Method for preparing coal chemical wastewater flocculant by using glutamic acid fermentation waste liquid, coal chemical wastewater flocculant and application thereof

Abstract

The present application relates to the technical field of fermentation wastewater in biological fermentation industry, and is a method for preparing coal chemical wastewater flocculant by using glutamic acid fermentation wastewater, which comprises the following steps: extracting and purifying the glutamic acid fermentation wastewater to obtain fermentation wastewater extract; adding a required amount of metal salt and sodium hydroxide into the fermentation wastewater extract to obtain a reaction mixture, grinding the reaction, and removing impurities from the reaction product to obtain the coal chemical wastewater flocculant, wherein the metal salt comprises magnesium salt, calcium salt, copper salt and trivalent iron salt. The present application realizes secondary utilization of the glutamic acid fermentation wastewater, fully utilizes the effective substances in the glutamic acid fermentation wastewater, and achieves excellent treatment effect of the prepared coal chemical wastewater flocculant on coal chemical wastewater. The preparation and treatment processes are both non-toxic, harmless, green and pollution-free, and the effect of turning waste into treasure and achieving more with less is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fermentation wastewater in biological fermentation industry, and is a method for preparing a coal chemical wastewater flocculant from glutamic acid fermentation wastewater, and a coal chemical wastewater flocculant and application thereof. BACKGROUND

[0002] The glutamic acid fermentation wastewater contains a large amount of glutamic acid, polyglutamic acid, reducing sugar, SS and ammonia nitrogen, and any discharge of the glutamic acid fermentation wastewater wastes valuable resources. According to the characteristics of the fermentation wastewater, comprehensive utilization of the fermentation wastewater can not only save resources, but also greatly reduce COD and NH 4+ -N in the wastewater, reduce the pollution of the wastewater to the environment, and bring high economic and social benefits.

[0003] Generally, the main components of the glutamic acid fermentation wastewater include protein, glutamic acid, polyglutamic acid, reducing sugar, free fat and amino nitrogen. At present, the glutamic acid fermentation wastewater is mostly reused by extracting useful components, such as extracting bacterial protein from the glutamic acid fermentation wastewater, making animal feed, and producing organic-inorganic compound fertilizer. For example, Mao Zhonggui et al. (Jiangnan University) disclosed a method for producing compound fertilizer from fermentation glutamic acid extraction wastewater in Chinese patent document CN101993280A. The reuse method is relatively simple, and specifically, the fermentation wastewater is concentrated and cooled to be granulated and solidified. However, since high-temperature flue gas is used for sintering granulation treatment in the granulation process, a large amount of tail gas is generated, and the high-temperature process causes loss of fertilizer nutrients, and the fertilizer cannot be melted in the field for several years, so there are problems of poor environmental protection and low recycling rate.

[0004] Chinese patent document CN106819398A discloses an animal feed prepared from glutamic acid fermentation waste. The animal feed is produced by mixing the glutamic acid fermentation wastewater as raw material with various nutrients. The feed is composed of the following raw materials: glutamic acid fermentation liquid, Chinese herbal medicine compound, compound vitamin, sorghum, soybean meal, rice bran and sorghum straw. The feed is prepared according to the following steps: step 1) filtration of the fermentation liquid, step 2) decolorization, concentration and crystallization, step 3) hydrolysis, step 4) preparation of compound medicine powder, step 5) preparation of main material, and step 6) preparation of feed. This method has complex steps, and the cost is relatively high compared with other feeds on the market.

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

[0006] Polyglutamic acid, as a typical green flocculant, has attracted great interest in the past few decades. However, the carboxyl group itself limits the potential application of γ-PGA due to its poor flocculation performance (Ravishankar S.A, Praip, Khosla N.K., 1995. Selective flocculation of iron oxide from its synthetic mixtures with clays: a comparison of polyacrylic avid and starch polymers. International Journal of Mineral Pprocessing

[0007] 43, 235-247.). Chen et al. (Chen, Jianxin, et al. Synthesis of Cationic Modified Poly (γ-Glutamic Acid) and Evaluation of its Flocculation Performance in Seawater. Chemical Engineering Transactions 61 (2017): 1765-1770.) prepared a flocculant by chemical reaction with γ-PGA and 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (CHPTMA) as raw materials. The results showed that the turbidity of seawater decreased from 95 NTU to 10 NTU after adding 2 mg / L of modified γ-PGA.

