A method for driving a battery waste residue in-situ to generate amorphous metal sulfide

Abstract

A method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria includes the following steps: S1, pretreatment of the battery waste; S2, ultrasonic treatment of the battery waste in choline-serine ionic liquid; S3, addition of a mixed bacterial seed culture medium to the battery waste for anaerobic reaction to generate amorphous metal sulfides. The mixed bacteria consist of desulfurized Vibrio broth, rumen-desulfurized Enterobacter rumen-desulfurized Enterobacter rumen-desulfurized microbacteria broth. This method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria can reduce sulfate from 1.75% to 0.17% in just 3 to 5 days, with a removal rate of 85.71% to 90.29%, thus rapidly and efficiently converting sulfate in battery waste into metal sulfides.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a method for preparing amorphous metal sulfides by synergistically driving the in-situ conversion of waste battery residue using microorganisms and green solvents. Background Technology

[0002] With the development of the new energy vehicle industry, the output of waste lithium batteries has surged. During the wet recycling and storage process, a large amount of free sulfuric acid and bound sulfate remain in the battery waste residue. These sulfur-containing components are not only prone to migration with leachate, causing water acidification and sulfate pollution, but also release in synergy with heavy metals, further aggravating the environmental risks to soil and groundwater.

[0003] Although some studies have explored the use of sulfate-reducing bacteria (SRB) to treat solid waste, their direct application to battery residue generally results in poor treatment outcomes: 1. Suppressed microbial activity: The acidic environment of the residue severely inhibits the metabolic activity of SRB, leading to low reduction efficiency; 2. Low substrate availability: Sulfate ions exist in the residue in a stable lattice or adsorbed state, making them difficult for microorganisms to utilize directly; 3. Low product value: Traditional processes focus primarily on "sulfurization and pollution reduction," resulting in crystalline sulfides that are prone to agglomeration and have a small specific surface area, lacking potential for high-value utilization.

[0004] Therefore, it is imperative to develop a new method that can simultaneously achieve rapid detoxification, efficient transformation, and high-value utilization. Summary of the Invention

[0005] This invention aims to solve the aforementioned technical problems by providing a method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria. This method utilizes choline-serine ionic liquid activation, ultrasonic assistance, and synergistic effects with specific bacterial communities to rapidly convert sulfate in the waste waste into highly active amorphous metal sulfides under mild conditions.

[0006] The above-mentioned objectives of the present invention are achieved through the following technical measures: A method for in-situ generation of amorphous metal sulfides from battery waste using sulfate-reducing bacteria is provided, comprising the following steps: S1. Pre-treatment of battery waste; S2. The battery waste residue will be added to choline serine ionic liquid for ultrasonic treatment. S3. Add the mixed bacterial seed culture medium to the battery waste residue and carry out an anaerobic reaction to generate amorphous metal sulfides. The mixed bacteria are composed of desulfurized Vibrio bronchiseptica liquid, rumen desulfurized Enterobacter rumen liquid and desulfurized microbacteria liquid.

[0007] Preferably, in the above-mentioned S1, the battery waste residue is crushed to 200 mesh to 300 mesh.

[0008] Preferably, S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:(1~3) to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 60 min to 120 min, wherein the ultrasonic intensity is 60 W / cm. 2 ~120W / cm 2 .

[0009] Preferably, S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue, wherein the volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is (1.0L~1.5L):1kg, and the mixed bacteria are composed of desulfurized Vibrio liquid, rumen desulfurized Enterobacter liquid and desulfurized microbacterial liquid in a volume ratio of 1:(0.5~0.8):(0.3~0.6); S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 25℃~35℃ for 3 to 5 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0010] Preferably, S1 specifically involves crushing the battery waste to 250 mesh.

[0011] Preferably, S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:1.8 to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 90 minutes, and the ultrasonic intensity is 100 W / cm. 2 .

