An aluminum ferric sulfate salt flocculant and a preparation method thereof

Abstract

The application relates to the technical field of water treatment flocculants, and discloses an aluminum-iron sulfate salt flocculant and a preparation method thereof. The method is characterized in that firstly, the attapulgite is subjected to acid activation, silanization, starch etherification grafting and free radical copolymerization modification, so as to obtain a modified attapulgite functional carrier which has a nano adsorption skeleton, an organic long chain and strong positive electricity; then, the carrier is taken as a core to carry out a hydrolysis-supporting reaction with ferric sulfate, aluminum sulfate and carbide slag under pH control; finally, sodium silicate is introduced to construct an inorganic gel network, and the aluminum-iron sulfate salt flocculant is obtained through ripening and drying. Through construction of an organic-inorganic hybrid structure, the application realizes multiple synergies of electric neutralization, adsorption bridging and net capture and sweeping, the product has high removal capacity for colloidal particles and dissolved organic matters, the flocculation body is compact and can be rapidly settled, and the product has the comprehensive advantages of low raw material cost, stable process and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of water treatment flocculant technology, specifically to an aluminum ferric sulfate flocculant and its preparation method. Background Technology

[0002] With rapid industrialization and urbanization, water pollution has become increasingly serious, making the development of efficient and economical water treatment technologies crucial. Chemical flocculation, due to its ease of operation and significant effects, has become one of the core processes in water treatment, and its effectiveness largely depends on the performance of the flocculant.

[0003] Currently, commonly used flocculants mainly include aluminum salts (such as polyaluminum chloride), iron salts (such as polyferric sulfate), and inorganic polymeric flocculants. Aluminum salt flocculants have good turbidity removal effects, but aluminum ions easily remain in the treated water, posing potential ecological and health risks. Iron salt flocculants form dense flocs that settle quickly, but they are highly corrosive. Single inorganic flocculants generally suffer from low charge density, small molecular weight, and limited effectiveness in removing dissolved organic matter.

[0004] Meanwhile, the preparation of flocculants or coagulants using natural minerals (such as attapulgite) as raw materials has also attracted attention. Attapulgite itself has a unique nanofiber structure and adsorption properties, but the surface inertness and single charge properties of the raw clay limit its effectiveness when used directly, and it usually needs to be modified to improve its performance. However, existing modification methods are mostly simple acid treatment or calcination, or only single-type organic grafting, which fail to fully integrate and synergistically utilize the skeletal role of inorganic minerals, the bridging ability of organic polymers, and the charge neutralization advantages of specific functional groups (such as strong cationic groups), thus limiting further improvement in its performance.

[0005] Therefore, developing a novel composite flocculant that can deeply integrate the properties of inorganic minerals and organic polymers, and possesses efficient turbidity removal, deep decolorization, rapid sedimentation, and good economic and environmental benefits, is of great practical significance for promoting the advancement of water treatment technology. Summary of the Invention

[0006] (a) Technical problems to be solved:

[0007] To address the shortcomings of existing technologies, this invention provides an aluminum sulfate-iron salt flocculant and its preparation method, which solves the problems of inherent performance defects of existing aluminum or iron salt flocculants, insufficient functional synergy of conventional composite flocculants and poor removal effect on dissolved organic matter, and poor performance of natural attapulgite as a flocculant after direct or simple modification.

[0008] (II) Technical Solution:

[0009] In a first aspect, the present invention provides an aluminum ferric sulfate flocculant, wherein the raw materials of the aluminum ferric sulfate flocculant include 8-15 parts by weight of aluminum sulfate, 15-30 parts by weight of ferric sulfate, 10-25 parts by weight of modified attapulgite, 1-5 parts by weight of carbide slag, and 3-10 parts by weight of sodium silicate.

[0010] Furthermore, the preparation method of modified attapulgite is as follows:

[0011] Step (1): Add attapulgite and hydrochloric acid solution to a beaker, stir and react for 2-3 hours, filter, wash with water, dry the filter cake, grind, and obtain acidified attapulgite.