[0008] Coal chemical industry wastewater has the characteristics of multiple pollutants, high concentration, complex composition, containing a large amount of organic pollutants such as phenols, esters, high total phenol content, high COD content, high turbidity and inorganic salts, and strong toxicity of phenols. The wastewater production is large, the treatment difficulty is high, the existing coal chemical industry wastewater treatment technology is difficult to achieve good treatment effect, the enterprises are faced with technical bottleneck and high cost pressure, and the wastewater discharge continues to increase, the environmental protection regulations are strict, and the treatment pressure is large. Most of the current research uses coagulant to compound and is aimed at single simulated wastewater, and the practicality and universality are insufficient, so it is important to prepare a coagulant for actual coal chemical industry wastewater without compounding, high efficiency flocculation and low dosage. SUMMARY

[0009] The present application provides a method for preparing a coal chemical industry wastewater flocculant from glutamic acid fermentation wastewater, which overcomes the shortcomings of the prior art and effectively solves the problems of complex treatment process and poor utilization effect of glutamic acid fermentation wastewater.

[0010] One of the technical solutions of the present application is achieved by the following measures: a method for preparing a coal chemical industry wastewater flocculant from glutamic acid fermentation wastewater, comprising the following steps:

[0011] Extracting and purifying the glutamic acid fermentation wastewater to obtain a fermentation wastewater extract;

[0012] Adding a required amount of metal salt and sodium hydroxide to the fermentation wastewater extract to obtain a reaction mixture, grinding the reaction, and removing impurities from the reaction product to obtain a coal chemical industry wastewater flocculant; wherein the metal salt includes magnesium salt, calcium salt, copper salt and trivalent iron salt.

[0013] The following is a further optimization or / and improvement of the above-mentioned technical solutions of the invention:

[0014] The above-mentioned step of extracting and purifying the glutamic acid fermentation wastewater comprises:

[0015] After solid-liquid separation of the glutamic acid fermentation wastewater, the bacterial bodies are removed to obtain a clear liquid one;

[0016] An equal volume of ethanol is added to the clear liquid one, and after refrigeration and separation, a clear liquid two is obtained;

[0017] The clear liquid two is subjected to dialysis treatment, and after concentration and drying of the dialyzed solution, a fermentation wastewater extract is obtained.

[0018] The above-mentioned dialysis is performed 2 to 4 times using a semi-permeable membrane with a specification of 7000 Da to 10000 Da.

[0019] The above-mentioned metal salt is a halide salt or a nitrate salt.

[0020] The mass ratio of the above-mentioned fermentation wastewater extract and metal salt is 1:1 to 1:3.

[0021] The grinding reaction time is 20-30 minutes, and the reaction temperature is 15-35 DEG C.

[0022] The amount of sodium hydroxide in the reaction mixture is 3-20% of the total mass of the fermentation waste liquid extract and the metal salt.

[0023] The step of removing impurities from the reaction product after the grinding reaction includes washing the reaction product after the grinding reaction with anhydrous ethanol.

[0024] The grinding reaction is a solid phase reaction carried out at room temperature using a ball mill at a rotation speed of 150-200 r / min.

[0025] The second technical solution of the present application is a coal chemical wastewater flocculant prepared by the method of preparing a coal chemical wastewater flocculant from glutamic acid fermentation waste liquid.

[0026] The third technical solution of the present application is the application of the coal chemical wastewater flocculant according to the second technical solution in coal chemical wastewater treatment, wherein the amount of the coal chemical wastewater flocculant used in each liter of coal chemical wastewater is 0.3-3 g.

[0027] The present application provides a method of preparing a coal chemical wastewater flocculant from glutamic acid fermentation waste liquid, which realizes the secondary use of glutamic acid fermentation waste liquid, fully utilizes the effective substances in the glutamic acid fermentation waste liquid, and prepares a coal chemical wastewater flocculant that has excellent treatment effect on coal chemical wastewater, and is non-toxic, harmless, green, and pollution-free in preparation and treatment processes, thereby achieving the effect of turning waste into treasure and achieving more with less. DETAILED DESCRIPTION

[0028] The present application is not limited by the following examples, and the specific implementation can be determined according to the technical solutions of the present application and the actual situation. The various chemical reagents and chemical supplies mentioned in the present application are well-known and commonly-used chemical reagents and chemical supplies in the prior art unless otherwise specified; the percentages in the present application are mass percentages unless otherwise specified; the solutions in the present application are aqueous solutions with water as the solvent unless otherwise specified, for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution; the normal temperature and room temperature in the present application generally refer to a temperature of 15-25 DEG C, and is generally defined as 25 DEG C.