[0012] Preferably, S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is 1.2L:1kg. The mixed bacteria are composed of desulfurized Vibrio liquid, rumen desulfurized Enterobacter liquid and desulfurized microbacterial liquid in a volume ratio of 1:0.6:0.5. S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 30°C for 4 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0013] Preferably, the above-mentioned choline serine ionic liquid is prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution and react them, then remove water by vacuum distillation to obtain a concentrated solution; and the molar amounts of L-serine in the L-serine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent to the concentrate, then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol. B4. The clear liquid obtained in B3 is distilled off under reduced pressure to remove acetonitrile and methanol, yielding choline serine ionic liquid.

[0014] Preferably, the above-mentioned choline serine ionic liquid is prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution at 0℃~5℃, then react at 10℃~15℃ for 10h~14h, and then remove water by vacuum distillation at 50℃~60℃ to obtain a concentrated solution; and the molar amounts of L-serine in the L-serine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of (0.5-0.8):1 to the concentrate and stir for 10-20 minutes. Then filter and take the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol, and the weight ratio of acetonitrile to methanol is (5-8):1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 50℃~60℃ to remove acetonitrile and methanol, yielding choline serine ionic liquid.

[0015] Preferably, the above-mentioned mixed bacterial seed culture medium is obtained by the following preparation method: A1. Prepare an anaerobic culture medium using ammonium chloride, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, sodium fumarate, sodium bicarbonate, yeast extract, L-cysteine ​​hydrochloride, resazurite, and deionized water. A2. Sterilize the anaerobic culture obtained in A1 to obtain a sterile anaerobic culture medium; A3. Inoculate the mixed bacterial solution into a sterile anaerobic culture medium according to the volume ratio, purge with nitrogen, and incubate in an anaerobic incubator for 2-3 days to obtain a mixed bacterial seed culture medium. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:(10-20).

[0016] The contents of each raw material in the anaerobic culture medium are as follows: Deionized water: 1000mL; Ammonium chloride: 1.1g; Dipotassium hydrogen phosphate: 0.7g; Magnesium sulfate heptahydrate: 0.2g; Calcium chloride dihydrate: 0.2g; Sodium fumarate: 1.8g; Sodium bicarbonate: 1.2g; Yeast extract: 0.15g; L-cysteine ​​hydrochloride: 0.5g; Rhabditis elata: 2mg.

[0017] Preferably, A3 specifically involves mixing the mixed bacteria with a sterile anaerobic culture medium and then incubating for 3 days, wherein the mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:15.

[0018] This invention discloses a method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria, comprising the following steps: S1, pretreatment of the battery waste; S2, ultrasonic treatment of the battery waste in choline-serine ionic liquid; S3, addition of a mixed bacterial seed culture medium to the battery waste for anaerobic reaction to generate amorphous metal sulfides, wherein the mixed bacteria consist of desulfurized Vibrio bronchiseptica liquid, rumen-desulfurized Enterobacter rumen-desulfurized Enterobacter rumen-desulfurized microbacteria liquid, and desulfurized microbacteria liquid. This method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria can reduce sulfate from 1.75% to 0.17% in just 3 to 5 days, with a removal rate of 85.71% to 90.29%, thereby rapidly and efficiently converting sulfate in battery waste into metal sulfides. Detailed Implementation

[0019] The technical solution of the present invention will be further described with reference to the following embodiments. Desulfurized Vibrio was purchased from Beijing Bio-Tech Biotechnology Co., Ltd., and its model number is ATCC 29577; Rumen desulfurized Enterobacter was purchased from Shanghai Beinuo Biotechnology Co., Ltd., and its model number is ATCC 23193; Desulfurized Microbes were purchased from Shanghai Xuanke Biotechnology Co., Ltd., and their model number is NCIMB 8310.

