-methylimidazolium chloride and 3-thiophene malonic acid onto the montmorillonite. 1-(carboxymethyl)-3-methylimidazolium chloride exhibits good ion exchange and charge regulation capabilities, while 3-thiophene malonic acid is rich in sulfur heterocycles and conjugated structures, enabling it to complex heavy metal ions in water and form π-π conjugations with benzene-containing organic compounds, thereby removing heavy metal ions and benzene-containing organic compounds from the water.

[0013] The present invention also discloses a method for preparing the nano-modified high-efficiency flocculant aluminum chloride water treatment agent, comprising the following steps: mixing modified montmorillonite, polyaluminum chloride and water evenly, then ultrasonically heating the mixture, filtering, collecting the solids, drying, grinding and sieving to obtain the nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention provides a nano-modified high-efficiency flocculant aluminum chloride water treatment agent. By modifying montmorillonite and compounding it with polyaluminum chloride, the flocculation performance of the water treatment agent is significantly improved. This water treatment agent can not only greatly improve the adsorption, capture and sedimentation efficiency of various pollutants such as suspended solids, colloidal substances and heavy metals in water, and achieve a higher water purification effect, but also has high stability and dispersibility, and can maintain high efficiency under different water quality conditions. Compared with traditional flocculants, this product has a lower dosage, faster floc formation speed and better sedimentation performance, which facilitates subsequent solid-liquid separation and treatment, and improves the economy and environmental protection of the water treatment process as a whole. (2) The nano-modified high-efficiency flocculating aluminum chloride water treatment agent of the present invention combines the characteristics of inorganic and organic flocculants. By blending modified montmorillonite with polyaluminum chloride, the high specific surface area of ​​modified montmorillonite provides a good carrier for polyaluminum chloride. During the flocculation process, it synergistically forms a spatial network structure with polyaluminum chloride, enhancing the capture and agglomeration sedimentation rate of particles. The large number of active groups (hydroxyl, amino, imidazole and thiophene) on the surface of modified montmorillonite can interact with pollutants in multiple ways, realizing the capture of inorganic suspended solids, organic matter and heavy metals, and constructing a hydrophilic-hydrophobic hybrid The highly efficient purification network relies on the synergistic effect of multiple flocculants. The combined action of polyaluminum chloride and various active functional groups on the surface of modified montmorillonite achieves complementarity in both electrical properties and structure, effectively capturing and stabilizing various negatively charged colloids and impurities in the water. This enhances the floc formation rate and sedimentation performance. By grafting polyethyleneimine, 1-(carboxymethyl)-3-methylimidazolium chloride, and 3-thiophene malonic acid onto montmorillonite, the risk of these substances remaining in the water is greatly reduced, promoting the filtration and dewatering effect of the flocs and improving the efficiency and environmental friendliness of the water treatment process. Detailed Implementation

[0015] 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.

[0016] The sources of some of the raw materials used in this invention are as follows: Montmorillonite, sodium-based, 325 mesh, purchased from Yangshi Mineral Products Co., Ltd. of Lingshou County.

[0017] Xanthan gum, 99% purity, purchased from Jiangsu Weizhirun Biotechnology Co., Ltd.

[0018] Polyaluminum chloride, 200 mesh, purchased from Henan Shuibiqing Environmental Protection Technology Co., Ltd.

[0019] Example 1 A method for preparing a nano-modified high-efficiency flocculant aluminum chloride water treatment agent includes the following steps: Mix 20g of modified montmorillonite, 20g of polyaluminum chloride, and 100g of water evenly, then heat and sonicate at 80℃ for 30 minutes. Filter, collect the solids, dry, grind, and sieve to obtain nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

