Treatment method of wastewater containing suspended solids and metal ions

Abstract

The invention relates to a method for treating wastewater containing suspended solids and metal ions, which comprises the following steps: introducing CO2-containing gas into the wastewater containing suspended solids and metal ions to carry out air flotation treatment, and adding a chemical agent Y1 which is an amino or amidino porous polymer at the same time; separating solids after treatment to obtain water, adding an agent Y2 for stirring treatment, and separating solids after reaction; the agent Y2 is a polysilicic acid-based inorganic-organic hybrid flocculating agent. According to the invention, suspended solids and metal ions in wastewater can be efficiently removed, secondary pollution of water is avoided, and the treatment process is simple, convenient and efficient.

Description

Technical Field

[0001] The invention belongs to the technical field of water pollution control, and in particular relates to a method for treating wastewater containing suspended matter and metal ions. Background Art

[0002] Metal ions and suspended solids are common pollutants in wastewater sources such as electroplating wastewater, thermal power generation wastewater, and nonferrous metallurgical wastewater. Current wastewater treatment processes often utilize a multi-step approach to remove metal ions and suspended solids, requiring the addition of various reagents. Furthermore, after chemical precipitation, metal ions often require further removal through flocculation.

[0003] Most metal ions, especially heavy metal ions, are toxic and cannot be biodegraded. Enrichment through the food chain will endanger the balance of the ecosystem and human health. Therefore, the treatment of heavy metal ions is currently a key issue in the field of wastewater treatment. It is worth mentioning that heavy metal ions are very easy to form complexes with EDTA, citrate or other organic anions, which significantly enhances the migration and transformation ability of heavy metal ions in water bodies and increases the difficulty of treatment. At present, the treatment methods of heavy metal ions mainly include chemical precipitation, adsorption, electrochemical method, ion exchange method, membrane separation method, etc. These methods can easily achieve the effective removal of free metal ions, but the removal efficiency of complexed metal ions is relatively limited.

[0004] The main methods for treating suspended solids include filtration, flotation and flocculation, among which flocculation is the most widely used. At present, a combination of inorganic flocculants (polyaluminum chloride PAC, polyferric sulfate PFS, polyaluminum silicate chloride PSAC, etc.) and organic flocculants (polyacrylamide PAM, etc.) is commonly used for treatment. However, when the suspended solids in the wastewater are finer in particle size, the flocculation effect is usually poor, and a large amount of flocculants are required, resulting in problems such as high reagent consumption, large amount of solid slag production, and long process flow. In addition, if the suspended solids are not handled properly, it is easy to cause problems such as pore blockage of subsequent separation membranes, catalysts or adsorbents, thereby affecting the long-term stable operation of the water treatment process.

[0005] CN116495938A discloses a method for treating nickel sulfate extraction wastewater, which uses a reagent sedimentation + combined ion exchange resin process to remove suspended matter and metal ions in the wastewater. The method specifically involves steps S1-S5, and step S3 alone requires four stages of treatment, including pH adjustment with liquid alkali, sodium carbonate decalcification, PAM flocculation, filtration, and chelating resin adsorption to remove heavy metal ions. The method has problems such as a complicated water treatment process and high reagent consumption.

[0006] Currently, existing technologies for treating wastewater containing pollutants such as metal ions and suspended solids, especially those containing complexed metal ions, still face a series of problems, including high chemical consumption, complex water treatment processes, and the risk of secondary water pollution. Therefore, the development of simple and efficient treatment methods is of great significance for achieving low-cost, short-process, and high-efficiency wastewater treatment. Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention provides a method for treating wastewater containing suspended matter and metal ions. The present invention can achieve efficient removal of suspended matter and metal ions in wastewater, avoid secondary pollution of the water body, and has a simple and efficient treatment process.

[0008] The present invention provides a method for treating wastewater containing suspended matter and metal ions, comprising the following steps: introducing CO2-containing gas into the wastewater containing suspended matter and metal ions for flotation treatment, and simultaneously adding a reagent Y1, wherein the reagent Y1 is an amino-based or amidine-based porous polymer; after treatment, solid matter is separated to obtain water, and then a reagent Y2 is added for stirring treatment, and solid matter is separated after reaction; the reagent Y2 is a polysilicic acid-based inorganic-organic hybrid flocculant.

