Composite water purifying agent based on polyaluminum ferric sulfate

Abstract

The invention discloses a composite water purifying agent based on polyaluminum ferric sulfate. The preparation process comprises the following steps: 1, reacting ferrous sulfate heptahydrate, aluminum sulfate, sodium chlorate, phosphoric acid and the like to prepare a polyaluminum ferric sulfate solution; 2, mixing the modified polyacrylamide solution with the polyaluminum ferric sulfate solution for reaction to obtain a composite system; and step 3, adding acidic ochre soil into the composite system to obtain the composite water purifying agent. The preparation method has the beneficial effects that a modified monomer is prepared through organic synthesis, and the modified monomer is copolymerized with monomers such as acrylamide to prepare modified polyacrylamide; then, the organic polymer is compounded with a polyaluminum ferric sulfate solution and acidic ochre soil, and an inorganic-organic-mineral ternary water purification system is constructed; the composite water purifying agent has the high-efficiency electricity neutralization capability of an inorganic flocculating agent, the bridging flocculation effect of organic macromolecules and the adsorption performance of minerals, and shows excellent flocculation and sedimentation effects and pollutant removal capability.

Description

Technical Field

[0001] The present invention belongs to the technical field of water purifiers, and in particular relates to a composite water purifier based on polyaluminium ferric sulfate. Background Art

[0002] With the rapid development of industrialization and urbanization, water pollution problems are becoming increasingly serious, especially colloidal particles, organic matter and heavy metal pollutants in water bodies, which pose a serious threat to the ecological environment and human health. At present, water purifiers have been widely used in the field of water treatment, among which inorganic flocculants (such as polyaluminum sulfate, polyferric sulfate, etc.) have become the mainstream choice due to their efficient electrical neutralization ability and cost advantages. However, traditional inorganic water purifiers have obvious defects: first, the flocs they form are small and loose, and the sedimentation rate is slow, resulting in low treatment efficiency; second, the removal effect of dissolved organic matter and heavy metals is limited, and it is difficult to meet the high-standard treatment requirements of complex water quality. In addition, when dealing with water bodies with high turbidity or high pollution load, a single inorganic water purifier often requires excessive dosage of agents, which not only increases treatment costs but may also introduce secondary pollution.

[0003] While organic polymer flocculants (such as polyacrylamide) can improve floc structure through bridging, their single charge limits their charge neutralization capabilities and poor adsorption of hydrophobic organic matter and heavy metals. Mineral materials (such as activated carbon and bentonite) possess adsorption properties, but they have poor dispersibility when used alone and struggle to effectively synergize with other components.

[0004] Therefore, in order to solve the above problems, the present invention provides a composite water purifier based on polyaluminum ferric sulfate. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects of the prior art and provide a composite water purifier based on polyaluminium ferric sulfate.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A preparation process of a composite water purifier based on polyaluminium ferric sulfate is as follows:

[0008] Step 1: Mix ferrous sulfate heptahydrate with deionized water, adjust the pH value to 0.5-1, add sodium chlorate, and stir for 30-40 minutes to obtain a ferrous sulfate mixture; add aluminum sulfate to the deionized water, stir evenly, mix with the ferrous sulfate mixture and phosphoric acid, increase the temperature to 80-90° C., stir for 30-40 minutes, add sodium carbonate, and continue stirring for 30-40 minutes to obtain a polyaluminum ferric sulfate solution;

[0009] Step 2: Add the modified polyacrylamide to deionized water to obtain a modified polyacrylamide solution; then slowly add the modified polyacrylamide solution dropwise to the polyaluminum ferric sulfate solution, increase the temperature to 60-70°C, and react for 2-3 hours to obtain a composite system;

[0010] Step 3: Add acidic ochre soil to the composite system, maintain 60-70°C, adjust the pH value to 4-5, and stir for 3-4 hours to obtain a composite water purifier.

[0011] In this scheme, ferrous sulfate heptahydrate is oxidized with sodium chlorate under acidic conditions, converting some ferrous ions into ferric ions. Aluminum sulfate is dissolved and mixed with the ferric ions. Phosphoric acid is added as a stabilizer to promote the hydrolysis and polymerization of the ferric and aluminum ions at high temperatures, forming a multi-nuclear hydroxyl-bridged structure. Sodium carbonate is then added to adjust the pH to further promote hydroxyl-bridged polymerization, ultimately producing a stable polyaluminum ferric sulfate solution.