[0029] The present application will be further described below in conjunction with examples:

[0030] Example 1: The method of preparing a coal chemical wastewater flocculant from glutamic acid fermentation waste liquid includes the following steps:

[0031] The glutamic acid fermentation waste liquid is extracted and purified to obtain a fermentation waste liquid extract.

[0032] The coal chemical wastewater flocculant is obtained by adding a required amount of metal salt and sodium hydroxide into the fermentation waste liquid extract, grinding the reaction, and removing impurities from the reaction product.

[0033] The glutamic acid fermentation waste liquid is a fermentation waste liquid generated in the production of glutamic acid liquid fertilizer.

[0034] In the embodiment, the steps of extracting and purifying the glutamic acid fermentation waste liquid include:

[0035] After the solid-liquid separation of the glutamic acid fermentation waste liquid, the bacteria are removed to obtain a clear liquid I.

[0036] An equal volume of ethanol is added to the clear liquid I, and the clear liquid II is obtained after cold storage and separation.

[0037] The clear liquid II is subjected to dialysis treatment, and the fermentation waste liquid extract is obtained after the concentration and drying of the dialyzed solution.

[0038] In the embodiment, the dialysis is performed 2 to 4 times using a semi-permeable membrane with a specification of 7000 Da to 10000 Da.

[0039] In the embodiment, the metal salt is a halide salt or a nitrate salt.

[0040] In the embodiment, the mass ratio of the fermentation waste liquid extract to the metal salt is 1:1 to 1:3.

[0041] In the embodiment, the grinding reaction time is 20 min to 30 min, and the reaction temperature is 15℃ to 35℃.

[0042] In the embodiment, the amount of sodium hydroxide in the reaction mixture is 3% to 20% of the total mass of the fermentation waste liquid extract and the metal salt.

[0043] In the 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.

[0044] In the embodiment, the grinding reaction is a solid-phase reaction performed by a ball mill at room temperature, and the rotation speed is 150 r / min to 200 r / min.

[0045] The present application obtains fermentation waste liquid extract by removing impurities and concentrating glutamic acid fermentation waste liquid, and prepares coal chemical industry wastewater flocculant by solid phase chemical reaction of the fermentation waste liquid extract and metal salt. During grinding reaction, the content of water in the reaction mixture is kept at 5% to 20% of the total mass of the reaction mixture, so that the reaction mixture keeps viscous state during grinding.

[0046] Example 10: The application of the coal chemical industry wastewater flocculant in coal chemical industry wastewater treatment, including the use amount of the coal chemical industry wastewater flocculant in each liter of coal chemical industry wastewater is 0.3g to 3g.

[0047] Example 11: The method for preparing coal chemical industry wastewater flocculant by using glutamic acid fermentation waste liquid, which is carried out according to the following steps:

[0048] In the first step, 10L of glutamic acid fermentation waste liquid is centrifuged to remove bacteria in the fermentation waste liquid, and the supernatant is collected. Ethanol with the same volume as the supernatant is added, and the mixture is refrigerated at 4℃ for 3h.

[0049] In the second step, the turbid liquid after refrigeration and standing in the first step is centrifuged to obtain the supernatant. The supernatant is dialyzed repeatedly three times through a 10000Da semi-permeable membrane. After concentration and drying of the dialyzed solution, fermentation waste liquid extract is obtained.

[0050] In the third step, 14.72g of fermentation waste liquid extract and 16.22g of ferric chloride are mixed, and 2g of sodium hydroxide and 2g of water are added. After mixing and grinding for 30min, the unchelated amino acids and metal salts are removed by washing with anhydrous ethanol. The mixture is dried in an oven to obtain dry product, i.e. coal chemical industry wastewater flocculant, which is recorded as AH-1.

[0051] In this example, the main components of glutamic acid fermentation waste liquid are: protein 2.4g / L, glutamic acid 2.6g / L, polyglutamic acid 12.4g / L, reducing sugar 0.213g / L, free fat 2.3g / L, and amino nitrogen 6.9g / L.

[0052] Example 12: The method for preparing coal chemical industry wastewater flocculant by using glutamic acid fermentation waste liquid, which is carried out according to the following steps:

[0053] In the first step, 10L of glutamic acid fermentation waste liquid is centrifuged to remove bacteria in the fermentation waste liquid, and the supernatant is collected. Ethanol with the same volume as the supernatant is added, and the mixture is refrigerated at 4℃ for 3h.

