Method for preparing polyaluminium chloride water purifier from aluminium mud

Abstract

The present invention belongs to the technical field of water treatment water purifiers, and specifically relates to a method for preparing a polyaluminium chloride water purifier from aluminium mud. The present invention prepares an aluminium-containing solution by ball milling, washing and acidolysis of aluminium mud, and then adds calcium aluminate to adjust the aluminium content of the solution for aging to prepare polyaluminium chloride, and then adds a polyaluminium chloride flocculant prepared by polymerizing cationic polyacrylamide and 2-ethylhexyl acrylate, which is easier to form macromolecular clusters, thereby improving the flocculation effect of water purification; bamboo fiber loads magnesium aluminium hydrotalcite, and the modified carbon adsorption material prepared by low temperature calcination carbonization has excellent adsorption capacity; catechol-modified cotton fiber is then attached to the oil adsorption aid prepared by the hydrophobic coating of silica sol, which has excellent selective oil absorption capacity; the polyaluminium chloride water purifier obtained by compounding the polyaluminium chloride flocculant with aluminium sulfate, the modified carbon adsorption material and the oil adsorption aid in a certain proportion has excellent adsorption sedimentation and temperature difference adaptability, and can realize the reuse of aluminium resources.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment purifiers, and in particular relates to a method for preparing a polyaluminium chloride purifier from aluminium mud. Background Art

[0002] Aluminum mud, also known as aluminum alum mud, is a soil weathering product formed by the reaction of aluminum and ammonium ions in water. The composition of aluminum mud is relatively complex, mainly containing aluminum oxide, aluminum hydroxide, metallic aluminum and other impurities, and has a certain strong acidity. my country produces a large amount of aluminum mud every year. The common method of dealing with aluminum mud is landfill treatment, but this method requires the occupation of land resources and may have potential environmental pollution risks. Therefore, it is necessary to study ways to expand the reuse of aluminum mud in order to achieve the purpose of increasing aluminum resources. The use of aluminum mud to prepare polyaluminum chloride water reducer can realize the reuse of aluminum resources and reduce the production cost of polyaluminum chloride, but the current polyaluminum chloride water purifier has the disadvantages of large dosage, slow hydrolysis rate, slow floc sedimentation rate and unstable flocculation effect.

[0003] The Chinese invention patent with publication number CN112897658B discloses a method for preparing polyaluminium chloride composite flocculant using sludge from an aluminium profile factory, wherein polyaluminium chloride is produced using sludge from an aluminium profile factory, calcium oxide and hydrochloric acid as main raw materials, and then neutral Al is added. 3+ Adsorption detection adsorbent can not only realize the recycling of resources, but also adsorb Al 3+ and metal ions, greatly reducing the consumption of aluminum resources. The Chinese invention patent with publication number CN104998620B discloses a modified peanut shell biochar / polyaluminium chloride sludge composite adsorption material, which is prepared from agricultural solid waste peanut shells and water plant polyaluminium chloride sludge according to the following process: peanut shell modification, peanut shell anaerobic pyrolysis, peanut shell biochar oxygen supplementation, peanut shell biochar vacuum acid treatment, polyaluminium chloride sludge modification, magnetic magnesium oxide bonding, adhesive preparation, and composite adsorption material preparation. The invention uses organic agricultural solid waste peanut shells and water plant sludge as raw materials to prepare a new composite adsorption material that has both efficient adsorption of organic pollutants and phosphorus in water. It has both the adsorption effect of modified biochar and the phosphorus removal ability of polyaluminium chloride sludge, especially for dye-containing wastewater and sewage deep phosphorus removal. It has a good removal effect. However, the prior art has a technical problem that after the aluminum sludge is preliminarily treated to obtain a polyaluminium chloride solution, the components of the polyaluminium chloride water purifier are not further improved to improve the flocculation effect and expand the applicable temperature range. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing a polyaluminium chloride water purifier from aluminium mud, so as to solve the technical problem that after the aluminium mud is preliminarily treated to obtain a polyaluminium chloride solution in the prior art, the components of the polyaluminium chloride water purifier are not improved to improve the flocculation effect and expand the applicable temperature range.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The method for preparing polyaluminium chloride water purifier from aluminium mud comprises the following steps:

