A method for preparing chitosan-modified montmorillonite loaded with microorganisms for treating black and odorous water bodies

Abstract

The present invention relates to a method for preparing chitosan-modified montmorillonite loaded with microorganisms for the treatment of black and odorous water bodies, comprising the following steps: (S1) preparation of sodium-based montmorillonite; (S2) chitosan-modified montmorillonite; (S3) loading nutrients; (S4) loading composite bacterial agents. The present invention uses cheap and efficient montmorillonite as an immobilized carrier, supplemented by a chitosan-modified coating, and loaded with microorganisms and required nutrients. The material source is widely available and easy to obtain, the preparation cost is low, and it can be efficiently and mass-produced; the product prepared by the present invention has strong impact resistance and high physical and chemical stability, has a large scope of application, can adapt to various closed waters and flowing waters, can effectively promote the oxidative decomposition of black and odorous sludge, increase the degradation efficiency of organic matter in black and odorous sludge, and can be used for the treatment and restoration of black and odorous sludge.

Description

Technical Field

[0001] The invention relates to a method for preparing chitosan modified montmorillonite loaded with microorganisms for treating black and smelly water bodies. Background Art

[0002] Due to the complex causes and numerous influencing factors of black and odorous water bodies, their treatment technologies often need to be considered comprehensively and comprehensively. Different causes of black and odorous water bodies and different types of pollution sources usually require systematic consideration of different technical measures to achieve comprehensive treatment of black and odorous water bodies and improve the water environment. Limited by factors such as the surrounding environment and water shoreline characteristics of black and odorous water bodies, the current treatment of water bodies and sediments in black and odorous waters is mainly based on in-situ treatment technology; the in-situ treatment of black and odorous water bodies mainly includes modular device filtration, agent flocculation and sedimentation, aquatic plant enrichment and absorption, high-efficiency composite microbial agent purification, composite enzyme in-situ purification, indigenous microbial amplification and biological promotion, etc.; the in-situ treatment technology of black and odorous sediments mainly includes oxidant treatment, new material covering and isolation, microbial agent remediation, aquatic plant purification and remediation, etc.

[0003] In the existing in-situ treatment technology, biological agents mainly based on microbial agents and complex enzymes are easy to lose, have a long treatment cycle, and are restricted by environmental factors. The Chinese patent application with publication number CN113371850A discloses a composite microbial agent for efficient water purification and its application. The composite microbial agent for efficient water purification described in the invention includes photosynthetic bacteria, lactic acid bacteria, actinomycetes, nitrifying bacteria, denitrifying bacteria and yeast. The invention method needs to be pre-cultured before being used for sewage treatment, so it is impossible to pre-culture the mobile black and smelly water with unstable water quality, and the loss is large due to the influence of water flow, and continuous supplementation is required. The treatment cycle is long and the cost is high. Water purifiers and bottom mud covering agents based on porous materials can achieve adsorption and coverage of pollutants, and can prevent the release of bottom mud to the overlying water body, but they cannot completely remove pollutants, and will still cause secondary pollution to the water environment in the long term. Summary of the invention

[0004] In response to the above technical deficiencies, the present invention provides a chitosan-modified montmorillonite loaded with microorganisms for the treatment of black and odorous water bodies. The prepared composition can effectively inhibit the rise of sediment pollutants, improve water transparency, reduce sediment pollutants, purify water bodies, improve water quality, combine aquatic plant community construction and aquatic biological community construction, reconstruct the water ecosystem through biological manipulation technology, improve water environment functions and achieve long-term stable maintenance.

[0005] In order to achieve the above object, the present invention provides a method for preparing chitosan-modified montmorillonite loaded with microorganisms for the treatment of black and odorous water bodies, comprising the following steps:

[0006] (S1) Preparation of sodium montmorillonite: Calcium montmorillonite is dispersed in water to form a suspension, a phosphate cationic surfactant and a sodium-forming agent are added, the temperature is raised and stirred for reaction for 20-30 hours, filtered, washed with water, dried, activated, and crushed to obtain sodium montmorillonite;

[0007] The present invention performs sodiumization on calcium-based montmorillonite to obtain sodium-based montmorillonite, which is easier to disperse in water, has a fast hydration speed, can be quickly swelled and dispersed when put into a water body, and improves the sewage treatment speed. However, the gel state of sodium-based montmorillonite in water is unstable after hydration. The present invention also modifies the montmorillonite with a phosphate ester quaternary ammonium salt cationic surfactant, so that the long-chain alkyl quaternary ammonium salt cation is intercalated into the montmorillonite interlayer, so that the montmorillonite interlayer spacing is enlarged, and has certain hydrophobicity, so that the swelling speed of montmorillonite put into the water body is slowed down, a certain slow-release effect is achieved, and the montmorillonite is more stable after hydration, and is more suitable as a carrier of the composite bacterial agent.

