CN115385456A

CN115385456A - Efficient denitrification sewage treatment agent and preparation method thereof

Info

Publication number: CN115385456A
Application number: CN202210964578.3A
Authority: CN
Inventors: 王丽华; 李晓伟; 卢玉强
Original assignee: Jiangsu Sigai Environmental Protection Technology Co ltd
Current assignee: Jiangsu Sigai Environmental Protection Technology Co ltd
Priority date: 2022-08-12
Filing date: 2022-08-12
Publication date: 2022-11-25
Anticipated expiration: 2042-08-12
Also published as: CN115385456B

Abstract

The invention discloses a sewage treatment agent for high-efficiency denitrification and a preparation method thereof, wherein the scheme is characterized in that waste citrus reticulata or orange peel pulp and waste fruits without edible conditions in life are squeezed and fermented, then fermentation liquor is extracted and screened, and the fermentation liquor is measured, so that the extraction solution is rich in monosaccharide, disaccharide, oligosaccharide and other water-soluble saccharides, cellulose, hemicellulose, starch, water-soluble pectin and other polysaccharide carbon source substances beneficial to microorganism propagation, and the extraction solution is rich in various dietary fibers, organic acids, proteins, vitamins, mineral substances and other nutrients beneficial to good microorganism propagation, can promote enzymatic reactions of various microorganism bacteria, and can be matched with a compound microbial agent to improve the sewage treatment efficiency during sewage treatment. Meanwhile, under the action of microorganisms, a carbon source can be efficiently utilized, the sludge production can be effectively reduced under the same dosage, and a sludge reduction effect is achieved by compounding a sludge reduction microbial inoculum.

Description

Efficient denitrification sewage treatment agent and preparation method thereof

Technical Field

The invention relates to the technical field of sewage treatment agents, in particular to a sewage treatment agent for high-efficiency denitrification and a preparation method thereof.

Background

If sewage containing nitrogen and phosphorus with higher concentration is discharged into a natural water body, the content of nitrogen and phosphorus is increased rapidly, blue algae and green algae in the water body are propagated in large quantity, the water body is anoxic and generates toxin, the water quality is deteriorated, and great harm is generated to aquatic organisms and human health. In order to effectively remove nitrogen and phosphorus in sewage, common methods for removing nitrogen mainly include physical and chemical methods such as ammonia stripping and ion exchange methods, and biological methods using microorganisms involved in denitrification. At present, the technology of biological denitrification by adopting an economic activated sludge method is generally adopted after sewage is collected and is conveyed to a sewage treatment plant (station) through a pipeline, and the technology which takes biological denitrification as a core is basically adopted in China, such as: A/O, A2/O, SBR, CASS and the like. The basic principle of biological nitrogen removal of sewage is that on the basis of converting organic nitrogen into ammonia nitrogen, firstly, an aerobic section is utilized to convert the ammonia nitrogen into nitrite nitrogen and nitrate nitrogen through nitrification under the synergistic action of nitrifying bacteria and nitrite bacteria, the nitrate nitrogen is converted into nitrogen through denitrification under the anoxic condition, and the overflowed water surface is released into the atmosphere to participate in the circulation of natural nitrogen. The nitrogen-containing substances in the water are greatly reduced, the potential danger of the effluent is reduced, and the aim of removing nitrogen from the wastewater is fulfilled.

In the biological denitrification process, glucose, starch, sodium acetate, methanol and other compound carbon sources are generally used for a supplementary organic carbon source in the denitrification reaction process. However, the above conventional carbon sources have different disadvantages. Wherein: methanol, acetic acid and ethanol are all easily degradable substances, do not contain nutrient substances (such as nitrogen and phosphorus), do not leave any intermediate products which are difficult to degrade after decomposition, but are flammable and explosive in practical application and are not widely popularized. Starch is a high-molecular saccharide substance, and is hydrolyzed and converted into the most easily degradable organic substances such as low-molecular organic acids including acetic acid, formic acid, propionic acid, etc., and thus the starch is not easily dissolved in water, and the amount of sludge generated is increased. The glucose consumption is large, the denitrification rate is greatly influenced by water quality, the accumulation of nitrite is easy to occur, and the sludge production is large. When the sodium acetate is used as a carbon source, the sodium acetate is a low-molecular organic acid salt, has stable properties and is easily utilized by microorganisms. But the cost of management and adding is higher due to higher price, lower liquid content, low solubility, easy blockage of an adding pipeline and the like in actual use.

Meanwhile, the existing sewage treatment agent has poor effect of removing heavy metal ions, high difficulty in subsequent separation and inconvenience in use, so based on the situation, the sewage treatment agent for efficient denitrification and the preparation method thereof are disclosed to solve the technical problem.