[0007] S1. Grind 200-300 g of aluminum mud with a ball mill for 1-2 h, sieve to remove solid impurities, add to deionized water, wash at 50-60 ° C for 6-12 h to remove soluble salts, add to a reactor, add 30-36.5 wt% hydrochloric acid under stirring, acid hydrolyze at 75-80 ° C for 2-3 h, filter to remove the filter residue to obtain an aluminum-containing solution, add calcium aluminate to the aluminum-containing solution, mature at 80-85 ° C for 2-3 h, filter to remove the filter residue, and obtain a polyaluminum chloride solution;

[0008] S2, 700-800 mL of polyaluminium chloride solution was adjusted to a specified concentration with deionized water, 70-90 g of cationic polyacrylamide and 2.5-3.5 g of 2-ethylhexyl acrylate were added, and 2-5 g of a surfactant was added, the temperature was raised and nitrogen was introduced, 1.5-2.5 g of an initiator was added dropwise within 1-2 h, and the mixture was kept warm for 4-6 h to obtain a gel;

[0009] S3, dissolving the gel in S2 in deionized water, adding acetone dropwise until floccules are precipitated, filtering and washing with ethanol, and drying to obtain a polyaluminium chloride flocculant;

[0010] S4. Put 50-70g of polyaluminium chloride flocculant, 10-15g of aluminium sulfate, 15-20g of modified carbon adsorption material and 15-20g of oil adsorption aid into a ball mill, ball mill for 30-40min, and package to obtain polyaluminium chloride water purifier product.

[0011] Preferably, the mesh size of the sieve in S1 is 100-150 meshes.

[0012] Preferably, in S1, the mass ratio of aluminum mud to deionized water is 1:4-6, the mass ratio of aluminum mud to hydrochloric acid is 1:1.5-2, and the mass ratio of aluminum-containing solution to calcium aluminate is 6-8:1.

[0013] Preferably, the polyaluminium chloride solution in S2 is adjusted to a concentration of 10-30 g / L using deionized water, and the surfactant is one or more combinations of dodecyltrimethylammonium bromide, dodecyl polyoxyethylene ether, and sodium lauroamphoacetate.

[0014] Preferably, the initiator in S2 is one or more combinations of ammonium persulfate-sodium bisulfite, azobisisobutyronitrile, and azobisdimethylvaleronitrile.

[0015] Preferably, the method for preparing the modified carbon adsorption material of S4 comprises the following steps:

[0016] S11, adding aluminum chloride and magnesium chloride into deionized water, adding bamboo fiber and then ultrasonically dispersing for 30-40 minutes;

[0017] S12, slowly dropwise add a mixed solution made of 139-141 g / L sodium hydroxide and 100-105 g / L sodium carbonate into the system, adjust the pH of the system to 10.0±0.3, raise the temperature to 80-90°C, crystallize under stirring for 10-14 hours, filter and collect the solid after cooling, and rinse with deionized water and ethanol in sequence;

[0018] S13. Calcine the solid at 400-450° C. for 4-6 hours under a nitrogen atmosphere to obtain a modified carbon adsorption material.

[0019] Preferably, the mass ratio of aluminum chloride to magnesium chloride in S11 is 1:2.5-3.5.

[0020] Preferably, the amount of bamboo fiber added in S11 is 5-8wt% of the total mass of aluminum chloride and magnesium chloride.

[0021] Preferably, the method for preparing the oil adsorption auxiliary agent of S4 comprises the following steps:

[0022] S21, adding 10-15 g of cotton fiber into a treatment solution composed of 3-5 g / L sodium hydroxide, 5-7 g / L hydrogen peroxide and 1-3 g / L dodecanol polyoxyethylene ether at 50-60° C. and soaking for 3-4 hours, taking out the cotton fiber, neutralizing it with 5 wt % hydrochloric acid, washing it with deionized water, and drying it at 80-90° C. to obtain pretreated cotton fiber;

[0023] S22, dissolving 1.41 g of tris(hydroxymethyl)aminomethane in 50 ml of deionized water, adding 36.5 wt % hydrochloric acid and stirring for 10 to 20 min, then adding 250 ml of deionized water to adjust the pH to 8.4 to 8.6 to prepare a buffer solution, dissolving 0.5 to 0.8 g of catechol in the buffer solution, soaking the pretreated cotton fiber for 12 to 18 h, and drying to obtain catechol-modified cotton fiber;

[0024] S23, adding catechol-modified cotton fiber into alkaline silica sol liquid, reacting for 12 to 18 hours, and drying to obtain an oil adsorption aid.

