Organic-inorganic hybrid flocculant as well as preparation method and application thereof

Abstract

The invention provides an organic-inorganic hybrid flocculant as well as a preparation method and application thereof, and belongs to the technical field of industrial wastewater treatment. The preparation method of the organic-inorganic hybrid flocculant comprises the following steps: mixing acrylamide, an initiator and an aluminum hydroxide colloidal solution, and carrying out polymerization reaction to obtain a first gel product; mixing the first gel product with water and an aldehyde compound, carrying out Mannich reaction, mixing the obtained product with diethylenetriamine, and carrying out amidation reaction to obtain a second gel product; and mixing the second gel product with carbon disulfide and a sodium hydroxide aqueous solution, carrying out nucleophilic addition reaction, mixing the obtained product with Prussian blue and water, and carrying out coordination reaction to obtain the organic-inorganic hybrid flocculant. The organic-inorganic hybrid flocculant prepared by the invention has good adsorption and sedimentation effects on lead, chromium, cadmium and other conventional heavy metals in wastewater, and also has good adsorption and sedimentation effects on thallium.

Description

Technical Field

[0001] The invention belongs to the technical field of industrial wastewater treatment, and specifically relates to an organic-inorganic hybrid flocculant and a preparation method and application thereof. Background Art

[0002] Heavy metal wastewater refers to wastewater rich in heavy metal elements such as lead, chromium, cadmium, and thallium. These heavy metal elements are stable in nature and difficult to decompose and destroy in the natural environment. They are also toxic and can enter the human body through the food chain and accumulate in organisms, causing harm to the human body and the environment. Therefore, effective treatment of heavy metal wastewater to reduce its pollution and harm to the environment has become an urgent problem to be solved in the current environmental protection field.

[0003] Flocculants are chemicals used to treat water pollution problems. They can adsorb and aggregate colloidal particles or metal ions suspended in liquids to form larger particles (or floccules) to promote the precipitation of these particles from stable suspensions. Therefore, flocculants have been widely used in water decolorization and turbidity removal, as well as coagulation and precipitation of pollutants in water.

[0004] However, currently commonly used flocculants (such as aluminum sulfate, polyacrylamide, compound Al(OH) 3 -PAM flocculant) has good coagulation sedimentation, decolorization and turbidity removal effects, but it is not effective in treating heavy metals in wastewater, especially thallium. Summary of the invention

[0005] The purpose of the present invention is to provide an organic-inorganic hybrid flocculant and its preparation method and application. The organic-inorganic hybrid flocculant prepared by the present invention not only has a good adsorption and sedimentation effect on conventional heavy metals such as lead, chromium, cadmium, etc. in wastewater, but also has a good adsorption and sedimentation effect on thallium.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing an organic-inorganic hybrid flocculant, comprising the following steps: providing an aluminum hydroxide colloidal solution; Mixing acrylamide, an initiator and the aluminum hydroxide colloidal solution to perform a polymerization reaction to obtain a first gel product; The first gel product is mixed with water and an aldehyde compound to perform a Mannich reaction, and the obtained product is mixed with diethylenetriamine to perform an amidation reaction to obtain a second gel product; The second gel product is mixed with carbon disulfide and sodium hydroxide aqueous solution to carry out nucleophilic addition reaction, and the obtained product is mixed with Prussian blue and water to carry out coordination reaction to obtain the organic-inorganic hybrid flocculant.

[0007] Preferably, the initiator comprises potassium persulfate and sodium bisulfite; the mass ratio of potassium persulfate to acrylamide is 0.6-0.8:100; the mass ratio of sodium bisulfite to acrylamide is 0.3-0.5:100; the polymerization reaction is carried out in an inert atmosphere; the temperature of the polymerization reaction is 40-55°C, and the time is 1-2h.

[0008] Preferably, the aldehyde compound includes at least one of formaldehyde, acetaldehyde, propionaldehyde, cinnamaldehyde and vanillin; the mass ratio of the aldehyde compound to acrylamide is 29-32:100; the temperature of the Mannich reaction is 45-55°C, and the time is 1-2h.

[0009] Preferably, the mass ratio of diethylenetriamine to acrylamide is 31-34:100; the temperature of the amidation reaction is 45-55° C., and the time is 2-4 hours.

[0010] Preferably, the mass ratio of carbon disulfide to acrylamide is 65-68:100; the mass percentage concentration of the sodium hydroxide aqueous solution is 20-30%, and the volume ratio of the sodium hydroxide aqueous solution to carbon disulfide is 2-2.5:0.8-1; the temperature of the nucleophilic addition reaction is 20-30°C, and the time is 4-6h.

