Inorganic-organic hybrid flocculant, its preparation and application
By introducing inorganic oxyacid anions and inert gases before the polymerization of organic monomers, an inorganic-organic hybrid flocculant with high intrinsic viscosity was prepared, which solved the problem of insufficient adsorption bridging capacity of flocculants in the prior art and realized the efficient sedimentation of nanoscale colloidal particles and the stable operation of water treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-11-18
- Publication Date
- 2026-06-02
AI Technical Summary
Existing inorganic-organic hybrid flocculants have low intrinsic viscosity, resulting in weak adsorption and bridging capabilities, making it difficult to effectively remove nano-sized colloidal suspended particles and affecting the normal operation of membrane treatment and catalyst processes.
By introducing inorganic oxyacid anions before the polymerization of organic monomers and passing inert gas in a constant temperature water bath, and adding an oxidation-reduction initiator to carry out the polymerization reaction, an inorganic-organic hybrid flocculant with high intrinsic viscosity is prepared, thereby improving its adsorption and bridging ability.
It significantly reduces wastewater turbidity with low dosage, enables rapid sedimentation of colloidal suspended particles, and ensures long-term stable operation of the water treatment process.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of environmental remediation composite material technology, and particularly relates to an inorganic-organic hybrid flocculant, its preparation method and application. Background Technology
[0002] Suspended particulate matter is one of the key pollutants to focus on in the pretreatment unit. Improper treatment of this type of pollutant can severely interfere with subsequent advanced treatment processes such as membrane filtration, oxidation, and adsorption. For membrane treatment, poor pretreatment of suspended particulate matter and other pollutants can lead to a significant decrease in membrane flux and desalination rate in a short period, requiring frequent replacement and cleaning operations. This affects the long-term operation of the membrane system and reduces membrane lifespan, thereby increasing water treatment costs. Studies have shown a strong correlation between the membrane fouling index and colloidal suspended particulate matter, indicating that colloidal suspended particulate matter in wastewater is the core substance causing membrane fouling. Due to their small particle size, these pollutants typically enter the pores, causing the most severe membrane fouling, i.e., membrane pore blockage. Besides adversely affecting the membrane treatment process, colloidal suspended particulate matter can also clog the pores of adsorbents and catalysts or alter the surface properties of these materials, thereby reducing their performance and lifespan.
[0003] Colloidal suspended particles, due to their fine size, typically have small settling diameters, which weakens the gravitational settling effect, enhances colloidal stability, and hinders particle aggregation and settling. Furthermore, these suspended solids carry surface charges, and the electrostatic repulsion between particles further impedes coagulation and flocculation, making their removal challenging. Therefore, the efficient removal of colloidal suspended particles has become a key and difficult problem to be solved in current wastewater pretreatment systems.
[0004] The paper "Experimental Study on Flocculation and Sedimentation of Fine Cyanide Tailings Particles" (Liu Ya et al. Gold Science and Technology [J], 2015, 23, 91-96.) points out that for the flocculation of particles of different sizes (average particle diameters of 30 μm, 14 μm, and 3 μm, respectively), compared with single organic flocculants, the smaller the particle size, the more obvious the advantages of inorganic-organic composite flocculants become. Therefore, for the flocculation of colloidal suspended particles with particle sizes in the nanometer range, as the particle size further decreases, the complementary effects of charge neutralization by inorganic components and adsorption bridging by organic components become even more necessary. Thus, the development of inorganic-organic composite flocculants has become an inevitable trend to achieve efficient removal of colloidal suspended matter.
[0005] The literature “Preparation and dilute solution behavior and flocculation performance of aluminum hydroxide-polyacrylamide hybrid material” (Yang Wuyuan, Zhejiang University, 2005) reported the synthesis of an inorganic-organic hybrid flocculant, in which the inorganic component is aluminum hydroxide colloid and the organic component is polyacrylamide. However, the intrinsic viscosity of this hybrid material is relatively low, ranging from 600 to 1300 mL / g.