[0008] Furthermore, in step (S1), the CEC of calcium-based montmorillonite is 60-80 cmoL / kg, and the specific surface area is 300-400 m2 / g.

[0009] Further, in step (S1), the mass concentration of calcium montmorillonite in the suspension formed by calcium montmorillonite dispersed in water is 5-10wt%; the surface modifier is a quaternary ammonium salt surfactant of phosphate, and the sodiumizing agent is at least one of sodium carbonate, sodium chloride, sodium silicate, sodium pyrophosphate, sodium sulfate, sodium oxalate, and sodium acetate; the mass ratio of calcium montmorillonite, phosphate cationic surfactant and sodiumizing agent is 100:5-8:20-30. Preferably, the sodiumizing agent is a compound of sodium pyrophosphate and ammonium acetate in a mass ratio of 2-4:1. The heating and stirring reaction is to heat up to 50-70°C. The inventors found that the above-mentioned compounded sodiumizing agent has the best sodiumizing effect, and the calcium montmorillonite obtained has the best comprehensive performance in hydration rate, expansion rate, and stability. The possible reason is that inorganic sodium and organic sodium cooperate with each other, and the inorganic and organic anions have different charges and volumes, which can make up for each other's defects, so that the sodiumization is smooth and sufficient.

[0010] Furthermore, the quaternary ammonium phosphate surfactant is obtained by a preparation method comprising the following steps: adjusting the pH of a sodium phosphate solution to 3-4 with nitric acid, dripping epichlorohydrin, heating to 70-80°C for reaction for 2-3h, maintaining 70-80°C, dripping a long-chain alkyl tertiary amine, adjusting the pH to 8-9 with alkali solution, heating to 85-95°C, continuing the reaction for 3-5h to complete quaternization, and drying to obtain a paste, which is a quaternary ammonium phosphate surfactant. The alkali solution is a 5-10wt% sodium hydroxide aqueous solution.

[0011] Furthermore, the molar ratio of sodium phosphate, epichlorohydrin and long-chain alkyl tertiary amine is 1:2.2-2.7:2.1-2.5. The long-chain alkyl tertiary amine is at least one selected from dodecyl dimethyl tertiary amine, tetradecyl dimethyl tertiary amine, hexadecyl dimethyl tertiary amine and octadecyl dimethyl tertiary amine.

[0012] The filtering, washing, drying, activation and crushing are well known in the art. In a specific technical scheme of the present invention, the filtering is suction filtration; the washing is washing with distilled water and / or deionized water; the drying is vacuum drying at 60-70°C and 0.01-0.1MPa; the activation is heating to 105-120°C and activating for 0.5-1h; and the crushing is performed to a particle size of 100-200 mesh, such as ball milling, grinding, air flow crushing, and high-speed crushing.

[0013] (S2) Chitosan-modified montmorillonite: a suspension of sodium montmorillonite dispersed in water is activated by adding nitric acid solution, carboxymethyl chitosan is added, heated and stirred for reaction, centrifuged, washed with water, and dried to obtain a powdery solid, which is chitosan-modified montmorillonite;

[0014] Chitosan has poor water solubility and needs to be prepared with acetic acid into a low-concentration chitosan solution before the modification of montmorillonite. The modification efficiency is low and the chitosan utilization efficiency is low. The present invention uses carboxymethyl chitosan, which has good water solubility and has a stabilizing effect on the hydration of montmorillonite to form a gel, and is safe and non-toxic. Montmorillonite can be modified conveniently, in large quantities and effectively.

[0015] The degree of substitution of the carboxymethyl chitosan is 70-90%, and the molecular weight is 50-200kDa. Furthermore, the carboxymethyl chitosan is a compound of a carboxymethyl chitosan with a molecular weight of 50-80kDa and a carboxymethyl chitosan with a molecular weight of 150-200kDa according to a mass ratio of 4-7:1. Low molecular weight carboxymethyl chitosan can easily enter the interlayer of montmorillonite; high molecular weight carboxymethyl chitosan can only partially enter the interlayer of montmorillonite, resulting in a rich intercalation and exfoliation structure, which is more conducive to the chitosan / montmorillonite composite material to play a role in treating sewage. The modified carboxymethyl chitosan modified montmorillonite has good water solubility, film-forming properties, moisture retention, good adsorption and ion exchange properties, and can quickly adsorb various pollutants such as ammonia nitrogen, phosphate, etc. in water bodies and sediments through ion exchange.