[0011] Preferably, the mass ratio of the Prussian blue to acrylamide is 35-40:100; the temperature of the coordination reaction is 50-60° C., and the time is 2-3 hours.

[0012] The present invention provides an organic-inorganic hybrid flocculant obtained by the preparation method described in the above technical scheme, comprising an inorganic component and an organic component wrapped on the surface of the inorganic component; the organic component comprises acrylamide, diethylenetriamine and an organic intermediate; the inorganic component comprises aluminum salt and Prussian blue.

[0013] The present invention provides the use of the organic-inorganic hybrid flocculant described in the above technical solution in the treatment of heavy metal-containing wastewater.

[0014] Preferably, the heavy metal elements in the heavy metal-containing wastewater include at least one of Tl, Pb, Cr, Hg, Cd, Cu and Zn; in the heavy metal-containing wastewater, the concentration of Tl is 1~2 mg / L; the concentration of Pb is 1~20 mg / L; the concentration of Cr is 1~10 mg / L; the concentration of Hg is 1~2 mg / L; the concentration of Cd is 1~3 mg / L; the concentration of Cu is 1~20 mg / L; the concentration of Zn is 1~20 mg / L.

[0015] Preferably, the heavy metal-containing wastewater also includes As; and the concentration of As in the heavy metal-containing wastewater is 1-3 mg / L.

[0016] The present invention provides a method for preparing an organic-inorganic hybrid flocculant, comprising the following steps: providing an aluminum hydroxide colloidal solution; mixing acrylamide and an initiator with the aluminum hydroxide colloidal solution, performing a polymerization reaction, and obtaining a first gel product; mixing the first gel product with water and an aldehyde compound, performing a Mannich reaction, mixing the obtained product with diethylenetriamine, performing an amidation reaction, and obtaining a second gel product; mixing the second gel product with carbon disulfide and an aqueous sodium hydroxide solution, performing a nucleophilic addition reaction, mixing the obtained product with Prussian blue and water, performing a coordination reaction, and obtaining the organic-inorganic hybrid flocculant. The present invention uses acrylamide and aluminum hydroxide colloid as raw materials, and a polymerization reaction occurs under the action of an initiator to prepare a first gel, wherein the first gel is an aluminum hydroxide-polyacrylamide flocculant having a hybrid structure and a structure similar to nerve cell fibers, specifically using inorganic aluminum hydroxide as the core, and wrapping an organic molecule outside the core, so that the distance between multiple groups can be increased, thereby weakening the effects of steric hindrance and mismatch, and improving the adsorption capacity of the obtained aluminum hydroxide-polyacrylamide flocculant. The present invention prepares a dithiocarbamate chelating functional group by adding diethylenetriamine and carbon disulfide, wherein the dithiocarbamate chelating functional group has the function of separating heavy metal ions. The present invention introduces the dithiocarbamate chelating functional group into the prepared intermediate product aluminum hydroxide-polyacrylamide flocculent body, wherein the presence of the aluminum hydroxide-polyacrylamide flocculent body can make the organic-inorganic hybrid flocculant have excellent flocculation ability, and the dithiocarbamate chelating functional group introduced on this basis can realize the efficient separation of heavy metal ions. The organic-inorganic hybrid flocculant prepared by the present invention is a brand-new hybrid material, has a high molecular weight, effectively improves the flocculation effect, not only has a good adsorption and sedimentation effect on conventional heavy metals such as lead, chromium, cadmium in wastewater, can remove conventional heavy metal elements in wastewater to the first-level standard for comprehensive sewage discharge (GB8978-1996), but also has a good adsorption and precipitation effect on thallium.

[0017] Furthermore, the present invention uses an in-situ polymerization method to initiate the polymerization of acrylamide in an inorganic sol, thereby achieving uniform hybridization of inorganic components and organic components, and synthesizing an organic-inorganic hybrid flocculant with a similar nerve cell fiber structure in which an organic component encapsulates an inorganic component and is uniformly dispersed. The organic-inorganic hybrid flocculant prepared by the present invention has a good adsorption and sedimentation effect on heavy metal elements and quasi-heavy metal elements (such as arsenic), and also has a good coagulation and sedimentation effect on suspended matter in wastewater.

[0018] Furthermore, the organic-inorganic hybrid flocculant of the present invention exhibits the characteristics of large flocs and fast sedimentation speed, high reagent utilization rate, and effective cost saving. DETAILED DESCRIPTION

[0019] The present invention provides a method for preparing an organic-inorganic hybrid flocculant, comprising the following steps: providing an aluminum hydroxide colloidal solution; Mixing acrylamide, an initiator and the aluminum hydroxide colloidal solution to perform a polymerization reaction to obtain a first gel product; The first gel product is mixed with water and an aldehyde compound to perform a Mannich reaction, and the obtained product is mixed with diethylenetriamine to perform an amidation reaction to obtain a second gel product; The second gel product is mixed with carbon disulfide and sodium hydroxide aqueous solution to carry out nucleophilic addition reaction, and the obtained product is mixed with Prussian blue and water to carry out coordination reaction to obtain the organic-inorganic hybrid flocculant.

