Method for preparing coal chemical industry wastewater flocculating agent by utilizing glutamic acid fermentation waste liquid, coal chemical industry wastewater flocculating agent and application of coal chemical industry wastewater flocculating agent

Abstract

The invention relates to the technical field of fermentation wastewater in the biological fermentation industry, in particular to a method for preparing a coal chemical wastewater flocculant from glutamic acid fermentation waste liquid, which comprises the following steps: extracting and purifying the glutamic acid fermentation waste liquid to obtain a fermentation waste liquid extract; the required amount of metal salt and sodium hydroxide are added into the fermentation waste liquid extract, a reaction mixture is obtained, grinding reaction and impurity removal of a reaction product are performed, the coal chemical industry wastewater flocculant is obtained, and the metal salt comprises magnesium salt, calcium salt, copper salt and ferric iron salt. The glutamic acid fermentation waste liquid is secondarily utilized, effective substances in the glutamic acid fermentation waste liquid are fully utilized, the prepared coal chemical industry wastewater flocculant achieves an excellent treatment effect on the coal chemical industry wastewater, the preparation and treatment processes are non-toxic, harmless, green and pollution-free, and the effects of turning waste into wealth and getting twofold results with half the effort are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of fermentation wastewater in the biological fermentation industry, and is a method for preparing a coal chemical wastewater flocculant by utilizing glutamic acid fermentation waste liquid, as well as a coal chemical wastewater flocculant and an application thereof. Background Art

[0002] my country is the world's largest producer of glutamate. A large amount of fermentation waste liquid is generated during the production process, with more than 10 million tons of highly concentrated organic wastewater discharged each year. Although enterprises and research institutes have conducted environmental remediation research, most enterprises cannot afford it due to high costs, and wastewater is often in an "over-limit" state. Glutamic acid fermentation waste liquid contains a large amount of glutamic acid, polyglutamic acid, reducing sugar, SS and ammonia nitrogen. Its arbitrary discharge not only wastes precious resources, but also causes serious environmental pollution and destroys the ecological balance. According to the characteristics of fermentation waste liquid, comprehensive utilization of fermentation waste liquid can not only save resources, but also greatly reduce COD and NH in wastewater. 4+ -N, reducing the pollution of wastewater to the environment, and at the same time will bring high economic and social benefits.

[0003] Usually, the main components of glutamate fermentation waste liquid include protein, glutamic acid, polyglutamic acid, reducing sugar, free fat and amino nitrogen etc. At present, the glutamate fermentation waste liquid is mostly used to extract useful components for reuse, mainly including utilizing glutamate fermentation waste liquid to extract bacterial protein, make animal feed, produce organic-inorganic compound fertilizer etc., such as Mao Zhonggui etc. (Jiangnan University. Publication number is CN101993280A Chinese patent literature discloses a method for utilizing fermentation glutamate to extract waste liquid to produce compound fertilizer, and its reuse method is relatively simple, specifically, fermentation waste liquid is concentrated and cooled granulation solidified to obtain. However, due to the use of high temperature flue gas for sintering granulation treatment in the process of granulation, a large amount of tail gas will be generated and the high temperature process will cause the loss of fertilizer nutrients, and the application field cannot be melted for several years, so there is the problem of poor environmental protection and low recycling rate.

[0004] The Chinese patent document with publication number CN106819398A discloses an animal feed prepared from glutamate fermentation waste, which uses glutamate fermentation waste liquid as raw material and mixes it with a variety of nutrients to produce animal feed. The feed is composed of the following raw materials: glutamate fermentation liquid, Chinese herbal compound, compound vitamins, sorghum, soybean meal, rice bran, and sorghum straw. It is prepared according to the following method: step 1) filtration of fermentation liquid, step 2) decolorization, concentration and crystallization, step 3) hydrolysis, step 4) preparation of composite powder, step 5) preparation of main ingredients, and step 6) preparation of feed. This method has relatively complicated steps and is more expensive than other feeds on the market.