[0016] Further, in step (S2), the sodium montmorillonite mass concentration in the suspension of sodium montmorillonite in water is 5-10wt%, the nitric acid concentration is 0.2-0.5mol / L, and the amount of nitric acid is to adjust the pH of the system to 3-4; the amount of carboxymethyl chitosan added is 60-80wt% of the mass of the sodium montmorillonite. The heating and stirring reaction is carried out at 60-70°C and the reaction is carried out for 3-5h under stirring conditions. The amount of carboxymethyl chitosan is relatively large, so that not only sufficient carboxymethyl chitosan will be intercalated into the interlayer of montmorillonite, but also part of the carboxymethyl chitosan will be coated around the montmorillonite to form an exfoliated chitosan / montmorillonite composite material. The amount of carboxymethyl chitosan should not be too little, otherwise the chitosan will only enter the interlayer of montmorillonite, and the montmorillonite cannot be coated / entangled, and the exfoliated chitosan / montmorillonite composite material cannot be formed; but the amount of carboxymethyl chitosan should not be too much, which will cause waste of materials on the one hand and hinder the hydration process of montmorillonite on the other hand.

[0017] Furthermore, in step (S2), the operations of centrifugation, washing and drying are well known in the art, and the centrifugation is performed at 3000-5000 rpm for 10-20 min; the washing is performed with distilled water and / or deionized water until the pH is neutral; and the drying is performed in an oven at 60-70°C or vacuum drying.

[0018] (S3) Loading nutrients: adding glucose and peptone to the suspension of chitosan-modified montmorillonite, heating and stirring under microwave conditions, filtering, and drying to obtain chitosan-modified montmorillonite loaded with nutrients;

[0019] Furthermore, in step (S3), the chitosan-modified montmorillonite suspension is obtained by dispersing chitosan-modified montmorillonite in water, the mass concentration of chitosan-modified montmorillonite is 5-10wt%; the mass ratio of chitosan-modified montmorillonite, glucose and protein is 100:30-50:20-30.

[0020] Furthermore, in step (S3), the microwave conditions are microwave power 200-300W, microwave frequency 300-500MHz; heating and stirring are performed to heat to 50-60°C.

[0021] The glucose is one of the initial nutrients required for activating the chitosan-modified montmorillonite material loaded with microorganisms, and can provide the microorganisms with a carbon source required for growth; the peptone is one of the initial nutrients required for activating the chitosan-modified montmorillonite material loaded with microorganisms, and can provide the microorganisms with a nitrogen source and a variety of growth factors.

[0022] (S4) Loading the composite bacterial agent: immersing the chitosan-modified montmorillonite loaded with nutrients in the composite bacterial solution, stirring at 30-35° C. for 2-3 hours, completing the loading, centrifuging, and vacuum freeze-drying to obtain the chitosan-modified montmorillonite loaded with microorganisms.

[0023] The composite bacterial liquid is a composite bacterial flora formed by mixing aerobic, anaerobic and facultative anaerobic bacterial flora, including nitrifying bacteria, denitrifying bacteria, nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria, bacillus, yeast and lactic acid bacteria.

[0024] Furthermore, in the composite bacterial solution, the total concentration of bacteria was 1×10 8 Up to 5×10 8 CFU / mL, and the concentration ratio of nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria, bacillus, yeast and lactic acid bacteria is 80-100: 80-100: 30-50: 10-30: 10-30: 10-30. The weight percentage of different bacterial groups can be adjusted to adapt to black and smelly water bodies with different water depths and different pollution states.

[0025] Furthermore, the vacuum freeze drying is carried out at -30 to -40°C and 1.3 to 130Pa.

[0026] The chitosan-modified montmorillonite material loaded with microorganisms can adapt to different application scenarios by adjusting the proportion of loaded microbial flora: products with high proportions of anaerobic and facultative anaerobic flora can be placed in deep water areas; products with high proportions of aerobic and facultative anaerobic flora are suitable for shallow water areas and aerated oxygenated waters.