[0012] Step (2): Add an aqueous ethanol solution and 3-aminopropyltriethoxysilane to a flask equipped with a reflux condenser and mix well. Then add hydrochloric acid solution to adjust the pH to 4-5. Stir the reaction at room temperature for 20-30 minutes. Add acidified attapulgite and heat to 75-80℃. Stir the reaction for 2-3 hours. Centrifuge, wash with anhydrous ethanol and centrifuge 3 times. Dry to obtain aminated attapulgite.

[0013] Step (3): Add aminated attapulgite and deionized water to a beaker and sonicate for 20-30 min. Add corn starch, heat to 80-90℃, stir for 20-30 min, then cool to 40-50℃. Add sodium hydroxide solution to adjust the pH to 10-11, add epichlorohydrin dropwise, stir for 2-3 h, and finally add hydrochloric acid solution to neutralize the pH of the system to 6-7. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with ethanol aqueous solution, filter, dry, and grind to obtain starch-grafted aminated attapulgite.

[0014] Step (4): Under a nitrogen atmosphere, add starch-grafted amino attapulgite, deionized water, acrylamide, and acryloyloxyethyltrimethylammonium chloride to a flask equipped with a reflux condenser and mix well. Stir for 30-40 minutes, add ammonium persulfate and sodium bisulfite, heat to 50-60℃, and stir for 4-5 hours. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with anhydrous ethanol, filter, and dry to obtain modified attapulgite.

[0015] Furthermore, the concentration of the hydrochloric acid solution is 1-3 mol / L; the concentration of the sodium hydroxide solution is 3-6 wt%; and the volume fraction of ethanol in the ethanol aqueous solution is 20-30%.

[0016] Furthermore, in step (1), the mass ratio of attapulgite clay to hydrochloric acid solution is 10:(100-120).

[0017] Furthermore, in step (2), the mass ratio of ethanol aqueous solution, 3-aminopropyltriethoxysilane, and acidified attapulgite is (100-150):(0.2-1):10.

[0018] Furthermore, in step (3), the mass ratio of aminated attapulgite, deionized water, corn starch, and epichlorohydrin is 10:(150-200):(3-10):(0.03-1).

[0019] Furthermore, in step (4), the mass ratio of starch-grafted aminoattapulgite, deionized water, acrylamide, acryloyloxyethyltrimethylammonium chloride, ammonium persulfate, and sodium bisulfite is 100:(1000-2000):(120-220):(20-100):(0.12-1.75):(0.06-0.88).

[0020] Secondly, the present invention also provides a method for preparing an aluminum ferric sulfate flocculant, characterized in that the method for preparing the aluminum ferric sulfate flocculant is as follows:

[0021] Add modified attapulgite clay and deionized water to a flask and sonicate for 20-30 minutes. Add aluminum sulfate, ferric sulfate, and carbide slag. Under stirring, add sodium hydroxide solution dropwise to adjust the pH to 5-6. Heat to 40-60℃ and stir for 1-2 hours. Add sodium silicate solution with a concentration of 8-10wt%, stir and mix for 20-30 minutes, let stand and mature for 18-20 hours, dry at 80-90℃ to constant weight, and pulverize to obtain aluminum ferric sulfate flocculant.

[0022] Furthermore, the amount of deionized water added is 8-15 times the total mass of modified attapulgite, aluminum sulfate, ferric sulfate, and carbide slag.

[0023] (III) Beneficial technical effects:

[0024] This invention involves sequentially activating attapulgite with acid, introducing amino groups through silanization, and grafting starch with etherification. Finally, it undergoes free radical graft copolymerization with acrylamide and cationic monomers to prepare a modified attapulgite carrier that combines a nano-adsorption framework, organic long chains, and strong positive charge. Using this carrier as the core, it undergoes a hydrolysis-loading reaction with ferric sulfate, aluminum sulfate, and carbide slag under controlled pH conditions to ensure stable adhesion of polyferric aluminum active components. Finally, sodium silicate solution is introduced to construct a polysilicate metal salt and calcium silicate gel network. After static curing and drying, an organic-inorganic hybrid composite aluminum sulfate ferric salt flocculant is obtained.