[0006] CN106745624A discloses an inorganic-organic hybrid flocculant in which the polymerization of acrylamide and dimethyldiallylammonium chloride is initiated in the inorganic flocculant. However, the presence of the inorganic component usually reduces the initiation activity of the free radical initiator, resulting in a lower degree of polymerization and intrinsic viscosity of the organic monomers. This flocculant is suitable for the flocculation of micron-sized suspended particles. When applied to the flocculation of nano-sized suspended particles, due to the low intrinsic viscosity of the material, the adsorption and bridging ability is weak, which is not conducive to the formation of larger flocs, thus hindering the rapid sedimentation of suspended particles and the high clarification of wastewater.
[0007] Based on the current research status, the intrinsic viscosity of inorganic-organic hybrid flocculants is still relatively low, that is, the viscosity-average molecular weight is relatively low. Viscosity-average molecular weight is a key indicator for assessing the adsorption and bridging ability of flocculants. If the viscosity-average molecular weight is low, it is not conducive to the formation of flocs with larger particle sizes, and therefore not conducive to the rapid sedimentation of suspended particles (especially colloidal suspended particles). Summary of the Invention
[0008] To address the problem that existing inorganic-organic hybrid flocculants have low intrinsic viscosity, resulting in weak adsorption and bridging capabilities, this invention provides an inorganic-organic hybrid flocculant, its preparation method, and its application. The flocculant prepared by this invention has an intrinsic viscosity of over 2000 mL / g and can be used to remove colloidal suspended solids from wastewater. At low dosages, it can reduce wastewater turbidity to below 3 NTU.
[0009] This invention provides a method for preparing an inorganic-organic hybrid flocculant, comprising the following steps:
[0010] (1) Prepare an inorganic flocculant or inorganic flocculant colloidal solution, add inorganic salt for modification, and then add organic monomers to obtain a mixture;
[0011] (2) Place the mixture in a constant temperature water bath, introduce nitrogen or inert gas, then add an initiator to start the polymerization reaction. After the reaction is completed, an inorganic-organic hybrid polymer gel is obtained.
[0012] (3) The inorganic-organic hybrid polymer gel was dissolved and extracted to obtain the precipitate;
[0013] (4) The precipitate is dried and ground to obtain the inorganic-organic hybrid flocculant.
[0014] The inorganic flocculant mentioned in step (1) is at least one of aluminum hydroxide, iron hydroxide, polyaluminum chloride, polyferric sulfate, polyaluminum silicate, and polyaluminum ferric silicate, preferably at least one of aluminum hydroxide, polyaluminum chloride, polyaluminum silicate, and polyaluminum ferric silicate, and more preferably a mixture of aluminum hydroxide and polyaluminum silicate in a mass ratio of (2-5):1.
[0015] In step (1), the concentration of the inorganic flocculant or inorganic flocculant colloidal solution is 0.05-2 mol / L, expressed as the molar concentration of Al or Fe.
[0016] The inorganic salt mentioned in step (1) is an inorganic oxyacid anion, specifically selected from at least one of soluble salts containing phosphate, monohydrogen phosphate, dihydrogen phosphate, metaphosphate, hypophosphite, citrate, borate, tartrate, acetate, ethylenediaminetetraacetic acid, etc., preferably at least one of soluble sodium salts containing phosphate, and more preferably a mixture of disodium hydrogen phosphate and sodium dihydrogen phosphate in a mass ratio of (1-5):1.
[0017] The amount of inorganic salt used in step (1) is 0.5%-10% of the mass of the organic monomer.
[0018] The inorganic salt in step (1) is added dropwise over a period of 10-60 minutes.