[0027] The nitrifying bacteria are autotrophic, aerobic bacteria. Under aerobic conditions, nitrite bacteria and nitrate bacteria can oxidize ammonia nitrogen into nitrite nitrogen and nitrate; the denitrifying bacteria are heterotrophic, facultative anaerobic bacteria. Under anaerobic conditions, denitrifying bacteria can reduce nitrate to release molecular nitrogen (N 2 ) or nitrous oxide (N 2 O); the photosynthetic bacteria are microorganisms that can use organic matter as a carbon source between hydrogen donors to perform photosynthesis under anaerobic light or aerobic dark conditions, and can degrade nitrite and sulfide pollutants in water bodies; the bacillus is one or more of Bacillus subtilis, Bacillus licheniformis, and Bacillus polymyxa, which are strictly aerobic or facultative anaerobic bacilli, and can decompose pollutants such as organic matter, nitrogen, phosphorus, and sulfide, and can compete with harmful algae and pathogens in water bodies to form a dominant bacterial community, inhibiting the reproduction and growth of harmful algae and pathogens; the ferment The mother bacteria is a facultative anaerobic organism, which is easy to form a dominant bacterial community in the water body, can decompose a variety of organic macromolecular pollutants, and destroy chlorophyll by secreting extracellular secretions, thereby inhibiting the growth of algae; the lactic acid bacteria are bacteria that can produce a large amount of lactic acid by fermenting carbohydrates, have both aerobic and anaerobic properties, and can decompose organic matter to produce organic acids, special mold systems, acid bacteria and other substances that can stabilize the acid-base of the water body and maintain the acid-base balance of the water body, and have a biological removal effect on microcystin toxins produced by cyanobacteria such as Microcystis aeruginosa, Anabaena aquatica, and Nostoc in eutrophic water bodies.

[0028] The bacterial expansion medium comprises: 25wt% glucose, 15wt% sodium acetate, 10wt% potassium dihydrogen phosphate K 2 HPO 4 , 10wt% sodium chloride, 15wt% ammonium chloride, 20wt% peptone, 5wt% trace element liquid, pH value 6.5-7.5; the trace element liquid ingredients are: ethylenediaminetetraacetic acid, zinc sulfate, calcium chloride, ferrous sulfate heptahydrate, ammonium molybdate, cobalt chloride hexahydrate. The culture temperature used for culturing the composite bacterial liquid in the culture medium is 25-35°C.

[0029] The chitosan-modified montmorillonite loaded with microorganisms prepared by the present invention has a large specific surface area, good adsorption and ion exchange properties, and can quickly adsorb various pollutants such as ammonia nitrogen and phosphate in water bodies and sediments through ion exchange, thereby improving the water body and sediment environment. Nutrients such as glucose and peptone loaded on montmorillonite can stimulate the growth and reproduction of loaded microorganisms in a high dissolved oxygen environment, continuously activate indigenous microorganisms in water bodies and sediments, assist in the formation of dominant flora, purify water bodies and improve the sediment environment. The loaded microbial flora is a composite flora composed of aerobic, anaerobic and facultative anaerobic flora; including flora that degrade conventional pollutants, flora that eliminates sulfur, flora that degrades persistent organic pollutants, flora that passivates and fixes heavy metals, flora that inhibits the growth of harmful microorganisms, etc. Various beneficial microorganisms work together to quickly adapt to changes in the water environment and continuously reduce sediment pollutants.

[0030] The second object of the present invention is to provide the use of the chitosan-modified montmorillonite loaded with microorganisms in the treatment of black and odorous water bodies, comprising the following steps:

[0031] According to the pollution status of the black and odorous waters to be treated, quantitative tests are carried out to determine the specific dosage of chitosan-modified montmorillonite loaded with microorganisms in a unit area; the general dosage is 200-600g / m 3 The general adding method is: uniformly spraying and adding by a ship-borne powder sprayer; activating the chitosan-modified montmorillonite loaded with microorganisms in the water environment.

[0032] The chitosan-modified montmorillonite loaded with microorganisms is evenly sprayed into the water body by a ship-borne powder sprayer. It has the property of absorbing water and swelling, and the cations between the montmorillonite layers undergo hydration reaction, wherein the montmorillonite particles are interconnected and expand in volume after absorbing water, and settle to the surface of the sediment to form a 5-10 mm covering layer; the sediment covering layer is a porous hydrated silicate crystal, which can block the water body and the sediment, and at the same time, the internal gaps of the covering layer carry a large amount of air, so that oxygen-rich environment and anoxic environment are formed in the upper and lower areas of the sediment covering layer, and the anaerobic and facultative anoxic bacteria in the anoxic environment under the covering layer can effectively eliminate sediment pollutants and reduce the thickness of black and smelly sediment, and the aerobic and facultative anoxic microorganisms in the oxygen-rich environment above the covering layer can eliminate water pollutants in a good water environment, purify the water body, improve the water transparency, and facilitate the subsequent construction of aquatic plant communities.