[0025] Preferably, the pH of the alkaline silica sol in S23 is 9-10, the silica sol has a silicon dioxide content of 15-30 wt %, and an average particle size of 2-10 nm.

[0026] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0027] The invention prepares an aluminum-containing solution by ball-milling, washing and acid-lyzing aluminum mud, then adds calcium aluminate to adjust the aluminum content of the solution, and then matures to prepare polyaluminum chloride, and then adds a polyaluminum chloride flocculant prepared by polymerization of cationic polyacrylamide and 2-ethylhexyl acrylate, and compounding with aluminum sulfate, modified carbon adsorption material and oil adsorption auxiliary agent in a certain proportion to obtain a polyaluminum chloride water purifier. The polyaluminum chloride water purifier has strong selective adsorption capacity for phosphorus elements and oil pollution in sewage, and can generate stable floccules even when the amount of the polyaluminum chloride water purifier added is small, and has excellent adsorption sedimentation and temperature difference adaptability. The aluminum mud is used to prepare polyaluminum chloride, and the aluminum resource can be recycled.

[0028] The invention uses polyaluminium chloride as the core, cationic polyacrylamide and 2-ethylhexyl acrylate as bridging agent polyaluminium chloride flocculant, which is easier to form macromolecular clusters, thereby generating large and dense floccules during the coagulation process, thereby improving the water purification flocculation effect.

[0029] The modified carbon adsorption material prepared by the present invention is prepared by loading magnesium aluminum hydrotalcite on bamboo fiber and then calcining and carbonizing it at low temperature. The modified carbon adsorption material has a relatively large mesoporous structure and a high specific surface area, can provide sufficient adsorption sites, has excellent adsorption and impurity removal capabilities, and the synthetic material is renewable and relatively environmentally friendly.

[0030] The invention uses catechol to modify cotton fibers and then attaches a hydrophobic coating through the reaction of catechol and silica sol. The prepared oil adsorption auxiliary agent has a super hydrophobic surface and excellent selective oil absorption capacity. The oil-water separation of sewage emulsion can be promoted when compounded with a polyaluminium chloride flocculant. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0032] The contents of the components of the aluminum mud used in the embodiments and comparative examples of the present invention are as follows: 64.3% aluminum oxide, 14.2% silicon dioxide, 3.6% aluminum hydroxide, 6.9% metallic aluminum, 4.2% calcium oxide, 5.4% chloride, and 1.4% other impurities.

[0033] Embodiment 1, the method for preparing polyaluminium chloride water purifier from aluminium mud of this embodiment comprises the following steps:

[0034] S1. Grind 300g of aluminum mud with a ball mill for 2h, remove solid impurities through a 150-mesh sieve, add deionized water, the mass ratio of aluminum mud to deionized water is 1:4, wash at 60°C for 10h to remove soluble salts, add to a reactor, add 36.5wt% hydrochloric acid under stirring, the mass ratio of aluminum mud to hydrochloric acid is 1:1.5, acid hydrolyze at 80°C for 2h, filter and remove the filter residue to obtain an aluminum-containing solution, add calcium aluminate to the aluminum-containing solution, the mass ratio of aluminum-containing solution to calcium aluminate is 7:1, mature at 80°C for 2h, filter and remove the filter residue to obtain a polyaluminum chloride solution;

[0035] S2, 700mL of polyaluminium chloride solution was adjusted to a concentration of 10g / L with deionized water, 70g of cationic polyacrylamide and 2.5g of 2-ethylhexyl acrylate were added, and 2g of dodecyltrimethylammonium bromide was added, the temperature was raised and nitrogen was introduced, 2g of ammonium persulfate-sodium bisulfite initiator was added dropwise, and the mixture was dripped within 2h, and the mixture was kept warm for 6h to obtain a gel;

[0036] S3, dissolving the gel in S2 in deionized water, adding acetone dropwise until floccules are precipitated, filtering and washing with ethanol, and drying to obtain a polyaluminium chloride flocculant;

[0037] S4. Put 60g of polyaluminium chloride flocculant, 10g of aluminium sulfate, 15g of modified carbon adsorption material and 15g of oil adsorption aid into a ball mill, ball mill for 30min, and package to obtain polyaluminium chloride water purifier product.

