Preparation and application of oil removal microbial inoculum loaded on nickel-iron-based biochar matrix and bio-based flocculant

Abstract

The invention belongs to the field of oily wastewater treatment, and discloses an oil removal microbial agent loaded on a nickel-iron-based biochar matrix and preparation and application of a bio-based flocculant. The preparation method of the oil removal microbial agent comprises the following steps: crushing ficus microcarpa, mixing the crushed ficus microcarpa with urea and ferronickel slag, and carrying out high-temperature coupling reaction to generate a ferronickel-based biochar fiber matrix; mixing a strain, a strain activating agent and water, stirring and activating to obtain an activated strain; adding the activated strain into a fermentation culture medium for fermentation propagation, then adding the ferro-nickel-based biochar fiber matrix for continuous fermentation, centrifuging after fermentation to obtain a precipitate, adding glycerol and cysteine into the precipitate, uniformly mixing, and drying to obtain the oil removal microbial agent loaded on the ferro-nickel-based biochar matrix. The oil removal effect of the oil removal microbial inoculum prepared from the mixed microbial inoculum is better than that of a microbial inoculum prepared from a single pure strain. The oil-removing microbial agent can be further used for preparing a bio-based flocculant, and the oil-removing microbial agent and the bio-based flocculant can be used for treating oil-containing wastewater.

Description

Technical Field

[0001] The invention belongs to the field of oily wastewater treatment, and particularly relates to the preparation and application of an oil removal bacterial agent loaded on a nickel-iron based biochar matrix and a bio-based flocculant. Background Art

[0002] Agricultural and forestry solid waste has the characteristics of large output, many types, and great pressure on the environment to accommodate. At present, except for a small amount of agricultural and forestry waste that is recycled, most of them are incinerated or landfilled. Incineration or landfilling causes the organic matter contained in agricultural and forestry waste to be mineralized, and releases a large amount of carbon dioxide into the environment, causing greenhouse gas emissions and ecosystem damage. At the same time, agricultural and forestry waste is a kind of biomass resource, and incineration or landfilling also causes huge waste of resources. Under the background of "carbon peak" and "carbon neutrality" in my country, how to quickly reduce agricultural and forestry waste and achieve the dual goals of carbon stabilization and resource utilization is one of the problems that need to be solved urgently.

[0003] As a kind of agricultural and forestry solid waste, how to efficiently utilize discarded banyan whiskers has attracted the attention of scientific researchers in today's exploration of sustainable resource utilization. Banyan whiskers are mainly composed of cellulose, lignin and polysaccharides. These natural polymers can be pyrolyzed under high temperature and hypoxic conditions and converted into biochar with excellent adsorption properties. After specific chemical treatment and physical processing, the originally loose banyan whiskers can be made into fibers, further expanding its application range in the field of materials science. Nickel-iron slag is one of the industrial solid wastes. At present, the main treatment method for nickel-iron slag is still landfill. In the case of the current shortage of land resources, it is necessary to find a way to utilize nickel slag as a resource. However, there is no report in the prior art on the preparation of degreasing bacteria agents using banyan whiskers and nickel slag together.

[0004] Commonly used flocculants can be divided into inorganic flocculants and organic polymer flocculants according to their properties. They have the advantages of low operating cost, short flocculation time and good flocculation effect. However, aluminum salt flocculants in inorganic flocculants have the risk of causing diseases such as Alzheimer's disease, osteomalacia, nervous system diseases, microcytic anemia, etc., while iron salt flocculants are prone to corrode pipeline equipment and affect water quality. The hydrolysis product monomers of organic polymer flocculants such as polyacrylamide (PAM) have certain toxicity. During use, they will not only produce "three-cause" effects (mutagenicity, carcinogenicity, and teratogenicity) on livestock and humans, but also easily cause secondary environmental pollution.