[0005] Duan Zuoying et al. (Duan Zuoying. Extraction of nucleic acid substances from glutamic acid bacteria [J]. Journal of Wuxi University of Light Industry, 2000, 19(4): 322-324) used glutamic acid bacteria to extract nucleic acid, and the yield of nucleic acid extraction was above 1.5%. The process flow is as follows: MSG waste liquid → flocculation sedimentation → precipitation → centrifugal separation → heating → filtration → extraction liquid → adjustment → precipitation → ethanol washing → vacuum drying → purification → nucleic acid. The process is simple and has good economic, environmental and social benefits, opening up a new way for the production of nucleic acid. However, the wastewater after nucleic acid extraction still contains a lot of pollutants and needs further treatment. Although there are many methods for the secondary utilization of glutamic acid fermentation broth, there are still many problems. Therefore, it is an inevitable trend to develop more secondary utilization methods.

[0006] As a symbolic green flocculant, polyglutamic acid has attracted great interest decades ago. However, the carboxyl group itself makes the flocculation performance of γ-PGA insufficient, thus limiting its potential application (Ravishankar SA, Praip, Khosla NK, 1995. Selective flocculation of iron oxide from its synthetic mixtures with clays: a comparison of polyacrylic avid and starch polymers. International Journal of Mineral Processing 43, 235-247.). Chen et al. (Chen, Jianxin, et al. Synthesis of CationicModified Poly (γ-Glutamic Acid) and Evaluation of its FlocculationPerformance in Seawater. Chemical Engineering Transactions 61 (2017): 1765-1770.) prepared a flocculant by chemical reaction using γ-PGA and 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTMA) as raw materials. The results showed that after adding 2 mg / L of modified γ-PGA, the turbidity of seawater decreased from 95 NTU to 10 NTU.

[0007] Coal chemical wastewater has the characteristics of many types of pollutants, high concentrations, and complex components. It contains a large number of organic pollutants such as phenols, esters, etc., with high total phenol content, high COD content, high turbidity and inorganic salts, and phenols are highly toxic. The amount of wastewater generated is large and the treatment is difficult. The existing coal chemical wastewater treatment technology is difficult to achieve good treatment effects. Enterprises are facing technical bottlenecks and high cost pressures, and the wastewater discharge continues to increase. Environmental protection regulations are strict and the treatment pressure is high. At present, most studies use compound coagulants and target single simulated wastewater, which lacks practical applicability and extensiveness. Therefore, it is very important to prepare flocculants that do not require compounding, have high flocculation efficiency, and low dosage for actual coal chemical wastewater. Summary of the invention

[0008] The present invention provides a method for preparing a coal chemical wastewater flocculant by utilizing glutamic acid fermentation waste liquid, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of complex treatment process and poor utilization effect of the existing glutamic acid fermentation waste liquid.

[0009] One of the technical solutions of the present invention is achieved by the following measures: a method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid, comprising the following steps: Extracting and purifying glutamic acid fermentation waste liquid to obtain a fermentation waste liquid extract; Adding required amounts of metal salt and sodium hydroxide to the fermentation waste liquid extract to obtain a reaction mixture, grinding the reaction, and removing impurities from the reaction product to obtain a coal chemical wastewater flocculant; wherein the metal salt includes magnesium salt, calcium salt, copper salt and trivalent iron salt.

[0010] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned step of extracting and purifying the glutamic acid fermentation waste liquid comprises: After solid-liquid separation of glutamic acid fermentation waste liquid, the bacterial cells are removed to obtain a clear liquid; An equal volume of ethanol is added to the clear solution 1, and the clear solution 2 is obtained after refrigeration and separation; The second clear liquid is dialyzed, and the dialyzed solution is concentrated and dried to obtain a fermentation waste liquid extract.

[0011] The above dialysis is performed 2 to 4 times using a semipermeable membrane, and the specification of the semipermeable membrane is 7000Da to 10000Da.

[0012] The above-mentioned metal salt is a halide or a nitrate.