[0020] In the present invention, unless otherwise specified, the raw materials used are commercially available products well known to those skilled in the art or are prepared by methods well known to those skilled in the art.

[0021] In the present invention, the preparation method of the aluminum hydroxide colloidal solution may include the following steps: mixing a soluble ammonium salt, a soluble aluminum salt and water and reacting to obtain an aluminum hydroxide colloidal solution. In the present invention, the soluble ammonium salt may include ammonium carbonate or ammonium bicarbonate; the soluble aluminum salt may include aluminum chloride or aluminum sulfate. The mass ratio of the soluble ammonium salt and the soluble aluminum salt in the present invention may be 80-90:100; in a specific embodiment of the present invention, the mass ratio of the soluble ammonium salt and the soluble aluminum salt is 80:100, 85:100 or 90:100. The mass ratio of the total mass of the soluble ammonium salt and the soluble aluminum salt to acrylamide may be 60-70:100; in a specific embodiment of the present invention, the mass ratio of the total mass of the soluble ammonium salt and the soluble aluminum salt to acrylamide is 60:100, 65:100 or 70:100. In the present invention, specifically, an aqueous solution of a soluble ammonium salt is added dropwise to an aqueous solution of a soluble aluminum salt, and an aluminum hydroxide colloidal solution is obtained after the reaction. The mass percentage concentration of the aqueous solution of the soluble ammonium salt of the present invention can be 10% to 20%; in a specific embodiment of the present invention, the mass percentage concentration of the aqueous solution of the soluble ammonium salt is 10%, 15% or 20%. The mass percentage concentration of the aqueous solution of the soluble aluminum salt of the present invention can be 5% to 10%; in a specific embodiment of the present invention, the mass percentage concentration of the aqueous solution of the soluble aluminum salt is 5%, 8% or 10%. The volume ratio of the aqueous solution of the soluble ammonium salt of the present invention to the aqueous solution of the soluble aluminum salt can be 1:2. In the present invention, the reaction temperature can be 25 to 35°C, and the time can be 0.5 to 1.5h; in a specific embodiment of the present invention, the reaction temperature is 25°C, 30°C or 35°C; the time is 0.5h, 1h or 1.5h.

[0022] After obtaining the aluminum hydroxide colloidal solution, the present invention mixes acrylamide and an initiator with the aluminum hydroxide colloidal solution to perform a polymerization reaction to obtain a first gel product. In the present invention, the initiator may include potassium persulfate and sodium bisulfite; the mass ratio of potassium persulfate to acrylamide may be 0.6-0.8:100; the mass ratio of sodium bisulfite to acrylamide may be 0.3-0.5:100. In a specific embodiment of the present invention, the mass ratio of potassium persulfate to acrylamide is 0.6:100, 0.7:100 or 0.8:100; the mass ratio of sodium bisulfite to acrylamide is 0.3:100, 0.4:100 or 0.5:100. In the present invention, specifically, acrylamide is mixed with the aluminum hydroxide colloidal solution, pre-treated to obtain a mixed liquid; an aqueous solution of the initiator is added to the mixed liquid to perform a polymerization reaction. In the present invention, the polymerization reaction may be carried out in an inert atmosphere; the inert atmosphere may include at least one of a nitrogen atmosphere, a helium atmosphere and an argon atmosphere. In the present invention, the pretreatment is carried out under water bath conditions; the temperature of the pretreatment can be 40-55°C, and the time can be 0.5-1.5h. In a specific embodiment of the present invention, the temperature of the pretreatment is 40°C, 45°C, 50°C or 55°C; the time is 0.5h, 1h or 1.5h. Before the polymerization reaction, the present invention introduces an inert gas into the system where the mixed liquid is located to remove oxygen, so as to facilitate the subsequent reaction. In the present invention, the aqueous solution of the initiator can include an aqueous potassium persulfate solution and an aqueous sodium bisulfite solution; the mass percentage concentration of the potassium persulfate solution can be 1.9-2.4%, and the mass percentage concentration of the sodium bisulfite solution can be 1-1.5%. In a specific embodiment of the present invention, the mass percentage concentration of the potassium persulfate solution is 1.9%, 2% or 2.4%; the mass percentage concentration of the sodium bisulfite solution is 1%, 1.06% or 1.5%. The volume ratio of the potassium persulfate solution and the sodium bisulfite solution of the present invention can be 1:1. The temperature of the polymerization reaction of the present invention can be 40~55℃, and the time can be 1~2h. In a specific embodiment of the present invention, the temperature of the polymerization reaction is 40℃, 45℃, 50℃ or 55℃; the time is 1h, 1.5h or 2h; the temperature of the polymerization reaction is the same as the temperature of the pretreatment. After the polymerization reaction is completed, the present invention can age the obtained reaction liquid to obtain an aged gel; the aged gel is added to acetone for extraction and precipitation to obtain a first gel product. In the present invention, the aging is carried out under closed conditions; the aging temperature can be 25~35℃, and the time can be 3~5h. In a specific embodiment of the present invention, the aging temperature is 25℃, 30℃ or 35℃; the time is 3h, 4h or 5h.