[0019] The organic monomers mentioned in step (1) include cationic quaternary ammonium salt monomers and acrylamide in a mass ratio of 1:9 to 1:1, wherein the cationic quaternary ammonium salt monomers are selected from at least one of dimethyl diallyl ammonium chloride, acryloylethoxytrimethyl ammonium chloride, methacryloylethoxytrimethyl ammonium chloride, (3-acrylamidopropyl)-trimethyl ammonium chloride and N,N,N-trimethyl-3-(2-methylallylamino)-1-propanium chloride, preferably a mixture of dimethyl diallyl ammonium chloride and (3-acrylamidopropyl)-trimethyl ammonium chloride in a mass ratio of (6-9):1.
[0020] In step (1), the mass ratio of inorganic flocculant to organic monomer is 1:9-2:1.
[0021] The temperature of the constant temperature water bath in step (1) is 25-90℃. Further, it is preferable to place the mixture in a constant temperature water bath at 25-50℃ for polymerization reaction. After reacting for 5-120 minutes, the water bath temperature is raised to 40-90℃ and the reaction is continued for 1-6 hours. After the reaction is completed, an inorganic-organic hybrid polymer gel is obtained.
[0022] The inert gas mentioned in step (2) is selected from any one or at least a combination of two of helium, argon, etc.
[0023] The initiator mentioned in step (2) is a redox initiator. The oxidant is selected from ammonium persulfate and / or potassium persulfate, and the reductant is selected from sodium bisulfite. The mass ratio of oxidant to reductant is 1.05:1-2:1. The mass of the initiator is 0.01%-3% of the mass of the organic monomer.
[0024] The polymerization reaction time in step (2) is 2-8 hours.
[0025] The inorganic-organic hybrid polymer gel described in step (3) is dissolved in deionized water. After dissolution, it is extracted with an organic solvent, which is selected from at least one of ethanol, acetone, etc.
[0026] The drying conditions described in step (4) are drying at 40-80℃ for 0.5-6 hours.
[0027] The inorganic-organic hybrid flocculant of this invention is prepared using the method described above. The prepared flocculant has an intrinsic viscosity of over 2000 mL / g and can be used to remove colloidal suspended solids from wastewater, reducing wastewater turbidity to below 3 NTU at low dosages.
[0028] In the hybrid flocculant of the present invention, the inorganic part is selected from at least one of aluminum hydroxide, ferric hydroxide, polyaluminum chloride, polyferric sulfate, polyaluminum silicate, and polyaluminum ferric silicate, preferably at least one of aluminum hydroxide, polyaluminum chloride, polyaluminum silicate, and polyaluminum ferric silicate, and more preferably a mixture of aluminum hydroxide and polyaluminum silicate in a mass ratio of (2-5):1.
[0029] In the hybrid flocculant of the present invention, the organic monomer of the organic part includes a cationic quaternary ammonium salt monomer and acrylamide in a mass ratio of 1:9 to 1:1. The cationic quaternary ammonium salt monomer is selected from at least one of dimethyl diallyl ammonium chloride, acryloylethoxytrimethyl ammonium chloride, methacryloylethoxytrimethyl ammonium chloride, (3-acrylamidopropyl)-trimethyl ammonium chloride, and N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediium chloride, preferably a mixture of dimethyl diallyl ammonium chloride and (3-acrylamidopropyl)-trimethyl ammonium chloride in a mass ratio of (6-9):1.
[0030] The present invention also provides an application of the above-mentioned inorganic-organic hybrid flocculant in wastewater treatment, comprising: contacting the above-mentioned inorganic-organic hybrid flocculant with wastewater containing colloidal suspended matter, thereby reducing the turbidity of the wastewater to below 3 NTU at a low dosage.
[0031] In this invention, the amount of the inorganic-organic hybrid flocculant is 10-50 mg / L.
[0032] In this invention, the particle size range of colloidal suspended matter in wastewater is 1-1000 nm.
[0033] In this invention, colloidal suspended matter in wastewater includes water-insoluble inorganic matter, organic matter, and microorganisms, including but not limited to ores, mud, clay, metal residues, fibers, plastic products, and paper products.