Disclosure of Invention

The invention aims to provide a sewage treatment agent for high-efficiency denitrification and a preparation method thereof, and aims to solve the problems in the background art.

In order to solve the technical problems, the invention provides the following technical scheme:

the sewage treatment agent comprises a nutrient solution, a compound microbial agent and an external carbon source, and comprises the following components in percentage by weight: by volume ratio, 3-5% of nutrient solution, 10-30% of compound microbial agent and the balance of external carbon source.

According to the existing research, the denitrification process is essentially the metabolic process of the microorganism, the selection of the external carbon source can influence the denitrification speed of the microorganism naturally, but the good growth of the microorganism is ensured, and the research of the control scheme is the focus of attention.

According to the scheme, the citrus reticulata blanco pulp discarded in life and fruits without edible conditions are squeezed and fermented, fermentation liquor is extracted and screened to obtain nutrient solution, and the nutrient solution is determined to be rich in monosaccharide, disaccharide, oligosaccharide and other water-soluble saccharides, cellulose, hemicellulose, starch, water-soluble pectin and other polysaccharide carbon source substances which are beneficial to microbial propagation, and in addition, the nutrient solution is rich in various dietary fibers, organic acids, proteins, vitamins, mineral substances and other nutrients which are beneficial to good microbial propagation, can promote enzymatic reaction of various types of microbial bacteria, can improve activity of denitrifying bacteria, and viscous substances in a fermented product increase adsorption of bacterial micelles, and the mucus contains antibiotic substances and has bactericidal effect on escherichia coli, other filamentous bacteria, viruses and the like in water. Therefore, the nutrient solution is added in the sewage treatment process, so that the good advantages of the compound microbial agent can be ensured, the denitrification efficiency is ensured, the optimal activity of bacteria can be kept in the whole sewage system, and the treatment effect of the sewage treatment system is improved.

In actual operation, the nutrient solution can be compounded with inorganic salt, and the conventional inorganic salt is a compound prepared from one or more of phosphorus salt, potassium salt, sodium salt and chloride. The main functions of inorganic salts are to participate in the composition of cellular structures, energy transfer, regulation of enzymatic activity and maintenance of cellular osmotic pressure equilibrium.

The optimized scheme is as follows: the contents of all components are as follows: 5 percent of nutrient solution, 30 percent of compound microbial agent and the balance of external carbon source by volume ratio.

The optimized scheme is as follows: the contents of all components are as follows: 5 percent of nutrient solution, 20 percent of compound microbial agent and the balance of external carbon source by volume ratio.

According to an optimized scheme, the compound microbial agent mainly comprises compound microorganisms, molasses and a carrier, wherein the compound microorganisms comprise lactic acid bacteria, saccharomycetes, bacillus and actinomycetes, and the content of each strain is as follows: 12-15% of yeast, 3-5% of bacillus, 2-5% of actinomycetes and the balance of lactic acid bacteria in percentage by mass.

In a more optimized scheme, the carrier is porous zeolite or magnetic graphene oxide.

According to an optimized scheme, the nutrient solution is mainly obtained by squeezing and fermenting waste fruits and then extracting.

According to an optimized scheme, the preparation method of the efficient denitrification sewage treatment agent comprises the following steps:

s1: uniformly mixing the compound microorganism and deionized water, adding molasses and carrier, stirring and mixing for 20-30min, and culturing at 35-40 deg.C under oxygen supply of 1L/min for 3-4 days to obtain compound microorganism bacterial agent;

s2: crushing waste fruits and vegetables to obtain fruit and vegetable pulp, placing the fruit and vegetable pulp in a water bath environment at 49-51 ℃, adding pectinase for enzymolysis for 110-120min, pasteurizing, adding activated saccharomycetes, and standing for fermentation to obtain a nutrient solution; the dosage of the pectinase is 1.6-1.8mL/kg. The usage amount of the yeast is 1-3wt% of the total mass of the system.

S3: and mixing and compounding the compound microbial agent, an external carbon source and a nutrient solution to obtain the sewage treatment agent.

In an optimized scheme, the using amount of the compound microorganism is 10-12wt% of deionized water; the using amount of the molasses is 10-12wt% of the deionized water; the dosage of the carrier is 0.1-0.2wt% of the ionized water.