[0054] In the second step, the turbid liquid after refrigeration and standing in the first step is centrifuged to obtain the supernatant. The supernatant is dialyzed repeatedly three times through a 10000Da semi-permeable membrane. After concentration and drying of the dialyzed solution, fermentation waste liquid extract is obtained.

[0055] Third step, 14.72 g of fermentation broth extract and 18.76 g of copper nitrate were mixed and 2 g of sodium hydroxide and 2 g of water were added, and after grinding for 30 min, the unchelated amino acids and metal salts were removed by washing with anhydrous ethanol, and the dried product was obtained by drying in an oven, which was recorded as AH-2.

[0056] The glutamic acid fermentation broth in this example is the same as that in Example 11.

[0057] Example 13: The method for preparing coal chemical wastewater flocculants using glutamic acid fermentation broth was carried out according to the following steps:

[0058] First step, 10 L of glutamic acid fermentation broth was centrifuged to remove the bacteria in the fermentation broth, and the supernatant was collected, and the same volume of ethanol as the supernatant was added, and refrigerated at 4°C for 3 h;

[0059] Second step, the turbid liquid after refrigeration and standing in the first step was centrifuged to obtain the supernatant, and the supernatant was repeatedly dialyzed multiple times through a 10000 Da semi-permeable membrane, and the dialyzed solution was concentrated and dried to obtain the fermentation broth extract.

[0060] Third step, 14.72 g of fermentation broth extract and 11.1 g of calcium chloride were mixed and 2 g of sodium hydroxide and 2 g of water were added, and after grinding for 30 min, the unchelated amino acids and metal salts were removed by washing with anhydrous ethanol, and the dried product was obtained by drying in an oven. Record as AH-3.

[0061] The glutamic acid fermentation broth in this example is the same as that in Example 11.

[0062] Example 14: The method for preparing coal chemical wastewater flocculants using glutamic acid fermentation broth was carried out according to the following steps:

[0063] First step, 10 L of glutamic acid fermentation broth was centrifuged to remove the bacteria in the fermentation broth, and the supernatant was collected, and the same volume of ethanol as the supernatant was added, and refrigerated at 4°C for 3 h;

[0064] Second step, the turbid liquid after refrigeration and standing in the first step was centrifuged to obtain the supernatant, and the supernatant was repeatedly dialyzed multiple times through a 10000 Da semi-permeable membrane, and the dialyzed solution was concentrated and dried to obtain the fermentation broth extract.

[0065] Third step, 14.72 g of fermentation broth extract and 9.531 g of magnesium chloride were mixed and 2 g of sodium hydroxide and 2 g of water were added, and after grinding for 30 min, the unchelated amino acids and metal salts were removed by washing with anhydrous ethanol, and the dried product was obtained by drying in an oven. Record as AH-4.

[0066] The glutamic acid fermentation broth in this example is the same as that in Example 11.

[0067] Comparative Example 1: Organic macromolecular flocculant polyacrylamide, denoted as D-1.

[0068] Comparative Example 2: Inorganic flocculant ferric chloride, denoted as D-2.

[0069] Comparative Example 3: The flocculant of the present comparative example is obtained by reacting pure γ-polyglutamic acid with ferric chloride, and the specific steps are as follows:

[0070] Take 2.20 g of pure γ-polyglutamic acid and 1.35 g of ferric chloride, mix and 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, and put into an oven to dry to obtain a dry product, denoted as D-3.

[0071] Comparative Example 4: The flocculant of the present comparative example is obtained by reacting pure glutamic acid with ferric chloride, and the specific steps are as follows:

[0072] Take 2.21 g of pure glutamic acid and 1.35 g of ferric chloride, mix and 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, and put into an oven to dry to obtain a dry product, denoted as D-4.

[0073] Experimental Example:

[0074] The coal chemical industry wastewater flocculants of Examples 11 to 14 and the products of Comparative Examples 1 to 4 are used to treat coal chemical industry wastewater, and the COD removal performance, turbidity removal performance, volatile phenol removal rate, and settling rate of the flocculants on the coal chemical industry wastewater are tested. The coal chemical industry 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 369.42 mg·L -1 , turbidity 1806.41 NTU, and color 19.79 PCU.