[0025] The aluminum ferric sulfate flocculant of this invention exhibits excellent flocculation performance. Its core lies in the modified attapulgite carrier, which constructs an organic-inorganic hybrid composite material. This material combines the adsorption capabilities of nanofibers, starch chain bridging, and cationic polymer charge neutralization. Synergistically with the iron and aluminum hydrolysis products and the sodium silicate network, it achieves extremely high capture efficiency for colloidal particles, resulting in a high turbidity removal rate. The acryloyloxyethyltrimethylammonium chloride grafted onto the modified attapulgite carrier provides strong positive charge, enabling efficient charge neutralization and adsorption of negatively charged dissolved organic matter, thus achieving a high COD (chemical oxygen demand) removal rate. Furthermore, the carbide slag in the aluminum ferric sulfate flocculant of Examples 1-3 provides Ca... 2+ It forms a calcium silicate network with sodium silicate, and together with the dense flocs, it creates a dense structure with large size, fast gravity settling, and a fast settling speed.

[0026] This invention realizes the resource utilization of industrial solid waste by utilizing carbide slag, which is both environmentally friendly and economical; the stable loading of flocculation active components on the carrier improves the storage and use time of the product; the composite system has a wider adaptability to water quality changes, good process reproducibility, and is easy to scale up production. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0028] The following attapulgite soil, 100 mesh, was purchased from Hebei Kexu Building Materials Co., Ltd.

[0029] All raw materials used in this invention are commercially available.

[0030] Example 1: A method for preparing an aluminum ferric sulfate flocculant:

[0031] Step (1): Add 10 parts by weight of attapulgite and 110 parts by weight of 2 mol / L hydrochloric acid solution to a beaker, stir and react for 2 hours, filter, wash with water, dry the filter cake, grind, and obtain acidified attapulgite.

[0032] Step (2): Add 100 parts by weight of 30% ethanol aqueous solution and 0.6 parts by weight of 3-aminopropyltriethoxysilane to a flask equipped with a reflux condenser and mix well. Then add 1 mol / L hydrochloric acid solution to adjust the pH to 4. Stir the reaction at room temperature for 20 min. Add 10 parts by weight of acidified attapulgite, heat to 80℃, stir the reaction for 2 h, centrifuge, wash with anhydrous ethanol and centrifuge 3 times, and dry to obtain aminated attapulgite.

[0033] Step (3): Add 10 parts by weight of aminated attapulgite and 180 parts by weight of deionized water to a beaker and sonicate for 20 min. Add 6 parts by weight of corn starch, heat to 90℃, stir and react for 20 min, then cool to 45℃. Add 3 wt% sodium hydroxide solution to adjust the pH to 10, add 0.06 parts by weight of epichlorohydrin, stir and react for 2 h, and finally add 1 mol / L hydrochloric acid solution to neutralize the pH of the system to 6. Pour the product into anhydrous ethanol to precipitate, wash the precipitate 3 times with 30% ethanol aqueous solution, filter, dry, and grind to obtain starch-grafted aminated attapulgite.

[0034] Step (4): Under a nitrogen atmosphere, add 100 parts by weight of starch-grafted amino attapulgite, 1500 parts by weight of deionized water, 170 parts by weight of acrylamide, and 60 parts by weight of acryloyloxyethyltrimethylammonium chloride to a flask equipped with a reflux condenser. Mix well and stir for 30 min. Add 0.95 parts by weight of ammonium persulfate and 0.45 parts by weight of sodium bisulfite. Heat to 50°C and stir for 5 h. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with anhydrous ethanol, filter, and dry to obtain modified attapulgite.