[0020] Example 1 A method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria includes the following steps: S1. Crush the battery waste residue to 200-300 mesh; S2. The battery waste residue will be added to choline serine ionic liquid for ultrasonic treatment. S3. Add the mixed bacterial seed culture medium to the battery waste residue and carry out an anaerobic reaction to produce amorphous metal sulfides. The mixed bacteria consist of desulfurized Vibrio bronchiseptica liquid, rumen desulfurized Enterobacter rumen liquid, and desulfurized microbacteria liquid.

[0021] It should be noted that the core activation, enhancement, and synergistic driving effects of the choline serine ionic liquid of this invention are key to achieving efficient and rapid reduction and conversion of sulfate in battery waste. Specifically: 1. Choline-serine ionic liquid has weak alkalinity and good pH buffering capacity, which can directly neutralize acidic substances such as free sulfuric acid and acidic degradation products in battery waste residue, and quickly stabilize the pH of the system in the weakly alkaline range suitable for sulfate-reducing bacteria, eliminating the inhibition of microbial activity by the acidity of the waste residue; at the same time, the serine group in its structure can continuously buffer the pH fluctuations during the reaction process through the binding and release of protons, avoiding sudden pH changes caused by SRB metabolism or the release of waste residue components, providing a stable, mild and biocompatible reaction environment for sulfate-reducing bacteria, and synergistically achieving efficient activation, dissolution and in-situ reduction and transformation of bound sulfate in the waste residue.

[0022] 2. It can effectively destroy the passivation layer and solid-bound state on the surface of battery waste particles, fully release the adsorbed and bound sulfate, greatly improve the availability of substrates by sulfate-reducing bacteria, and solve the problem that sulfate is difficult for microorganisms to utilize in traditional processes.

[0023] 3. Improve the dispersibility of waste residue particles in the system, reduce agglomeration, increase the contact area between sulfate-reducing bacteria and substrate, accelerate the sulfate reduction rate, and make the conversion time shorter and the treatment more thorough.

[0024] 4. It provides good biocompatibility and pH buffering capacity, which can alleviate the inhibition of microorganisms by the acidity of waste residue, protect the activity of sulfate-reducing bacteria, and improve the stability of anaerobic reduction.

[0025] 5. By reducing the solid-liquid interface resistance through the cavitation and impact of ultrasound, the choline serine ionic liquid enters the interior of the waste residue particles, fully destroying the binding bonds of sulfate in the solid phase, allowing the adsorbed and bound sulfate to be released more completely, and improving the substrate availability.

[0026] S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:(1~3) to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 60 min to 120 min, and the ultrasonic intensity is 60 W / cm. 2 ~120W / cm 2 .

[0027] S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is (1.0L~1.5L):1kg. The mixed bacteria consist of desulfurized Vibrio culture, rumen-desulfurized Enterobacter rumen culture, and desulfurized microbial culture in a volume ratio of 1:(0.5~0.8):(0.3~0.6); wherein the concentration of each of the desulfurized Vibrio culture, rumen-desulfurized Enterobacter rumen culture, and desulfurized microbial culture is 1.0×10⁻⁶. 8 CFU / mL; S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 25℃~35℃ for 3 to 5 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0028] The choline serine ionic liquid was prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution at 0℃~5℃, then react at 10℃~15℃ for 10h~14h, and then remove water by vacuum distillation at 50℃~60℃ to obtain concentrated solution; and the molar amounts of L-serine in L-serine aqueous solution and choline hydroxide in choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of (0.5-0.8):1 to the concentrate and stir for 10-20 minutes. Then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol, and the weight ratio of acetonitrile to methanol is (5-8):1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 50℃~60℃ to remove acetonitrile and methanol, yielding choline serine ionic liquid.

[0029] The mixed bacterial seed culture medium is prepared by the following method: A1. Prepare an anaerobic culture medium using ammonium chloride, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, sodium fumarate, sodium bicarbonate, yeast extract, L-cysteine ​​hydrochloride, resazurite, and deionized water. A2. Sterilize the anaerobic culture obtained in A1 to obtain a sterile anaerobic culture medium; A3. Inoculate the mixed bacterial solution into the sterile anaerobic culture medium according to the volume ratio, purge with nitrogen for 10 min, and incubate in a 30℃ anaerobic incubator for 2-3 days to obtain the mixed bacterial seed culture medium. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:(10-20).