[0020] The preparation method of the modified montmorillonite includes the following steps: 1) Dissolve 15g xanthan gum in 200mL of 80℃ hot water, add 6.8g epichlorohydrin and 12.6g polyethyleneimine, heat at 90℃ for 2h, cool and filter, freeze dry the solid to obtain pretreated xanthan gum; 2) Disperse 20g of montmorillonite in a mixed solution consisting of 100mL of ethanol and 100mL of water, add 5.3g of γ-glycidoxypropyltrimethoxysilane, stir and react at 50℃ for 4h, filter, collect the solid, wash and dry to obtain epoxy montmorillonite. 3) Disperse 16g of epoxy montmorillonite in 200mL of water, add 5g of pretreated xanthan gum, heat to 80℃ and react for 6h, filter, collect the solid and add it to 200mL of N,N-dimethylformamide, then add 3g of 1-(carboxymethyl)-3-methylimidazolium chloride, 4g of 3-thiophene malonic acid, 3.6g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 2.5g of N-hydroxysuccinimide, reflux at 55℃ for 7h, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0021] Example 2 A method for preparing a nano-modified high-efficiency flocculant aluminum chloride water treatment agent includes the following steps: 10g of modified montmorillonite, 20g of polyaluminum chloride and 100g of water are mixed evenly and then heated and ultrasonically treated at 80℃ for 30min. After filtration, the solids are collected, dried, ground and sieved to obtain the nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

[0022] The preparation method of the modified montmorillonite includes the following steps: 1) Dissolve 12g xanthan gum in 200mL of 80℃ hot water, add 5.1g epichlorohydrin and 10g polyethyleneimine, heat at 80℃ for 2h, cool and filter, freeze dry the solid to obtain pretreated xanthan gum; 2) Disperse 15g of montmorillonite in a mixed solution consisting of 100mL of ethanol and 100mL of water, add 4g of γ-glycidoxypropyltrimethoxysilane, stir and react at 50℃ for 4h, filter, collect the solid, wash and dry to obtain epoxy montmorillonite. 3) Disperse 12g of epoxy montmorillonite in 200mL of water, add 4g of pretreated xanthan gum, heat to 80℃ and react for 6h, filter, collect the solid and add it to 200mL of N,N-dimethylformamide, then add 2g of 1-(carboxymethyl)-3-methylimidazolium chloride, 2.4g of 3-thiophene malonic acid, 3.2g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 2.2g of N-hydroxysuccinimide, reflux at 55℃ for 7h, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0023] Example 3 A method for preparing a nano-modified high-efficiency flocculant aluminum chloride water treatment agent includes the following steps: 30g of modified montmorillonite, 10g of polyaluminum chloride and 100g of water are mixed evenly and then heated at 80℃ and ultrasonically treated for 30min. After filtration, the solids are collected, dried, ground and sieved to obtain the nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

[0024] The preparation method of the modified montmorillonite includes the following steps: 1) Dissolve 18g xanthan gum in 200mL of 80℃ hot water, add 8g epichlorohydrin and 15g polyethyleneimine, heat at 90℃ for 2h, cool and filter, freeze dry the solid to obtain pretreated xanthan gum. 2) Disperse 24g of montmorillonite in a mixed solution consisting of 100mL of ethanol and 100mL of water, add 8g of γ-glycidoxypropyltrimethoxysilane, stir and react at 50℃ for 4h, filter, collect the solid, wash and dry to obtain epoxy montmorillonite. 3) Disperse 20g of epoxy montmorillonite in 200mL of water, add 6g of pretreated xanthan gum, heat to 80℃ and react for 6h, filter, collect the solid and add it to 200mL of N,N-dimethylformamide, then add 4g of 1-(carboxymethyl)-3-methylimidazolium chloride, 4.4g of 3-thiophene malonic acid, 4g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 3g of N-hydroxysuccinimide, reflux at 55℃ for 7h, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0025] Comparative Example 1 A method for preparing a nano-modified high-efficiency flocculant aluminum chloride water treatment agent is similar to that in Example 1, except that the modified montmorillonite is not grafted with 3-thiophene malonic acid. The method includes the following steps: 20g of modified montmorillonite, 20g of polyaluminum chloride, and 100g of water are mixed evenly and then heated and ultrasonically treated at 80°C for 30min. The mixture is then filtered, the solids are collected, dried, ground, and sieved to obtain the nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