[0009] In the present invention, the wastewater containing suspended matter and metal ions comes from any one of electroplating wastewater, thermal power generation wastewater, non-ferrous metallurgical wastewater, etc., or a mixture of several of them.

[0010] In the present invention, the concentration of suspended matter in the wastewater is 50-200 mg / L, the concentration of metal ions is 10-50 mg / L, and the molar ratio of the complexing agent to the metal ions is 0.05-0.95. The metal ions are Cu 2+ 、Ni 2+ 、Hg 2+ 、Mn 2+ 、Zn 2 + 、Fe 3+ , Ca 2+ Mg 2+ At least one of these metal ions forms a complexed metal ion with a complexing agent, and the complexing agent is at least one of ethylenediaminetetraacetic acid, citrate or pyrophosphate.

[0011] In the present invention, relative to 100 mg of the amino or amidine porous polymer material, the CO2 gas flow rate is 50-200 mL / min, and the time is 10-60 min.

[0012] In the present invention, the mass ratio of the dosage of the agent Y1 to the metal ion is 2-200. After treatment, the solid matter is separated, preferably by static sedimentation, with a static sedimentation time of 0.5-1.0h.

[0013] In the present invention, the dosage of the agent Y2 is 10-200 mg / L. After addition, the reaction is stirred at 200-500 rpm for 5-30 minutes, and the solid matter is separated. The separation is preferably carried out by static sedimentation, and the static sedimentation time is 0.5-1.0 hours.

[0014] In the present invention, the preparation method of the agent Y1, i.e., an amino or amidine porous polymer, is as follows: (a) an amino or amidine polymer, an organic solvent I, a cross-linking agent, and an inorganic salt are mixed to obtain a mixed polymer solution; (b) the mixed polymer solution obtained in step (a) is divided into spherical molds, cross-linked, and obtained polymer pellets; (c) the polymer pellets obtained in step (b) are immersed in pure water and dried to obtain the amino or amidine porous polymer.

[0015] In the present invention, the agent Y2 is a polysilicic acid-based inorganic-organic hybrid flocculant, specifically a copolymer of polysilicic acid and poly (carboxylic acid-sulfonic acid), the carboxylic acid is at least one of acrylic acid, methacrylic acid or maleic acid, and the sulfonic acid is at least one of vinyl sulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid.

[0016] The preparation method of the polysilicic acid-based inorganic-organic hybrid flocculant comprises:

[0017] (1) preparing a sodium silicate solution, adjusting the pH to 3-6, and activating the solution to obtain a mixed solution I;

[0018] (2) preparing an organic monomer solution, wherein the organic monomers are carboxylic acid monomers and sulfonic acid monomers, and adjusting the pH to 3-6 to obtain a mixed solution II;

[0019] (3) Mixing the mixed solutions I and II, placing them in a constant temperature water bath, adding an initiator under an inert atmosphere, and carrying out a polymerization reaction to obtain a polysilicic acid-based inorganic-organic hybrid flocculant.

[0020] In step (1) of the above method, the sodium silicate solution has a SiO2 molar concentration of 0.1-0.5 mol / L.

[0021] In step (1) of the above method, the pH is adjusted with an inorganic acid or an organic acid. The inorganic acid may be at least one of hydrochloric acid, sulfuric acid, phosphoric acid, or hydrobromic acid, preferably phosphoric acid; the organic acid may be at least one of citric acid, oxalic acid, formic acid, or acetic acid, preferably acetic acid. The inorganic acid or organic acid is used at a concentration of 0.1-1 mol / L. After pH adjustment, the activation reaction is carried out at room temperature for 0.5-1 h.

[0022] In step (2) of the above method, the carboxylic acid monomer may be at least one of acrylic acid, methacrylic acid or maleic acid, and the concentration of the carboxylic acid monomer solution is 0.5-2.0 mol / L.

[0023] In step (2) of the above method, the sulfonic acid monomer can be at least one of vinyl sulfonic acid or 2-acrylamido-2-methylpropanesulfonic acid, and the mass ratio of the sulfonic acid monomer to the carboxylic acid monomer is 1:9-1:1.