[0030] The contents of each raw material in the anaerobic culture medium are as follows: Deionized water: 1000mL; Ammonium chloride: 1.1g; Dipotassium hydrogen phosphate: 0.7g; Magnesium sulfate heptahydrate: 0.2g; Calcium chloride dihydrate: 0.2g; Sodium fumarate: 1.8g; Sodium bicarbonate: 1.2g; Yeast extract: 0.15g; L-cysteine ​​hydrochloride: 0.5g; Rhabditis elata: 2mg.

[0031] This method of using sulfate-reducing bacteria to generate amorphous metal sulfides in situ from battery waste can reduce sulfate from 1.75% to 0.17% in just 3 to 5 days, with a removal rate of 85.71% to 90.29%, thus enabling rapid and efficient conversion of sulfate in battery waste into metal sulfides.

[0032] Example 2 A method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria, which is otherwise the same as in Example 1, except that it includes the following steps: S1. Crush the battery waste to 200 mesh; S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:1 to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 120 min at an ultrasonic intensity of 60 W / cm. 2 .

[0033] S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue, with a volume-to-weight ratio of 1.0 L: 1 kg. The mixed bacteria consist of desulfurized Vibrio culture, rumen-desulfurized Enterobacter rumen culture, and desulfurized microbial culture in a volume ratio of 1:0.8:0.3; the concentration of each of the desulfurized Vibrio culture, rumen-desulfurized Enterobacter rumen culture, and desulfurized microbial culture is 1.0 × 10⁻⁶. 8 CFU / mL; S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 25°C for 3 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0034] The choline serine ionic liquid was prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution at 0℃, then react at 10℃ for 14h, and then remove water by vacuum distillation at 60℃ to obtain concentrated solution; and the molar amounts of L-serine in L-serine aqueous solution and choline hydroxide in choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of 1.0:1 to the concentrate and stir for 10 minutes. Then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol with a weight ratio of 5:1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 60°C to remove acetonitrile and methanol, yielding choline serine ionic liquid.

[0035] The mixed bacterial seed culture medium is prepared by the following method: A1. Prepare an anaerobic culture medium using ammonium chloride, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, sodium fumarate, sodium bicarbonate, yeast extract, L-cysteine ​​hydrochloride, resazurite, and deionized water. A2. Sterilize the anaerobic culture obtained in A1 to obtain a sterile anaerobic culture medium; A3. Inoculate the mixed bacterial solution into the sterile anaerobic culture medium according to the volume ratio, purge with nitrogen for 10 min, and incubate in a 30℃ anaerobic incubator for 2 days to obtain the mixed bacterial seed culture medium. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:20.

[0036] The contents of each raw material in the anaerobic culture medium are as follows: Deionized water: 1000mL; Ammonium chloride: 1.1g; Dipotassium hydrogen phosphate: 0.7g; Magnesium sulfate heptahydrate: 0.2g; Calcium chloride dihydrate: 0.2g; Sodium fumarate: 1.8g; Sodium bicarbonate: 1.2g; Yeast extract: 0.15g; L-cysteine ​​hydrochloride: 0.5g; Rhabditis elata: 2mg.

[0037] Example 3 A method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria, which is the same as Example 1 except that it includes the following steps: S1, crushing the battery waste to 300 mesh; S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:3 to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 60 minutes at an ultrasonic intensity of 120 W / cm. 2 .