[0033] After the vacuum freeze-drying treatment, the microorganisms are in a dormant state and need to be activated. The specific activation method is: the chitosan-modified montmorillonite loaded with microorganisms is mixed with deionized water in a ratio of 1:50 and then oxygenated and activated; or the chitosan-modified montmorillonite loaded with microorganisms is evenly added to the black and smelly water area that needs to be treated, and the microorganisms are activated in situ by artificial aeration and oxygenation. The artificial aeration methods include but are not limited to microporous hose aeration, plug flow aeration, mixed flow aeration, underwater jet aeration, impeller aeration, fountain aeration, mobile aeration boat aeration, mobile micro-nano aeration platform aeration, and multiple forms are used alone or in combination. The specific aeration form can be selected according to the water environment conditions of the black and smelly water body.

[0034] The aeration volume is 10-20m 3 / m 3 .h, according to oxygen is 2-5m 3 / m 3 .h, the aeration time during activation is 3-6h. After activation, the aeration is changed to once every 5-10h, each time for 0.5-1h.

[0035] The present invention performs surface modification of quaternary ammonium phosphate and modification of carboxymethyl chitosan before loading nutrients and composite microbial agents on montmorillonite, so that after the montmorillonite composite material is put into water, the hydration speed is moderate, the nutrients and composite microorganisms can be slowly released, and the composite microorganisms can be stably present in the water for a long time and play a role for a long time.

[0036] Generally, chitosan-modified montmorillonite materials loaded with microorganisms are added, and an aquatic plant community is constructed after a week. The aquatic plant community stabilizes the sediment, further purifies the water, reduces pollutants in the sediment and water, and improves the water ecosystem.

[0037] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0038] 1. The present invention uses cheap and efficient montmorillonite as an immobilized carrier, supplemented by a chitosan modified coating, and loaded with microorganisms and required nutrients. The material source is widely available and easy to obtain, the preparation cost is low, and it can be efficiently and mass-produced; the product prepared by the present invention has strong impact resistance and high physical and chemical stability, has a large scope of application, and can adapt to various closed waters and flowing waters.

[0039] 2. The interlayer spacing, interlayer charge capacity, specific surface area and porosity of the product prepared by the present invention are significantly improved, and it can be directly added into the sediment to stabilize the riverbed structure and prevent the sediment from resuspension; the high porosity and corresponding high oxygen content of the product can provide suitable space for the growth and reproduction of the self-loaded microorganisms; it can effectively promote the oxidation and decomposition of black and smelly sediment, increase the degradation efficiency of organic matter in the black and smelly sediment, and can be used for the treatment and restoration of black and smelly sediment;

[0040] 3. The product prepared by the present invention can maintain the activity of microorganisms for a long time, realize the slow release of active microorganisms, and at the same time provide space for bacteria to grow, reproduce and attach. It can release active microorganisms into the water body for a long time, thereby playing a role in continuously purifying the water body.

[0041] 4. The chitosan-modified montmorillonite material loaded with microorganisms provided by the present invention combines microbial preparations, microbial domestication enzymes, water purifiers, and sediment covering materials, overcoming the single functionality of materials in the prior art for the restoration of black and odorous water bodies, and simultaneously achieving multiple effects such as removing suspended matter, improving water transparency, purifying water bodies, removing nitrogen and phosphorus pollution, covering black and odorous sediment, preventing the re-suspension of black and odorous sediment and the release of sediment pollutants to the overlying water body, and reducing sediment pollutants. DETAILED DESCRIPTION

[0042] The chitosan-modified montmorillonite material loaded with microorganisms of the present invention and its use are described below with specific examples.

[0043] Unless otherwise specified, the “parts” in the embodiments of the present invention are parts by mass, and the “%” are percentages by mass.

[0044] Calcium-based montmorillonite was purchased from Nanyu Mineral Products Processing Plant in Lingshou County. The CEC is about 63cmoL / kg and the specific surface area is 340㎡ / g.

[0045] Carboxymethyl chitosan was purchased from Nantong Lusheng Holy Object Engineering Co., Ltd.

[0046] The compound bacterial agent was purchased from Fujian Zhongwei Pu Chuang Biotechnology Co., Ltd.; it is a compound bacteria composed of nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria, Bacillus subtilis, yeast and lactic acid bacteria in a quantitative ratio of 100:80:30:20:20:20.