[0023] After obtaining the first gel product, the present invention mixes the first gel product with water and an aldehyde compound, performs a Mannich reaction, and obtains a gel intermediate. In a specific embodiment of the present invention, the first gel product is mixed with water to obtain a first gel product aqueous solution; the first gel product aqueous solution is mixed with an aldehyde compound to perform a Mannich reaction to obtain a liquid containing a gel intermediate. In the present invention, the mass percentage concentration of the first gel product aqueous solution may be 0.5-1.5%; in a specific embodiment of the present invention, the mass percentage concentration of the first gel product aqueous solution is 0.5%, 1% or 1.5%. Before mixing the first gel product aqueous solution with the aldehyde compound, the present invention may adjust the pH value of the first gel product aqueous solution to 7-9. In a specific embodiment of the present invention, the pH value of the first gel product aqueous solution may be adjusted to 7, 8 or 9. In the present invention, the reagent used to adjust the pH value may be a sodium hydroxide aqueous solution. In the present invention, the aldehyde compound may include at least one of formaldehyde, acetaldehyde, propionaldehyde, cinnamaldehyde and vanillin; the mass ratio of the aldehyde compound to acrylamide may be 29-32:100. In a specific embodiment of the present invention, the aldehyde compound may be formaldehyde, acetaldehyde, propionaldehyde, cinnamaldehyde or vanillin. The mass ratio of the aldehyde compound to acrylamide in the present invention is 29:100, 30:100, 31:100 or 32:100. In a specific embodiment of the present invention, the Mannich reaction may be carried out under water bath conditions; the temperature of the Mannich reaction may be 45-55°C, and the time may be 1-2h. In a specific embodiment of the present invention, the temperature of the Mannich reaction is 45°C, 50°C or 55°C; the time is 1h, 1.5h or 2h. After preparing the liquid containing the gel intermediate, the present invention can carry out subsequent operations without post-treatment.

[0024] After obtaining the gel intermediate, the present invention mixes the gel intermediate with diethylenetriamine, performs an amidation reaction, and obtains a second gel product. In a specific embodiment of the present invention, a feed liquid containing the gel intermediate is mixed with diethylenetriamine for an amidation reaction to obtain a feed liquid containing the second gel product. In the present invention, the mass ratio of diethylenetriamine to acrylamide can be 31-34:100. In a specific embodiment of the present invention, the mass ratio of diethylenetriamine to acrylamide is 31:100, 32:100, 33:100 or 34:100. In the present invention, the amidation reaction can be carried out under water bath conditions; the temperature of the amidation reaction can be 45-55°C, and the time can be 1-2h. In a specific embodiment of the present invention, the temperature of the amidation reaction is 45°C, 50°C or 55°C; the time is 1h, 1.5h or 2h.

[0025] After obtaining the second gel product, the present invention mixes the second gel product with carbon disulfide and sodium hydroxide aqueous solution to perform nucleophilic addition reaction to obtain a nucleophilic addition reaction gel product. In the present invention, the mass percentage concentration of the sodium hydroxide aqueous solution can be 20-30%; in a specific embodiment of the present invention, the mass percentage concentration of the sodium hydroxide aqueous solution is 25%. The volume ratio of the sodium hydroxide aqueous solution to carbon disulfide in the present invention can be 2-2.5:0.8-1; in a specific embodiment of the present invention, the volume ratio of the sodium hydroxide aqueous solution to carbon disulfide is 2:1. In a specific embodiment of the present invention, a feed liquid containing the second gel product is mixed with a sodium hydroxide aqueous solution, and then carbon disulfide is added to the obtained mixed feed liquid for nucleophilic addition reaction to obtain a feed liquid containing a nucleophilic addition reaction gel product. In the present invention, the mass ratio of carbon disulfide to acrylamide can be 65-68:100. In a specific embodiment of the present invention, the mass ratio of carbon disulfide to acrylamide is 65:100, 66:100, 67:100 or 68:100. The temperature of the nucleophilic addition reaction of the present invention can be 20-30°C, and the time can be 4-6 hours. In a specific embodiment of the present invention, the temperature of the nucleophilic addition reaction is 20°C, 25°C or 30°C; the time is 4 hours, 5 hours or 6 hours. In the present invention, the sodium hydroxide aqueous solution can create an alkaline environment, promote the cleavage of the NH bond, and provide a base for the CS 2 Provides substitution sites.