[0024] In step (2) of the above method, an alkali solution is added dropwise to adjust the pH under stirring at a stirring rate of 200-500 rpm and a dropwise addition rate of 0.1-0.5 mL / min. The alkali solution may be at least one of NaOH, KOH, or NH3·H2O, and the concentration of the alkali solution is 0.1-1.0 mol / L.

[0025] In step (3) of the above method, the mixed solutions I and II are mixed at a volume ratio of 5:1-50:1. The temperature of the constant temperature water bath is 40-90°C.

[0026] In step (3) of the above method, the inert atmosphere is in the presence of nitrogen or an inert gas, and the inert gas is at least one of helium, argon, etc.

[0027] In step (3) of the above method, the initiator may be at least one of a redox initiator or an azo initiator. The redox initiator may be at least one of ammonium persulfate and sodium bisulfite, potassium persulfate and sodium bisulfite, etc. The azo initiator may be at least one of azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, etc., preferably an azo initiator.

[0028] In step (3) of the above method, the mass ratio of the initiator to the organic monomer is 1:1000-1:50. The polymerization reaction time is 8-24 hours.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) For wastewater containing pollutants such as metal ions and suspended solids, especially wastewater containing complexed metal ions, the present invention first adds reagent Y1 and introduces CO2, separates the solid matter after treatment to obtain water, and then adds reagent Y2 for treatment. Through the synergistic effect of the two reagents, the suspended solids and metal ions, especially the complexed metal ions, are efficiently removed. The treatment method is simple and efficient. Compared with traditional methods, the present invention can achieve efficient removal of free and complexed metal ions without changing the pH of the water body, thereby reducing the consumption of reagents (such as acids, alkalis, precipitants, adsorbents, etc.) and the amount of slag produced, avoiding secondary pollution of the water body, and effectively reducing the desalination load and water treatment cost of subsequent stages.

[0031] (2) The amino or amidine porous polymer provided by the present invention will undergo protonation under the stimulation of CO2 gas, and metal ions, especially complex metal ions, will be adsorbed on the surface of the material by electrostatic attraction, which has a significant removal effect.

[0032] (3) The suspended solids after treatment with agent Y1 are smaller, and some free metal ions that cannot be removed by agent Y1 remain. By adding agent Y2, which acts on the suspended solids and free metal ions at the same time, flocs with larger particle sizes are eventually formed, which can effectively shorten the separation time of pollutants and ultimately achieve the simultaneous and efficient removal of residual suspended solids and metal ions.

[0033] (4) The present invention can effectively simplify the water treatment process, thereby reducing the equipment footprint and investment, and providing a simple, efficient, and low-cost treatment method for wastewater containing suspended matter and metal ions. DETAILED DESCRIPTION

[0034] The method of the present invention and its effects are further illustrated below with reference to specific examples. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples.

[0035] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, were purchased from conventional biochemical reagent stores.

[0036] In the present invention, the concentration of the suspended solids was determined by gravimetric method, and the Cu 2+ 、Ni 2+ 、Hg 2+ 、Mn 2+ 、Zn 2+ 、Fe 3+ The concentration of plasma was determined by ion chromatography (Aquion-RFIC) 2+ and Mg 2+ concentration.

[0037] The calculation formula for the removal rate of suspended solids and metal ions is shown in (1):

[0038]

[0039] Wherein, R% represents the removal rate of pollutants, C0 represents the initial concentration of pollutants (i.e. suspended solids or metal ions), and C represents the concentration of pollutants (i.e. suspended solids or metal ions) after treatment.

[0040] The preparation method of the amino- or amidine-based porous polymer of the present invention comprises the following steps: (a) mixing an amino- or amidine-based polymer, an organic solvent I, a crosslinking agent, and an inorganic salt to obtain a mixed polymer solution; (b) dispensing the mixed polymer solution obtained in step (a) into a spherical mold, crosslinking, and obtaining polymer pellets; and (c) impregnating the polymer pellets obtained in step (b) with pure water and drying to obtain the amino- or amidine-based porous polymer.