[0047] Preparation Example 1

[0048] Sodium phosphate (0.5 mol / L, 1 moleq.) solution was adjusted to pH 4 with nitric acid, epichlorohydrin (2.5 moleq.) was added dropwise, the temperature was raised to 70°C for reaction for 2 h, the temperature was maintained at 70°C, hexadecyldimethyl tertiary amine (2.1 moleq.) was added dropwise, the pH was adjusted to 8 with 5 wt% sodium hydroxide aqueous solution, the temperature was raised to 90°C, the reaction was continued for 3 h to complete quaternization, and the paste was obtained by drying, which is a phosphate quaternary ammonium salt surfactant.

[0049] Preparation Example 2

[0050] The other conditions were the same as those in Preparation Example 1, except that hexadecyldimethyl tertiary amine was replaced with an equal molar amount of dodecyldimethyl tertiary amine.

[0051] Example 1

[0052] (S1) Preparation of sodium montmorillonite: 100 parts of calcium montmorillonite are dispersed in deionized water to form a 5 wt% suspension, 5 parts of the phosphate quaternary ammonium salt surfactant prepared in Preparation Example 1 and 20 parts of a sodiumizing agent are added, wherein the sodiumizing agent is a compound of sodium pyrophosphate and ammonium acetate in a mass ratio of 2:1, the temperature is raised to 60° C., the reaction is maintained at a constant temperature and stirred for 24 hours, filtered, washed with deionized water, dried in an oven at 70° C., activated at 105° C. for 0.5 hours, and ground to a particle size of 200 mesh to obtain sodium montmorillonite;

[0053] (S2) Polysaccharide modified montmorillonite: 100 parts of sodium montmorillonite were dispersed in deionized water to form a 5 wt% suspension, and a 0.2 mol / L nitric acid solution was added to adjust the system pH to 3 for activation; 60 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% were added, the temperature was raised to 70°C and stirred for reaction for 5 h, the mixture was centrifuged at 3000 rpm for 20 min, washed with deionized water, and dried in an oven at 60°C to obtain a powdery solid, which is chitosan modified montmorillonite;

[0054] (S3) Loading nutrients: 100 parts of chitosan-modified montmorillonite were dispersed in deionized water to form a 5 wt% suspension, 30 parts of glucose and 20 parts of peptone were added, and the mixture was heated to 50° C. and stirred for 10 h under microwave-assisted conditions of microwave power of 300 W and microwave frequency of 500 MHz to complete the loading of nutrients, and then filtered and dried in an oven at 60° C. to obtain chitosan-modified montmorillonite loaded with nutrients;

[0055] (S4) Loading composite bacterial agent: 100 portions of chitosan-modified montmorillonite loaded with nutrients were immersed in the composite bacterial solution, and the total bacterial concentration in the composite bacterial solution was 5×10 8CFU / mL, the composite bacteria include nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria, Bacillus, yeast and lactic acid bacteria in a quantitative ratio of 100:80:30:20:20:20. The mixture was stirred at 30°C for 3h to complete the loading of the composite bacteria. The mixture was centrifuged at 3000rpm for 30min and vacuum freeze-dried at -30°C and 13Pa to obtain chitosan-modified montmorillonite loaded with microorganisms.

[0056] Example 2

[0057] Other conditions and operations are the same as those in Example 1, except that in step (S1), 5 parts of the phosphate ester quaternary ammonium salt surfactant prepared in Preparation Example 1 are replaced by 8 parts of the phosphate ester quaternary ammonium salt surfactant prepared in Preparation Example 1.

[0058] Example 3

[0059] Other conditions and operations are the same as those in Example 1, except that in step (S1), the sodiumizing agent is replaced by 30 parts of sodium acetate.

[0060] Example 4

[0061] Other conditions and operations are the same as those in Example 1, except that in step (S1), the sodiumizing agent is replaced by 20 parts of sodium pyrophosphate.

[0062] Example 5

[0063] Other conditions and operations are the same as those in Example 1, except that in step (S2), 60 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% are replaced by 80 parts of carboxymethyl chitosan with a molecular weight of 200 kDa and a degree of substitution of 85%.

[0064] Example 6

[0065] Other conditions and operations are the same as those in Example 1, except that in step (S2), 60 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% are replaced by a compound of 48 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% and 12 parts of carboxymethyl chitosan with a molecular weight of 200 kDa and a degree of substitution of 85%.