According to an optimized scheme, the carrier is porous zeolite or magnetic graphene oxide, wherein the preparation method of the magnetic graphene oxide comprises the following steps:

(1) Taking ferroferric oxide particles and toluene, carrying out ultrasonic dispersion, adding mercaptopropyltrimethoxysilane, stirring for 20-30min at 25-30 ℃, reacting for 10-12 h at 90-95 ℃, collecting products after reaction, washing and drying to obtain sulfhydrylation magnetic particles;

(2) Mixing an amination reagent and methanol, stirring for 10-15 min in a nitrogen environment, adding a mixed solution of methyl acrylate and methanol, stirring and reacting for 4-6 h at 25-30 ℃, adding propinyl acrylate, continuing to react for 3-4 h, evaporating methanol under reduced pressure, reacting for 50-60 min at 60-65 ℃ under a vacuum condition, heating to 100-105 ℃, reacting for 2-3 h at a constant temperature, heating to 130-140 ℃, and continuing to react for 2-3 h to obtain an amino hyperbranched polymer containing alkynyl;

(3) Taking sulfhydrylation graphene and tetrahydrofuran, carrying out ultrasonic dispersion, adding an amino hyperbranched polymer containing alkynyl and a photoinitiator, reacting for 20-30min under ultraviolet light, adding sulfhydrylation magnetic particles, reacting for 1-2 h under ultraviolet light, carrying out magnetic separation on a product, washing and drying to obtain a finished product.

According to a more optimized scheme, in the step (2), the amination reagent is a mixture of diethylenetriamine and triethylene tetramine, and the molar ratio of the diethylenetriamine to the triethylene tetramine is 1:1;

in the step (3), the mass ratio of the thiolated graphene to the amino hyperbranched polymer containing alkynyl to the thiolated magnetic particles is 1:5:3.

in a more optimized scheme, in the step (2), the molar ratio of the methyl acrylate to the propinyl acrylate to the amination reagent is 1:2:1.

according to a more optimized scheme, in the step (2), the amination reagent is a mixture of diethylenetriamine and triethylene tetramine, and the molar ratio of the diethylenetriamine to the triethylene tetramine is 1:1.

according to an optimized scheme, in the step (3), the mass ratio of the thiolated graphene to the amino hyperbranched polymer containing alkynyl to the thiolated magnetic particles is 1:5:3.

according to an optimized scheme, in the step (3), the preparation steps of the sulfhydrylation graphene are as follows: taking graphene oxide and deionized water, performing ultrasonic dispersion for 40-50 min under the power of 200-300W, transferring to a water bath at the temperature of 60-65 ℃, adding concentrated sulfuric acid and thioacetanol, performing heat preservation reaction for 4-5 h, cooling after the reaction is finished, performing suction filtration to collect a product, washing the product to be neutral by using the deionized water, and performing vacuum drying to obtain the thiolated graphene.

According to an optimized scheme, in the step (1), the preparation steps of the ferroferric oxide particles are as follows: mixing ferric trichloride hexahydrate, ferrous sulfate heptahydrate and deionized water, stirring for 20-30min in a nitrogen environment, heating to 75-80 ℃, adding ammonia water, controlling the pH of the system to be 9-10, stirring for reaction for 10-15 min, adding citric acid, continuing to react for 4-5 h, collecting a product after the reaction is finished, washing and drying to obtain the ferroferric oxide particles.

In an optimized scheme, the molar ratio of ferric trichloride hexahydrate to ferrous sulfate heptahydrate is 1.8-2; the dosage of the citric acid is 0.16 to 0.18 percent of the molar weight of ferric chloride hexahydrate.

Compared with the prior art, the invention has the following beneficial effects:

the application discloses a preparation method of a sewage treatment agent for efficient denitrification, the scheme is that a nutrient solution and compound microorganisms are compounded, the nutrient solution can improve the activity of denitrifying bacteria, promote the dominant position of the denitrifying bacteria in a short time, and further serve as an electron donor when denitrification is carried out in a cell body, NOx-N is an electron acceptor, the influence of key enzymes in certain approaches is reduced and avoided, the loss of a carbon source for other metabolic approaches is reduced, the utilization and propagation of the carbon source by other microorganisms are avoided, and the rapid accumulation of sludge concentration is basically avoided while the efficiency is improved.

Meanwhile, DHA-P (dihydroxyacetone phosphate) is formed by compounding microbial floras, is a key material for denitrification, shortens the metabolic time for converting the substances into the DHA-P compared with other carbon sources, indirectly improves the denitrification efficiency of a biochemical system, effectively improves the denitrification capacity in unit time, is more favorable for improving the coping capacity of the system for overload and over-standard sewage, and is favorable for ensuring the water quality safety. The compounded microorganism can remove the odor caused by the anaerobic fermentation product of the organic matters by activating the aerobic microorganism under the aerobic condition operated by a sewage treatment plant.