[0012] In the compounding stage of the composite water purifier, the modified polyacrylamide solution is slowly added to the polyaluminum ferric sulfate solution to combine the inorganic flocculant with the organic polymer. The long chain structure of the modified polyacrylamide can bridge the polyaluminum ferric sulfate colloid to form a larger flocculation network. At the same time, its cationic groups enhance the electrical neutralization ability. Then, acidic ochre soil is added, and the iron ions on its surface can react with the anionic groups (—COO - ) coordination, thus obtaining an "inorganic-organic-mineral" composite water purification system.

[0013] More optimally, the ferrous sulfate mixed solution raw material comprises the following components: by weight, 15-18 parts of ferrous sulfate heptahydrate, 30-35 parts of deionized water, and 1.2-1.5 parts of sodium chlorate;

[0014] The raw materials of the polyaluminum ferric sulfate solution include the following components: by weight, 12-14 parts of aluminum sulfate, 30-45 parts of deionized water, 0.3-0.5 parts of phosphoric acid, 45-55 parts of ferrous sulfate mixed solution, and 1.8-2.2 parts of sodium carbonate.

[0015] More optimally, the raw materials of the composite system include the following components: by weight, 0.1-0.2 parts of modified polyacrylamide, 10-12 parts of deionized water, and 60-70 parts of polyaluminum ferric sulfate solution.

[0016] More optimally, the raw materials of the composite water purifier include the following components: 5-8 parts of acidic ochre soil and 60-80 parts of the composite system, by weight.

[0017] More optimally, the preparation process of the modified polyacrylamide is:

[0018] S1: Add dehydroabietic acid to anhydrous dichloromethane, cool to 0°C in an ice bath, slowly add oxalyl chloride and N,N-dimethylformamide, maintaining the temperature below 5°C throughout the process, remove the ice bath, stir at room temperature for 1-2 hours, and remove the solvent by rotary evaporation to obtain dehydroabietic acid chloride;

[0019] S2: Dehydroabietic acid chloride is added to tetrahydrofuran, cooled to 0°C in an ice bath, and 3-bromopropanol and triethylamine are slowly added dropwise in sequence, maintaining the temperature below 10°C. The reaction is carried out at room temperature for 6-8 hours. After the reaction is completed, triethylamine hydrochloride is removed by filtration, and the filtrate is concentrated under reduced pressure and purified by column chromatography to obtain dehydroabietic acid propyl bromide;

[0020] S3: Under a protective atmosphere, propyl bromide dehydroabietic acid, N-vinylimidazole, and methanol are mixed, the temperature is raised to 60-70° C., and the mixture is refluxed for 12-15 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, washed, and dried to obtain a modified monomer;

[0021] S4: dissolving the modified monomer in ethanol to obtain a modified monomer solution; under a protective atmosphere, adding acrylamide, methacryloyloxyethyltrimethylammonium chloride, the modified monomer solution, and acrylic acid to deionized water in sequence, stirring until completely dissolved, adjusting the pH to 5-6, adding ammonium persulfate dropwise, raising the temperature to 50-60°C, reacting for 3-4 hours, then adding hydroquinone, stirring for 10-15 minutes, filtering, washing, and drying to obtain modified polyacrylamide.

[0022] In the scheme, dehydroabietic acid and oxalyl chloride undergo chlorination reaction under the catalysis of N,N-dimethylformamide to generate more active dehydroabietic acid chloride. The specific reaction process is as follows:

[0023]

[0024] In the scheme, dehydroabietyl chloride and 3-bromopropanol are esterified in the presence of triethylamine (acid binding agent) to generate ester compounds containing bromine end groups (introducing active sites for subsequent reactions). The specific reaction process is shown below:

[0025]

[0026] In the scheme, the brominated ester reacts with N-vinyl imidazole through a nucleophilic substitution reaction (SN2), and the bromine atom is replaced by the imidazole group to form a modified monomer, the structural formula of which is shown below:

[0027]

[0028] In the scheme, the modified monomer is copolymerized with acrylamide (AM), methacryloyloxyethyltrimethylammonium chloride (DMC), and acrylic acid (AA), and free radical polymerization is initiated by ammonium persulfate to generate amphoteric (anionic / cationic) modified polyacrylamide.

[0029] More optimally, the dehydroabietic acid chloride raw material comprises the following components: by weight, 50-55 parts of dehydroabietic acid, 250-300 parts of anhydrous dichloromethane, 30-35 parts of oxalyl chloride, and 1-2 parts of N,N-dimethylformamide.