[0034] In this invention, the contact reaction is controlled in three stages: in the first stage, the stirring rate is 400-500 rpm and the stirring time is 1-2 min; in the second stage, the stirring rate is 200-300 rpm and the stirring time is 5-8 min; in the third stage, the mixture is allowed to stand for 10-30 min.
[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0036] (1) The present invention introduces inorganic oxyacid radicals before the polymerization of organic monomers to enhance the initiation activity of sulfate radicals in the initiator, thereby effectively improving the degree of polymerization and intrinsic viscosity of inorganic-organic hybrid flocculants.
[0037] (2) By introducing an inorganic salt modifier, the present invention can obtain an inorganic-organic hybrid flocculant with high intrinsic viscosity at low temperature and in a short time. The preparation method is simple, energy-saving and environmentally friendly.
[0038] (3) Applying inorganic-organic hybrid flocculants with high intrinsic viscosity to the removal of colloidal suspended particles. Since the material has a strong adsorption bridging ability, it is easy to form flocs with larger particle size, thereby achieving rapid and efficient sedimentation of suspended particles. This can significantly reduce the turbidity of wastewater, i.e. the residue of colloidal suspended particles, reduce interference with subsequent membrane treatment, catalytic oxidation and other processes, and ensure the long-term stable operation of the entire water treatment process. Attached Figure Description
[0039] Figure 1 Thermogravimetric spectra of the inorganic-organic hybrid flocculant and the inorganic-organic compound flocculant prepared in Example 1 are shown. Detailed Implementation
[0040] The inorganic-organic hybrid flocculant of the present invention and its effects are further illustrated below with specific embodiments. The embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.
[0041] Unless otherwise specified, the experimental methods used in the following examples are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following examples were purchased from conventional biochemical reagent stores.
[0042] In this invention, the intrinsic viscosity of the inorganic-organic hybrid flocculant is measured using an intelligent viscosity meter (IVS400-6, Zhongwang Technology), and the turbidity of the wastewater is measured using a turbidity meter (TL2300EPA, Hach, USA).
[0043] Example 1
[0044] (1) Prepare an Al(OH)3 colloidal solution with a concentration of 0.4 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a time of 20 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0045] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0046] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0047] (4) The precipitate was dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0048] The intrinsic viscosity of the inorganic-organic hybrid flocculant was measured to be 2239 mL / g.
[0049] Thermogravimetric analysis of inorganic-organic hybrid flocculants is as follows: Figure 1 As shown, compared with the inorganic-organic hybrid flocculant (obtained by physically blending aluminum hydroxide colloid with poly(acrylamide-dimethyldiallylammonium chloride)), the two exhibit significantly different thermogravimetric behaviors at temperatures above 450℃, corresponding to the thermal decomposition process of long polymer chains. The inorganic-organic hybrid flocculant demonstrates significantly better thermal stability at this stage than the inorganic-organic composite flocculant. This is because the in-situ polymerization of organic monomers within the inorganic component creates bonds between the inorganic and organic components, restricting the polymer chain ends and hindering the thermal motion of the long polymer chains. This, in turn, enhances the thermal decomposition stability of the polymer backbone. The thermogravimetric analysis confirms the hybrid structure of the material, rather than a simple mixture of inorganic and organic components.
[0050] The prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles. At a dosage of 30 mg / L, the turbidity of the wastewater decreased from an initial 123 NTU to 2.89 NTU. Simultaneously, an inorganic-organic composite flocculant was used as a control for the treatment of the same wastewater containing colloidal suspended particles; at a dosage of 30 mg / L, the turbidity of the wastewater decreased to 32.89 NTU.
[0051] Example 2
[0052] (1) Prepare an Al(OH)3 colloidal solution with a concentration of 0.05 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a period of 10 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:5, the mass ratio of DMDAAC to AM is 1:1, and the mass of Na3PO4 is 0.5% of the mass of the organic monomer.