In the actual research and development process, in order to make this sewage treatment agent of follow-up separation convenient, the application further improves the carrier of compound microbial inoculant, utilize magnetism graphite oxide as microorganism load carrier, use graphite oxide as the base member during the scheme preparation, and the amino hyperbranched polymer that contains the alkynyl grafts on its surface, contain end amino in this hyperbranched polymer, the introduction of hyperbranched end amino structure also can provide a large amount of adsorption sites for sewage treatment agent surface, the introduction of end amino not only can improve the adsorption efficiency of sewage treatment agent to the nitrate in the sewage, thereby effectively supply and solve behind the basic function of denitrification carbon source consumption, further consolidate and improve denitrogenation efficiency, can also effectively adsorb and get rid of the heavy metal ion in the sewage simultaneously.

The invention discloses a sewage treatment agent for efficient denitrification and a preparation method thereof, the process design is reasonable, the component proportion is proper, the prepared sewage treatment agent not only has excellent denitrification effect, but also can effectively adsorb heavy metal ions, and the sewage treatment agent is subsequently separated by magnetism, so that the practicability is higher.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In this embodiment, the graphene oxide is prepared by a Hummers method, which includes the specific steps of: the graphite powder and the potassium permanganate are extracted, wherein the mass ratio of the graphene to the potassium permanganate is 1:6, adding a mixed solution of concentrated sulfuric acid and phosphoric acid (the volume ratio of the concentrated sulfuric acid to the phosphoric acid is 9; the using amount of the graphite powder and the mixed solution is 3g:400mL.

In the embodiment, ferric chloride hexahydrate, ferrous sulfate heptahydrate, ammonia water and citric acid are all purchased from national medicine group chemical reagent limited; mercaptopropyltrimethoxysilane was purchased from alfa aesar; thioacetates were purchased from alatin reagent. In this embodiment, the waste fruits and vegetables are apples.

Example 1:

a preparation method of a sewage treatment agent for high-efficiency denitrification comprises the following steps:

s1: uniformly mixing the compound microorganism and deionized water, adding molasses and a carrier, stirring and mixing for 20min, and culturing for 4 days at 35 ℃ under the condition that the oxygen supply is 1L/min to obtain a compound microorganism bacterium agent; the compound microorganism comprises lactic acid bacteria, saccharomycetes, bacillus and actinomycetes, and the content of each strain is as follows: the microbial inoculum comprises, by mass, 15% of yeast, 3% of bacillus, 2% of actinomycetes and 80% of lactic acid bacteria. The carrier is porous zeolite. The using amount of the compound microorganism is 10wt% of deionized water; the using amount of the molasses is 10wt% of the deionized water; the carrier is used in an amount of 0.1wt% of the ionized water.

S2: crushing waste fruits and vegetables to obtain fruit and vegetable pulp, placing the fruit and vegetable pulp in a water bath environment at 50 ℃, adding pectinase for enzymolysis for 120min, adding activated saccharomycetes after pasteurization, and standing for fermentation to obtain a nutrient solution; the dosage of the pectinase is 1.8mL/kg. The usage amount of the yeast is 3wt% of the total mass of the system.

S3: and mixing and compounding the compound microbial agent, an external carbon source and a nutrient solution to obtain the sewage treatment agent. 5 percent of nutrient solution, 30 percent of compound microbial agent and the balance of external carbon source by volume ratio.

Example 2:

s1: uniformly mixing the compound microorganism and deionized water, adding molasses and a carrier, stirring and mixing for 25min, and culturing for 3 days at 40 ℃ under the condition that the oxygen supply is 1L/min to obtain a compound microorganism bacterium agent; the compound microorganism comprises lactic acid bacteria, saccharomycetes, bacillus and actinomycetes, and the content of each strain is as follows: the microbial inoculum comprises, by mass, 15% of yeast, 3% of bacillus, 2% of actinomycetes and 80% of lactic acid bacteria. The carrier is porous zeolite. The using amount of the compound microorganism is 10wt% of deionized water; the using amount of the molasses is 10wt% of the deionized water; the carrier is used in an amount of 0.1wt% of the ionized water.

S2: crushing waste fruits and vegetables to obtain fruit and vegetable pulp, placing the fruit and vegetable pulp in a water bath environment at 50 ℃, adding pectinase for enzymolysis, wherein the enzymolysis time is 120min, adding activated saccharomycetes after pasteurization, and standing for fermentation to obtain a nutrient solution; the dosage of the pectinase is 1.8mL/kg. The usage amount of the yeast is 3wt% of the total mass of the system.