[0030] More optimally, the raw material of dehydroabietin propyl bromide includes the following components: 50-55 parts of dehydroabietin acid chloride, 200-250 parts of tetrahydrofuran, 25-30 parts of 3-bromopropanol, and 20-25 parts of triethylamine, by weight.

[0031] More optimally, the modified monomer raw material comprises the following components: by weight, 50-55 parts of propyl bromide-dehydroabietate, 15-20 parts of N-vinylimidazole, and 150-200 parts of methanol.

[0032] More optimally, the modified polyacrylamide raw material includes the following components: by weight, 5-10 parts of modified monomer, 50-80 parts of ethanol, 60-70 parts of acrylamide, 20-30 parts of methacryloyloxyethyltrimethylammonium chloride, 1-5 parts of acrylic acid, 500-600 parts of deionized water, 0.05-0.1 parts of ammonium persulfate, and 0.1-0.2 parts of hydroquinone.

[0033] More optimally, the preparation process of the acidic ochre soil is as follows: crushing the ochre soil to 200 mesh, stirring and reacting with 10-15% sulfuric acid at 80-90°C for 2-3 hours, filtering and washing with deionized water until neutral, and drying at 105°C to obtain acidic ochre soil; the mass ratio of the ochre soil to sulfuric acid is 1:3.

[0034] Beneficial effects of the present invention:

[0035] The present invention prepares a modified monomer through organic synthesis and copolymerizes it with monomers such as acrylamide to produce modified polyacrylamide. Subsequently, the organic polymer is compounded with a polyaluminum ferric sulfate solution and acidic ochre soil to construct an "inorganic-organic-mineral" ternary water purification system. This composite water purifier combines the efficient electrical neutralization ability of an inorganic flocculant, the bridging flocculation effect of an organic polymer, and the adsorption properties of a mineral, exhibiting excellent flocculation and sedimentation effects and pollutant removal capabilities. The details are as follows:

[0036] First: In the scheme, the modified polyacrylamide prepared is an amphoteric organic polymer, which can form a synergistic effect with the positively charged multinuclear hydroxyl complex produced by the hydrolysis of polyaluminum ferric sulfate. This double positive charge system can more effectively neutralize the negatively charged colloidal particles and organic matter in the water, significantly reduce the Zeta potential of the colloidal system, and make the destabilization process more thorough; at the same time, the anionic group (COO -) can also react with Fe on the surface of acidic ochre soil 3+ Produce coordination effect, tightly combining the three components into an overall network structure;

[0037] Second, the long molecular chain of modified polyacrylamide acts as a bridge, with one end bonded to the hydroxyl complex of polyaluminum ferric sulfate through a coordination bond, and the other end connected to the ochre soil particles through electrostatic interaction. This unique connection allows the inorganic flocculant and mineral material to be evenly dispersed within the organic polymer network, forming a composite floc with a three-dimensional structure. Compared with single components, this composite floc is not only larger and denser, but also contains a porous framework provided by the ochre soil, giving it both good settling properties and sufficient porosity to absorb and retain pollutants.

[0038] Third: Polyaluminium ferric sulfate is mainly used to remove colloidal particles and some heavy metals, modified polyacrylamide is good at capturing dissolved organic matter, and acidic ochre soil provides additional adsorption sites and catalytic active sites; among them, the hydrophobic dehydroabietic acid chain segment of modified polyacrylamide can adsorb hydrophobic organic matter, and the imidazole group can also capture polar pollutants through coordination, further improving the water purification effect. DETAILED DESCRIPTION

[0039] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] Example 1: A preparation process of a composite water purifier based on polyaluminium ferric sulfate is as follows:

[0041] Step 1: 15 parts of ferrous sulfate heptahydrate were mixed with 30 parts of deionized water, the pH value was adjusted to 0.5, 1.2 parts of sodium chlorate were added, and the mixture was stirred for 30 minutes to obtain a ferrous sulfate mixture; 12 parts of aluminum sulfate were added to 30 parts of deionized water, stirred evenly, and mixed with 45 parts of the ferrous sulfate mixture and 0.3 parts of phosphoric acid, the temperature was increased to 80° C., the mixture was stirred for 30 minutes, 1.8 parts of sodium carbonate were added, and the mixture was stirred for 30 minutes to obtain a polyaluminum ferric sulfate solution;

[0042] Step 2: Add 0.1 parts of modified polyacrylamide to 10 parts of deionized water to obtain a modified polyacrylamide solution; then slowly add the modified polyacrylamide solution dropwise to 60 parts of polyaluminum ferric sulfate solution, increase the temperature to 60°C, and react for 2 hours to obtain a composite system;