[0075] Test one: 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, 3.0 g of AH-1 was added into 1 L of Lan carbon wastewater respectively, after standing for 3 h, each group of samples was taken to remove flocculation impurities through 0.2 nm membrane, referring to national environmental protection standard HJ828-2017, the COD removal rate, turbidity removal rate and volatile phenol removal rate were tested, and the determination results are shown in Table 1. As shown in Table 1, when the addition amount of AH-1 is 3.0 g / L, the COD removal rate can reach the maximum value of 88.86%, and when it is 1.5 g / L, it can reach 84.62%, and when it is 1.8 g / L, it can also reach more than 80% although it decreases slightly. In addition, the turbidity removal effect of AH-1 is very excellent, and the turbidity removal rate can reach 99.99% when only 0.3 g / L is added, which is almost completely removed. As shown in Table 1, the volatile phenol removal rate gradually increases with the increase of the addition amount of the flocculant, and when the addition amount is greater than 1.2 g / L, the removal rate can be greater than 90%, and when the addition amount is 3.0 g / L, the volatile phenol removal rate can reach 95.07%.

[0076] .

[0077] Test two: 1.5 g of AH-1 was used to treat 1 L of Lan carbon wastewater, and the supernatant was taken at 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 45 min, 60 min, 120 min and 3 h and passed through 0.2 nm membrane, and the COD removal rate and turbidity removal rate were tested, and the determination results are shown in Table 2. As shown in Table 2, when AH-1 is added for 30 min, the COD removal rate can reach 61.54%; AH-1 can have a relatively obvious turbidity removal effect on wastewater within 15 min, and the turbidity removal rate can reach 51.06% at 15 min and 74.24% at 30 min, which shows that the coal chemical wastewater flocculant of the present application has excellent treatment effect. After AH-1 treats the wastewater for 120 min, the COD value and turbidity tend to be stable, and when the coal chemical wastewater flocculant of the present application is used to treat coal chemical wastewater, the treatment time can be 2 h to 3 h, which has a high treatment efficiency.

[0078] .

[0079] Test three: the sample AH-1 in the above embodiment 11 was prepared into a 3 g / L solution, and the height of the clarified layer was determined according to national standard GBT13200-1991 at 5, 10, 15, 20, 25, 30 min, and the settling rate was calculated, and the results are shown in Table 3. As shown in Table 3, the settling speed of AH-1 is fast, and it shows obvious layering within 10 min.

[0080] .

[0081] Test four: 1.5g of AH-1, AH-2, AH-3, AH-4, D-1, D-2, D-3 and D-4 were added into 1L of Lan carbon wastewater respectively, and after standing for 3h, each group of samples was taken through 0.2nm membrane to remove flocculation impurities, the COD content was determined according to the national environmental protection standard HJ828-2017, and the COD removal rate was calculated, and the results are shown in Table 4. In Table 4, after adding D-1 organic macromolecular flocculant polyacrylamide into the Lan carbon wastewater, the waste liquid is not settled and not layered, and the waste liquid forms a stable colloidal substance, therefore, the COD removal rate cannot be tested. As can be seen from Table 4, the flocculants (D-3 and D-4) prepared from pure polyglutamic acid and glutamic acid chelate both have a certain COD removal capacity, among which the COD removal rate of D-3 prepared from polyglutamic acid is greater than that of D-4 prepared from glutamic acid, and the COD removal rate is 65.26%, because polyglutamic acid has a larger molecular weight, more pollutants can be adsorbed in the adsorption and settlement process. The COD removal rate of the product is not much different from that of the commonly used inorganic flocculant D-2, which shows that the treatment effect of the product on Lan carbon wastewater is very ideal.

[0082] .

[0083] The method for preparing the coal chemical industry wastewater flocculant from glutamic acid fermentation wastewater of the application utilizes glutamic acid and polyglutamic acid and metal salt in the fermentation wastewater generated in glutamic acid production to prepare the coal chemical industry wastewater flocculant under room temperature solid phase conditions. The chelate of polyglutamic acid and glutamic acid both have positive charges, and also have important chemical groups such as carboxyl and amino groups. These characteristics endow them with good adsorption performance and excellent flocculation performance. In actual application, the coal chemical industry wastewater flocculant shows strong adsorption and coagulation capacity for pollutants in coal chemical industry wastewater, and can effectively separate the pollutants from the wastewater. In addition, the coal chemical industry wastewater flocculant is insoluble in organic solvents, and this characteristic makes it more stable in storage and transportation, and not easy to be affected by the external environment; at the same time, the coal chemical industry wastewater flocculant has good water solubility, and since the generated chelate bond is a covalent bond, this stable chemical bond structure makes the flocculant have only a small amount of free metal ions after being dissolved in water. This feature greatly reduces the potential harm to the environment, and also reduces the adverse effects on the treatment equipment.