[0041] In step (a), the mass fraction of the polymer in the mixed polymer solution is 5%-30%, the mass ratio of the crosslinking agent to the polymer is 1:200-1:50, and the mass ratio of the inorganic salt to the polymer is 2:1-10:1. The volume of the organic solvent I is 3-20 mL / g based on the mass of the polymer. The inorganic salt is selected from one of sodium chloride, sodium sulfate, and calcium chloride. The amino or amidine polymer is selected from at least one of polydiethylaminoethyl methacrylate, polydimethylaminoethyl methacrylate, polyamide-amine, poly-N-vinylcaprolactam, or poly-3(1H-imidazole-4-yl)methyl acrylate. The organic solvent I is selected from one or more of ethanol, methanol, isopropanol, and tert-butanol. The crosslinking agent is selected from one or more of polyethylene glycol, glyoxal, and trimethylolethane.

[0042] In step (a), the amino or amidine polymer is prepared by free radical polymerization or polycondensation. The specific operation steps are: mixing the amino or amidine polymer monomer and organic solvent II, passing an inert gas (such as nitrogen) for 10-30 minutes, then adding an initiator, placing in a 40-90°C oil bath or a 0-25°C water bath, reacting under an inert atmosphere (such as nitrogen) for 4-24 hours, then stopping the ventilation to terminate the reaction; adding dichloromethane to dilute (1.5-3 times) the reaction solution, adding the diluted reaction solution to 1-5 times the volume of n-hexane to precipitate, filtering, repeating the dissolution-filtration 2-4 times, and placing in a forced air drying oven at 40-80°C to dry for 4-12 hours to obtain the amino or amidine polymer. The amino or amidine-based polymerizable monomer is selected from at least one of diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate, methyl acrylate, ethylenediamine, N-vinylcaprolactam, or methyl 3(1H-imidazol-4-yl)acrylate. The organic solvent II is selected from at least one of 1,4-dioxane, dimethylformamide, toluene, or methanol; and the initiator is selected from at least one of azobisisobutyronitrile, benzoyl peroxide, or dicumyl peroxide. The mass ratio of the amino or amidine-based polymerizable monomer to the initiator is 2000:1 to 100:1; and the volume of the organic solvent II is 0.6 to 5 mL / g based on the mass of the polymerizable monomer.

[0043] In step (b), the diameter of the spherical mold is 0.5-2 cm. The cross-linking temperature is 80-120° C. and the time is 8-12 hours. The cross-linking reaction can be carried out in a forced air drying oven.

[0044] In step (c), the immersion time is 4-8 hours. The drying conditions are: drying at 50-70°C for 4-6 hours. The drying process can be carried out in a forced air drying oven.

[0045] Example 1

[0046] Preparation of Agent Y1: Diethylaminoethyl methacrylate (7.5 g) and 1,4-dioxane (10 mL) were added to a reaction flask and thoroughly mixed under magnetic stirring while purging with high-purity nitrogen. After a continuous nitrogen purge for 30 minutes, azobisisobutyronitrile (7.5 mg) was added as the initiator and placed in an 80°C oil bath for 4 hours under nitrogen. After the reaction, the nitrogen flow was stopped and the reaction flask was opened to the atmosphere to terminate the polymerization reaction. After the reaction flask cooled to room temperature, the 1,4-dioxane solvent was removed from the reaction system using a rotary evaporator, and 5 mL of dichloromethane was added to the reaction flask to dissolve the reaction product. The reaction product solution was added dropwise to 20 mL of n-hexane for precipitation, filtered, and the dissolution and filtration were repeated once to obtain the product, polydiethylaminoethyl methacrylate, which was dried in a vacuum drying oven at 60°C for 4 hours. Dissolve 2 g of the poly(diethylaminoethyl methacrylate) obtained above in 20 mL of ethanol, add 20 mg of polyethylene glycol and 10 g of sodium chloride granules, and stir to obtain a mixed polymer solution. The resulting polymer solution was dispensed into spherical molds with a diameter of 1 cm and dried and cross-linked in a forced-air drying oven at 100°C for 8 h to obtain polymer pellets. The resulting polymer pellets were removed from the spherical molds and immersed in pure water for 6 h. The pellets were then dried in a forced-air drying oven at 60°C for 6 h to obtain Agent Y1.