[0053] (2) The mixture was placed in a constant temperature water bath at 40 °C and high-purity argon gas was introduced for about 30 min. Then, a mixture of potassium persulfate (K2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 8 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.01% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.05:1.
[0054] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0055] (4) The precipitate obtained by extraction is dried at 40°C for 6 hours and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0056] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2362 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 1.89 NTU at a dosage of 30 mg / L.
[0057] Example 3
[0058] (1) Prepare an Al(OH)3 colloidal solution with a concentration of 2 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a time of 60 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 2:1, the mass ratio of DMDAAC to AM is 1:5, and the mass of Na3PO4 is 10% of the mass of the organic monomer.
[0059] (2) The mixture was placed in a 90 ℃ constant temperature water bath and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed and the polymerization reaction was stopped after 2 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 3% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 2:1.
[0060] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to ethanol for extraction, and obtain the precipitate;
[0061] (4) The precipitate obtained by extraction is dried at 80°C for 0.5 h and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0062] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2006 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 2.99 NTU at a dosage of 30 mg / L.
[0063] Example 4
[0064] (1) Prepare a 0.4 mol / L polyferric sulfate solution (based on the molar concentration of Fe), add sodium phosphate (Na3PO4) modifier dropwise over a time of 20 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixture. The mass ratio of polyferric sulfate to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0065] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0066] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0067] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0068] The intrinsic viscosity of the inorganic-organic hybrid flocculant was measured to be 2022 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 2.96 NTU at a dosage of 30 mg / L.
[0069] Example 5
[0070] (1) Prepare a 0.4 mol / L (based on the molar concentration of Al) polyaluminum silicate solution, add sodium phosphate (Na3PO4) modifier dropwise over a period of 20 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of polyaluminum silicate to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0071] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0072] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0073] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0074] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2316 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 2.13 NTU at a dosage of 30 mg / L.
[0075] Example 6
[0076] (1) Prepare a mixed solution of aluminum hydroxide and polyaluminum silicate with a concentration of 0.4 mol / L (based on the molar concentration of Al), wherein the mass ratio of aluminum hydroxide to polyaluminum silicate is 2:1. Add sodium phosphate (Na3PO4) modifier dropwise over a time of 20 min. After the addition is complete, add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of the aluminum hydroxide and polyaluminum silicate mixture to the organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0077] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0078] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0079] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0080] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2405 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 1.32 NTU at a dosage of 30 mg / L.
[0081] Example 7
[0082] (1) Prepare an aluminum hydroxide colloidal solution with a concentration of 0.4 mol / L (based on the molar concentration of Al). Add a mixture of disodium hydrogen phosphate (Na2HPO4) and sodium dihydrogen phosphate (NaH2PO4) in a mass ratio of 3:1 dropwise over a time of 20 min. After the addition is complete, add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of the Na2HPO4 and NaH2PO4 mixture is 1% of the mass of the organic monomer.
[0083] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0084] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0085] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0086] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2396 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 1.63 NTU at a dosage of 30 mg / L.
[0087] Example 8
[0088] (1) Prepare an aluminum hydroxide colloid with a concentration of 0.4 mol / L (based on the molar concentration of Al), add dipotassium hydrogen phosphate (K2HPO4) modifier dropwise over a time of 20 min. After the addition is complete, add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of K2HPO4 is 1% of the mass of the organic monomer.
[0089] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0090] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0091] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0092] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2120 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 2.93 NTU at a dosage of 30 mg / L.
[0093] Example 9
[0094] (1) Prepare an aluminum hydroxide colloid with a concentration of 0.4 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a time of 20 min, and then add acrylamide (AM) and (3-acrylamidopropyl)-trimethylammonium chloride (AMPTMA) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of AMPTA to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0095] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0096] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0097] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0098] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2360 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 1.69 NTU at a dosage of 30 mg / L.