[0084] The coal chemical wastewater flocculant synthesized by the glutamic acid fermentation waste liquid has obvious advantages compared with traditional metal salt flocculants and organic macromolecular flocculants. After treating the coal chemical wastewater, there is almost no residual metal salt, thereby avoiding the problem of pipeline corrosion caused by residual metal salt. At the same time, the flocculant is non-toxic and harmless, and has no pollution to the environment, and is a truly green and environmentally friendly product. Moreover, the pollutants flocculated by the flocculant are easy to collect and treat, greatly improving the efficiency and convenience of wastewater treatment. Compared with the existing secondary utilization of glutamic acid fermentation waste liquid, the method does not produce contaminated products, the raw materials are easy to obtain, the cost is low, the steps are simple, and the yield is high. And compared with most of the research on biological flocculants, the present application is more unique. The present application uses glutamic acid fermentation waste liquid as the main raw material, without the need for compounding with other flocculation aids, greatly reducing the production cost and process complexity. Moreover, this flocculant can be directly applied to coal chemical wastewater and can achieve good treatment effect. In the treatment process, it is environmentally friendly and can effectively reduce metal residues and soluble organic matter residues, providing a new and efficient solution for coal chemical wastewater treatment. For the secondary utilization of glutamic acid fermentation liquid and the development of coal wastewater treatment agent, the present application has important promoting significance, and opens up a new road for the technical progress and sustainable development of the field.

[0085] In summary, the present application uses glutamic acid fermentation waste liquid to prepare a flocculant for coal chemical wastewater treatment, which has excellent flocculation and demulsification, and excellent phenolic and COD removal effect, and has biodegradability, non-toxicity, non-pollution and other characteristics. Not only is the glutamic acid fermentation waste liquid utilized twice, but also the coal chemical wastewater is treated with excellent effect, achieving the effect of turning waste into treasure and achieving more with less.

[0086] The above technical features respectively constitute embodiments of the present application, which have strong adaptability and implementation effect, and unnecessary technical features can be added or reduced according to actual needs to meet the needs of different situations.

Claims

1. A method for preparing flocculant for coal chemical wastewater using glutamic acid fermentation waste liquid, characterized in that... Includes the following steps: The fermentation waste liquid of glutamic acid was extracted and purified to obtain the fermentation waste liquid extract; The required amount of metal salt and sodium hydroxide are added to the fermentation waste liquid extract to obtain a reaction mixture. The mixture is then ground and the reaction product is purified to obtain a flocculant for coal chemical wastewater. The mass ratio of the fermentation waste liquid extract to the metal salt is 1:1 to 1:

3. The metal salt includes magnesium salt, calcium salt, copper salt and ferric salt. The steps for extracting and purifying the glutamic acid fermentation waste liquid include: After solid-liquid separation of the glutamic acid fermentation waste liquid, the bacterial cells were removed to obtain clear liquid 1; An equal volume of ethanol was added to the first clear liquid, and after refrigeration and separation, the second clear liquid was obtained. The second clear liquid was dialyzed, and the dialyzed solution was concentrated and dried to obtain the fermentation waste liquid extract.

2. The method for preparing coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to claim 1, characterized in that... Dialysis is performed 2 to 4 times using a semipermeable membrane with a specification of 7000 Da to 10000 Da.

3. The method for preparing coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to claim 1 or 2, characterized in that... Metal salts are either halides or nitrates.

4. The method for preparing coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to claim 1, characterized in that... In the reaction mixture, the amount of sodium hydroxide is 3% to 20% of the total mass of the fermentation waste extract and the metal salt.

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

6. The method for preparing coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to claim 1 or 4, characterized in that... The steps for removing impurities from the reaction product include washing the reaction product after grinding with anhydrous ethanol.

7. A coal chemical wastewater flocculant prepared by the method for preparing coal chemical wastewater flocculant using glutamic acid fermentation waste liquid according to any one of claims 1 to 6.

8. The application of the coal chemical wastewater flocculant according to claim 7 in the treatment of coal chemical wastewater, characterized in that... The usage of flocculant in coal chemical wastewater is 0.3g to 3g per liter.