[0047] Preparation of agent Y2: (1) Prepare a sodium silicate solution with a molar concentration of SiO2 of 0.2 mol / L, adjust the pH value to 4 with the help of 0.5 mol / L hydrochloric acid solution, and activate the reaction at room temperature for 1 hour to obtain a mixed solution I; (2) Prepare acrylic acid and vinyl sulfonic acid solutions, control the concentration of the acrylic acid solution to 0.5 mol / L, and the mass ratio of vinyl sulfonic acid to acrylic acid to 1:5, and slowly add 0.5 mol / L NaOH solution at a rate of 0.3 mL / min under stirring at 300 rpm, and the pH at the end of the addition is 4 to obtain a mixed solution II; (3) Mix the mixed solutions I and II in a volume ratio of 10:1, place them in a constant temperature water bath at 70°C, pass nitrogen for 0.5 hour, add azobisisobutylamidine hydrochloride initiator, control the mass ratio of initiator to organic monomer to 1:200, and carry out polymerization reaction for 10 hours to obtain agent Y2.

[0048] The water quality parameters of a wastewater are: suspended solids concentration is 200mg / L, Cu 2+ The concentration is 30 mg / L, EDTA and Cu 2+ The molar ratio is 0.7.

[0049] First, CO2 gas was introduced into 100mL of wastewater for flotation treatment. At the same time, reagent Y1 was added at 1g / L, the CO2 gas flow rate was controlled at 100mL / min, and the purge time was 30min. The solid matter was separated to obtain water. Then, reagent Y2 was added at 100mg / L, stirred at 250rpm for 30min, and then allowed to stand for 0.5h. After the solid matter was separated, the residual suspended matter and metal ion content in the wastewater were measured. The test results showed that the removal rate of suspended matter was 98.2%, and the removal rate of Cu 2+ The removal rate is 97.1%.

[0050] Example 2

[0051] Preparation of Agent Y1: Dimethylaminoethyl methacrylate (10 g) and dimethylformamide (10 mL) were added to a reaction flask, thoroughly mixed under magnetic stirring, and high-purity nitrogen was introduced during the process. After nitrogen was continuously purged for 10 minutes, the initiator benzoyl peroxide (20 mg) was connected and placed in a 50°C oil bath to react for 24 hours under nitrogen protection. After the reaction was completed, the nitrogen was stopped and the reaction flask was opened to the atmosphere to terminate the polymerization reaction. After the reaction flask was cooled to room temperature, the dimethylformamide solvent in the reaction system was removed by means of a rotary evaporator, and 10 mL of dichloromethane was added to the reaction flask to dissolve the reaction product. The reaction product solution was dripped dropwise into 40 mL of n-hexane for precipitation, filtered, and the dissolution-filtration was repeated twice. The obtained product was polydimethylaminoethyl methacrylate, which was placed in a 50°C vacuum drying oven and dried for 8 hours. Dissolve 4 g of the polydimethylaminoethyl methacrylate obtained above in 20 mL of isopropyl alcohol, add 20 mg of glyoxal and 8 g of sodium sulfate particles, and stir to obtain a mixed polymer solution. The resulting polymer solution is dispensed into spherical molds with a diameter of 0.5 cm and dried and crosslinked in a forced air drying oven at 90°C for 10 h to obtain polymer pellets. The resulting polymer pellets are removed from the spherical molds, immersed in pure water for 4 h, and then dried in a forced air drying oven at 50°C for 4 h to obtain Agent Y1.

[0052] Preparation of agent Y2: (1) Prepare a sodium silicate solution with a molar concentration of SiO2 of 0.2 mol / L, adjust the pH value to 4 with the help of 0.5 mol / L hydrochloric acid solution, and activate the reaction at room temperature for 1 hour to obtain a mixed solution I; (2) Prepare acrylic acid and vinyl sulfonic acid solutions, control the concentration of the acrylic acid solution to 0.5 mol / L, and the mass ratio of vinyl sulfonic acid to acrylic acid to 1:5, and slowly add 0.5 mol / L NaOH solution at a rate of 0.3 mL / min under stirring at 300 rpm, and the pH at the end of the addition is 4 to obtain a mixed solution II; (3) Mix the mixed solutions I and II in a volume ratio of 10:1, place them in a constant temperature water bath at 70°C, pass nitrogen for 0.5 hour, add azobisisobutylamidine hydrochloride initiator, control the mass ratio of initiator to organic monomer to 1:200, and carry out polymerization reaction for 10 hours to obtain agent Y2.

