Search

CN-121717460-B - Composite polyaluminium chloride water purifying agent and preparation method thereof

CN121717460BCN 121717460 BCN121717460 BCN 121717460BCN-121717460-B

Abstract

The invention belongs to the technical field of water purifying agent preparation, and provides a compound polyaluminium chloride water purifying agent and a preparation method thereof; firstly, preparing a polyaluminium chloride mother solution with high polymerization degree by a high-temperature high-pressure hydrothermal method to serve as an inorganic skeleton, hydrothermally synthesizing ferrous sulfide/magnetic ferric oxide composite nanocrystal cores by utilizing ferrous sulfate heptahydrate, thiourea and trisodium citrate, constructing an anionic/cationic polymer composite template by utilizing sodium lignin sulfonate and cationic polyacrylamide, further introducing glycine-chelated calcium and magnesium ions to form a chemical precipitation precursor capable of slowly releasing in water, sequentially adding the functional modules into the polyaluminium chloride mother solution according to an optimized adding sequence, and sequentially self-assembling the nanocrystal cores, the polymer template and the calcium and magnesium precursor in the mother solution to obtain the integrated composite coagulant with functions of coagulation, adsorption and chemical precipitation dephosphorization.

Inventors

  • OU GUOHUA
  • TANG YUNFENG

Assignees

  • 上海高桥大同净水材料有限公司

Dates

Publication Date
20260508
Application Date
20260227

Claims (10)

  1. 1. A composite polyaluminium chloride water purifying agent is characterized by comprising the following components of composite dispersion liquid, sodium lignin sulfonate solution, glycine chelated calcium magnesium precursor solution, polyacrylamide solution and polyaluminium chloride mother solution; the preparation method of the composite polyaluminium chloride water purifying agent comprises the following steps: s1, mixing hydrochloric acid solution with deionized water to obtain a dilute hydrochloric acid solution, and mixing aluminum hydroxide with the dilute hydrochloric acid solution to react to obtain polyaluminium chloride mother liquor; s2, dispersing ferrous sulfate heptahydrate, thiourea and trisodium citrate in deionized water in sequence and performing hydrothermal reaction to obtain a composite solid, and dispersing the composite solid in new deionized water to obtain a composite dispersion liquid; S3, dispersing sodium lignin sulfonate in deionized water to obtain a sodium lignin sulfonate solution, and dispersing cationic polyacrylamide in deionized water to obtain a polyacrylamide solution; s4, dispersing calcium chloride dihydrate, magnesium chloride hexahydrate and glycine in deionized water in sequence for reaction to obtain glycine chelated calcium magnesium precursor solution; And S5, sequentially adding the composite dispersion liquid, the sodium lignin sulfonate solution, the glycine chelated calcium magnesium precursor solution and the polyacrylamide solution into the polyaluminum chloride mother solution to obtain the composite polyaluminum chloride water purifying agent.
  2. 2. The composite polyaluminum chloride water purifying agent according to claim 1, wherein the mass ratio of the composite dispersion liquid, the sodium lignin sulfonate solution, the glycine chelated calcium magnesium precursor solution, the polyacrylamide solution and the polyaluminum chloride mother solution is (3-6): 1-3): 15-25): 3-6: 65-75.
  3. 3. A method of preparing a composite polyaluminum chloride water purifying agent according to any one of claims 1 to 2, comprising: s1, mixing hydrochloric acid solution with deionized water to obtain a dilute hydrochloric acid solution, and mixing aluminum hydroxide with the dilute hydrochloric acid solution to react to obtain polyaluminium chloride mother liquor; s2, dispersing ferrous sulfate heptahydrate, thiourea and trisodium citrate in deionized water in sequence and performing hydrothermal reaction to obtain a composite solid, and dispersing the composite solid in new deionized water to obtain a composite dispersion liquid; S3, dispersing sodium lignin sulfonate in deionized water to obtain a sodium lignin sulfonate solution, and dispersing cationic polyacrylamide in deionized water to obtain a polyacrylamide solution; s4, dispersing calcium chloride dihydrate, magnesium chloride hexahydrate and glycine in deionized water in sequence for reaction to obtain glycine chelated calcium magnesium precursor solution; And S5, sequentially adding the composite dispersion liquid, the sodium lignin sulfonate solution, the glycine chelated calcium magnesium precursor solution and the polyacrylamide solution into the polyaluminum chloride mother solution to obtain the composite polyaluminum chloride water purifying agent.
  4. 4. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in the step S1: the mass ratio of the hydrochloric acid solution to deionized water to aluminum hydroxide is (26-30): 68-76): 12-22.
  5. 5. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in the step S1: The mass fraction of Al 2 O 3 in the polyaluminum chloride mother liquor is 10wt.%, and the basicity is 70%.
  6. 6. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in the step S2: the mass ratio of the ferrous sulfate heptahydrate, the thiourea, the trisodium citrate and the deionized water is (45-55): (25-30): (0.8-1.2): (190-210).
  7. 7. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in the step S2: the solid content of the composite dispersion was 10%.
  8. 8. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in the step S3: in the sodium lignin sulfonate solution, the mass ratio of the sodium lignin sulfonate to the deionized water is (4.5-5.5) (94.5-95.5).
  9. 9. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in the step S3: In the polyacrylamide solution, the mass ratio of the cationic polyacrylamide to deionized water is (0.45-0.55): 99.45-99.55.
  10. 10. The method for preparing a composite polyaluminum chloride water purifying agent according to claim 3, wherein in S4: the mass ratio of the calcium chloride dihydrate, the magnesium chloride hexahydrate and the glycine to the deionized water is (20-24): (14-17): (35-40): (420-430); The total molar concentration of calcium and magnesium in the glycine chelated calcium and magnesium precursor solution is 0.44-0.46mol/kg, and the mass fraction of total solid solution is 15.0wt.%.