[0013] The mass ratio of the fermentation waste liquid extract to the metal salt is 1:1 to 1:3.

[0014] The grinding reaction time is 20 min to 30 min, and the reaction temperature is 15° C. to 35° C.

[0015] In the above reaction mixture, the amount of sodium hydroxide used is 3% to 20% of the total mass of the fermentation waste liquid extract and the metal salt.

[0016] The step of removing impurities from the reaction product comprises: washing the reaction product after the grinding reaction with anhydrous ethanol.

[0017] The grinding reaction is carried out in a ball mill at room temperature for solid phase reaction at a rotation speed of 150 r / min to 200 r / min.

[0018] The second technical solution of the present invention is achieved through the following measures: a coal chemical wastewater flocculant prepared by a method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid.

[0019] The third technical solution of the present invention is achieved through the following measures: an application of the coal chemical wastewater flocculant according to the above-mentioned technical solution 2 in the treatment of coal chemical wastewater, including the use of 0.3g to 3g of the coal chemical wastewater flocculant per liter of coal chemical wastewater.

[0020] The invention provides a method for preparing a coal chemical wastewater flocculant by utilizing glutamate fermentation waste liquid. The method performs secondary utilization of the glutamate fermentation waste liquid, thereby achieving full utilization of effective substances in the glutamate fermentation waste liquid. The prepared coal chemical wastewater flocculant achieves excellent treatment effect on the coal chemical wastewater. The preparation and treatment processes are both non-toxic and harmless, green and pollution-free, achieving the effect of turning waste into treasure and achieving twice the result with half the effort. DETAILED DESCRIPTION

[0021] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0022] The present invention will be further described below in conjunction with embodiments: Embodiment 1: The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid comprises the following steps: Extracting and purifying glutamic acid fermentation waste liquid to obtain a fermentation waste liquid extract; Adding required amounts of metal salt and sodium hydroxide to the fermentation waste liquid extract to obtain a reaction mixture, grinding the reaction, and removing impurities from the reaction product to obtain a coal chemical wastewater flocculant; wherein the metal salt includes magnesium salt, calcium salt, copper salt and trivalent iron salt.

[0023] The glutamate fermentation waste liquid of the present invention is fermentation waste liquid generated in the process of producing glutamate from glutamate liquid fertilizer.

[0024] Embodiment 2: As an optimization of the above embodiment, the steps of extracting and purifying the glutamate fermentation waste liquid include: After solid-liquid separation of glutamic acid fermentation waste liquid, the bacterial cells are removed to obtain a clear liquid; An equal volume of ethanol is added to the clear solution 1, and the clear solution 2 is obtained after refrigeration and separation; The second clear liquid is dialyzed, and the dialyzed solution is concentrated and dried to obtain a fermentation waste liquid extract.

[0025] Example 3: As an optimization of the above example, the dialysis is performed 2 to 4 times using a semipermeable membrane, and the specification of the semipermeable membrane is 7000Da to 10000Da.

[0026] Embodiment 4: As an optimization of the above embodiment, the metal salt is a halide salt or a nitrate.

[0027] Example 5: As an optimization of the above example, the mass ratio of the fermentation waste liquid extract and the metal salt is 1:1 to 1:3.

[0028] Example 6: As an optimization of the above example, the grinding reaction time is 20 min to 30 min, and the reaction temperature is 15°C to 35°C.

[0029] Example 7: As an optimization of the above example, in the reaction mixture, the amount of sodium hydroxide used is 3% to 20% of the total mass of the fermentation waste liquid extract and the metal salt.

[0030] Embodiment 8: As an optimization of the above embodiment, the step of removing impurities from the reaction product includes: washing the reaction product after the grinding reaction with anhydrous ethanol. After the grinding reaction, the reaction product is washed 2 to 4 times with anhydrous ethanol to remove unchelated amino acids and metal salts in the reaction product.