S3: and mixing and compounding the compound microbial agent, an external carbon source and a nutrient solution to obtain the sewage treatment agent. By volume ratio, 3% of nutrient solution, 20% of compound microbial agent and the balance of external carbon source.

Example 3:

s1: uniformly mixing the compound microorganism and deionized water, adding molasses and a carrier, stirring and mixing for 30min, and culturing for 3 days at 40 ℃ under the condition that the oxygen supply is 1L/min to obtain a compound microorganism bacterium agent; the compound microorganism comprises lactic acid bacteria, saccharomycetes, bacillus and actinomycetes, and the content of each strain is as follows: the microbial inoculum comprises, by mass, 15% of yeast, 3% of bacillus, 2% of actinomycetes and 80% of lactic acid bacteria. The carrier is porous zeolite. The using amount of the compound microorganism is 10wt% of deionized water; the using amount of the molasses is 10wt% of the deionized water; the carrier is used in an amount of 0.1wt% of the ionized water.

S3: and mixing and compounding the compound microbial agent, an external carbon source and a nutrient solution to obtain the sewage treatment agent. 5 percent of nutrient solution, 20 percent of compound microbial agent and the balance of external carbon source by volume ratio.

Example 4: according to the method disclosed in the embodiment 1, the proportion of the sewage treatment agent is adjusted, and the specific proportion is as follows: 5 percent of nutrient solution, 11.5 percent of compound microbial agent and the balance of external carbon source by volume ratio.

Example 5: according to the method disclosed in the embodiment 1, the proportion of the sewage treatment agent is adjusted, and the specific proportion is as follows: by volume ratio, 3% of nutrient solution, 11.5% of compound microbial agent and the balance of external carbon source.

Example 6: according to the method disclosed in the embodiment 1, the carrier of the compound microbial agent is replaced by magnetic graphene oxide.

A preparation method of a sewage treatment agent for efficient denitrification comprises the following steps:

s1: uniformly mixing the compound microorganism and deionized water, adding molasses and a carrier, stirring and mixing for 20min, and culturing for 4 days at 35 ℃ under the condition that the oxygen supply is 1L/min to obtain a compound microorganism bacterium agent; the compound microorganism comprises lactic acid bacteria, saccharomycetes, bacillus and actinomycetes, and the content of each strain is as follows: the bacillus subtilis comprises, by mass, 15% of yeast, 3% of bacillus, 2% of actinomycetes and 80% of lactic acid bacteria. The using amount of the compound microorganism is 10wt% of deionized water; the using amount of the molasses is 10wt% of the deionized water; the carrier is used in an amount of 0.1wt% of the ionized water.

The carrier in the S1 is magnetic graphene oxide, wherein the preparation steps of the magnetic graphene oxide are as follows:

(1) Mixing ferric trichloride hexahydrate, ferrous sulfate heptahydrate and deionized water, stirring for 25min in a nitrogen environment, heating to 78 ℃, adding ammonia water, controlling the pH of the system to be 9, stirring for reacting for 15min, adding citric acid, continuing to react for 4.5h, collecting a product after the reaction is finished, washing and drying to obtain the ferroferric oxide particles. The molar ratio of ferric trichloride hexahydrate to ferrous sulfate heptahydrate is 1.8; the dosage of the citric acid is 0.16 percent of the molar weight of ferric chloride hexahydrate.

Taking ferroferric oxide particles and toluene, carrying out ultrasonic dispersion for 30min, adding mercaptopropyl trimethoxy silane, stirring for 20min at 30 ℃, reacting for 10h at 95 ℃, collecting products after reaction, washing and drying to obtain sulfhydrylated magnetic particles; the dosage of the ferroferric oxide particles and the mercaptopropyl trimethoxysilane is 1g:2mL.

(2) Mixing an amination reagent and methanol, stirring for 15min in a nitrogen environment, adding a mixed solution of methyl acrylate and methanol, stirring at 30 ℃ for reaction for 4h, adding propinyl acrylate, continuing the reaction for 4h, evaporating the methanol under reduced pressure, reacting at 65 ℃ for 50min under a vacuum condition, heating to 105 ℃, preserving the temperature for reaction for 2h, heating to 140 ℃, and continuing the reaction for 2h to obtain an amino hyperbranched polymer containing alkynyl; the mol ratio of the methyl acrylate to the propinyl acrylate to the amination reagent is 1:2:1. the amination reagent is a mixture of diethylenetriamine and triethylene tetramine, and the molar ratio of the diethylenetriamine to the triethylene tetramine is 1:1.