[0053] The water quality parameters of a wastewater are: suspended solids concentration is 200mg / L, Hg 2+ The concentration is 30 mg / L, EDTA and Hg 2+ The molar ratio is 0.5.

[0054] First, CO2 gas was introduced into 100 mL of wastewater for flotation treatment. At the same time, reagent Y1 was added at 1 g / L, the CO2 gas flow rate was controlled at 100 mL / min, the purge time was 30 min, and the solid matter was separated from the water. Then, reagent Y2 was added at 100 mg / L, and the reaction was carried out at a stirring rate of 250 rpm for 30 min. After that, the mixture was allowed to stand for 0.5 h. After the solid matter was separated, the residual suspended matter and Hg in the wastewater were measured. 2+ The test results show that the removal rate of suspended matter is 98.5%, Hg 2+ The removal rate is 92.6%.

[0055] Example 3

[0056] Preparation of Agent Y1: 2.5 g of methyl 3(1H-imidazol-4-yl)acrylate and 1,4-dioxane (10 mL) were added to a reaction flask and thoroughly mixed under magnetic stirring while purging with high-purity nitrogen. After a continuous nitrogen purge for 30 minutes, 2.5 mg of azobisisobutyronitrile (2) was added as an initiator and the mixture was placed in a 90°C oil bath for 10 hours under nitrogen. After the reaction, the nitrogen flow was stopped and the reaction flask was opened to the atmosphere to terminate the polymerization. After the reaction flask cooled to room temperature, the 1,4-dioxane solvent was removed from the reaction system using a rotary evaporator, and 15 mL of dichloromethane was added to the reaction flask to dissolve the reaction product. The reaction product solution was added dropwise to 100 mL of n-hexane for precipitation, filtered, and the dissolution and filtration cycle was repeated twice to obtain the product, poly(3(1H-imidazol-4-yl)methyl acrylate), which was then dried in a vacuum drying oven at 60°C for 12 hours. Dissolve 2 g of the poly(3-(1H-imidazole-4-yl)methyl acrylate) obtained above in 20 mL of ethanol, add 20 mg of polyethylene glycol and 10 g of sodium chloride particles, and stir to obtain a mixed polymer solution. The resulting polymer solution was dispensed into spherical molds with a diameter of 1 cm and placed in a forced air drying oven at 120°C for 10 hours to dry and crosslink the mixture, yielding polymer pellets. The resulting polymer pellets were removed from the spherical molds and immersed in pure water for 8 hours. The pellets were then dried in a forced air drying oven at 60°C for 6 hours to obtain Agent Y1.

[0057] Preparation of agent Y2: (1) Prepare a sodium silicate solution with a molar concentration of SiO2 of 0.5 mol / L, adjust the pH value to 3 with the help of 1 mol / L sulfuric acid solution, and activate the reaction at room temperature for 45 minutes to obtain a mixed solution I; (2) Prepare maleic acid and vinyl sulfonic acid solutions, control the concentration of the maleic acid solution to 2 mol / L, and the mass ratio of vinyl sulfonic acid to maleic acid to be 1:9. Under the condition of stirring at 500 rpm, slowly add 1 mol / L KOH solution at a rate of 0.5 mL / min, and control the pH value at the end point of the addition to be 6, to obtain a mixed solution II; (3) Mix the mixed solutions I and II in a volume ratio of 50:1, place them in a constant temperature water bath at 90°C, pass nitrogen for 0.5 h, add azobisisobutylimidazoline hydrochloride initiator, control the mass ratio of initiator to organic monomer to be 1:1000, and carry out polymerization reaction for 8 hours to obtain agent Y2.

[0058] The water quality parameters of a wastewater are: suspended solids concentration is 200 mg / L, Mn 2+ The concentration is 30 mg / L, EDTA and Mn 2+ The molar ratio is 0.8.

[0059] First, CO2 gas was introduced into 100 mL of wastewater for flotation treatment. At the same time, reagent Y1 was added at 1 g / L, the CO2 gas flow rate was controlled at 100 mL / min, the purge time was 30 min, and the solid matter was separated from the water. Then, reagent Y2 was added at 100 mg / L, and the reaction was carried out at a stirring rate of 250 rpm for 30 min. After that, the mixture was allowed to stand for 0.5 h. After the solid matter was separated, the residual suspended matter and Mn in the wastewater were measured. 2+ The test results show that the removal rate of suspended matter is 93.6%, Mn 2+ The removal rate is 95.7%.