[0026] After obtaining the gel product of the nucleophilic addition reaction, the present invention mixes the gel product of the nucleophilic addition reaction with Prussian blue and water to carry out a coordination reaction to obtain the organic-inorganic hybrid flocculant. In the present invention, the mass ratio of the Prussian blue to acrylamide can be 35-40:100; in a specific embodiment of the present invention, the mass ratio of the Prussian blue to acrylamide is 35:100, 38:100 or 40:100. In a specific embodiment of the present invention, the feed liquid containing the gel product of the nucleophilic addition reaction is mixed with a Prussian blue aqueous solution to carry out a coordination reaction. In the present invention, the mass percentage concentration of the Prussian blue aqueous solution can be 20%. The temperature of the coordination reaction of the present invention can be 50-60°C, and the time can be 2-3h. In a specific embodiment of the present invention, the temperature of the coordination reaction is 50°C, 55°C or 60°C; the time is 2h, 2.5h or 3h. After the coordination reaction is completed, the present invention can add the obtained reaction liquid to acetone for extraction and precipitation to obtain a flocculant colloid; the flocculant colloid is dried and ground in sequence to obtain the organic-inorganic hybrid flocculant. In the present invention, Prussian blue can be dispersed in the gel to adsorb thallium.

[0027] The present invention also provides an organic-inorganic hybrid flocculant obtained by the preparation method described in the above technical solution, comprising an inorganic component and an organic component wrapped on the surface of the inorganic component; the organic component comprises acrylamide, diethylenetriamine and an organic intermediate; the inorganic component comprises aluminum salt and Prussian blue. The organic-inorganic hybrid flocculant of the present invention is a light blue solid powder.

[0028] The present invention also provides the use of the organic-inorganic hybrid flocculant described in the above technical solution in the treatment of heavy metal-containing wastewater. In the present invention, the heavy metal elements in the heavy metal-containing wastewater may include at least one of Tl, Pb, Cr, Hg, Cd, Cu and Zn. In the heavy metal-containing wastewater of the present invention, the concentration of Tl may be 1-2 mg / L; in a specific embodiment of the present invention, the concentration of Tl in the heavy metal-containing wastewater is 1.05 mg / L. In the heavy metal-containing wastewater of the present invention, the concentration of Pb may be 1-20 mg / L; in a specific embodiment of the present invention, the concentration of Pb in the heavy metal-containing wastewater is 11.50 mg / L. In the heavy metal-containing wastewater of the present invention, the concentration of Cr may be 1-10 mg / L; in a specific embodiment of the present invention, the concentration of Cr in the heavy metal-containing wastewater is 6.70 mg / L. In the heavy metal-containing wastewater of the present invention, the concentration of Hg may be 1-2 mg / L; in a specific embodiment of the present invention, the concentration of Hg in the heavy metal-containing wastewater is 1.25 mg / L. In the heavy metal-containing wastewater of the present invention, the concentration of Cd may be 1-3 mg / L; in a specific embodiment of the present invention, the concentration of Cd in the heavy metal-containing wastewater is 2.50 mg / L. In the heavy metal-containing wastewater of the present invention, the concentration of Cu may be 1-20 mg / L; in a specific embodiment of the present invention, the concentration of Cu in the heavy metal-containing wastewater is 15.00 mg / L. In the heavy metal-containing wastewater of the present invention, the concentration of Zn may be 1-20 mg / L; in a specific embodiment of the present invention, the concentration of Zn in the heavy metal-containing wastewater is 14.62 mg / L. In the present invention, the heavy metal-containing wastewater may also include quasi-heavy metal elements, and the quasi-heavy metal elements may include As. In the heavy metal-containing wastewater of the present invention, the concentration of As can be 1-3 mg / L; in a specific embodiment of the present invention, the concentration of As in the heavy metal-containing wastewater is 2.10 mg / L. The organic-inorganic hybrid flocculant prepared by the present invention has good adsorption and sedimentation effects on heavy metal elements (such as thallium, lead, chromium, cadmium, etc.) and quasi-heavy metal elements (such as As), and also has good coagulation and sedimentation effects on suspended matter in wastewater.

[0029] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1 10 mL of ammonium carbonate aqueous solution (mass percent concentration of 15%) was added dropwise to 20 mL of aluminum chloride aqueous solution (mass percent concentration of 8%), and the mixture was reacted at 30° C. for 1 h to obtain an aluminum hydroxide colloidal solution.