[0035] Step (5): Add 10 parts by weight of modified attapulgite clay and 270 parts by weight of deionized water to the flask and sonicate for 20 min. Add 8 parts by weight of aluminum sulfate, 15 parts by weight of ferric sulfate and 1 part by weight of carbide slag. Under stirring, add 6 wt% sodium hydroxide solution to adjust the pH to 6. Heat to 40°C and stir for 2 h. Add 80 parts by weight of 9 wt% sodium silicate solution and stir for 30 min. Let stand for 18 h to mature. Dry at 90°C to constant weight and pulverize to obtain aluminum ferric sulfate flocculant.

[0036] Example 2: A method for preparing an aluminum ferric sulfate flocculant:

[0037] Step (1): Add 10 parts by weight of attapulgite and 100 parts by weight of 3 mol / L hydrochloric acid solution to a beaker, stir and react for 3 hours, filter, wash with water, dry the filter cake, grind, and obtain acidified attapulgite.

[0038] Step (2): Add 125 parts by weight of 20% ethanol aqueous solution and 0.2 parts by weight of 3-aminopropyltriethoxysilane to a flask equipped with a reflux condenser and mix well. Then add 2 mol / L hydrochloric acid solution to adjust the pH to 4. Stir the reaction at room temperature for 30 min. Add 10 parts by weight of acidified attapulgite, heat to 75°C, stir the reaction for 3 h, centrifuge, wash with anhydrous ethanol and centrifuge 3 times, and dry to obtain aminated attapulgite.

[0039] Step (3): Add 10 parts by weight of aminated attapulgite and 150 parts by weight of deionized water to a beaker and sonicate for 20 min. Add 3 parts by weight of corn starch, heat to 80℃, stir and react for 30 min, then cool to 40℃. Add 5 wt% sodium hydroxide solution to adjust the pH to 10, add 0.03 parts by weight of epichlorohydrin, stir and react for 3 h, and finally add 2 mol / L hydrochloric acid solution to neutralize the pH of the system to 7. Pour the product into anhydrous ethanol to precipitate, wash the precipitate 3 times with 20% ethanol aqueous solution, filter, dry, and grind to obtain starch-grafted aminated attapulgite.

[0040] Step (4): Under a nitrogen atmosphere, add 100 parts by weight of starch-grafted amino attapulgite, 1000 parts by weight of deionized water, 120 parts by weight of acrylamide, and 100 parts by weight of acryloyloxyethyltrimethylammonium chloride to a flask equipped with a reflux condenser. Mix well and stir for 40 min. Add 1.75 parts by weight of ammonium persulfate and 0.06 parts by weight of sodium bisulfite. Heat to 60°C and stir for 4 h. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with anhydrous ethanol, filter, and dry to obtain modified attapulgite.

[0041] Step (5): Add 18 parts by weight of modified attapulgite clay and 550 parts by weight of deionized water to the flask and sonicate for 20 min. Add 12 parts by weight of aluminum sulfate, 22 parts by weight of ferric sulfate and 3 parts by weight of carbide slag. Under stirring, add 3 wt% sodium hydroxide solution to adjust the pH to 6. Heat to 60°C and stir for 1 h. Add 125 parts by weight of 8 wt% sodium silicate solution and stir for 20 min. Let stand for 20 h to mature. Dry at 80°C to constant weight and pulverize to obtain aluminum ferric sulfate flocculant.

[0042] Example 3: A method for preparing an aluminum ferric sulfate flocculant:

[0043] Step (1): Add 10 parts by weight of attapulgite and 120 parts by weight of 2 mol / L hydrochloric acid solution to a beaker, stir and react for 2 hours, filter, wash with water, dry the filter cake, grind, and obtain acidified attapulgite.