[0031] Example 9: As an optimization of the above example, the grinding reaction is carried out using a ball mill at room temperature for solid phase reaction at a rotation speed of 150 r / min to 200 r / min.

[0032] The present invention removes impurities and concentrates glutamic acid fermentation waste liquid to obtain a fermentation waste liquid extract, and conducts a solid-phase chemical reaction between the fermentation waste liquid extract and a metal salt to prepare a coal chemical wastewater flocculant. During the grinding reaction, the water content in the reaction mixture is maintained at 5% to 20% of the total mass of the reaction mixture, so that the reaction mixture remains in a viscous state during the grinding process.

[0033] Example 10: Application of the coal chemical wastewater flocculant in coal chemical wastewater treatment, including using an amount of 0.3 g to 3 g of the coal chemical wastewater flocculant per liter of coal chemical wastewater.

[0034] Example 11: The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation wastewater is carried out according to the following steps: In the first step, 10 L of glutamate fermentation waste liquid was centrifuged to remove the bacteria in the fermentation waste liquid, the supernatant was collected, ethanol with the same volume as the supernatant was added, and refrigerated at 4°C for 3 h; In the second step, the turbid liquid after the first step of refrigeration and standing is centrifuged to obtain the supernatant, and the supernatant is dialyzed three times through a 10000Da semipermeable membrane. The dialyzed solution is concentrated and dried to obtain the fermentation waste liquid extract.

[0035] In the third step, 14.72 g of fermentation waste liquid extract and 16.22 g of ferric chloride were mixed, and 2 g of sodium hydroxide and 2 g of water were added. After mixing and grinding for 30 minutes, the unchelated amino acids and metal salts were removed by washing with anhydrous ethanol, and the mixture was dried in an oven to obtain a dry product, which was a chemical wastewater flocculant and was recorded as AH-1.

[0036] In this embodiment, the main components of the glutamate fermentation waste liquid are: 2.4 g / L protein, 2.6 g / L glutamic acid, 12.4 g / L polyglutamic acid, 0.213 g / L reducing sugar, 2.3 g / L free fat, and 6.9 g / L amino nitrogen.

[0037] Example 12: The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid is carried out according to the following steps: In the first step, 10 L of glutamate fermentation waste liquid was centrifuged to remove the bacteria in the fermentation waste liquid, the supernatant was collected, ethanol with the same volume as the supernatant was added, and refrigerated at 4°C for 3 h; In the second step, the turbid liquid after the first step of refrigeration and standing is centrifuged to obtain the supernatant, and the supernatant is repeatedly dialyzed through a 10000Da semipermeable membrane. The dialyzed solution is concentrated and dried to obtain the fermentation waste liquid extract.

[0038] In the third step, 14.72 g of fermentation waste liquid extract and 18.76 g of copper nitrate were mixed, and 2 g of sodium hydroxide and 2 g of water were added. After mixing and grinding for 30 min, the unchelated amino acids and metal salts were removed by rinsing with anhydrous ethanol, and the mixture was placed in an oven for drying to obtain a dry product, which was recorded as AH-2.

[0039] The glutamate fermentation waste liquid in this embodiment is the same as that in Example 11.

[0040] Example 13: The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid is carried out according to the following steps: In the first step, 10 L of glutamate fermentation waste liquid was centrifuged to remove the bacteria in the fermentation waste liquid, the supernatant was collected, ethanol with the same volume as the supernatant was added, and refrigerated at 4°C for 3 h; In the second step, the turbid liquid after the first step of refrigeration and standing is centrifuged to obtain the supernatant, and the supernatant is repeatedly dialyzed through a 10000Da semipermeable membrane. The dialyzed solution is concentrated and dried to obtain the fermentation waste liquid extract.

[0041] In the third step, 14.72 g of fermentation waste liquid extract and 11.1 g of calcium chloride were mixed, and 2 g of sodium hydroxide and 2 g of water were added. After mixing and grinding for 30 min, the unchelated amino acids and metal salts were removed by washing with anhydrous ethanol, and the dried product was placed in an oven for drying to obtain a dry product, which was recorded as AH-3.