[0031] 5g of acrylamide was added to the aluminum hydroxide colloidal solution, and the mixture was kept in a constant temperature water bath at 45°C for 0.5h to obtain a mixed liquid. Nitrogen was introduced into the system where the mixed liquid was located to deoxygenate, and 1.5mL of potassium persulfate aqueous solution (mass percentage concentration of 2%) and 1.5mL of sodium bisulfite aqueous solution (mass percentage concentration of 1%) were added to the mixed liquid under nitrogen protection, and the polymerization reaction was carried out in a constant temperature water bath at 45°C for 1h. After the reaction was completed, the obtained reaction liquid was sealed and aged at 25°C for 3h to obtain an aged gel. The aged gel was added dropwise to acetone for extraction and precipitation to obtain a first gel product.

[0032] The first gel product was mixed with pure water to prepare a first gel product aqueous solution with a mass percentage concentration of 0.5%. Sodium hydroxide was added to the first gel product aqueous solution to adjust the pH value to 7, and then 1.45 mL of formaldehyde was added dropwise to the first gel product aqueous solution, and the reaction was carried out in a constant temperature water bath at 45° C. for 1 hour, and a feed solution containing a gel intermediate was obtained after the reaction was completed.

[0033] 1.55 mL of diethylenetriamine was added to the feed solution containing the gel intermediate, and the mixture was reacted for 2 h in a constant temperature water bath at 45° C., to obtain a feed solution containing a second gel product.

[0034] 6.5 mL of sodium hydroxide aqueous solution (mass percentage concentration of 25%) was added to the feed liquid containing the second gel product, and then 3.25 mL of carbon disulfide was added to the obtained mixed feed liquid, and a nucleophilic addition reaction was carried out in a constant temperature water bath at 20° C. for 4 hours to obtain a feed liquid containing a nucleophilic addition reaction gel product.

[0035] 8.75 mL of Prussian blue aqueous solution (mass percentage concentration of 20%) was added to the feed liquid containing the gel product of the nucleophilic addition reaction, and the reaction was carried out in a constant temperature water bath at 50° C. for 2 hours. After the reaction, the obtained reaction liquid was added dropwise to acetone for extraction and precipitation to obtain a flocculant colloid. The flocculant colloid was dried and ground in sequence to obtain an organic-inorganic hybrid flocculant (light blue solid powder).

[0036] Test Example 1 The wastewater used in the test example is thallium-containing heavy metal wastewater from a smelter, and the water quality is shown in Table 1.

[0037] Table 1 Component content of wastewater containing heavy metals such as thallium

[0038] Take 1000mL of thallium heavy metal wastewater, add 500mg of the organic-inorganic hybrid flocculant prepared in Example 1, stir for 15min and then let stand for 0.5h. After standing, it can be found that the water body is obviously stratified, the upper layer of water is obviously clear, and flocculated sediments can be seen in the lower layer. The upper layer of water is tested, and the results are shown in Table 2.

[0039] Example 2 10 mL of ammonium carbonate aqueous solution (mass percent concentration of 15%) was added dropwise to 20 mL of aluminum chloride aqueous solution (mass percent concentration of 8%), and the mixture was reacted at 30° C. for 1 h to obtain an aluminum hydroxide colloidal solution.

[0040] 4.77g of acrylamide was added to the aluminum hydroxide colloidal solution, and the mixture was kept in a constant temperature water bath at 50°C for 1h to obtain a mixed liquid. Helium was introduced into the system where the mixed liquid was located to deoxygenate, and 1.8mL of potassium persulfate aqueous solution (mass percentage concentration of 1.9%) and 1.8mL of sodium bisulfite aqueous solution (mass percentage concentration of 1.06%) were added to the mixed liquid under the protection of helium, and the polymerization reaction was carried out in a constant temperature water bath at 50°C for 1.5h. After the reaction was completed, the obtained reaction liquid was sealed and aged at 30°C for 4h to obtain an aged gel. The aged gel was added dropwise to acetone for extraction and precipitation to obtain a first gel product.

[0041] The first gel product was mixed with pure water to prepare a first gel product aqueous solution with a mass percentage concentration of 1%. Sodium hydroxide was added to the first gel product aqueous solution to adjust the pH value to 8, and then 1.43 mL of formaldehyde was added dropwise to the first gel product aqueous solution, and the reaction was carried out in a constant temperature water bath at 50° C. for 1.5 hours, and a feed solution containing a gel intermediate was obtained after the reaction was completed.

[0042] 1.53 mL of diethylenetriamine was added to the feed solution containing the gel intermediate, and the mixture was reacted for 3 h in a constant temperature water bath at 50° C., to obtain a feed solution containing a second gel product.