[0044] Step (2): Add 150 parts by weight of 20% ethanol aqueous solution and 1 part by weight of 3-aminopropyltriethoxysilane to a flask equipped with a reflux condenser and mix well. Then add 1 mol / L hydrochloric acid solution to adjust the pH to 5. Stir the reaction at room temperature for 20 min. Add 10 parts by weight of acidified attapulgite, heat to 80℃, stir the reaction for 3 h, centrifuge, wash with anhydrous ethanol and centrifuge 3 times, and dry to obtain aminated attapulgite.

[0045] Step (3): Add 10 parts by weight of aminated attapulgite and 200 parts by weight of deionized water to a beaker and sonicate for 30 min. Add 10 parts by weight of corn starch, heat to 90℃, stir and react for 20 min, then cool to 50℃. Add 6 wt% sodium hydroxide solution to adjust the pH to 11, add 1 part by weight of epichlorohydrin, stir and react for 2 h, and finally add 1 mol / L hydrochloric acid solution to neutralize the pH of the system to 6. Pour the product into anhydrous ethanol to precipitate, wash the precipitate 3 times with 20% ethanol aqueous solution, filter, dry, and grind to obtain starch-grafted aminated attapulgite.

[0046] Step (4): Under a nitrogen atmosphere, add 100 parts by weight of starch-grafted amino attapulgite, 2000 parts by weight of deionized water, 220 parts by weight of acrylamide, and 20 parts by weight of acryloyloxyethyltrimethylammonium chloride to a flask equipped with a reflux condenser. Mix well and stir for 40 min. Add 0.12 parts by weight of ammonium persulfate and 0.88 parts by weight of sodium bisulfite. Heat to 60°C and stir for 4 h. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with anhydrous ethanol, filter, and dry to obtain modified attapulgite.

[0047] Step (5): Add 25 parts by weight of modified attapulgite clay and 1125 parts by weight of deionized water to the flask and sonicate for 30 min. Add 15 parts by weight of aluminum sulfate, 30 parts by weight of ferric sulfate and 5 parts by weight of carbide slag. Under stirring, add 5 wt% sodium hydroxide solution to adjust the pH to 5. Heat to 50°C and stir for 2 h. Add 30 parts by weight of 10 wt% sodium silicate solution and stir for 20 min. Let stand for 20 h to mature. Dry at 80°C to constant weight and pulverize to obtain aluminum ferric sulfate flocculant.

[0048] Comparative Example 1: The difference from Example 1 is that no modified attapulgite clay was added.

[0049] Comparative Example 2: The difference from Example 1 is that sodium silicate is not added.

[0050] Comparative Example 3: The difference from Example 1 is that no carbide slag is added.

[0051] Comparative Example 4: The difference from Example 1 is that ordinary attapulgite soil is used instead of modified attapulgite soil.

[0052] Comparative Example 5: The difference from Example 1 is that starch-grafted amino attapulgite is used instead of modified attapulgite.

[0053] Dissolve 1.5g of kaolin in tap water to prepare a 1.5g / L water sample. Weigh 0.3g of aluminum ferric sulfate flocculant and dissolve it in distilled water, bringing the volume to 50mL. Use a pipette to take 5mL of this solution and add it to 500mL of the water sample while stirring. Stir at 300r / min for 1min, then at 100r / min for 3min, and finally at 50r / min for 5min. Let it stand for 5min, collect the supernatant, and measure the turbidity using a spectrophotometer. Calculate the turbidity removal rate. Turbidity removal rate = (A0 - A) / A0 × 100%, where A0 is the absorbance of the water sample before treatment, and A is the absorbance of the water sample after treatment.

[0054] Take samples of dyeing and printing wastewater and determine the chemical oxygen demand (COD) of the wastewater samples before treatment (COD0) and after treatment with the flocculant of this invention according to the method of GB / T 11914-1989, and calculate the COD removal rate. COD removal rate = (COD0 - COD) / COD0 × 100%, where COD0 is the COD value of the water sample before treatment and COD is the COD value of the water sample after treatment.

[0055] In the above turbidity removal rate test, after the settling process begins, the time required for the floc-clear liquid interface 2 cm below the liquid surface to descend to the 500 mL mark (bottom) on the graduated cylinder is recorded to evaluate the floc settling speed.