[0042] The glutamate fermentation waste liquid in this embodiment is the same as that in Example 11.

[0043] Example 14: The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid is carried out according to the following steps: In the first step, 10 L of glutamate fermentation waste liquid was centrifuged to remove the bacteria in the fermentation waste liquid, the supernatant was collected, ethanol with the same volume as the supernatant was added, and refrigerated at 4°C for 3 h; In the second step, the turbid liquid after the first step of refrigeration and standing is centrifuged to obtain the supernatant, and the supernatant is repeatedly dialyzed through a 10000Da semipermeable membrane. The dialyzed solution is concentrated and dried to obtain the fermentation waste liquid extract.

[0044] In the third step, 14.72 g of fermentation waste liquid extract and 9.531 g of magnesium chloride were mixed, and 2 g of sodium hydroxide and 2 g of water were added. After mixing and grinding for 30 min, the unchelated amino acids and metal salts were removed by washing with anhydrous ethanol, and the dried product was placed in an oven for drying to obtain a dry product, which was recorded as AH-4.

[0045] The glutamate fermentation waste liquid in this embodiment is the same as that in Example 11.

[0046] Comparative Example 1: Organic macromolecular flocculant polyacrylamide, denoted as D-1.

[0047] Comparative Example 2: Inorganic flocculant ferric chloride, denoted as D-2.

[0048] Comparative Example 3: The flocculant of this comparative example is obtained by reacting pure γ-polyglutamic acid with ferric chloride, and the specific steps are as follows: Weigh 2.20 g of pure γ-polyglutamic acid and 1.35 g of ferric chloride, mix them, add 2 g of sodium hydroxide and 2 g of water, mix and grind for 30 min, then wash with anhydrous ethanol to remove unchelated amino acids and metal salts, put them in an oven for drying, and obtain a dry product, which is recorded as D-3.

[0049] Comparative Example 4: The flocculant in this comparative example is obtained by reacting pure glutamic acid with ferric chloride, and the specific steps are as follows: Weigh 2.21 g of pure glutamic acid and 1.35 g of ferric chloride, mix them, add 2 g of sodium hydroxide and 2 g of water, mix and grind for 30 min, wash with anhydrous ethanol to remove unchelated amino acids and metal salts, put them in an oven for drying, and obtain a dry product, which is recorded as D-4.

[0050] Experimental example: The coal chemical wastewater flocculants of Examples 11 to 14 and the products of Comparative Examples 1 to 4 were used to treat the coal chemical wastewater, and the COD removal performance, turbidity removal performance, volatile phenol removal rate, sedimentation rate and other indicators of the flocculants on the coal chemical wastewater were tested. Among them, the coal chemical wastewater is semi-coke wastewater, and its basic parameters are: COD 6487.03 mg·L -1 , volatile phenol content 128.87 mg·L -1 , TOC 369.42mg·L -1 , turbidity 1806.41NTU, color 19.79PCU.

[0051] Test 1: 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, 3.0g AH-1 were added to 1L of blue carbon wastewater, and each group of samples was taken after standing for 3 hours to remove flocculated impurities through a 0.2nm membrane. The COD removal rate, turbidity removal rate and volatile phenol removal rate were tested with reference to the national environmental protection standard HJ828-2017. The test results are shown in Table 1. As can be seen from Table 1, when the addition amount of AH-1 is 3.0g / L, the COD removal rate can reach a maximum value of 88.86%, and it can reach 84.62% at 1.5g / L. Although it has a slight decrease after 1.8g / L, it can still reach more than 80%. In addition, the turbidity removal effect of AH-1 is very excellent. When only 0.3g / L is added, the turbidity removal rate can reach 99.99%, which is almost completely turbid. It can be seen from Table 1 that with the increase in the amount of AH-1 added, the removal rate of volatile phenols gradually increased with the addition of flocculants. When the addition amount was greater than 1.2 g / L, the removal rate was greater than 90%. At 3.0 g / L, the removal rate of volatile phenols could reach 95.07%.