[0066] Example 7

[0067] Other conditions and operations are the same as those in Example 1, except that in step (S2), 60 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% are replaced by a compound of 70 parts of carboxymethyl chitosan with a molecular weight of 50 kDa and a degree of substitution of 85% and 10 parts of carboxymethyl chitosan with a molecular weight of 150 kDa and a degree of substitution of 85%.

[0068] Example 8

[0069] Other conditions and operations are the same as those in Example 1, except that in step (S2), 60 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% are replaced by a compound of 30 parts of carboxymethyl chitosan with a molecular weight of 80 kDa and a degree of substitution of 85% and 10 parts of carboxymethyl chitosan with a molecular weight of 200 kDa and a degree of substitution of 85%.

[0070] Comparative Example 1

[0071] Other conditions and operations are the same as those in Example 1, except that in step (S1), the phosphate ester quaternary ammonium salt surfactant prepared in Preparation Example 1 is replaced by an equal mass of hexadecyltrimethylammonium chloride.

[0072] Comparative Example 2

[0073] Other conditions and operations were the same as those in Example 1, except that step (S2) was omitted, that is, the modification of montmorillonite with carboxymethyl chitosan was not performed.

[0074] Comparative Example 3

[0075] Other conditions and operations are the same as those in Example 1, except that in step (S3), the nutrient is 50 parts of glucose and no peptone is added.

[0076] Comparative Example 4

[0077] Other conditions and operations are the same as those in Example 1, except that in step (S3), the nutrient is 50 parts of peptone and no glucose is added.

[0078] Application Examples

[0079] In a polluted lake treatment project, 10m3 of polluted lake sewage was added to each simulated treatment pool. 3 The sewage indicators are COD82.6mg / L, total phosphorus 1.1mg / L, ammonia nitrogen 3.4mg / L, chlorophyll a 0.14mg / L, and water transmittance 65.8% (483nm); and 0.5 tons of sludge from the bottom of the polluted lake is added. In each simulated treatment pool, 200g / m 3 The chitosan-modified montmorillonite loaded with microorganisms prepared in the above examples and comparative examples was added, and air aeration was performed at an aeration rate of 10 m 3 / m 3 .h, that is, every hour, every m 3 Air is introduced into the wastewater for 10 m 3 , aeration time 4h, fully activate the added microorganism-loaded chitosan-modified montmorillonite. After activation, reduce aeration to 8 hours for aeration, aeration time 0.5h, to ensure sufficient dissolved oxygen content in water extraction, after 10 days of continuous aeration, the main water quality indicators of the simulated treatment pool were tested. The results are shown in Table 1 below:

[0080] Table 1 Simulated black and odorous water treatment effect

[0081] project COD removal rate Total phosphorus removal rate Ammonia nitrogen removal rate Chlorophyll a removal rate Water transmittance Example 1 83.8％ 75.2％ 86.4％ 75.8％ 82.7％ Example 2 84.2％ 74.7％ 86.6％ 77.3％ 83.1％ Example 3 81.5％ 72.6％ 84.5％ 73.6％ 80.5％ Example 4 82.1％ 73.0％ 85.2％ 73.8％ 81.9％ Example 5 80.6％ 75.5％ 85.7％ 73.6％ 79.6％ Example 6 84.3％ 76.4％ 86.8％ 79.2％ 85.4％ Example 7 84.7％ 77.1％ 87.0％ 78.3％ 84.8％ Example 8 81.2％ 73.5％ 83.4％ 71.3％ 78.6％ Comparative Example 1 80.5％ 71.3％ 81.7％ 72.8％ 79.6％ Comparative Example 2 72.8％ 68.5％ 77.8％ 70.3％ 77.2％ Comparative Example 3 76.3％ 71.2％ 80.6％ 71.6％ 79.2％ Comparative Example 4 75.4％ 73.6％ 78.5％ 72.3％ 80.0％

[0082] The invention can stabilize the suppressed sediment pollutants by constructing aquatic plant communities in cooperation with aeration and oxygenation equipment, and the aquatic plant roots and microorganisms can cooperate with each other to effectively reduce sediment pollutants. The invention can maintain the activity of microorganisms for a long time, realize the slow release of active microorganisms, and provide bacterial growth and reproduction attachment space, and can release active microorganisms to the water body for a long time, playing a role in continuous purification of the water body.