[0043] 6.3 mL of sodium hydroxide aqueous solution (mass percentage concentration of 25%) was added to the feed liquid containing the second gel product, and then 3.15 mL of carbon disulfide was added to the obtained mixed feed liquid, and a nucleophilic addition reaction was carried out in a constant temperature water bath at 25° C. for 5 hours to obtain a feed liquid containing a nucleophilic addition reaction gel product.

[0044] 8.85 mL of Prussian blue aqueous solution (mass percentage concentration of 20%) was added to the liquid containing the gel of the nucleophilic addition reaction product, and the reaction was carried out in a constant temperature water bath at 55° C. for 2.5 hours. After the reaction, the obtained reaction liquid was added dropwise to acetone for extraction and precipitation to obtain a flocculant colloid. The flocculant colloid was dried and ground in sequence to obtain an organic-inorganic hybrid flocculant (light blue solid powder).

[0045] Test Example 2 The organic-inorganic hybrid flocculant prepared in Example 1 was replaced by the organic-inorganic hybrid flocculant prepared in Example 2, and the performance test of the organic-inorganic hybrid flocculant was carried out according to the conditions of Test Example 1. The results are shown in Table 2.

[0046] Example 3 10 mL of ammonium carbonate aqueous solution (mass percent concentration of 20%) was added dropwise to 20 mL of aluminum chloride aqueous solution (mass percent concentration of 10%), and the mixture was reacted at 30° C. for 1 h to obtain an aluminum hydroxide colloidal solution.

[0047] 5.4 g of acrylamide was added to the aluminum hydroxide colloidal solution, and the mixture was kept in a constant temperature water bath at 55° C. for 1.5 h to obtain a mixed liquid. Helium was introduced into the system where the mixed liquid was located to deoxygenate, and 1.8 mL of potassium persulfate aqueous solution (mass percent concentration of 2.4%) and 1.8 mL of sodium bisulfite aqueous solution (mass percent concentration of 1.5%) were added to the mixed liquid under the protection of helium, and the polymerization reaction was carried out in a constant temperature water bath at 55° C. for 2 h. After the reaction was completed, the obtained reaction liquid was sealed and aged at 35° C. for 5 h to obtain an aged gel. The aged gel was added dropwise to acetone for extraction and precipitation to obtain a first gel product.

[0048] The first gel product was mixed with pure water to prepare a first gel product aqueous solution with a mass percentage concentration of 1.5%. Sodium hydroxide was added to the first gel product aqueous solution to adjust the pH value to 9, and then 1.72 mL of formaldehyde was added dropwise to the first gel product aqueous solution, and the reaction was carried out in a constant temperature water bath at 55° C. for 2 hours, and a feed solution containing a gel intermediate was obtained after the reaction was completed.

[0049] 1.83 mL of diethylenetriamine was added to the feed solution containing the gel intermediate, and the mixture was reacted for 4 h in a constant temperature water bath at 55° C., to obtain a feed solution containing a second gel product.

[0050] 7.3 mL of sodium hydroxide aqueous solution (mass percentage concentration of 25%) was added to the feed liquid containing the second gel product, and then 3.67 mL of carbon disulfide was added to the obtained mixed feed liquid, and a nucleophilic addition reaction was carried out in a constant temperature water bath at 30° C. for 6 hours to obtain a feed liquid containing a nucleophilic addition reaction gel product.

[0051] 10.8 mL of Prussian blue aqueous solution (mass percentage concentration of 20%) was added to the feed liquid containing the gel product of the nucleophilic addition reaction, and the reaction was carried out in a constant temperature water bath at 60° C. for 3 hours. After the reaction, the obtained reaction liquid was added dropwise to acetone for extraction and precipitation to obtain a flocculant colloid. The flocculant colloid was dried and ground in sequence to obtain an organic-inorganic hybrid flocculant (light blue solid powder).

[0052] Test Example 3 The organic-inorganic hybrid flocculant prepared in Example 1 was replaced by the organic-inorganic hybrid flocculant prepared in Example 3, and the performance test of the organic-inorganic hybrid flocculant was carried out according to the conditions of Test Example 1. The results are shown in Table 2.

[0053] Comparative Example 1 An organic-inorganic hybrid flocculant was prepared according to the manner and conditions of Example 1, except that no Prussian blue was added.

[0054] Comparative test example 1 The organic-inorganic hybrid flocculant prepared in Example 1 was replaced by the organic-inorganic hybrid flocculant prepared in Comparative Example 1, and the performance test of the organic-inorganic hybrid flocculant was carried out according to the conditions of Test Example 1. The results are shown in Table 2.