[0038] The method for preparing the modified carbon adsorption material of this embodiment comprises the following steps:

[0039] S11, adding 13.4 g of aluminum chloride and 33.5 g of magnesium chloride into deionized water, adding 2.4 g of bamboo fiber and then ultrasonically dispersing for 30 min;

[0040] S12, slowly dropwise add a mixed solution of 140 g / L sodium hydroxide and 105 g / L sodium carbonate into the system, adjust the pH of the system to 10.0, raise the temperature to 90° C., crystallize under stirring for 10 h, filter and collect the solid after cooling, and rinse with deionized water and ethanol in sequence;

[0041] S13. Calcine the solid at 450° C. for 6 h under a nitrogen atmosphere to obtain a modified carbon adsorption material.

[0042] The preparation method of the oil adsorption auxiliary agent of this embodiment comprises the following steps:

[0043] S21, adding 15 g of cotton fiber into a treatment solution composed of 5 g / L sodium hydroxide, 5 g / L hydrogen peroxide and 1 g / L dodecanol polyoxyethylene ether at 60° C. and soaking for 3 h, taking out the cotton fiber, neutralizing it with 5 wt % hydrochloric acid, washing it with deionized water, and drying it at 80-90° C. to obtain pretreated cotton fiber;

[0044] S22, dissolving 1.41 g of tris(hydroxymethyl)aminomethane in 50 ml of deionized water, adding 36.5 wt % hydrochloric acid and stirring for 10 min, then adding 250 ml of deionized water to adjust the pH to 8.5 to prepare a buffer solution, dissolving 0.6 g of catechol in the buffer solution, soaking the pretreated cotton fiber for 12 h, and drying to obtain catechol-modified cotton fiber;

[0045] S23, adding catechol-modified cotton fiber to an alkaline silica sol liquid with a silica content of 15 wt %, an average particle size of 7 nm, and a pH of 10, reacting for 12 hours, and drying to obtain an oil adsorption aid.

[0046] Embodiment 2, the method for preparing polyaluminium chloride water purifier from aluminium mud of this embodiment comprises the following steps:

[0047] S1. Grind 250g of aluminum mud with a ball mill for 1h, remove solid impurities through a 150-mesh sieve, add deionized water, the mass ratio of aluminum mud to deionized water is 1:4.5, wash at 50°C for 12h to remove soluble salts, add to a reactor, add 30wt% hydrochloric acid under stirring, the mass ratio of aluminum mud to hydrochloric acid is 1:1.6, acid hydrolyze at 75°C for 3h, filter and remove the filter residue to obtain an aluminum-containing solution, add calcium aluminate to the aluminum-containing solution, the mass ratio of aluminum-containing solution to calcium aluminate is 6:1, mature at 80°C for 2h, filter and remove the filter residue to obtain a polyaluminum chloride solution;

[0048] S2, 800mL of polyaluminium chloride solution was adjusted to a concentration of 15g / L with deionized water, 80g of cationic polyacrylamide and 3g of 2-ethylhexyl acrylate were added, and 3g of dodecyl polyoxyethylene ether was added, the temperature was raised and nitrogen was introduced, 1.5g of ammonium persulfate-sodium bisulfite initiator was added dropwise, and the mixture was dripped within 1h, and the mixture was kept warm for 4h to obtain a gel;

[0049] S3, dissolving the gel in S2 in deionized water, adding acetone dropwise until floccules are precipitated, filtering and washing with ethanol, and drying to obtain a polyaluminium chloride flocculant;

[0050] S4. Put 50g of polyaluminium chloride flocculant, 15g of aluminium sulfate, 15g of modified carbon adsorption material and 20g of oil adsorption aid into a ball mill, ball mill for 30min, and package to obtain polyaluminium chloride water purifier product.

[0051] The method for preparing the modified carbon adsorption material of this embodiment comprises the following steps:

[0052] S11, adding 13.4 g of aluminum chloride and 38.0 g of magnesium chloride into deionized water, adding 3.1 g of bamboo fiber and then ultrasonically dispersing for 30 min;

[0053] S12, slowly dropwise add a mixed solution of 139 g / L sodium hydroxide and 100 g / L sodium carbonate into the system, adjust the pH of the system to 9.7, raise the temperature to 80°C, crystallize under stirring for 14 h, cool and filter to collect the solid, and rinse with deionized water and ethanol in turn;

[0054] S13. Calcine the solid at 400° C. for 4 h under a nitrogen atmosphere to obtain a modified carbon adsorption material.