[0056] Table 1 Performance Tests of Aluminum Ferric Sulfate Flocculants

[0057]

[0058] As shown in Table 1, the aluminum ferric sulfate flocculants of Examples 1-3 exhibit excellent flocculation performance. Their core lies in the modified attapulgite carrier, which constructs an organic-inorganic hybrid composite material. This material combines nanofiber adsorption, starch chain bridging, and cationic polymer charge neutralization capabilities. Synergistically with the iron and aluminum hydrolysis products and the sodium silicate network, it achieves extremely high capture efficiency for colloidal particles, resulting in a high turbidity removal rate. The acryloyloxyethyltrimethylammonium chloride grafted onto the modified attapulgite carrier provides strong positive charge, enabling efficient charge neutralization and adsorption of negatively charged dissolved organic matter, thus achieving a high COD removal rate. Furthermore, the carbide slag in the aluminum ferric sulfate flocculants of Examples 1-3 provides Ca... 2+ It forms a calcium silicate network with sodium silicate, and together with the dense flocs, it creates a dense structure with large size, fast gravity settling, and a fast settling speed.

[0059] Comparative Example 1: The difference from Example 1 is that the aluminum sulfate ferric salt flocculant was prepared without the addition of modified attapulgite. The flocculant relied solely on the ferric and aluminum salts, resulting in a severe deficiency in adsorption bridging and charge neutralization capabilities, which prevented the formation of stable flocs. Therefore, the turbidity removal rate and COD removal rate were the lowest, and the sedimentation was slow.

[0060] Comparative Example 2: The difference from Example 1 is that sodium silicate was not added to prepare aluminum ferric sulfate flocculant. The lack of sodium silicate to form polysilicate metal salt and calcium silicate gel network means that the system can only rely on charge neutralization and preliminary bridging, resulting in small and loose flocs, significantly slower sedimentation speed, and incomplete turbidity removal effect.

[0061] Comparative Example 3: The difference from Example 1 is that aluminum ferric sulfate flocculant was prepared without the addition of calcium carbide slag, thus lacking the Ca provided by calcium carbide slag. 2+ This weakens the synergistic network-forming effect with sodium silicate; at the same time, the pH buffering capacity of the system decreases, affecting the optimal hydrolysis and polymerization morphology of iron and aluminum salts, resulting in poor floc density and settling velocity.

[0062] Comparative Example 4: The difference from Example 1 is that ordinary attapulgite was used instead of modified attapulgite to prepare aluminum ferric sulfate flocculant. Ordinary attapulgite lacks active amino groups, grafted polymer chains and cationic charges on its surface. Its specific surface area could not be functionalized and it was almost only used as an inert filler. It could not play the core role of adsorption, bridging and charge neutralization, and the COD removal rate was low.

[0063] Comparative Example 5: The difference from Example 1 is that starch-grafted amino attapulgite was used instead of modified attapulgite to prepare aluminum ferric sulfate flocculant. Although starch-grafted amino attapulgite possesses a certain adsorption bridging ability, it lacks high-density quaternary ammonium salt cationic groups and fully extended polymer chains, resulting in weak charge neutralization ability and limited capture efficiency for negatively charged colloids, especially dissolved organic matter, leading to a low COD removal rate.

[0064] The embodiments described above merely illustrate the implementation of the present invention, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make several improvements without departing from the concept of the present invention, and these improvements all fall within the protection scope of the present invention.