Claims

1. A method for preparing chitosan-modified montmorillonite loaded with microorganisms for treating black and smelly water bodies, characterized in that: The following steps are involved: (S1) Preparation of sodium montmorillonite: Calcium montmorillonite is dispersed in water to form a suspension, a quaternary ammonium phosphate surfactant and a sodium-forming agent are added, the temperature is raised and stirred for reaction for 20 h to 30 h, filtered, washed with water, dried, activated, and crushed to obtain sodium montmorillonite; the mass ratio of calcium montmorillonite, quaternary ammonium phosphate surfactant and sodium-forming agent is 100:5-8:20-30; The quaternary ammonium phosphate surfactant is obtained by a preparation method comprising the following steps: adjusting the pH value of a sodium phosphate solution to 3-4 with nitric acid, dropping epichlorohydrin, heating to 70-80°C for reaction for 2-3h, maintaining 70-80°C, dropping a long-chain alkyl tertiary amine, adjusting the pH value to 8-9 with an alkali solution, heating to 85-95°C, continuing the reaction for 3-5h to complete quaternization, and drying to obtain a paste, which is the quaternary ammonium phosphate surfactant; (S2) Chitosan-modified montmorillonite: a suspension of sodium montmorillonite dispersed in water is activated by adding nitric acid solution, carboxymethyl chitosan is added, heated and stirred for reaction, centrifuged, washed with water, and dried to obtain a powdery solid, which is chitosan-modified montmorillonite; The carboxymethyl chitosan has a degree of substitution of 70%-90% and a molecular weight of 50 kDa-200 kDa; (S3) Loading nutrients: adding glucose and peptone to the suspension of chitosan-modified montmorillonite, heating and stirring under microwave conditions, filtering, and drying to obtain chitosan-modified montmorillonite loaded with nutrients; Chitosan modified montmorillonite, the mass ratio of glucose to protein is 100:30-50:20-30; (S4) Loading a composite bacterial agent: immersing the chitosan-modified montmorillonite loaded with nutrients in a composite bacterial solution, stirring at 30°C-35°C for 2h-3h to complete the loading, centrifuging, and vacuum freeze-drying to obtain the chitosan-modified montmorillonite loaded with microorganisms; the composite bacterial solution includes nitrifying bacteria, nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria, bacillus, yeast, and lactic acid bacteria.

2. The preparation method according to claim 1, characterized in that: In step (S1), the sodiumizing agent is at least one of sodium carbonate, sodium chloride, sodium silicate, sodium pyrophosphate, sodium sulfate, sodium oxalate, and sodium acetate.

3. The preparation method according to claim 2, characterized in that: The sodiumizing agent is a compound of sodium pyrophosphate and sodium acetate in a mass ratio of 2-4:

1.

4. The preparation method according to claim 1, characterized in that: In step (S1), the molar ratio of sodium phosphate, epichlorohydrin and long-chain alkyl tertiary amine is 1:2.2-2.7:2.1-2.

5.

5. The preparation method according to claim 1, characterized in that: In step (S2), the carboxymethyl chitosan is a compound of carboxymethyl chitosan with a molecular weight of 50 kDa-80 kDa and carboxymethyl chitosan with a molecular weight of 150 kDa-200 kDa in a mass ratio of 4-7:

1.

6. The preparation method according to claim 1, characterized in that: In step (S2), the concentration of nitric acid is 0.2-0.5 mol / L, and the amount of nitric acid used is to adjust the pH of the system to 3-4; the amount of carboxymethyl chitosan added is 60-80wt% of the mass of sodium montmorillonite; and the heating and stirring reaction is carried out at 60°C-70°C and under stirring conditions for 3h-5h.

7. The preparation method according to claim 1, characterized in that: In step (S3), the microwave conditions are: microwave power 200W-300W, microwave frequency 300MHz-500MHz; heating and stirring to heat to 50°C-60°C.

8. The preparation method according to claim 1, characterized in that: In step (S4), the total concentration of bacteria in the composite bacterial solution is 1×10 8 CFU / mL to 5×10 8 CFU / mL, and the concentration ratio of nitrifying bacteria, denitrifying bacteria, photosynthetic bacteria, Bacillus, yeast and lactic acid bacteria is 80-100:80-100:30-50:10-30:10-30:10-30.

9. The preparation method according to claim 8, characterized in that: In step (S4), the vacuum freeze drying is carried out at -30°C to -40°C and 1.3Pa to 130Pa.

10. A method for treating black and smelly water, characterized in that: The following steps are involved: The chitosan-modified montmorillonite loaded with microorganisms prepared by any one of the preparation methods of claims 1 to 9 is added and activated.

11. The method for treating black and smelly water according to claim 10, characterized in that: The dosage of chitosan-modified montmorillonite loaded with microorganisms is 200 g / m³-600 g / m³.