[0099] Example 10
[0100] (1) Prepare an aluminum hydroxide colloid with a concentration of 0.4 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a time of 20 min. After the addition is complete, add acrylamide (AM), dimethyl diallyl ammonium chloride (DMDAAC), and (3-acrylamidopropyl)-trimethylammonium chloride (AMPTMA) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of the DMDAAC and AMPTMA mixture to AM is 1:9, the mass ratio of DMDAAC to AMPTA is 7:1, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0101] (2) The mixture was placed in a constant temperature water bath at 25 °C and high-purity nitrogen gas was introduced for about 30 min. Then, a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) was added. The reaction system was sealed, and the polymerization reaction was stopped after 3 h to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0102] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0103] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0104] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2493 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 1.03 NTU at a dosage of 30 mg / L.
[0105] Example 11
[0106] (1) Prepare an Al(OH)3 colloidal solution with a concentration of 0.4 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a time of 20 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of the organic monomer.
[0107] (2) Place the mixture from step (1) in a constant temperature water bath at 25°C and purge with high-purity nitrogen for about 30 minutes. Then add a mixture of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3) and seal the reaction system. After reacting for 60 minutes, raise the water bath temperature to 60°C and continue the reaction for 2 hours. After the reaction is complete, an inorganic-organic hybrid polymer gel is obtained. The initiator mass is 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 is 1.5:1.
[0108] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0109] (4) The precipitate was dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0110] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2896 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 0.65 NTU at a dosage of 30 mg / L.
[0111] Example 12
[0112] (1) Prepare an Al(OH)3 colloidal solution with a concentration of 0.05 mol / L (based on the molar concentration of Al), add sodium phosphate (Na3PO4) modifier dropwise over a period of 10 min, and then add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution. The mass ratio of aluminum hydroxide to organic monomer is 1:5, the mass ratio of DMDAAC to AM is 1:1, and the mass of Na3PO4 is 0.5% of the mass of the organic monomer.
[0113] (2) Place the mixture from step (1) in a constant temperature water bath at 40℃ and purge with high-purity argon gas for about 30 minutes. Then add a mixture of potassium persulfate (K2S2O8) and sodium bisulfite (NaHSO3) and seal the reaction system. After reacting for 60 minutes, raise the water bath temperature to 90℃ and continue the reaction for 2 hours. After the reaction is complete, an inorganic-organic hybrid polymer gel is obtained. The initiator mass is 0.01% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 is 1.05:1.
[0114] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate;
[0115] (4) The precipitate obtained by extraction is dried at 40°C for 6 hours and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0116] The intrinsic viscosity of the inorganic-organic hybrid flocculant was tested to be 2579 mL / g. When the prepared flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater decreased from an initial 123 NTU to 0.89 NTU at a dosage of 30 mg / L.
[0117] Comparative Example 1
[0118] (1) Prepare an Al(OH)3 colloid with a concentration of 0.4 mol / L (based on the molar concentration of Al), add acrylamide (AM) and dimethyl diallyl ammonium chloride (DMDAAC) to obtain a mixed solution, and place it in a constant temperature water bath at 25 ℃. The mass ratio of aluminum hydroxide to organic monomer is 1:9, the mass ratio of DMDAAC to AM is 1:9, and the mass of Na3PO4 is 1% of the mass of organic monomer.
[0119] (2) High-purity nitrogen gas was introduced for about 30 minutes, followed by the addition of a mixed solution of ammonium persulfate ((NH4)2S2O8) and sodium bisulfite (NaHSO3). The reaction system was sealed, and the polymerization reaction was terminated after 3 hours to obtain an inorganic-organic hybrid polymer gel. The initiator mass was 0.1% of the organic monomer mass, and the mass ratio of (NH4)2S2O8 to NaHSO3 was 1.5:1.
[0120] (3) Dissolve the inorganic-organic hybrid polymer gel with deionized water, add it dropwise to acetone for extraction, and obtain the precipitate.
[0121] (4) The precipitate obtained by extraction is dried at 60°C for 1 hour and then ground to obtain the inorganic-organic hybrid flocculant powder.