[0043] Step 3: Add 5 parts of acidic ochre soil to 60 parts of the composite system, maintain 60°C, adjust the pH value to 4, and stir for 3 hours to obtain a composite water purifier;

[0044] The preparation process of acidic ochre soil is as follows: pulverizing ochre soil to 200 mesh, stirring with 10% sulfuric acid at 80°C for 2 hours, filtering, washing with deionized water until neutral, and drying at 105°C to obtain acidic ochre soil; the mass ratio of ochre soil to sulfuric acid is 1:3;

[0045] Wherein, the preparation process of modified polyacrylamide is:

[0046] S1: Add 50 parts of dehydroabietic acid to 250 parts of anhydrous dichloromethane, cool to 0°C in an ice bath, slowly add 30 parts of oxalyl chloride and 1 part of N,N-dimethylformamide, keeping the temperature below 5°C throughout the process, remove the ice bath, stir at room temperature for 1 hour, and remove the solvent by rotary evaporation to obtain dehydroabietic acid chloride;

[0047] S2: Add 50 parts of dehydroabietic acid chloride to 200 parts of tetrahydrofuran, cool to 0°C in an ice bath, slowly dropwise add 25 parts of 3-bromopropanol and 20 parts of triethylamine, maintain the temperature below 10°C, and react at room temperature for 6 hours. After the reaction is completed, filter to remove triethylamine hydrochloride, concentrate the filtrate under reduced pressure, and purify by column chromatography to obtain dehydroabietic acid propyl bromide;

[0048] S3: Under a protective atmosphere, 50 parts of propyl bromide dehydroabietic acid, 15 parts of N-vinylimidazole, and 150 parts of methanol were mixed, the temperature was raised to 60° C., and the mixture was refluxed for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and dried to obtain a modified monomer;

[0049] S4: Dissolve 5 parts of modified monomer in 50 parts of ethanol to obtain a modified monomer solution; under a protective atmosphere, add 60 parts of acrylamide, 20 parts of methacryloyloxyethyltrimethylammonium chloride, the modified monomer solution, and 1 part of acrylic acid to 500 parts of deionized water in sequence, stir until completely dissolved, adjust the pH to 5, add 0.05 parts of ammonium persulfate dropwise, increase the temperature to 50°C, react for 3 hours, then add 0.1 parts of hydroquinone, stir for 10 minutes, filter, wash, and dry to obtain modified polyacrylamide.

[0050] Example 2: A preparation process of a composite water purifier based on polyaluminium ferric sulfate is as follows:

[0051] Step 1: 18 parts of ferrous sulfate heptahydrate were mixed with 35 parts of deionized water, the pH value was adjusted to 1, 1.5 parts of sodium chlorate were added, and the mixture was stirred for 40 minutes to obtain a ferrous sulfate mixture; 14 parts of aluminum sulfate were added to 45 parts of deionized water, the mixture was stirred evenly, and the mixture was mixed with 55 parts of the ferrous sulfate mixture and 0.5 parts of phosphoric acid, the temperature was increased to 90° C., the mixture was stirred for 40 minutes, 2.2 parts of sodium carbonate were added, and the mixture was stirred for another 40 minutes to obtain a polyaluminum ferric sulfate solution;

[0052] Step 2: Add 0.2 parts of modified polyacrylamide to 12 parts of deionized water to obtain a modified polyacrylamide solution; then slowly add the modified polyacrylamide solution dropwise to 70 parts of polyaluminum ferric sulfate solution, increase the temperature to 70°C, and react for 3 hours to obtain a composite system;

[0053] Step 3: Add 8 parts of acidic ochre soil to 80 parts of the composite system, maintain 70°C, adjust the pH value to 5, and stir for 4 hours to obtain a composite water purifier;

[0054] The preparation process of acidic ochre soil is as follows: pulverizing ochre soil to 200 mesh, stirring with 10% sulfuric acid at 80°C for 2 hours, filtering, washing with deionized water until neutral, and drying at 105°C to obtain acidic ochre soil; the mass ratio of ochre soil to sulfuric acid is 1:3;

[0055] Wherein, the preparation process of modified polyacrylamide is:

[0056] S1: Add 55 parts of dehydroabietic acid to 300 parts of anhydrous dichloromethane, cool to 0°C in an ice bath, slowly add 35 parts of oxalyl chloride and 2 parts of N,N-dimethylformamide, keeping the temperature below 5°C during the entire process, remove the ice bath, stir at room temperature for 2 hours, and remove the solvent by rotary evaporation to obtain dehydroabietic acid chloride;

[0057] S2: Add 55 parts of dehydroabietic acid chloride to 250 parts of tetrahydrofuran, cool to 0°C in an ice bath, slowly dropwise add 30 parts of 3-bromopropanol and 25 parts of triethylamine, maintain the temperature below 10°C, and react at room temperature for 8 hours. After the reaction is completed, filter to remove triethylamine hydrochloride, concentrate the filtrate under reduced pressure, and purify by column chromatography to obtain dehydroabietic acid propyl bromide;

[0058] S3: Under a protective atmosphere, 55 parts of propyl bromide dehydroabietic acid, 20 parts of N-vinylimidazole, and 200 parts of methanol were mixed, the temperature was raised to 70° C., and the mixture was refluxed for 15 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and dried to obtain a modified monomer;

[0059] S4: Dissolve 10 parts of modified monomer in 80 parts of ethanol to obtain a modified monomer solution; under a protective atmosphere, add 70 parts of acrylamide, 30 parts of methacryloyloxyethyltrimethylammonium chloride, the modified monomer solution, and 5 parts of acrylic acid to 600 parts of deionized water in sequence, stir until completely dissolved, adjust the pH to 6, add 0.1 parts of ammonium persulfate dropwise, increase the temperature to 60°C, react for 4 hours, then add 0.2 parts of hydroquinone, stir for 15 minutes, filter, wash, and dry to obtain modified polyacrylamide.

[0060] Example 3: A preparation process of a composite water purifier based on polyaluminium ferric sulfate is as follows:

[0061] Step 1: 16.5 parts of ferrous sulfate heptahydrate were mixed with 32.5 parts of deionized water, the pH value was adjusted to 0.75, 1.35 parts of sodium chlorate were added, and the mixture was stirred for 35 minutes to obtain a ferrous sulfate mixture; 13 parts of aluminum sulfate were added to 37.5 parts of deionized water, the mixture was stirred evenly, and the mixture was mixed with 50 parts of the ferrous sulfate mixture and 0.4 parts of phosphoric acid, the temperature was increased to 85° C., the mixture was stirred for 35 minutes, 2.0 parts of sodium carbonate were added, and the mixture was stirred for 35 minutes to obtain a polyaluminum ferric sulfate solution;

[0062] Step 2: Add 0.15 parts of modified polyacrylamide to 11 parts of deionized water to obtain a modified polyacrylamide solution; then slowly add the modified polyacrylamide solution dropwise to 65 parts of polyaluminum ferric sulfate solution, increase the temperature to 65°C, and react for 2.5 hours to obtain a composite system;

[0063] Step 3: Add 6.5 parts of acidic ochre soil to 70 parts of the composite system, maintain 65°C, adjust the pH value to 4.5, and stir for 3.5 hours to obtain a composite water purifier;

[0064] The preparation process of acidic ochre soil is as follows: pulverizing ochre soil to 200 mesh, stirring with 10% sulfuric acid at 80°C for 2 hours, filtering, washing with deionized water until neutral, and drying at 105°C to obtain acidic ochre soil; the mass ratio of ochre soil to sulfuric acid is 1:3;

[0065] Wherein, the preparation process of modified polyacrylamide is:

[0066] S1: Add 52.5 parts of dehydroabietic acid to 275 parts of anhydrous dichloromethane, cool to 0°C in an ice bath, slowly add 32.5 parts of oxalyl chloride and 1.5 parts of N,N-dimethylformamide, maintaining the temperature below 5°C throughout the process, remove the ice bath, stir at room temperature for 1.5 hours, and remove the solvent by rotary evaporation to obtain dehydroabietic acid chloride;

[0067] S2: Add 52.5 parts of dehydroabietic acid chloride to 225 parts of tetrahydrofuran, cool to 0°C in an ice bath, slowly add 27.5 parts of 3-bromopropanol and 22.5 parts of triethylamine dropwise in sequence, maintain the temperature below 10°C, and react at room temperature for 7 hours. After the reaction is complete, filter to remove triethylamine hydrochloride, concentrate the filtrate under reduced pressure, and purify by column chromatography to obtain dehydroabietic acid propyl bromide;