[0060] Example 4

[0061] Same as Example 1, except that the wastewater quality parameters are: suspended solids concentration is 200 mg / L, Ni 2+ The concentration is 10 mg / L, Ca 2+ The concentration is 20 mg / L, and the molar ratio of EDTA to metal ions is 0.7. The test results show that the removal rate of suspended solids is 98.1%, Ni 2+ The removal rate of Ca was 96.8%, 2+ The removal rate is 95.9%.

[0062] Example 5

[0063] Same as Example 2, except that the wastewater quality parameters are: suspended solids concentration is 200 mg / L, Zn 2+ The concentration is 15 mg / L, Fe 3+ The concentration is 15 mg / L, and the molar ratio of EDTA to metal ions is 0.7. The test results show that the removal rate of suspended matter is 98.2%, Zn 2+ The removal rate of Fe 3+ The removal rate is 95.2%.

[0064] Example 6

[0065] Same as Example 1, except that: the wastewater quality parameters are: suspended solids concentration is 200 mg / L, Fe 3+ The concentration is 30 mg / L, and the molar ratio of citrate to metal ions is 0.7. The test results show that the removal rate of suspended solids is 98.5%, Fe 3+ The removal rate is 97.2%.

[0066] Comparative Example 1

[0067] Same as Example 1, except that Y2 is used instead of Y1, i.e. Y2 is used in both treatment steps. The test results show that the removal rate of suspended solids is 90.3%, Cu 2+ The removal rate is 20.5%.

[0068] Comparative Example 2

[0069] Same as Example 1, except that Y1 is used instead of Y2, i.e. Y1 is used in both treatment steps. The test results show that the removal rate of suspended solids is 17.8%, Cu 2+ The removal rate is 87.5%.

[0070] Comparative Example 3

[0071] Same as Example 1, except that the order of reagents Y1 and Y2 is changed, that is, Y2 is added first, then Y1. The test results show that the removal rate of suspended solids is 88.5%, Cu 2+ The removal rate is 90.3%.

Claims

1. A method for treating wastewater containing suspended matter and metal ions, characterized in that The method comprises the following steps: introducing CO2-containing gas into wastewater containing suspended matter and metal ions for flotation treatment, and simultaneously adding agent Y1, wherein the agent Y1 is an amino or amidine-based porous polymer; after treatment, the solid matter is separated to obtain water, and then adding agent Y2 for stirring treatment, and separating the solid matter after reaction; the agent Y2 is a polysilicic acid-based inorganic-organic hybrid flocculant.

2. The method according to claim 1, wherein: The wastewater containing suspended matter and metal ions comes from any one of electroplating wastewater, thermal power generation wastewater, and non-ferrous metallurgical wastewater, or a mixture of several of them. The concentration of suspended matter in the wastewater is 50-200 mg / L, and the concentration of metal ions is 10-50 mg / L. The molar ratio of the complexing agent to the metal ions is 0.05-0.

95.

3. The method according to claim 1 or 2, characterized in that: The metal ion is Cu 2+ 、Ni 2+ 、Hg 2+ 、Mn 2+ 、Zn 2+ 、Fe 3+ , Ca 2+ Mg 2+ One or more of the metal ions are mixed, at least one of the metal ions forms a complex metal ion with a complexing agent, and the complexing agent is at least one of ethylenediaminetetraacetic acid, citrate or pyrophosphate.

4. The method according to claim 1, wherein: Relative to 100 mg of the amino- or amidine-based porous polymer material, the CO2 gas flow rate is 50-200 mL / min, and the time is 10-60 min.

5. The method according to claim 1, wherein: The mass ratio of the dosage of the agent Y1 to the metal ions is 2-200; after treatment, the solid matter is separated, and the separation is preferably carried out by static sedimentation, and the static sedimentation time is 0.5-1.0h.