(3) Taking graphene oxide and deionized water, performing ultrasonic dispersion for 50min under the power of 200W, transferring to a water bath at 5 ℃, adding concentrated sulfuric acid and thioacetanol, performing heat preservation reaction for 4h, cooling after the reaction is finished, performing suction filtration to collect a product, washing the product to be neutral by using the deionized water, and performing vacuum drying to obtain the thiolated graphene. The dosage of the graphene oxide, concentrated sulfuric acid and thioacetic alcohol is 1g:5mL of: 20mL.

Taking sulfhydrylation graphene and tetrahydrofuran, carrying out ultrasonic dispersion for 30min, adding an amino hyperbranched polymer containing alkynyl and a photoinitiator, reacting for 30min under ultraviolet light, wherein the wavelength of the ultraviolet light is 365nm, adding sulfhydrylation magnetic particles, reacting for 2h under the ultraviolet light, carrying out magnetic separation on a product, washing and drying to obtain a finished product. The mass ratio of the sulfhydrylation graphene to the amino hyperbranched polymer containing alkynyl to the sulfhydrylation magnetic particles is 1:5:3. the photoinitiator is 2-hydroxy-2-methyl-1-phenyl acetone, and the dosage of the photoinitiator is 2wt% of the amino hyperbranched polymer containing alkynyl.

Comparative example 1: comparative example 1 only an additional carbon source is added during sewage treatment, and no nutrient solution or compound microbial agent is added, wherein the additional carbon source is a compound carbon source purchased in the market.

Comparative example 2: comparative example 2 only an additional carbon source is added during sewage treatment, and no nutrient solution or compound microbial agent is added, wherein the additional carbon source is 10% by mass of sodium acetate solution.

Comparative example 3: comparative example 3 a control was carried out on the basis of example 3, in comparative example 1 no thiolated graphene oxide was introduced, and the remaining steps were kept unchanged.

Comparative example 4: comparative example 3 a control was carried out on the basis of example 3, and comparative example 4 was carried out by loading ferroferric oxide by a conventional process.

The preparation method of the magnetic graphene oxide comprises the following steps:

(1) Taking graphene oxide and deionized water, carrying out ultrasonic dispersion for 50min under the power of 200W, adding ferric trichloride hexahydrate and ferrous sulfate heptahydrate into the dispersion liquid with the concentration of 2mg/mL, stirring for 25min under the nitrogen environment, heating to 78 ℃, adding ammonia water, controlling the pH of the system to be 9, stirring for reaction for 15min, adding citric acid, continuing to react for 4.5h, collecting a product after the reaction is finished, washing and drying to obtain the magnetic graphene oxide. The molar ratio of ferric trichloride hexahydrate to ferrous sulfate heptahydrate is 1.8; the using amount of the citric acid is 0.16 percent of the molar weight of ferric chloride hexahydrate, and the mass ratio of the graphene oxide to the ferric chloride hexahydrate is 1:10.

(3) Taking magnetic graphene oxide and deionized water, performing ultrasonic dispersion for 50min under the power of 200W, transferring to a water bath at 5 ℃, adding concentrated sulfuric acid and thioacetanol, performing heat preservation reaction for 4h, cooling after the reaction is finished, performing suction filtration to collect a product, washing the product to be neutral by using the deionized water, and performing vacuum drying to obtain the thiolated graphene. The dosage of the magnetic graphene oxide, concentrated sulfuric acid and thioacetanol is 1g:5mL of: 20mL.

Taking sulfhydrylation graphene and tetrahydrofuran, carrying out ultrasonic dispersion for 30min, adding an amino hyperbranched polymer containing alkynyl and a photoinitiator, reacting for 2h under ultraviolet light, wherein the wavelength of the ultraviolet light is 365nm, carrying out magnetic separation on a product, washing and drying to obtain a finished product. The mass ratio of the sulfhydrylation graphene to the amino hyperbranched polymer containing alkynyl is 1:5. the photoinitiator is 2-hydroxy-2-methyl-1-phenyl acetone, and the dosage of the photoinitiator is 2wt% of the amino hyperbranched polymer containing alkynyl.

Comparative example 5: comparative example 5 a control was performed on the basis of comparative example 4, and comparative example 5 was carried out by loading ferroferric oxide by a conventional process.

(2) Mixing an amination reagent and methanol, stirring for 15min in a nitrogen environment, adding a mixed solution of methyl acrylate and methanol, stirring and reacting for 6h at 30 ℃, removing the methanol by reduced pressure evaporation, reacting for 50min at 65 ℃ under a vacuum condition, heating to 105 ℃, preserving heat and reacting for 2h, heating to 140 ℃, and continuing to react for 2h to obtain an amino hyperbranched polymer; the molar ratio of the methyl acrylate to the amination reagent is 1:1. the amination reagent is a mixture of diethylenetriamine and triethylene tetramine, and the molar ratio of the diethylenetriamine to the triethylene tetramine is 1:1.