[0068] S3: Under a protective atmosphere, 52.5 parts of propyl bromide dehydroabietic acid, 17.5 parts of N-vinylimidazole, and 175 parts of methanol were mixed, the temperature was raised to 65° C., and the mixture was refluxed for 13.5 hours. After the reaction was completed, the mixture was cooled to room temperature, filtered, washed, and dried to obtain a modified monomer;

[0069] S4: Dissolve 7.5 parts of modified monomer in 65 parts of ethanol to obtain a modified monomer solution; under a protective atmosphere, add 65 parts of acrylamide, 25 parts of methacryloyloxyethyltrimethylammonium chloride, the modified monomer solution, and 3 parts of acrylic acid to 550 parts of deionized water in sequence, stir until completely dissolved, adjust the pH to 5.5, add 0.075 parts of ammonium persulfate dropwise, increase the temperature to 55°C, react for 3.5 hours, then add 0.15 parts of hydroquinone, stir for 12.5 minutes, filter, wash, and dry to obtain modified polyacrylamide.

[0070] Comparative Example 1: Using a single polyaluminium ferric sulfate water purifier, the details are as follows:

[0071] Mix 16.5 parts of ferrous sulfate heptahydrate with 32.5 parts of deionized water, adjust the pH value to 0.75, add 1.35 parts of sodium chlorate, and stir for 35 minutes to obtain a ferrous sulfate mixture; add 13 parts of aluminum sulfate to 37.5 parts of deionized water, stir evenly, mix with 50 parts of ferrous sulfate mixture and 0.4 parts of phosphoric acid, increase the temperature to 85°C, stir for 35 minutes, add 2.0 parts of sodium carbonate, and continue stirring for 35 minutes to obtain a polyaluminum ferric sulfate water purifier.

[0072] Comparative Example 2: Unmodified polyacrylamide was used instead of modified polyacrylamide, and the rest was the same as Example 3, specifically as follows:

[0073] Step 1: 16.5 parts of ferrous sulfate heptahydrate were mixed with 32.5 parts of deionized water, the pH value was adjusted to 0.75, 1.35 parts of sodium chlorate were added, and the mixture was stirred for 35 minutes to obtain a ferrous sulfate mixture; 13 parts of aluminum sulfate were added to 37.5 parts of deionized water, the mixture was stirred evenly, and the mixture was mixed with 50 parts of the ferrous sulfate mixture and 0.4 parts of phosphoric acid, the temperature was increased to 85° C., the mixture was stirred for 35 minutes, 2.0 parts of sodium carbonate were added, and the mixture was stirred for 35 minutes to obtain a polyaluminum ferric sulfate solution;

[0074] Step 2: Add 0.15 parts of polyacrylamide to 11 parts of deionized water to obtain a modified polyacrylamide solution; then slowly add the modified polyacrylamide solution dropwise to 65 parts of polyaluminum ferric sulfate solution, increase the temperature to 65°C, and react for 2.5 hours to obtain a composite system;

[0075] Step 3: Add 6.5 parts of acidic ochre soil to 70 parts of the composite system, maintain 65°C, adjust the pH value to 4.5, and stir for 3.5 hours to obtain a composite water purifier;

[0076] The preparation process of acidic ochre soil is as follows: pulverizing ochre soil to 200 mesh, stirring with 10% sulfuric acid at 80°C for 2 hours, filtering, washing with deionized water until neutral, and drying at 105°C to obtain acidic ochre soil; the mass ratio of ochre soil to sulfuric acid is 1:3;

[0077] Wherein, the preparation process of polyacrylamide is:

[0078] Under a protective atmosphere, 65 parts of acrylamide, 25 parts of methacryloyloxyethyltrimethylammonium chloride, and 3 parts of acrylic acid were added sequentially to 550 parts of deionized water, stirred until completely dissolved, the pH was adjusted to 5.5, 0.075 parts of ammonium persulfate were added dropwise, the temperature was raised to 55°C, and the reaction was carried out for 3.5 hours. Then, 0.15 parts of hydroquinone were added, stirred for 12.5 minutes, filtered, washed, and dried to obtain modified polyacrylamide.