Claims

1. An aluminum ferric sulfate flocculant, characterized in that, The raw materials for the aluminum sulfate ferric salt flocculant include 8-15 parts by weight of aluminum sulfate, 15-30 parts by weight of ferric sulfate, 10-25 parts by weight of modified attapulgite, 1-5 parts by weight of carbide slag, and 3-10 parts by weight of sodium silicate. The method for preparing the modified attapulgite is as follows: Step (1): Add attapulgite and hydrochloric acid solution to a beaker, stir and react for 2-3 hours, filter, wash with water, dry the filter cake, grind, and obtain acidified attapulgite. Step (2): Add ethanol aqueous solution and 3-aminopropyltriethoxysilane to a flask equipped with a reflux condenser and mix well. Then add hydrochloric acid solution to adjust the pH to 4-5. Stir the reaction at room temperature for 20-30 minutes. Add acidified attapulgite and heat to 75-80℃. Stir the reaction for 2-3 hours. Centrifuge, wash with anhydrous ethanol and centrifuge 3 times. Dry to obtain aminated attapulgite. Step (3): Add aminated attapulgite and deionized water to a beaker and sonicate for 20-30 min. Add corn starch, heat to 80-90℃, stir for 20-30 min, then cool to 40-50℃. Add sodium hydroxide solution to adjust the pH to 10-11, add epichlorohydrin dropwise, stir for 2-3 h, and finally add hydrochloric acid solution to neutralize the pH of the system to 6-7. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with ethanol aqueous solution, filter, dry, and grind to obtain starch-grafted aminated attapulgite. Step (4): Under a nitrogen atmosphere, add starch-grafted amino attapulgite, deionized water, acrylamide, and acryloyloxyethyltrimethylammonium chloride to a flask equipped with a reflux condenser and mix well. Stir for 30-40 minutes, add ammonium persulfate and sodium bisulfite, heat to 50-60℃, and stir for 4-5 hours. Pour the product into anhydrous ethanol to precipitate, wash the precipitate three times with anhydrous ethanol, filter, and dry to obtain modified attapulgite.

2. The aluminum ferric sulfate flocculant according to claim 1, characterized in that, The concentration of the hydrochloric acid solution is 1-3 mol / L; the concentration of the sodium hydroxide solution is 3-6 wt%; and the volume fraction of ethanol in the ethanol aqueous solution is 20-30%.

3. The aluminum ferric sulfate flocculant according to claim 1, characterized in that, In step (1), the mass ratio of attapulgite clay to hydrochloric acid solution is 10:(100-120).

4. The aluminum ferric sulfate flocculant according to claim 1, characterized in that, In step (2), the mass ratio of ethanol aqueous solution, 3-aminopropyltriethoxysilane, and acidified attapulgite is (100-150):(0.2-1):

10.

5. The aluminum ferric sulfate flocculant according to claim 1, characterized in that, In step (3), the mass ratio of aminated attapulgite, deionized water, corn starch, and epichlorohydrin is 10:(150-200):(3-10):(0.03-1).

6. The aluminum ferric sulfate flocculant according to claim 1, characterized in that, In step (4), the mass ratio of starch-grafted aminoattapulgite, deionized water, acrylamide, acryloyloxyethyltrimethylammonium chloride, ammonium persulfate, and sodium bisulfite is 100:(1000-2000):(120-220):(20-100):(0.12-1.75):(0.06-0.88).

7. A method for preparing an aluminum ferric sulfate flocculant as described in any one of claims 1-6, characterized in that, The preparation method of the aluminum ferric sulfate flocculant is as follows: Add modified attapulgite clay and deionized water to a flask and sonicate for 20-30 minutes. Add aluminum sulfate, ferric sulfate, and carbide slag. Under stirring, add sodium hydroxide solution dropwise to adjust the pH to 5-6. Heat to 40-60℃ and stir for 1-2 hours. Add sodium silicate solution with a concentration of 8-10wt%, stir and mix for 20-30 minutes, let stand and mature for 18-20 hours, dry at 80-90℃ to constant weight, and pulverize to obtain aluminum ferric sulfate flocculant.

8. The method for preparing the aluminum ferric sulfate flocculant according to claim 7, characterized in that, The amount of deionized water added is 8-15 times the total mass of modified attapulgite, aluminum sulfate, ferric sulfate, and carbide slag.

Images