[0055] The preparation method of the oil adsorption auxiliary agent of this embodiment comprises the following steps:

[0056] S21, adding 15 g of cotton fiber into a treatment solution composed of 3 g / L sodium hydroxide, 6 g / L hydrogen peroxide and 1 g / L polyoxyethylene dodecanol at 50° C. and soaking for 4 hours, taking out the cotton fiber, neutralizing it with 5 wt % hydrochloric acid, washing it with deionized water, and drying it at 90° C. to obtain pretreated cotton fiber;

[0057] S22, dissolving 1.41 g of tris(hydroxymethyl)aminomethane in 50 ml of deionized water, adding 36.5 wt % hydrochloric acid and stirring for 10 min, then adding 250 ml of deionized water to adjust the pH to 8.4 to prepare a buffer solution, dissolving 0.5 g of catechol in the buffer solution, soaking the pretreated cotton fiber for 14 h, and drying to obtain catechol-modified cotton fiber;

[0058] S23, adding catechol-modified cotton fiber to an alkaline silica sol liquid with a silica content of 30 wt %, an average particle size of 9 nm, and a pH of 9.5, reacting for 12 hours, and drying to obtain an oil adsorption aid.

[0059] Embodiment 3, the method for preparing polyaluminium chloride water purifier from aluminium mud of this embodiment comprises the following steps:

[0060] S1. Grind 300g of aluminum mud with a ball mill for 2h, remove solid impurities through a 120-mesh sieve, add deionized water, the mass ratio of aluminum mud to deionized water is 1:5, wash at 60°C for 6h to remove soluble salts, add to a reactor, add 35wt% hydrochloric acid under stirring, the mass ratio of aluminum mud to hydrochloric acid is 1:1.8, acid hydrolyze at 80°C for 2.5h, filter and remove the filter residue to obtain an aluminum-containing solution, add calcium aluminate to the aluminum-containing solution, the mass ratio of aluminum-containing solution to calcium aluminate is 6:1, mature at 80°C for 2h, filter and remove the filter residue to obtain a polyaluminum chloride solution;

[0061] S2, 700mL of polyaluminium chloride solution was adjusted to a concentration of 20g / L with deionized water, 75g of cationic polyacrylamide and 2.5g of 2-ethylhexyl acrylate were added, and 2.5g of dodecyltrimethylammonium bromide was added, the temperature was raised and nitrogen was introduced, 2.5g of azobisisobutyronitrile initiator was added dropwise, and the mixture was dripped within 1.5h, and the mixture was kept warm for 5h to obtain a gel;

[0062] S3, dissolving the gel in S2 in deionized water, adding acetone dropwise until floccules are precipitated, filtering and washing with ethanol, and drying to obtain a polyaluminium chloride flocculant;

[0063] S4. Put 60g of polyaluminium chloride flocculant, 10g of aluminium sulfate, 15g of modified carbon adsorption material and 15g of oil adsorption aid into a ball mill, ball mill for 40min, and package to obtain polyaluminium chloride water purifier product.

[0064] The method for preparing the modified carbon adsorption material of this embodiment comprises the following steps:

[0065] S11, adding 6.7g aluminum chloride and 19.0g magnesium chloride into deionized water, adding 1.5g bamboo fiber and then ultrasonically dispersing for 30min;

[0066] S12, slowly dropwise add a mixed solution of 140 g / L sodium hydroxide and 100 g / L sodium carbonate into the system, adjust the pH of the system to 10.0, raise the temperature to 85°C, crystallize for 12 h under stirring, cool and filter to collect the solid, and rinse with deionized water and ethanol in sequence;

[0067] S13. Calcine the solid at 450° C. for 4 h under a nitrogen atmosphere to obtain a modified carbon adsorption material.

[0068] The preparation method of the oil adsorption auxiliary agent of this embodiment comprises the following steps:

[0069] S21, adding 10 g of cotton fiber into a treatment solution composed of 5 g / L sodium hydroxide, 7 g / L hydrogen peroxide and 3 g / L dodecanol polyoxyethylene ether at 60° C. and soaking for 4 hours, taking out the cotton fiber, neutralizing it with 5 wt % hydrochloric acid, washing it with deionized water, and drying it at 90° C. to obtain pretreated cotton fiber;

[0070] S22, dissolving 1.41 g of tris(hydroxymethyl)aminomethane in 50 ml of deionized water, adding 36.5 wt % hydrochloric acid and stirring for 15 min, then adding 250 ml of deionized water to adjust the pH to 8.6 to prepare a buffer solution, dissolving 0.8 g of catechol in the buffer solution, soaking the pretreated cotton fiber for 18 h, and drying to obtain catechol-modified cotton fiber;

[0071] S23, adding catechol-modified cotton fiber to an alkaline silica sol liquid with a silica content of 30 wt %, an average particle size of 9 nm, and a pH of 9.5, reacting for 12 hours, and drying to obtain an oil adsorption aid.