[0038] S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is 1.5L:1kg. The mixed bacteria consist of desulfurized Vibrio culture, rumen-desulfurized Enterobacter culture, and desulfurized microbial culture in a volume ratio of 1:0.5:0.6. The concentration of each of the desulfurized Vibrio culture, rumen-desulfurized Enterobacter culture, and desulfurized microbial culture is 1.0×10⁻⁶. 8 CFU / mL; S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 35°C for 5 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0039] The choline serine ionic liquid was prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution at 5°C, react at 15°C for 10 hours, and then remove water by vacuum distillation at 50°C to obtain a concentrated solution; and the molar amounts of L-serine in the L-serine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of 0.5:1 to the concentrate and stir for 20 minutes. Then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol with a weight ratio of 8:1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 50°C to remove acetonitrile and methanol, yielding choline serine ionic liquid.

[0040] The mixed bacterial seed culture medium is prepared by the following method: A1. Prepare an anaerobic culture medium using ammonium chloride, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, sodium fumarate, sodium bicarbonate, yeast extract, L-cysteine ​​hydrochloride, resazurite, and deionized water. A2. Sterilize the anaerobic culture obtained in A1 to obtain a sterile anaerobic culture medium; A3. Inoculate the mixed bacterial solution into the sterile anaerobic culture medium according to the volume ratio, purge with nitrogen for 10 min, and incubate in a 30℃ anaerobic incubator for 3 days to obtain the mixed bacterial seed culture medium. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:10.

[0041] Example 4 A method for in-situ generation of amorphous metal sulfides from battery waste driven by sulfate-reducing bacteria, which is otherwise the same as in Example 1, except that it includes the following steps: S1. Crush the battery waste to 250 mesh; S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:1.8 to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 90 minutes at an ultrasonic intensity of 100 W / cm. 2 .

[0042] S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is 1.2L:1kg. The mixed bacteria consist of desulfurized Vibrio culture, rumen-desulfurized Enterobacter culture, and desulfurized microbial culture in a volume ratio of 1:0.6:0.5. The concentration of each of the desulfurized Vibrio culture, rumen-desulfurized Enterobacter culture, and desulfurized microbial culture is 1.0×10⁻⁶. 8 CFU / mL; S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 30°C for 4 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0043] The choline serine ionic liquid was prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution at 3°C, react at 13°C for 12 hours, and then remove water by vacuum distillation at 55°C to obtain a concentrated solution; and the molar amounts of L-serine in the L-serine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of 0.6:1 to the concentrate and stir for 15 minutes. Then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol with a weight ratio of 6:1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 55°C to remove acetonitrile and methanol, yielding choline serine ionic liquid.

[0044] The mixed bacterial seed culture medium is prepared by the following method: A1. Prepare an anaerobic culture medium using ammonium chloride, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, sodium fumarate, sodium bicarbonate, yeast extract, L-cysteine ​​hydrochloride, resazurite, and deionized water. A2. Sterilize the anaerobic culture obtained in A1 to obtain a sterile anaerobic culture medium; A3. Inoculate the mixed bacterial solution into the sterile anaerobic culture medium according to the volume ratio, purge with nitrogen for 10 min, and incubate in an anaerobic incubator at 30℃ for 2.5 days to obtain the mixed bacterial seed culture medium. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:15.

[0045] Comparative Example 1 A method for treating battery waste residue with sulfate-reducing bacteria, which is otherwise the same as in Example 4, except that it includes the following steps: S1. Crush the battery waste to 250 mesh; S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:1.8 to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 30 minutes at an ultrasonic intensity of 200 W / cm. 2 .

[0046] S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is 0.8L:1kg. The mixed bacteria consist of desulfurized Vibrio bronchiseptica solution, rumen desulfurized Enterobacter rumen solution, and desulfurized microbial solution in a volume ratio of 1:0.2:1. S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 30°C for 4 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0047] Comparative Example 2 A method for treating battery waste residue with sulfate-reducing bacteria, which is otherwise the same as in Example 4, except that it includes the following steps: S1. Crush the battery waste to 250 mesh; S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:0.5 to obtain a mixture; S2.2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 150 min at an ultrasonic intensity of 20 W / cm. 2 .