[0055] Comparative test example 2 The organic-inorganic hybrid flocculant prepared in Example 1 was replaced by a composite Al(OH) 3 -PAM flocculant (laboratory compounding), the performance test of organic-inorganic hybrid flocculant was carried out according to the conditions of Test Example 1, and the results are shown in Table 2.

[0056] Table 2 Removal effects of different organic-inorganic hybrid flocculants on heavy metals and heavy metal elements in wastewater

[0057] As shown in Table 2, the organic-inorganic hybrid flocculant without Prussian blue prepared in Comparative Example 1 has no selective adsorption of thallium in wastewater, and the composite Al(OH) 3-PAM flocculant has a good coagulation and sedimentation effect on suspended matter in wastewater, but has a poor removal effect on heavy metals and heavy metal-like substances. The organic-inorganic hybrid flocculant prepared in Examples 1 to 3 of the present invention has an excellent treatment effect on heavy metals and heavy metal-like substances in wastewater, and also has a good coagulation and sedimentation effect, which can effectively remove suspended matter in wastewater. All elements in wastewater can meet the first-level standard emission standards of the "Comprehensive Sewage Discharge Standard" (GB 8978-1996), among which thallium meets the "Industrial Wastewater Thallium Pollutant Discharge Standard" (DB36T1149-2019).

[0058] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing an organic-inorganic hybrid flocculant, characterized in that: The following steps are involved: providing an aluminum hydroxide colloidal solution; Mixing acrylamide, an initiator and the aluminum hydroxide colloidal solution to perform a polymerization reaction to obtain a first gel product; The first gel is mixed with water and an aldehyde compound to perform a Mannich reaction, and the obtained product is mixed with diethylenetriamine to perform an amidation reaction to obtain a second gel product; The second gel product is mixed with carbon disulfide and sodium hydroxide aqueous solution to carry out nucleophilic addition reaction, and the obtained product is mixed with Prussian blue and water to carry out coordination reaction to obtain the organic-inorganic hybrid flocculant.

2. The preparation method according to claim 1, characterized in that: The initiator comprises potassium persulfate and sodium bisulfite; the mass ratio of potassium persulfate to acrylamide is 0.6-0.8:100; the mass ratio of sodium bisulfite to acrylamide is 0.3-0.5:100; the polymerization reaction is carried out in an inert atmosphere; the temperature of the polymerization reaction is 40-55°C and the time is 1-2h.

3. The preparation method according to claim 1, characterized in that: The aldehyde compound comprises at least one of formaldehyde, acetaldehyde, propionaldehyde, cinnamaldehyde and vanillin; the mass ratio of the aldehyde compound to acrylamide is 29-32:100; the temperature of the Mannich reaction is 45-55°C, and the time is 1-2h.

4. The preparation method according to claim 1, characterized in that: The mass ratio of diethylenetriamine to acrylamide is 31-34:100; the temperature of the amidation reaction is 45-55° C., and the time is 2-4 hours.

5. The preparation method according to claim 1, characterized in that: The mass ratio of carbon disulfide to acrylamide is 65-68:100; the mass percentage concentration of the sodium hydroxide aqueous solution is 20-30%, and the volume ratio of the sodium hydroxide aqueous solution to carbon disulfide is 2-2.5:0.8-1; the temperature of the nucleophilic addition reaction is 20-30°C, and the time is 4-6 hours.

6. The preparation method according to claim 1, characterized in that: The mass ratio of Prussian blue to acrylamide is 35-40:100; the temperature of the coordination reaction is 50-60°C, and the time is 2-3 hours.

7. The organic-inorganic hybrid flocculant obtained by the preparation method according to any one of claims 1 to 6 comprises an inorganic component and an organic component wrapped on the surface of the inorganic component; the organic component comprises acrylamide, diethylenetriamine and an organic intermediate; the inorganic component comprises aluminum salt and Prussian blue.

8. Use of the organic-inorganic hybrid flocculant according to claim 7 in the treatment of heavy metal-containing wastewater.

9. The use according to claim 8, characterized in that: The heavy metal elements in the heavy metal-containing wastewater include at least one of Tl, Pb, Cr, Hg, Cd, Cu and Zn; in the heavy metal-containing wastewater, the concentration of Tl is 1~2 mg / L; the concentration of Pb is 1~20 mg / L; the concentration of Cr is 1~10 mg / L; the concentration of Hg is 1~2 mg / L; the concentration of Cd is 1~3 mg / L; the concentration of Cu is 1~20 mg / L; and the concentration of Zn is 1~20 mg / L.

10. The use according to claim 8 or 9, wherein the heavy metal-containing wastewater further comprises As; and the concentration of As in the heavy metal-containing wastewater is 1-3 mg / L.

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