Taking sulfhydrylation graphene and tetrahydrofuran, carrying out ultrasonic dispersion for 30min, adding an amino hyperbranched polymer, mixing and stirring for 2h, carrying out magnetic separation on a product, washing and drying to obtain a finished product. The mass ratio of the sulfhydrylation graphene to the amino hyperbranched polymer is 1:5.

detection experiment:

1. sufficient amount of water and sludge in an anaerobic tank are taken from a certain sewage treatment plant, the sewage treatment is carried out by using the sewage treatment agent disclosed in the example 1, static comparison experiments are continuously carried out for three days and for a plurality of batches, a control group is a comparative example 1, and the specific data are as follows:

and (4) conclusion: as can be seen from the table above, under the condition of the same dosage of the sewage treatment agent, the limit which can be reached by the composite carbon source (comparative example 1) can be realized by only using 36.33% of COD equivalent, and even the denitrification reaction rate and the removal rate are superior to those of the composite carbon source. The method also fully proves that the denitrification rate is improved by at least more than 15 percent by adding the nutrient and compounding the special microbial inoculum.

2. And (2) taking enough water from a denitrification tank at a certain sewage station, adding 500ml of prepared mixed liquor (raw water and sludge in the tank) into 5 devices respectively, adding different dosages and different carbon sources, continuously stirring for 3 hours, and then measuring TN and COD indexes respectively.

Wherein test group 1: the sewage treatment agent disclosed in example 2 was added in amounts of 20ml, 30ml and 50ml, respectively.

Test group 2: the sewage treatment agent disclosed in example 3 was added in amounts of 20ml, 30ml and 50ml, respectively.

Test group 3: the sewage treatment agent disclosed in example 4 was added in amounts of 20ml, 30ml and 50ml, respectively.

Test group 4: the sewage treatment agent disclosed in example 5 was added in amounts of 20ml, 30ml and 50ml, respectively.

Test group 5: the sewage treatment agent disclosed in comparative example 2 was added in an amount of 280ml, 120ml and 200ml, respectively.

And (4) conclusion: as can be seen from the data in the table above, the removal rate is obviously increased with the increase of the dosage, which indicates that the activity of the microorganism is good; meanwhile, under the condition of similar COD equivalent, the sewage treatment agent disclosed by the invention can promote denitrification reaction to be smoothly carried out; after 20ml of sewage treatment agent is added for treatment, the treated sewage treatment agent basically reaches below the first-class A standard in the pollutant discharge standard (GB 18918-2002) of the urban sewage treatment plant, but the TN result in the test group 5 only reaches 16.25mg/l under the condition of adding 200ml of sewage treatment agent, and the effect is obviously inferior to that of the application.

3. The sewage treatment agents disclosed in example 6 and comparative examples 3 to 5 were used to perform a heavy metal adsorption experiment: during testing, 0.1g of sewage treatment agent is placed in 100mL of 500mg/L nickel solution, the pH value is 5, the sewage treatment agent is placed on a turntable at the rotating speed of 300r/min, adsorption reaction is carried out at room temperature, the adsorption time is 4 hours, and after the adsorption is finished, the adsorption quantity is measured and calculated.

And (3) taking a sewage treatment agent, immersing the sewage treatment agent into deionized water, performing ultrasonic oscillation for 20 hours under the power of 500W, performing magnetic separation, weighing and recording, and then comparing with the mass before testing, and calculating the mass retention rate. Specific assay data are shown in the following table:

item	Example 6	Comparative example 3	Comparative example 4	Comparative example 5
					Adsorption capacity of nickel ion	151.4	138.2	147.3	129.1
Mass retention rate	96.8％	97.5％	74.6％	65.2％

And (4) conclusion: according to the scheme, an amination reagent, methyl acrylate and propinyl acrylate are used for polymerization reaction to obtain an amino hyperbranched polymer containing alkynyl, and propinyl acrylate is used for polymerization in the preparation process to introduce alkynyl, and the reason is that: the existing sewage treatment agent is difficult to separate after sewage treatment and cannot be recycled for the second time, so that a common method is to introduce ferroferric oxide to endow magnetism, and then separation is performed through an external magnetic field in the separation process, but currently, the ferroferric oxide and graphene oxide are generally mixed, and a graphene oxide hierarchical structure is used for loading, or hydrothermal generation is performed on the surface of the graphene oxide, but the sewage treatment agent obtained through the method is short in magnetic service life, and the ferroferric oxide is easy to fall off in the sewage treatment process, so that the subsequent separation is not thorough.