[0048] S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is 1.8L:1kg. The mixed bacteria consist of desulfurized Vibrio bronchiseptica solution, rumen desulfurized Enterobacter rumen desulfurized Enterobacter rumen desulfurized microbacteria solution, and desulfurized microbacteria solution in a volume ratio of 0.6:1:1. S3.2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 30°C for 4 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

[0049] Comparative Example 3 A method for treating battery waste residue with sulfate-reducing bacteria, which is otherwise the same as in Example 4, except that ultrasonic treatment is not performed.

[0050] Comparative Example 4 A method for treating battery waste with sulfate-reducing bacteria, which is otherwise the same as in Example 4, except that choline serine ionic liquid is replaced with deionized water.

[0051] Comparative Example 5 A method for treating battery waste residue with sulfate-reducing bacteria, which is otherwise the same as embodiment 4, except that the choline serine ionic liquid is replaced with a 5wt% sodium bicarbonate aqueous solution.

[0052] Comparative Example 6 A method for treating battery waste with sulfate-reducing bacteria, which is otherwise the same as in Example 4, except that the choline serine ionic liquid is replaced with the choline alanine ionic liquid.

[0053] Choline-alanine ionic liquids are prepared by the following method: B1. Dissolve alanine in water to obtain an aqueous solution of alanine; B2. Mix alanine aqueous solution and choline hydroxide aqueous solution at 5°C, react at 15°C for 10 hours, and then remove water by vacuum distillation at 50°C to obtain a concentrated solution; and the molar amounts of alanine in the alanine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of 0.5:1 to the concentrate and stir for 20 minutes. Then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol with a weight ratio of 8:1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 50°C to remove acetonitrile and methanol, yielding a choline alanine ionic liquid.

[0054] Comparative Example 7 A method for treating battery waste residue with sulfate-reducing bacteria, which is otherwise the same as in Example 4, except that the mixed bacteria are a single desulfurizing Vibrio solution.

[0055] Test case 1. Determination of sulfate concentration Under identical conditions, using the same batch of waste lithium iron phosphate (LFP) cathode slag as raw material, and employing the methods of Examples 2-4 and Comparative Examples 1 to 7, the reduction products were obtained. The raw material and reduction products were then subjected to sulfate (SO4) treatment. 2- The data in Table 1 were obtained using the determination method. Among them, sulfate (SO4) 2- The determination method is as follows: Step 1: Accurately weigh 1g of sample into a crucible, use 5g of anhydrous sodium carbonate as flux, and melt at 750℃ for 1 hour to convert sparingly soluble sulfate into soluble sodium sulfate.

[0056] Step 2: Add 100mL of hot water to the crucible to leach the molten material. Heat to boiling for 20 minutes to completely leach out the molten material. Filter while hot to remove insoluble substances such as metal oxides, graphite, and sulfides. Wash the crucible and precipitate with 50mL of hot water.

[0057] Step 3: Add concentrated hydrochloric acid dropwise to the filtrate until the solution reaches pH=1, and boil for 3-5 minutes; Step 4: Add 5 mL of 1% AlCl3 solution and 5 mL of 1% EDTA disodium solution, filter and collect the filtrate; Step 5: Add 10% barium chloride solution dropwise to the filtrate under gentle boiling to precipitate sulfate ions, stirring constantly until no more white precipitate is produced. Add an excess of 2-3 mL, continue gentle boiling for 2 minutes, and then place in a water bath to age for 30 minutes. Step 6: Filter and wash the solid, ignite it at 800℃ to constant weight, and calculate the sulfate content in the sample based on the mass of barium sulfate.

[0058] Table 1. Sulfate content after treating battery waste residue by different methods.