[0072] Embodiment 4, the method for preparing polyaluminium chloride water purifier from aluminium mud of this embodiment comprises the following steps:

[0073] S1. Grind 200g of aluminum mud with a ball mill for 1h, remove solid impurities through a 150-mesh sieve, add deionized water, the mass ratio of aluminum mud to deionized water is 1:6, wash at 55°C for 8h to remove soluble salts, add to a reactor, add 36.5wt% hydrochloric acid under stirring, the mass ratio of aluminum mud to hydrochloric acid is 1:2, acid hydrolyze at 80°C for 2h, filter and remove the filter residue to obtain an aluminum-containing solution, add calcium aluminate to the aluminum-containing solution, the mass ratio of aluminum-containing solution to calcium aluminate is 8:1, mature at 85°C for 2h, filter and remove the filter residue to obtain a polyaluminum chloride solution;

[0074] S2, 800mL of polyaluminium chloride solution was adjusted to a concentration of 30g / L with deionized water, 80g of cationic polyacrylamide and 3.5g of 2-ethylhexyl acrylate were added, and 5g of sodium lauroylamphoacetate was added, the temperature was raised and nitrogen was introduced, 1.5g of azobisdimethylvaleronitrile was added dropwise, and the mixture was dripped within 1h, and the mixture was kept warm for 4h to obtain a gel;

[0075] S3, dissolving the gel in S2 in deionized water, adding acetone dropwise until floccules are precipitated, filtering and washing with ethanol, and drying to obtain a polyaluminium chloride flocculant;

[0076] S4. Put 55g of polyaluminium chloride flocculant, 10g of aluminium sulfate, 20g of modified carbon adsorption material and 15g of oil adsorption aid into a ball mill, ball mill for 35min, and package to obtain polyaluminium chloride water purifier product.

[0077] The method for preparing the modified carbon adsorption material of this embodiment comprises the following steps:

[0078] S11, adding 13.4 g of aluminum chloride and 33.3 g of magnesium chloride into deionized water, adding 3.7 g of bamboo fiber and then ultrasonically dispersing for 30 min;

[0079] S12, slowly dropwise add a mixed solution of 141 g / L sodium hydroxide and 100 g / L sodium carbonate into the system, adjust the pH of the system to 10.0, raise the temperature to 90° C., crystallize under stirring for 10 h, filter and collect the solid after cooling, and rinse with deionized water and ethanol in sequence;

[0080] S13. Calcine the solid at 450° C. for 6 h under a nitrogen atmosphere to obtain a modified carbon adsorption material.

[0081] The preparation method of the oil adsorption auxiliary agent of this embodiment comprises the following steps:

[0082] S21, adding 10 g of cotton fiber into a treatment solution composed of 4 g / L sodium hydroxide, 6 g / L hydrogen peroxide and 2 g / L polyoxyethylene dodecanol at 50° C. and soaking for 3 h, taking out the cotton fiber, neutralizing it with 5 wt % hydrochloric acid, washing it with deionized water, and drying it at 90° C. to obtain pretreated cotton fiber;

[0083] S22, dissolving 1.41 g of tris(hydroxymethyl)aminomethane in 50 ml of deionized water, adding 36.5 wt % hydrochloric acid and stirring for 20 min, then adding 250 ml of deionized water to adjust the pH to 8.5 to prepare a buffer solution, dissolving 0.6 g of catechol in the buffer solution, soaking the pretreated cotton fiber for 12 h, and drying to obtain catechol-modified cotton fiber;

[0084] S23, adding catechol-modified cotton fiber to an alkaline silica sol liquid with a silica content of 25 wt %, an average particle size of 9 nm, and a pH of 9.5, reacting for 16 hours, and drying to obtain an oil adsorption aid.

[0085] Comparative Example 1: The difference between this comparative example and Example 1 is that the modified carbon adsorption material is replaced by activated carbon.

[0086] Comparative Example 2: The difference between this comparative example and Example 1 is that the pretreated cotton fiber is directly added into the alkaline silica sol liquid to prepare the oil adsorption auxiliary agent.