Simultaneously, in this in-process, this application utilizes thioacetic acid alcohol and graphene oxide to take place esterification reaction to introduce the sulfydryl on the graphene oxide surface, on the one hand, the sulfydryl has more excellent adsorption efficiency to heavy metal ion, and the introduction of sulfydryl can improve the metal ion adsorption effect of sewage treatment agent, and another scheme utilizes graphene oxide surface sulfydryl in order to realize magnetic load, guarantees the separation effect of sewage treatment agent.

The invention discloses a sewage treating agent for high-efficiency denitrification and a preparation method thereof, the process design is reasonable, the component proportion is proper, the prepared sewage treating agent has excellent denitrification effect, can ensure and promote the preferential denitrification process of a carbon source, and achieves the effect of sludge reduction under the action of a compound microbial inoculum; meanwhile, in the application scene of heavy metal removal demand, the efficiency of adsorbing heavy metal ions is solved and realized after the medicament is added and the adding point is preposed through the adjustment and the application of the carrier, and the magnetic separation is subsequently utilized, so that the practicability is higher.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The sewage treatment agent for high-efficiency denitrification is characterized in that: the sewage treatment agent comprises a nutrient solution, a compound microbial agent and an external carbon source, and the content of each component is as follows: by volume ratio, 3-5% of nutrient solution, 10-30% of compound microbial agent and the balance of external carbon source.

2. The sewage treatment agent for high-efficiency denitrification according to claim 1, wherein: the contents of all components are as follows: 5 percent of nutrient solution, 30 percent of compound microbial agent and the balance of external carbon source by volume ratio.

3. The sewage treatment agent for high-efficiency denitrification according to claim 1, wherein: the contents of all components are as follows: 5 percent of nutrient solution, 20 percent of compound microbial agent and the balance of external carbon source by volume ratio.

4. The sewage treatment agent for high-efficiency denitrification according to claim 1, wherein: the compound microbial agent mainly comprises compound microorganisms, molasses and a carrier, wherein the compound microorganisms comprise lactic acid bacteria, saccharomycetes, bacillus and actinomycetes, and the content of each strain is as follows: 12-15% of yeast, 3-5% of bacillus, 2-5% of actinomycetes and the balance of lactic acid bacteria in percentage by mass.

5. The sewage treatment agent for high-efficiency denitrification according to claim 1, wherein: the carrier is porous zeolite or magnetic graphene oxide.

6. The sewage treatment agent for high-efficiency denitrification according to claim 1, wherein: the nutrient solution is mainly obtained by squeezing and fermenting waste fruits and then extracting.

7. A preparation method of a sewage treatment agent for efficient denitrification is characterized by comprising the following steps: the method comprises the following steps:

s1: uniformly mixing the compound microorganism and deionized water, adding molasses and carrier, stirring and mixing for 20-30min, and culturing at 35-40 deg.C under oxygen supply of 1L/min for 3-4 days to obtain compound microorganism bacterial agent; the compound microorganism comprises lactobacillus, yeast, bacillus and actinomycetes;

s2: crushing waste fruits and vegetables to obtain fruit and vegetable pulp, placing the fruit and vegetable pulp in a water bath environment at 49-51 ℃, adding pectinase for enzymolysis for 110-120min, pasteurizing, adding activated saccharomycetes, and standing for fermentation to obtain a nutrient solution;

8. The method for preparing a sewage treatment agent for high efficiency denitrification according to claim 7, wherein the method comprises the following steps: the using amount of the compound microorganism is 10-12wt% of deionized water; the using amount of the molasses is 10-12wt% of the deionized water; the dosage of the carrier is 0.1-0.2wt% of the ionized water.

9. The method for preparing a sewage treatment agent for high efficiency denitrification according to claim 7, wherein the method comprises the following steps: the carrier is porous zeolite or magnetic graphene oxide, wherein the preparation method of the magnetic graphene oxide comprises the following steps:

(3) Taking sulfhydrylation graphene and tetrahydrofuran, performing ultrasonic dispersion, adding an alkynyl-containing amino hyperbranched polymer and a photoinitiator, reacting for 20-30min under ultraviolet light, adding sulfhydrylation magnetic particles, reacting for 1-2 h under ultraviolet light, performing magnetic separation on a product, washing and drying to obtain a finished product.

10. The method for preparing a sewage treatment agent for high efficiency denitrification according to claim 9, wherein: in the step (2), the amination reagent is a mixture of diethylenetriamine and triethylene tetramine, and the molar ratio of the diethylenetriamine to the triethylene tetramine is 1:1;