[0059] As shown in Table 1, the sulfate content in the raw lithium iron phosphate cathode slag is 1.75%. After treatment using the method of the present invention in Examples 2 to 4, the sulfate content in the waste slag is significantly reduced to 0.23%, 0.25%, and 0.17%, respectively, with removal rates of 86.86%, 85.71%, and 90.29%. Among them, Example 4 is the best, achieving a sulfate removal rate of up to 90.29% in just 4 days. This indicates that the present invention, through activation by choline serine ionic liquid, ultrasonic assistance, and the synergistic effect of sulfate-reducing bacteria in a specific ratio, can efficiently reduce and degrade sulfate in waste slag and generate amorphous metal sulfides in situ.

[0060] Furthermore, due to the deterioration of process parameters, treatment solvents, or bacterial strains in each comparative example, the sulfate removal effect significantly worsened. Among them, the sulfate contents of comparative examples 4, 5, and 6 were as high as 1.68%, 1.53%, and 0.76%, respectively. This is because water, as a dispersion medium, does not have the ability to activate sulfate, neutralize acidity, or stabilize pH; sodium bicarbonate can only temporarily adjust pH but cannot activate bound sulfate and has limited buffering capacity; and choline alanine ionic liquid, due to the lack of hydroxyl functional groups in its side chains, has significant deficiencies in solid-phase activation, hydrogen bonding, and pH buffering efficiency. The choline serine ionic liquid of this invention, with its hydroxyl (-OH) on the side chain and zwitterionic structure, can efficiently disrupt the interfacial bonds of bound sulfate in battery waste through hydrogen bonding and coordination, significantly improving sulfate dissolution and substrate availability. It also has the ability to neutralize weak alkalinity, provide efficient pH buffering and microenvironment stabilization, and can continuously maintain the pH of the system within the suitable range for sulfate-reducing bacteria. Furthermore, it can improve the dispersibility of waste particles, promote the coordination and dispersion of heavy metal ions, and directionally generate amorphous metal sulfides, thereby achieving significant improvements in sulfate reduction efficiency, heavy metal stabilization and product controllability.

[0061] 2. Phase characterization of the sample The reduced products obtained in Examples 2-4 were analyzed by X-ray diffraction (XRD), with a scanning range of 2θ = 10°~80° and a scanning speed of 5° / min. The XRD patterns showed no obvious sharp diffraction peaks, weakly broadened peaks at 15°~25°, strong and broad diffuse peaks at 30°~40°, and weakly broadened diffuse peaks at 45°~55°. No sharp crystalline diffraction peaks were observed, and no characteristic peaks of metal oxides, elemental metals, or sulfates were found, indicating that the products have a typical amorphous structure. The main phases are amorphous cobalt sulfide (CoS), amorphous nickel sulfide (NiS), amorphous manganese sulfide (MnS), amorphous iron sulfide (FeS), and amorphous copper sulfide (CuS).

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria, characterized in that, Includes the following steps: S1. Pre-treatment of battery waste; S2. The battery waste residue will be added to choline serine ionic liquid for ultrasonic treatment. S3. Add the mixed bacterial seed culture medium to the battery waste residue and carry out an anaerobic reaction to generate amorphous metal sulfides. The mixed bacteria are composed of desulfurized Vibrio bronchiseptica liquid, rumen desulfurized Enterobacter rumen liquid and desulfurized microbacteria liquid.

2. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 1, characterized in that, Specifically, S1 involves crushing battery waste to a mesh size of 200-300 mesh.

3. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 2, characterized in that, S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:(1~3) to obtain a mixture; S2.

2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 60 min to 120 min, wherein the ultrasonic intensity is 60 W / cm. 2 ~120W / cm 2 .

4. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 3, characterized in that, S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue, wherein the volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is (1.0L~1.5L):1kg, and the mixed bacteria are composed of desulfurized Vibrio liquid, rumen desulfurized Enterobacter liquid and desulfurized microbacterial liquid in a volume ratio of 1:(0.5~0.8):(0.3~0.6); S3.

2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 25℃~35℃ for 3 to 5 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

5. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 4, characterized in that, S1 specifically involves crushing battery waste residue to 250 mesh; S2 is performed by the following steps: S2.1 Add battery waste residue to choline serine ionic liquid, and the weight ratio of battery waste residue to choline serine ionic liquid is 1:1.8 to obtain a mixture; S2.