[0052] .

[0053] Test 2: 1.5g AH-1 was used to treat 1L of semi-coal wastewater. The supernatant was taken at 5min, 10min, 15min, 20min, 25min, 30min, 45min, 60min, 120min and 3h, and passed through a 0.2nm membrane, and the COD removal rate and turbidity removal rate were tested. The results are shown in Table 2. As can be seen from Table 2, after adding AH-1 for 30min, the COD removal rate can reach 61.54%; AH-1 can have a more obvious turbidity removal effect on wastewater within 15min, the turbidity removal rate can reach 51.06% at 15min, and the turbidity removal rate can reach 74.24% at 30min, which shows that the coal chemical wastewater flocculant of the present invention has an excellent treatment effect. After AH-1 treated the wastewater for 120 minutes, the COD value and turbidity tended to be stable. In specific applications, when the coal chemical wastewater flocculant of the present invention is used to treat coal chemical wastewater, the treatment time can be 2 to 3 hours, with high treatment efficiency.

[0054] .

[0055] Test 3: Sample AH-1 of Example 11 was prepared into a 3 g / L solution, and the height of the clear layer was measured according to the national standard GBT13200-1991 at 5, 10, 15, 20, 25, and 30 minutes, and the sedimentation rate was calculated. The results are shown in Table 3. Table 3 shows that the sedimentation rate of AH-1 is fast, and obvious stratification is shown within 10 minutes.

[0056] .

[0057] Test 4: 1.5g AH-1, AH-2, AH-3, AH-4, D-1, D-2, D-3 and D-4 were added to 1L of semi-carbon wastewater, and after standing for 3 hours, each group of samples was passed through a 0.2nm membrane to remove flocculated impurities. The COD content was determined and the COD removal rate was calculated in accordance with the national environmental protection standard HJ828-2017. The results are shown in Table 4. In Table 4, after adding D-1 organic macromolecular flocculant polyacrylamide to the semi-carbon wastewater, the waste liquid had no sedimentation and no stratification, and the waste liquid formed a stable colloid, so its COD removal rate could not be tested. It can be seen from Table 4 that the flocculants (D-3 and D-4) made from pure polyglutamic acid and glutamic acid chelate have a certain COD removal capacity, among which the COD removal rate of D-3 made from polyglutamic acid is greater than that of D-4 made from glutamic acid, and the COD removal rate is 65.26%. This is because polyglutamic acid has a larger molecular weight and will adsorb more pollutants during the adsorption and sedimentation process. The COD removal rate of this product is not much different from that of the commonly used inorganic flocculant D-2, indicating that this product has a very ideal treatment effect on semi-coke wastewater.

[0058] .

[0059] The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation wastewater of the present invention uses glutamic acid, polyglutamic acid and metal salts in the fermentation wastewater produced by glutamic acid production to prepare a coal chemical wastewater flocculant under room temperature solid phase conditions. The chelates of polyglutamic acid and glutamic acid both carry positive charges and also have important chemical groups such as carboxyl and amino groups. These characteristics give them good adsorption performance and excellent flocculation performance. In practical applications, the coal chemical wastewater flocculant exhibits strong adsorption and coagulation capabilities for pollutants in coal chemical wastewater, and can effectively separate pollutants from wastewater. In addition, the coal chemical wastewater flocculant is insoluble in organic solvents, and this characteristic makes it more stable during storage and transportation, and is not easily affected by the external environment; at the same time, the coal chemical wastewater flocculant has good water solubility, and because the generated chelate bond is a covalent bond, this stable chemical bond structure makes the flocculant have only very few free metal free substances after being dissolved in water. This feature greatly reduces the potential harm to the environment and also reduces the adverse effects on treatment equipment.