[0122] The intrinsic viscosity of the inorganic-organic hybrid flocculant was measured to be 852 mL / g.
[0123] When the prepared inorganic-organic hybrid flocculant was applied to the treatment of wastewater containing colloidal suspended particles, the turbidity of the wastewater could be reduced to 10.23 NTU when the dosage was 30 mg / L.
Claims
1. A method for preparing an inorganic-organic hybrid flocculant, characterized by Includes the following steps: (1) Prepare an inorganic flocculant or inorganic flocculant colloidal solution, add an inorganic salt for modification, and then add an organic monomer to obtain a mixture; the inorganic salt is at least one of the soluble sodium salts containing phosphate, and the inorganic salt is added by dropping, with a dropping time of 10-60 min; (2) Place the mixture in a constant temperature water bath, introduce nitrogen or inert gas, then add an initiator to start the polymerization reaction. After the reaction is completed, an inorganic-organic hybrid polymer gel is obtained. The initiator is a redox initiator. The oxidant is selected from ammonium persulfate and / or potassium persulfate, and the reducing agent is selected from sodium bisulfite. The mass ratio of oxidant to reducing agent is 1.05:1-2:
1. (3) The inorganic-organic hybrid polymer gel was dissolved and extracted to obtain the precipitate; (4) The precipitate is dried and ground to obtain the inorganic-organic hybrid flocculant.
2. The method of claim 1, wherein: The inorganic flocculant mentioned in step (1) is at least one of aluminum hydroxide, iron hydroxide, polyaluminum chloride, polyferric sulfate, polyaluminum silicate, and polyaluminum ferric silicate.
3. The preparation method according to claim 2, characterized in that: The inorganic flocculant mentioned in step (1) is at least one of aluminum hydroxide, polyaluminum chloride, polyaluminum silicate, and polyaluminum ferric silicate.
4. The preparation method according to claim 3, characterized in that: The inorganic flocculant mentioned in step (1) is a mixture of aluminum hydroxide and polyaluminum silicate in a mass ratio of (2-5):
1.
5. The preparation method according to claim 1, 2, 3, or 4, characterized in that: In step (1), the concentration of the inorganic flocculant or inorganic flocculant colloidal solution is 0.05-2 mol / L, expressed as the molar concentration of Al or Fe.
6. The preparation method according to claim 1, characterized in that: The inorganic salt mentioned in step (1) is a mixture of disodium hydrogen phosphate and sodium dihydrogen phosphate in a mass ratio of (1-5):
1.
7. The preparation method according to claim 1 or 6, characterized in that: The amount of inorganic salt used in step (1) is 0.5%-10% of the mass of the organic monomer.
8. The preparation method according to claim 1, characterized in that: The organic monomers mentioned in step (1) include a cationic quaternary ammonium salt monomer and acrylamide in a mass ratio of 1:9 to 1:1, wherein the cationic quaternary ammonium salt monomer is selected from at least one of dimethyl diallyl ammonium chloride, acryloylethoxytrimethyl ammonium chloride, methacryloylethoxytrimethyl ammonium chloride, (3-acrylamidopropyl)-trimethylammonium chloride and N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediium chloride.
9. The preparation method according to claim 8, characterized in that: The cationic quaternary ammonium salt monomer in step (1) is a mixture of dimethyl diallyl ammonium chloride and (3-acrylamidopropyl)-trimethyl ammonium chloride in a mass ratio of (6-9):
1.
10. The preparation method according to claim 1, 2, 3, 4, 8 or 9, characterized in that: In step (1), the mass ratio of inorganic flocculant to organic monomer is 1:9-2:
1.
11. The preparation method according to claim 1, characterized in that: The temperature of the constant temperature water bath mentioned in step (1) is 25-90℃.