[0079] Comparative Example 3: No modified polyacrylamide was added, and the rest was the same as in Example 3, specifically as follows:

[0080] Step 1: 16.5 parts of ferrous sulfate heptahydrate were mixed with 32.5 parts of deionized water, the pH value was adjusted to 0.75, 1.35 parts of sodium chlorate were added, and the mixture was stirred for 35 minutes to obtain a ferrous sulfate mixture; 13 parts of aluminum sulfate were added to 37.5 parts of deionized water, the mixture was stirred evenly, and the mixture was mixed with 50 parts of the ferrous sulfate mixture and 0.4 parts of phosphoric acid, the temperature was increased to 85° C., the mixture was stirred for 35 minutes, 2.0 parts of sodium carbonate were added, and the mixture was stirred for 35 minutes to obtain a polyaluminum ferric sulfate solution;

[0081] Step 2: Add 6.5 parts of acidic ochre soil to 70 parts of polyaluminum ferric sulfate solution, maintain 65° C., adjust the pH value to 4.5, and stir for 3.5 hours to obtain a composite water purifier;

[0082] The preparation process of acidic ochre soil is as follows: pulverizing the ochre soil to 200 mesh, stirring and reacting with 10% sulfuric acid at 80°C for 2 hours, filtering and washing with deionized water until neutral, and drying at 105°C to obtain acidic ochre soil; the mass ratio of the ochre soil to sulfuric acid is 1:3.

[0083] Detection test: Dissolve kaolin in deionized water to prepare a suspension with a turbidity of 100 NTU, add humic acid (20 mg / L) to simulate COD pollution, add Pb(NO3)2 and K2Cr2O7 solution to make Pb 2+ Cr 6+ The concentration of each was 10 mg / L to obtain simulated sewage; 500 mL of simulated sewage was placed in a beaker, the pH was adjusted to 7, 50 mg / L of the composite water purifier obtained in the embodiment and the comparative example was added, stirred, and the following test was performed:

[0084] (1) Take the supernatant and measure the absorbance at a wavelength of 550 nm using a spectrophotometer, convert it into NTU, and calculate the turbidity removal rate;

[0085] (2) COD removal rate was determined using the potassium dichromate method (GB11914-89);

[0086] (3) After filtering the supernatant, the residual Pb was detected by atomic absorption spectrophotometer. 2+ , calculated to obtain Pb 2+ removal rate;

[0087] (4) Record the settling time; the data obtained are shown in the following table:

[0088]

[0089] Table 1

[0090] Conclusion: The composite water purifier obtained in the embodiment achieves efficient and rapid water purification effect through the ternary synergistic effect, and its comprehensive performance far exceeds that of single or binary components, and is suitable for treating complex sewage (containing turbidity, organic matter and heavy metal pollution).

[0091] Comparative Example 1 relies solely on inorganic flocculants and lacks the bridging effect of organic polymers, resulting in small flocs and slow sedimentation (15min), and low removal rates of organic matter (COD) and heavy metals (≤70%), due to the lack of adsorption assistance from ochre soil; Comparative Example 2 The bridging effect of ordinary polyacrylamide improves the turbidity removal rate (90.1%), but lacks amphoteric charges and hydrophobic groups, and the removal of COD and heavy metals is limited; Comparative Example 3 Ochre soil adsorption improves Pb 2+ The removal rate was high (82.3%), but the polyacrylamide bridging network was lacking and the flocs were loose (settling time 12 min).

[0092] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0093] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A composite water purifier based on polyaluminium ferric sulfate, characterized in that: The preparation process of the composite water purifier is: Step 1: Mix ferrous sulfate heptahydrate with deionized water, adjust the pH value to 0.5-1, add sodium chlorate, and stir for 30-40 minutes to obtain a ferrous sulfate mixture; add aluminum sulfate to the deionized water, stir evenly, mix with the ferrous sulfate mixture and phosphoric acid, increase the temperature to 80-90° C., stir for 30-40 minutes, add sodium carbonate, and continue stirring for 30-40 minutes to obtain a polyaluminum ferric sulfate solution; Step 2: Add the modified polyacrylamide to deionized water to obtain a modified polyacrylamide solution; then slowly add the modified polyacrylamide solution dropwise to the polyaluminum ferric sulfate solution, increase the temperature to 60-70°C, and react for 2-3 hours to obtain a composite system; Step 3: Add acidic ochre soil to the composite system, maintain 60-70°C, adjust the pH value to 4-5, and stir for 3-4 hours to obtain a composite water purifier.

2. A composite water purifier based on polyaluminium ferric sulfate according to claim 1, characterized in that: The ferrous sulfate mixed solution raw material comprises the following components: 15-18 parts of ferrous sulfate heptahydrate, 30-35 parts of deionized water, and 1.2-1.5 parts of sodium chlorate, by weight; The raw materials of the polyaluminum ferric sulfate solution include the following components: by weight, 12-14 parts of aluminum sulfate, 30-45 parts of deionized water, 0.3-0.5 parts of phosphoric acid, 45-55 parts of ferrous sulfate mixed solution, and 1.8-2.2 parts of sodium carbonate.