[0087] Comparative Example 3: The difference between this comparative example and Example 1 is that no calcium aluminate is added to the aluminum-containing solution, and polyaluminum chloride is prepared by direct aging.

[0088] Performance Testing

[0089] Preparation of sewage:

[0090] 1. Add 100 mg of sodium dihydrogen phosphate to 1 L of deionized water to prepare simulated phosphorus-containing wastewater with a total phosphorus concentration of 100 mg / L;

[0091] 2. Mix 5 g of kerosene and 500 mL of deionized water, add 6 g of sodium bicarbonate and 0.2 g of sodium dodecylbenzene sulfonate, stir at a speed of 4000-5000 rpm for 15 min, then add 4500 mL of deionized water, stir evenly, let stand for 30 min, remove the floating oil on the surface, and obtain simulated oily wastewater with an oil content of 100 mg / L.

[0092] Phosphorus removal test

[0093] 3 g of the polyaluminium chloride water purifier sample prepared in each embodiment and comparative example was added to 100 mL of simulated phosphorus-containing sewage, and phosphorus was removed for 12 h at 20° C., 40° C. and 60° C. and a stirring speed of 100 rpm. The phosphate concentration of the supernatant of the simulated phosphorus-containing sewage after 12 h of phosphorus removal was measured, and the phosphorus removal rate was calculated. The calculation formula of the phosphorus removal rate is as follows:

[0094]

[0095] η is the phosphorus removal rate;

[0096] C0 is the initial phosphorus concentration of the simulated phosphorus-containing wastewater, in mg / L;

[0097] C n It is the phosphorus concentration of the simulated phosphorus-containing wastewater after 12 hours of reaction, in mg / L.

[0098] The test results are shown in Table 1:

[0099] Table 1 Phosphorus removal test

[0100]

[0101] Oil removal test

[0102] The polyaluminium chloride water purifier samples prepared in the embodiments and comparative examples were added to the simulated oily wastewater, and the oil was removed for 12 hours at 20°C, 40°C and 60°C, respectively, and the stirring speed was 100 rpm. The oil content of the middle layer of wastewater after 12 hours of oil removal was measured, and the oil removal rate was calculated. The calculation formula of the oil removal rate is as follows:

[0103]

[0104] Υ is the oil removal rate;

[0105] ρ0 is the initial oil content of the simulated oily wastewater, in mg / L;

[0106] ρ1 is the oil content measured in the middle layer of wastewater simulating oily wastewater after 12 hours of oil removal, in mg / L.

[0107] The test results are shown in Table 2:

[0108] Table 2 Oil removal test

[0109]

[0110] According to the data in the above table, the phosphorus removal rates of the polyaluminium chloride water purifiers prepared in Examples 1 to 4 are all in the range of 97.3% to 98.1% in the temperature range of 20 to 60°C. The aluminum-containing solution in Comparative Example 3 is directly slaked to prepare polyaluminium chloride without adding calcium aluminate, which makes the basicity of polyaluminium chloride low, thereby affecting the coagulation effect and stability of the polyaluminium chloride water purifier in water, resulting in a phosphorus removal rate of 93.4% to 93.7% in the temperature range of 20 to 60°C, indicating that the polyaluminium chloride water purifier prepared by the present invention has excellent phosphorus removal capacity and a large temperature difference adaptability. The oil removal rates of the polyaluminium chloride water purifiers prepared in Examples 1 to 4 are all in the range of 99.2% to 99.6% within the temperature range of 20 to 60°C. In Comparative Example 2, the oil adsorption aid prepared by directly adding the pretreated cotton fiber into the alkaline silica sol liquid has no catechol-assisted silica sol attached to the surface and fails to form a hydrophobic coating, resulting in an oil removal rate of only 96.3% to 96.4% within the temperature range of 20 to 60°C, indicating that the oil adsorption aid can assist the polymerization of aluminum chloride flocculants to separate oil and water from sewage emulsions, further illustrating that the polyaluminium chloride water purifier prepared by the present invention has excellent oil removal ability.