2. The mixture obtained in S2.1 is subjected to ultrasonic treatment for 90 minutes, and the ultrasonic intensity is 100 W / cm. 2 ; S3 is performed by the following steps: S3.1 Add the mixed bacterial seed culture medium to the battery waste residue. The volume-to-weight ratio of the mixed bacterial seed culture medium to the battery waste residue is 1.2L:1kg. The mixed bacteria are composed of desulfurized Vibrio liquid, rumen desulfurized Enterobacter liquid and desulfurized microbacterial liquid in a volume ratio of 1:0.6:0.

5. S3.

2. The anaerobic reaction was carried out in an anaerobic incubator at a temperature of 30°C for 4 days. S3.3 After the anaerobic reaction, the mixture is filtered, and the filter residue is dried to obtain the reduction product.

6. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to any one of claims 1-5, characterized in that: The choline serine ionic liquid was prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution and react them, then remove water by vacuum distillation to obtain a concentrated solution; and the molar amounts of L-serine in the L-serine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent to the concentrate, then filter to obtain the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol. B4. The clear liquid obtained in B3 is distilled off under reduced pressure to remove acetonitrile and methanol, yielding choline serine ionic liquid.

7. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 6, characterized in that: The choline serine ionic liquid was prepared by the following method: B1. Dissolve L-serine in water to obtain an aqueous solution of L-serine; B2. Mix L-serine aqueous solution and choline hydroxide aqueous solution at 0℃~5℃, then react at 10℃~15℃ for 10h~14h, and then remove water by vacuum distillation at 50℃~60℃ to obtain a concentrated solution; and the molar amounts of L-serine in the L-serine aqueous solution and choline hydroxide in the choline hydroxide aqueous solution are equal. B3. Add a mixed solvent with a weight ratio of (0.5-0.8):1 to the concentrate and stir for 10-20 minutes. Then filter and take the clear liquid. The mixed solvent is a mixture of acetonitrile and methanol, and the weight ratio of acetonitrile to methanol is (5-8):

1. B4. The clear liquid obtained in B3 is distilled off under reduced pressure at 50℃~60℃ to remove acetonitrile and methanol, yielding choline serine ionic liquid.

8. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to any one of claims 1-5, characterized in that, The mixed bacterial seed culture medium is prepared by the following method: A1. Prepare an anaerobic culture medium using ammonium chloride, dipotassium hydrogen phosphate, magnesium sulfate heptahydrate, calcium chloride dihydrate, sodium fumarate, sodium bicarbonate, yeast extract, L-cysteine ​​hydrochloride, resazurite, and deionized water. A2. Sterilize the anaerobic culture obtained in A1 to obtain a sterile anaerobic culture medium; A3. Inoculate the mixed bacterial solution into a sterile anaerobic culture medium according to the volume ratio, purge with nitrogen, and incubate in an anaerobic incubator for 2-3 days to obtain a mixed bacterial seed culture medium. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:(10-20).

9. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 8, characterized in that, The contents of each raw material in the anaerobic culture medium are as follows: Deionized water: 1000mL; Ammonium chloride: 1.1g; Dipotassium hydrogen phosphate: 0.7g; Magnesium sulfate heptahydrate: 0.2g; Calcium chloride dihydrate: 0.2g; Sodium fumarate: 1.8g; Sodium bicarbonate: 1.2g; Yeast extract: 0.15g; L-cysteine ​​hydrochloride: 0.5g; Rhabditis elata: 2mg.

10. The method for in-situ generation of amorphous metal sulfides from battery waste residue driven by sulfate-reducing bacteria according to claim 9, characterized in that, Specifically, A3 involves mixing the mixed bacteria with a sterile anaerobic culture medium and then incubating for 3 days. The mixing ratio of the mixed bacteria to the sterile anaerobic culture medium is 1:15.

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