[0060] The present invention utilizes glutamic acid fermentation waste liquid to synthesize the coal chemical wastewater flocculant, which has significant advantages over traditional metal salt flocculants and organic macromolecular flocculants. After treating the coal chemical wastewater, there is almost no metal salt residue, thereby avoiding the pipeline corrosion problem caused by the metal salt residue. At the same time, the flocculant is non-toxic and harmless, and has no pollution to the environment at all, and is a truly green and environmentally friendly product. Moreover, the pollutants obtained by flocculation of the flocculant are easy to collect and treat, which greatly improves the efficiency and convenience of wastewater treatment. Compared with the existing secondary utilization of glutamic acid fermentation waste liquid, the present method does not produce polluting products, the raw materials are easy to obtain, the cost is low, the steps are simple, and the yield is high. And compared with the vast majority of research biological flocculants, the present invention is even more unique. The present invention uses glutamic acid fermentation waste liquid as the main raw material, and does not need to use other flocculant aids for compounding, which greatly reduces the production cost and process complexity. Moreover, the flocculant can be directly applied to coal chemical wastewater, and can achieve good treatment effects. During the treatment process, it is environmentally friendly and can effectively reduce metal residues and soluble organic residues, providing a new and efficient solution for the treatment of coal chemical wastewater. The invention has important driving significance for the secondary utilization of glutamic acid fermentation broth and the development of coal wastewater treatment agents, and has opened up a new path for technological progress and sustainable development in this field.

[0061] In summary, the present invention utilizes glutamate fermentation waste liquid to prepare a flocculant for coal chemical wastewater treatment, which has excellent flocculation and demulsification as well as excellent phenol and COD removal effects, and has the characteristics of biodegradability, non-toxicity, and pollution-free. It not only performs secondary utilization of glutamate fermentation waste liquid, but also achieves excellent treatment effect on coal chemical wastewater, realizing the effect of turning waste into treasure and achieving twice the result with half the effort.

[0062] The above technical features respectively constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation wastewater, characterized in that The following steps are involved: Extracting and purifying glutamic acid fermentation waste liquid to obtain a fermentation waste liquid extract; Adding required amounts of metal salt and sodium hydroxide to the fermentation waste liquid extract to obtain a reaction mixture, grinding the reaction, and removing impurities from the reaction product to obtain a coal chemical wastewater flocculant; wherein the metal salt includes magnesium salt, calcium salt, copper salt and trivalent iron salt.

2. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to claim 1, characterized in that The steps of extracting and purifying the glutamic acid fermentation waste liquid include: After solid-liquid separation of glutamic acid fermentation waste liquid, the bacterial cells are removed to obtain a clear liquid; An equal volume of ethanol is added to the clear solution 1, and the clear solution 2 is obtained after refrigeration and separation; The second clear liquid is dialyzed, and the dialyzed solution is concentrated and dried to obtain a fermentation waste liquid extract.

3. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to claim 2, characterized in that The dialysis is performed 2 to 4 times using a semipermeable membrane with a specification of 7000Da to 10000Da.

4. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 3, characterized in that The metal salt is a halide or a nitrate.

5. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 4, characterized in that The mass ratio of the fermentation waste liquid extract to the metal salt is 1:1 to 1:

3.

6. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 5, characterized in that In the reaction mixture, the amount of sodium hydroxide used is 3% to 20% of the total weight of the fermentation waste liquid extract and the metal salt.

7. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 6, characterized in that The grinding reaction time is 20 min to 30 min, and the reaction temperature is 15° C. to 35° C.; or / and, the grinding reaction is carried out by using a ball mill for solid phase reaction at room temperature, and the rotation speed is 150 r / min to 200 r / min.

8. The method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 7, characterized in that The step of removing impurities from the reaction product comprises: washing the reaction product after the grinding reaction with anhydrous ethanol.

9. A coal chemical wastewater flocculant prepared by the method for preparing a coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 8.

10. An application of the coal chemical wastewater flocculant according to claim 9 in the treatment of coal chemical wastewater, characterized in that The usage of coal chemical wastewater flocculant in each liter of coal chemical wastewater is 0.3g to 3g.