[0111] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0112] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a polyaluminium chloride water purifier from aluminium mud, characterized in that: The steps include: S1. Grind 200-300 g of aluminum mud with a ball mill for 1-2 h, sieve to remove solid impurities, add to deionized water, wash at 50-60 ° C for 6-12 h to remove soluble salts, add to a reactor, add 30-36.5 wt% hydrochloric acid under stirring, acid hydrolyze at 75-80 ° C for 2-3 h, filter to remove the filter residue to obtain an aluminum-containing solution, add calcium aluminate to the aluminum-containing solution, mature at 80-85 ° C for 2-3 h, filter to remove the filter residue, and obtain a polyaluminum chloride solution; S2, 700-800 mL of polyaluminium chloride solution was adjusted to a concentration of 10-30 g / L with deionized water, 70-90 g of cationic polyacrylamide and 2.5-3.5 g of 2-ethylhexyl acrylate were added, and 2-5 g of a surfactant was added, the temperature was raised and nitrogen was introduced, 1.5-2.5 g of an initiator was added dropwise within 1-2 h, and the mixture was kept warm for 4-6 h to obtain a gel; S3, dissolving the gel in S2 in deionized water, adding acetone dropwise until floccules are precipitated, filtering and washing with ethanol, and drying to obtain a polyaluminium chloride flocculant; S4, putting 50-70g of polyaluminium chloride flocculant, 10-15g of aluminium sulfate, 15-20g of modified carbon adsorption material and 15-20g of oil adsorption aid into a ball mill, ball milling for 30-40min, and packaging to obtain a polyaluminium chloride water purifier product; the preparation method of the oil adsorption aid of S4 comprises the following steps: S21, adding 10-15 g of cotton fiber into a treatment solution composed of 3-5 g / L sodium hydroxide, 5-7 g / L hydrogen peroxide and 1-3 g / L dodecanol polyoxyethylene ether at 50-60° C. and soaking for 3-4 hours, taking out the cotton fiber, neutralizing it with 5 wt % hydrochloric acid, washing it with deionized water, and drying it at 80-90° C. to obtain pretreated cotton fiber; S22, dissolving 1.41 g of tris(hydroxymethyl)aminomethane in 50 ml of deionized water, adding 36.5 wt % hydrochloric acid and stirring for 10 to 20 min, then adding 250 ml of deionized water to adjust the pH to 8.4 to 8.6 to prepare a buffer solution, dissolving 0.5 to 0.8 g of catechol in the buffer solution, soaking the pretreated cotton fiber for 12 to 18 h, and drying to obtain catechol-modified cotton fiber; S23, adding catechol-modified cotton fiber into alkaline silica sol liquid, reacting for 12 to 18 hours, and drying to obtain an oil adsorption aid.

2. The method for preparing polyaluminium chloride water purifier from aluminium mud according to claim 1, characterized in that: The mesh number of the sieve in S1 is 100-150 meshes, the mass ratio of aluminum mud to deionized water is 1:4-6, the mass ratio of aluminum mud to hydrochloric acid is 1:1.5-2, and the mass ratio of aluminum-containing solution to calcium aluminate is 6-8:

1.

3. The method for preparing polyaluminium chloride water purifier from aluminium mud according to claim 1, characterized in that: The surfactant in S2 is one or more combinations of dodecyltrimethylammonium bromide, dodecyl polyoxyethylene ether, and sodium lauroylamphoacetate, and the initiator is one or more combinations of ammonium persulfate-sodium bisulfite, azobisisobutyronitrile, and azobisdimethylvaleronitrile.

4. The method for preparing polyaluminium chloride water purifier from aluminium mud according to claim 1, characterized in that: The method for preparing the modified carbon adsorption material of S4 comprises the following steps: S11, adding aluminum chloride and magnesium chloride into deionized water, adding bamboo fiber and then ultrasonically dispersing for 30-40 minutes; S12, slowly dropwise add a mixed solution made of 139-141 g / L sodium hydroxide and 100-105 g / L sodium carbonate into the system, adjust the pH of the system to 10.0±0.3, raise the temperature to 80-90°C, crystallize under stirring for 10-14 hours, filter and collect the solid after cooling, and rinse with deionized water and ethanol in sequence; S13. Calcine the solid at 400-450° C. for 4-6 hours under a nitrogen atmosphere to obtain a modified carbon adsorption material.

5. The method for preparing polyaluminium chloride water purifier from aluminium mud according to claim 4, characterized in that: The mass ratio of aluminum chloride to magnesium chloride in S11 is 1:2.5-3.5; the amount of bamboo fiber added is 5-8wt% of the total mass of aluminum chloride and magnesium chloride.

6. The method for preparing polyaluminium chloride water purifier from aluminium mud according to claim 1, characterized in that: The pH of the alkaline silica sol in S23 is 9-10, the silica sol has a silicon dioxide content of 15-30 wt %, and an average particle size of 2-10 nm.

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