6. The method according to claim 1, wherein: The dosage of the agent Y2 is 10-200 mg / L; after addition, the mixture is stirred at 200-500 rpm for 5-30 minutes to separate the solid matter; the separation is preferably carried out by static sedimentation, and the static sedimentation time is 0.5-1.0 h.

7. The method according to claim 1, wherein: The preparation method of the amino- or amidine-based porous polymer comprises the following steps: (a) mixing an amino-based polymer, an organic solvent I, a crosslinking agent, and an inorganic salt to obtain a mixed polymer solution; the amino-based polymer is polydiethylaminoethyl methacrylate; (b) dispensing the mixed polymer solution obtained in step (a) into a spherical mold, crosslinking, and obtaining polymer pellets; and (c) soaking the polymer pellets obtained in step (b) in pure water and drying to obtain the amino- or amidine-based porous polymer.

8. The method according to claim 1, wherein: The agent Y2 is a polysilicic acid-based inorganic-organic hybrid flocculant, specifically a copolymer of polysilicic acid and poly (carboxylic acid-sulfonic acid), the carboxylic acid is at least one of acrylic acid, methacrylic acid or maleic acid, and the sulfonic acid is at least one of vinyl sulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid.

9. The method according to claim 1 or 8, characterized in that: The preparation method of a polysilicic acid-based inorganic-organic hybrid flocculant comprises the following steps: (1) preparing a sodium silicate solution, adjusting the pH to 3-6, and activating the solution to obtain a mixed solution I; (2) preparing an organic monomer solution, wherein the organic monomers are carboxylic acid monomers and sulfonic acid monomers, adjusting the pH to 3-6, and obtaining a mixed solution II; (3) mixing the mixed solutions I and II, placing the mixed solutions in a constant temperature water bath, adding an initiator under an inert atmosphere, and conducting a polymerization reaction to obtain a polysilicic acid-based inorganic-organic hybrid flocculant.

10. The method according to claim 9, characterized in that: In step (1), the sodium silicate solution has a SiO2 molar concentration of 0.1-0.5 mol / L.

11. The method according to claim 9, wherein: In step (1), the pH is adjusted with the aid of an inorganic acid or an organic acid, wherein the inorganic acid is at least one of hydrochloric acid, sulfuric acid, phosphoric acid or hydrobromic acid, preferably phosphoric acid; the organic acid is at least one of citric acid, oxalic acid, formic acid or acetic acid, preferably acetic acid; the inorganic acid or organic acid is configured to a concentration of 0.1-1 mol / L; after adjusting the pH, the activation reaction is carried out at room temperature for a reaction time of 0.5-1 h.

12. The method according to claim 9, wherein: In step (2), the carboxylic acid monomer is at least one of acrylic acid, methacrylic acid or maleic acid, and the concentration of the carboxylic acid monomer solution is 0.5-2.0 mol / L.

13. The method according to claim 9, wherein: In step (2), the sulfonic acid monomer may be at least one of vinyl sulfonic acid or 2-acrylamido-2-methylpropanesulfonic acid, and the mass ratio of the sulfonic acid monomer to the carboxylic acid monomer is 1:9-1:

1.

14. The method according to claim 9, wherein: In step (2), an alkali solution is added dropwise to adjust the pH under stirring conditions at a stirring rate of 200-500 rpm and a dropping rate of 0.1-0.5 mL / min; the alkali is at least one of NaOH, KOH or NH3·H2O, and the concentration of the alkali solution is 0.1-1.0 mol / L.

15. The method according to claim 9, wherein: In step (3), the mixed solutions I and II are mixed in a volume ratio of 5:1-50:1; the temperature of the constant temperature water bath is 40-90°C.

16. The method according to claim 9, wherein: In step (3), the inert atmosphere is in the presence of nitrogen or an inert gas, and the inert gas is at least one of helium and argon.

17. The method according to claim 9, wherein: The initiator is at least one of a redox initiator or an azo initiator; the redox initiator is at least one of ammonium persulfate and sodium bisulfite, potassium persulfate and sodium bisulfite; the azo initiator is at least one of azobisisobutylamidine hydrochloride and azobisisobutylimidazoline hydrochloride, preferably an azo initiator.

18. The method according to claim 9, wherein: In step (3), the mass ratio of the initiator to the organic monomer is 1:1000-1:50; and the polymerization reaction time is 8-24 hours.

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