[0026] The preparation method of the modified montmorillonite includes the following steps: 1) Dissolve 15g xanthan gum in 200mL of 80℃ hot water, add 6.8g epichlorohydrin and 12.6g polyethyleneimine, heat at 90℃ for 2h, cool and filter, freeze dry the solid to obtain pretreated xanthan gum; 2) Disperse 20g of montmorillonite in a mixed solution consisting of 100mL of ethanol and 100mL of water, add 5.3g of γ-glycidoxypropyltrimethoxysilane, stir and react at 50℃ for 4h, filter, collect the solid, wash and dry to obtain epoxy montmorillonite. 3) Disperse 16g of epoxy montmorillonite in 200mL of water, add 5g of pretreated xanthan gum, heat to 80℃ and react for 6h, filter, collect the solid and add it to 200mL of N,N-dimethylformamide, then add 3g of 1-(carboxymethyl)-3-methylimidazolium chloride, 3.6g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 2.5g of N-hydroxysuccinimide, reflux at 55℃ for 7h, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0027] Comparative Example 2 A method for preparing a nano-modified high-efficiency flocculant aluminum chloride water treatment agent is similar to that in Example 1, except that the modified montmorillonite is not grafted with 1-(carboxymethyl)-3-methylimidazolium chloride. Specifically, the method includes the following steps: 20g of modified montmorillonite, 20g of polyaluminum chloride, and 100g of water are mixed evenly and then heated and ultrasonically treated at 80°C for 30min. The mixture is then filtered, the solids are collected, dried, ground, and sieved to obtain the nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

[0028] The preparation method of the modified montmorillonite includes the following steps: 1) Dissolve 15g xanthan gum in 200mL of 80℃ hot water, add 6.8g epichlorohydrin and 12.6g polyethyleneimine, heat at 90℃ for 2h, cool and filter, freeze dry the solid to obtain pretreated xanthan gum; 2) Disperse 20g of montmorillonite in a mixed solution consisting of 100mL of ethanol and 100mL of water, add 5.3g of γ-glycidoxypropyltrimethoxysilane, stir and react at 50℃ for 4h, filter, collect the solid, wash and dry to obtain epoxy montmorillonite. 3) Disperse 16g of epoxy montmorillonite in 200mL of water, add 5g of pretreated xanthan gum, heat to 80℃ and react for 6h, filter, collect the solid and add it to 200mL of N,N-dimethylformamide, then add 4g of 3-thiophene malonic acid, 3.6g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 2.5g of N-hydroxysuccinimide, reflux at 55℃ for 7h, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0029] Comparative Example 3 A method for preparing a nano-modified high-efficiency flocculating aluminum chloride water treatment agent is similar to that in Example 1, except that the modified montmorillonite is not combined with pretreated xanthan gum. The method includes the following steps: 20g of modified montmorillonite, 20g of polyaluminum chloride and 100g of water are mixed evenly and then heated and ultrasonically treated at 80°C for 30min. The mixture is then filtered, the solids are collected, dried, ground and sieved to obtain the nano-modified high-efficiency flocculating aluminum chloride water treatment agent.

[0030] The preparation method of the modified montmorillonite includes the following steps: 1) Disperse 20g of montmorillonite in a mixed solution consisting of 100mL of ethanol and 100mL of water, add 5.3g of γ-glycidoxypropyltrimethoxysilane, stir and react at 50℃ for 4h, filter, collect the solid, wash and dry to obtain epoxy montmorillonite; 2) Disperse 16g of epoxy montmorillonite in 200mL of N,N-dimethylformamide, then add 3g of 1-(carboxymethyl)-3-methylimidazolium chloride, 4g of 3-thiophene malonic acid, 3.6g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and 2.5g of N-hydroxysuccinimide. Reflux at 55℃ for 7h, filter, collect the solid, wash and dry to obtain modified montmorillonite.