3. A composite water purifier based on polyaluminium ferric sulfate according to claim 1, characterized in that: The composite system raw materials include the following components: by weight, 0.1-0.2 parts of modified polyacrylamide, 10-12 parts of deionized water, and 60-70 parts of polyaluminum ferric sulfate solution.

4. A composite water purifier based on polyaluminium ferric sulfate according to claim 1, characterized in that: The composite water purifier raw materials include the following components: 5-8 parts of acidic ochre soil and 60-80 parts of a composite system, calculated by weight.

5. The composite water purifier based on polyaluminium ferric sulfate according to claim 1, characterized in that: The preparation process of the modified polyacrylamide is as follows: S1: Add dehydroabietic acid to anhydrous dichloromethane, cool to 0°C in an ice bath, slowly add oxalyl chloride and N,N-dimethylformamide, maintaining the temperature below 5°C throughout the process, remove the ice bath, stir at room temperature for 1-2 hours, and remove the solvent by rotary evaporation to obtain dehydroabietic acid chloride; S2: Dehydroabietic acid chloride is added to tetrahydrofuran, cooled to 0°C in an ice bath, and 3-bromopropanol and triethylamine are slowly added dropwise in sequence, maintaining the temperature below 10°C. The reaction is carried out at room temperature for 6-8 hours. After the reaction is completed, triethylamine hydrochloride is removed by filtration, and the filtrate is concentrated under reduced pressure and purified by column chromatography to obtain dehydroabietic acid propyl bromide; S3: Under a protective atmosphere, propyl bromide dehydroabietic acid, N-vinylimidazole, and methanol are mixed, the temperature is raised to 60-70° C., and the mixture is refluxed for 12-15 hours. After the reaction is completed, the mixture is cooled to room temperature, filtered, washed, and dried to obtain a modified monomer; S4: dissolving the modified monomer in ethanol to obtain a modified monomer solution; Under a protective atmosphere, acrylamide, methacryloyloxyethyltrimethylammonium chloride, modified monomer solution, and acrylic acid are added to deionized water in sequence, stirred until completely dissolved, the pH is adjusted to 5-6, ammonium persulfate is added dropwise, the temperature is increased to 50-60°C, the reaction is carried out for 3-4 hours, and then hydroquinone is added, stirred for 10-15 minutes, filtered, washed, and dried to obtain modified polyacrylamide.

6. A composite water purifier based on polyaluminium ferric sulfate according to claim 5, characterized in that: The dehydroabietic acid chloride raw material comprises the following components: by weight, 50-55 parts of dehydroabietic acid, 250-300 parts of anhydrous dichloromethane, 30-35 parts of oxalyl chloride, and 1-2 parts of N,N-dimethylformamide.

7. The composite water purifier based on polyaluminium ferric sulfate according to claim 5, characterized in that: The raw material of dehydroabietin propyl bromide comprises the following components: by weight, 50-55 parts of dehydroabietin acid chloride, 200-250 parts of tetrahydrofuran, 25-30 parts of 3-bromopropanol, and 20-25 parts of triethylamine.

8. The composite water purifier based on polyaluminium ferric sulfate according to claim 5, characterized in that: The modified monomer raw material comprises the following components: 50-55 parts by weight of propyl bromide-dehydroabietate, 15-20 parts by weight of N-vinyl imidazole, and 150-200 parts by weight of methanol.

9. The composite water purifier based on polyaluminium ferric sulfate according to claim 5, characterized in that: The modified polyacrylamide raw material includes the following components: by weight, 5-10 parts of modified monomer, 50-80 parts of ethanol, 60-70 parts of acrylamide, 20-30 parts of methacryloyloxyethyltrimethylammonium chloride, 1-5 parts of acrylic acid, 500-600 parts of deionized water, 0.05-0.1 parts of ammonium persulfate, and 0.1-0.2 parts of hydroquinone.

10. The composite water purifier based on polyaluminium ferric sulfate according to claim 1, characterized in that: The preparation process of the acidic ochre soil comprises the following steps: crushing the ochre soil to 200 meshes, stirring and reacting with 10-15% sulfuric acid at 80-90° C. for 2-3 hours, filtering, washing with deionized water until neutral, and drying at 105° C. to obtain the acidic ochre soil; the mass ratio of the ochre soil to the sulfuric acid is 1:3.

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