12. The preparation method according to claim 1 or 11, characterized in that: The mixture was placed in a constant temperature water bath at 25-50℃ for polymerization. After 5-120 minutes of reaction, the water bath temperature was raised to 40-90℃ and the reaction was continued for 1-6 hours. After the reaction was completed, an inorganic-organic hybrid polymer gel was obtained.
13. The preparation method according to claim 1, characterized in that: The inert gas mentioned in step (2) is selected from any one or a combination of at least two of helium and argon.
14. The preparation method according to claim 1, characterized in that: The initiator mass is 0.01%-3% of the organic monomer mass.
15. The preparation method according to claim 1, characterized in that: The polymerization reaction time in step (2) is 2-8 hours.
16. The preparation method according to claim 1, characterized in that: The inorganic-organic hybrid polymer gel described in step (3) is dissolved in deionized water; after dissolution, it is extracted with an organic solvent, which is selected from at least one of ethanol and acetone.
17. The preparation method according to claim 1, characterized in that: The drying conditions described in step (4) are drying at 40-80℃ for 0.5-6 hours.
18. An inorganic-organic hybrid flocculant, characterized in that... It is prepared by the method described in any one of claims 1-17.
19. The flocculant according to claim 18, characterized in that: The intrinsic viscosity of the prepared flocculant is above 2000 mL / g.
20. The flocculant according to claim 18 or 19, characterized in that: In the hybrid flocculant, the inorganic part is selected from at least one of aluminum hydroxide, ferric hydroxide, polyaluminum chloride, polyferric sulfate, polyaluminum silicate, and polyaluminum ferric silicate; the organic monomer of the organic part includes a cationic quaternary ammonium salt monomer and acrylamide in a mass ratio of 1:9 to 1:1, wherein the cationic quaternary ammonium salt monomer is selected from at least one of dimethyl diallyl ammonium chloride, acryloylethoxytrimethyl ammonium chloride, methacryloylethoxytrimethyl ammonium chloride, (3-acrylamidopropyl)-trimethylammonium chloride, and N,N,N-trimethyl-3-(2-methylallylamino)-1-propanediamine chloride.
21. The flocculant according to claim 20, characterized in that: The inorganic part is selected from at least one of aluminum hydroxide, ferric hydroxide, polyaluminum chloride, polyferric sulfate, polyaluminum silicate, and polyaluminum ferric silicate.
22. The flocculant according to claim 21, characterized in that: The inorganic component is selected from a mixture of aluminum hydroxide and polyaluminum silicate in a mass ratio of (2-5):
1.
23. The flocculant according to claim 20, characterized in that: The cationic quaternary ammonium salt monomer is selected from a mixture of dimethyl diallyl ammonium chloride and (3-acrylamidopropyl)-trimethyl ammonium chloride in a mass ratio of (6-9):
1.
24. The application of a flocculant prepared by the method according to any one of claims 1-18 or the flocculant according to any one of claims 18-23 in wastewater treatment, characterized in that: The above-mentioned inorganic-organic hybrid flocculant was contacted with wastewater containing colloidal suspended solids, and the turbidity of the wastewater was reduced to below 3 NTU at a low dosage.
25. The application according to claim 24, characterized in that: The dosage of the inorganic-organic hybrid flocculant is 10-50 mg / L.
26. The application according to claim 24, characterized in that: The particle size range of colloidal suspended matter in wastewater is 1-1000 nm.
27. The application according to claim 24 or 26, characterized in that: Colloidal suspended solids in wastewater include water-insoluble inorganic matter, organic matter, and microorganisms.
28. The application according to claim 27, characterized in that: Colloidal suspended solids in wastewater include ores, mud, clay, metal residues, fibers, plastic products, and paper products.
29. The application according to claim 24, characterized in that: The contact reaction is controlled in three stages: in the first stage, the stirring rate is 400-500 rpm and the stirring time is 1-2 min; in the second stage, the stirring rate is 200-300 rpm and the stirring time is 5-8 min; in the third stage, the mixture is allowed to stand for 10-30 min.