[0031] Performance testing Wastewater from an industrial park was used as test water. The initial COD of the test water was... cr The concentrations of the initial and final concentrations were as follows: 5367 mg / L (ammonia nitrogen, 1356 mg / L), 0.47 g / L (suspended solids, 0.38 mg / L), 0.2 mg / L (total phosphorus, 1.2 mg / L), and pH 8.6. Test water at 10°C was treated using the nano-modified high-efficiency flocculant aluminum chloride water treatment agents from Examples 1-3 and Comparative Examples 1-3, respectively. The dosage of the nano-modified high-efficiency flocculant aluminum chloride water treatment agent was controlled at 1 g / L. After treatment, the removal rates of various indicators in the treated test water were measured, and the removal rates were calculated. The removal rate was calculated as: [(initial concentration - treated concentration) / initial concentration] × 100%. The test results are shown in Table 1. Table 1 Performance test results of nano-modified high-efficiency flocculant aluminum chloride water treatment agent As can be seen from the experimental results in Table 1, the nano-modified high-efficiency flocculating aluminum chloride water treatment agent prepared in this invention has a good flocculation effect.

[0032] 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 nano-modified high-efficiency flocculant aluminum chloride water treatment agent, characterized in that, It includes modified montmorillonite and polyaluminum chloride, wherein the mass ratio of the modified montmorillonite to polyaluminum chloride is 1-3:1-3; The preparation method of the modified montmorillonite includes the following steps: 1) Dissolve xanthan gum in hot water, add epichlorohydrin and polyethyleneimine, heat to react, cool and filter, freeze-dry the solid to obtain pretreated xanthan gum; 2) Disperse montmorillonite in a mixed solution of ethanol and water, add γ-glycidoxypropyltrimethoxysilane, stir the reaction, filter, collect the solid, wash and dry to obtain epoxy montmorillonite; 3) Disperse epoxy montmorillonite in water, add pretreated xanthan gum, heat and react for a period of time, filter, collect the solid and add it to N,N-dimethylformamide, then add 1-(carboxymethyl)-3-methylimidazolium chloride, 3-thiophene malonic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and N-hydroxysuccinimide, reflux, filter, collect the solid, wash and dry to obtain modified montmorillonite.

2. The water treatment agent according to claim 1, characterized in that: In step 1), the mass ratio of xanthan gum, epichlorohydrin, and polyethyleneimine is 12-18:5-8:10-15.

3. The water treatment agent according to claim 1, characterized in that: In step 1), the heating reaction temperature is 80-95℃, and the reaction time is 2-4h.

4. The water treatment agent according to claim 1, characterized in that: In step 2), the mass ratio of montmorillonite to γ-glycidoxypropyltrimethoxysilane is 15-24:4-8.

5. The water treatment agent according to claim 1, characterized in that: In step 2), the stirring reaction temperature is 40-60℃ and the reaction time is 3-5h.

6. The water treatment agent according to claim 1, characterized in that: In step 3), the mass ratio of epoxy montmorillonite, pretreated xanthan gum, 1-(carboxymethyl)-3-methylimidazolium chloride, and 3-thiophene malonic acid is 6-10:2-3:1-2:1.2-2.

2.

7. The water treatment agent according to claim 1, characterized in that: In step 3), the temperature for raising the temperature is 50-80℃ and the reaction time is 5-7h.

8. The water treatment agent according to claim 1, characterized in that: In step 3), the reflux reaction temperature is 50-60℃ and the reaction time is 6-8h.

9. A method for preparing the water treatment agent according to any one of claims 1-8, characterized in that, The process includes the following steps: mixing modified montmorillonite, polyaluminum chloride, and water evenly, then ultrasonically heating the mixture, filtering, collecting the solids, drying, grinding, and sieving to obtain a nano-modified high-efficiency flocculant aluminum chloride water treatment agent.

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