Description

Composite polyaluminium chloride water purifying agent and preparation method thereof Technical Field The invention belongs to the technical field of water purifying agent preparation, and relates to a composite polyaluminium chloride water purifying agent and a preparation method thereof. Background Eutrophication of water is one of the main problems facing the current water environment field, and the root cause is that the content of nutrient salts such as nitrogen, phosphorus and the like in the water exceeds the standard for a long time. Therefore, in municipal wastewater and various industrial wastewater treatments, the realization of efficient removal of phosphorus has become a key technical link and a necessary requirement in wastewater treatment processes. The chemical precipitation method is one of the most widely applied dephosphorization technologies at the present stage, and the basic idea is to add a metal salt coagulant into water to convert soluble phosphate into insoluble precipitate and separate the insoluble phosphate from the water along with flocs. As an inorganic high-molecular coagulant with excellent performance, the polyaluminium chloride has the advantages of small dosage, wide applicable pH range, large volume of formed floccules, compact structure and the like, and is applied in the field of water treatment on a large scale. Traditional polyaluminum chloride mainly relies on the positive charge carried by its polynuclear hydroxy aluminum complex to neutralize negatively charged colloidal pollutants in water, thereby removing suspended matters and simultaneously removing part of inorganic phosphate. However, under the conditions of deep dephosphorization and complex water quality, the limitations of the traditional polyaluminium chloride are increasingly remarkable, on one hand, the dephosphorization is realized mainly by generating aluminum phosphate precipitation, the solubility product of the aluminum phosphate is relatively high, the concentration of the discharged phosphorus is difficult to be stably controlled at an extremely low level, on the other hand, the action mechanism is relatively single, the effect mechanism is relatively sensitive to the fluctuation of the water quality of the inflow water, the dephosphorization effect is easy to be fluctuated when the phosphorus with complex forms or the water quality condition is changed, and the removal capability of the phosphorus with complex forms such as organic phosphorus is relatively limited. In order to improve the dephosphorization effect, physical blending or simple copolymerization modification is attempted to be carried out on polyaluminium chloride, ferric salt and the like in the prior art, but most of the compound modes are mechanical superposition of functions of all components, the degree of cooperation of the structure and the functions is limited, the improvement range of the comprehensive performance of the product is still small, and the requirements of deep dephosphorization and stable operation are difficult to meet. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide a composite polyaluminium chloride water purifying agent and a preparation method thereof, which are characterized in that polyaluminium chloride is prepared by a high-temperature high-pressure method, a composite dispersion liquid, a synergistic network template formed by anion and cation polymers and a calcium-magnesium ion precursor which is chelated by organic acid and can realize chemical precipitation dephosphorization are introduced, and the functional modules are orderly compounded on a polyaluminium chloride matrix through a specific self-assembly path, so that the composite polyaluminium chloride is constructed, and the actual production requirement is met. To achieve the purpose, the invention adopts the following technical scheme: in the first aspect, the invention provides a composite polyaluminium chloride water purifying agent which specifically comprises a composite dispersion liquid, a sodium lignin sulfonate solution, a glycine chelated calcium magnesium precursor solution, a polyacrylamide solution and polyaluminium chloride mother solution. In some alternative embodiments, the mass ratio of the composite dispersion, sodium lignin sulfonate solution, glycine chelated calcium magnesium precursor solution, polyacrylamide solution, and polyaluminum chloride mother liquor is (3-6): 1-3): 15-25): 3-6): 65-75. In a second aspect, the invention provides a preparation method of a composite polyaluminum chloride water purifying agent, which comprises the following steps: s1, mixing hydrochloric acid solution with deionized water to obtain a dilute hydrochloric acid solution, and mixing aluminum hydroxide with the dilute hydrochloric acid solution to react to obtain polyaluminium chloride mother liquor; S2, dispersing ferrous sulfate heptahydrate, thiourea and trisodium citrate in de