[0005] Microbial flocculants can overcome the inherent defects of these commercial flocculants and are expected to become a safer alternative to traditional flocculants. Microbial flocculants (MBF) are a type of microbial metabolites with flocculation activity. They can condense and precipitate non-degradable solid suspended particles and colloidal particles in liquids. They are highly efficient, non-toxic, non-secondary pollution-free, biodegradable and safe green water treatment agents. Compared with traditional commonly used flocculants, microbial flocculants are safe and non-toxic, have high flocculation efficiency, are easy to biodegrade, and have no secondary pollution. They are of great significance to human health and environmental protection, and are becoming more and more a research hotspot for flocculants. However, the existing microbial flocculant extraction technology is mostly directly extracted and prepared by fermenting bacterial strains. The extraction amount of biological flocculants is small and the extraction cost is high. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing an oil removal bacterial agent loaded on a nickel-iron based biochar matrix.

[0007] Another object of the present invention is to provide an oil removal bacterial agent loaded on a nickel-iron based biochar matrix prepared by the above method.

[0008] Another object of the present invention is to provide a bio-based flocculant.

[0009] Another object of the present invention is to provide the application of the above-mentioned oil removal bacteria agent and bio-based flocculant loaded on the nickel-iron based biochar matrix.

[0010] The purpose of the present invention is achieved through the following solutions:

[0011] A method for preparing an oil removal bacterial agent loaded on a nickel-iron based biochar matrix comprises the following steps:

[0012] (1) crushing banyan tree whiskers, mixing them with urea and nickel-iron slag, and then subjecting them to a high-temperature coupling reaction to generate a nickel-iron-based biochar fiber matrix;

[0013] (2) mixing the bacterial strain, bacterial strain activator and water, stirring and activating the mixture, and obtaining an activated bacterial strain;

[0014] (3) adding the activated bacteria to the fermentation medium for fermentation and expansion, and then adding the nickel-iron-based biochar fiber matrix of step (1) to continue fermentation. After the fermentation is completed, centrifugation is performed to obtain a precipitate, glycerol and cysteine ​​are added to the precipitate, the mixture is mixed evenly, and then dried to obtain an oil removal bacterial agent loaded on the nickel-iron-based biochar matrix.

[0015] The banyan tree whiskers described in step (1) are crushed and then passed through a 100-mesh sieve for later use; the nickel slag described in step (1) is preferably dried before mixing and then crushed to pass through a 100-mesh sieve.

[0016] The mass ratio of the crushed banyan tree hair, urea and nickel-iron slag in step (1) is 200-100:20-10:2-1, preferably 100:10:1.

[0017] The high temperature coupling described in step (1) refers to heating to 750-850°C at a heating rate of 30-15°C / min and keeping warm for 1.5-2.5h in a CO2 atmosphere, preferably heating to 800°C at a heating rate of 20°C / min and keeping warm for 2h.

[0018] After the high temperature coupling in step (1), the obtained sample is washed with sterile water, dried, ground and passed through a 100-mesh sieve for later use. The drying is preferably carried out at 80°C.

[0019] The bacterial species described in step (2) is at least one of Achromobacter sp., Pseudomonas sp., Candida lipolytica, and Microbacterium oleivorans, preferably a mixture of the four bacterial species, and more preferably a mixture of Achromobacter sp., Pseudomonas sp., Candida lipolytica, and Microbacterium oleivorans in a volume ratio of 2:2:1:1.

[0020] The bacterial strain activator described in step (2) is at least one of the bacterial strain activator of Water Country or the bacterial strain activator of Fanxing Biology;

[0021] The amount ratio of the bacteria, bacteria activator, and water in step (2) is 25-10g:5-1g:200-100mL, preferably 10g:1g:100mL.

[0022] The stirring activation in step (2) refers to stirring activation at 30-35° C. for 2-4 hours, and the stirring speed is preferably 100-150 r / min.

[0023] The formula of the fermentation medium described in step (3) includes D-glucose, yeast extract, sodium thiosulfate, sodium carbonate, cysteine ​​(mass fraction 1%), sodium chloride, disodium hydrogen phosphate, and water.

[0024] Preferably, the formula of the culture medium includes 8-15 g / L D-glucose, 4-8 g / L yeast extract, 0.5-2 g / L sodium thiosulfate, 1-5 g / L sodium carbonate, 2-6 g / L cysteine, 2-8 g / L sodium chloride, 1-2 g / L disodium hydrogen phosphate, and water is added to make up the volume.

[0025] Further preferably, the formula of the culture medium is: D-glucose 10g / L, yeast extract 5g / L, sodium thiosulfate 1g / L, sodium carbonate 2g / L, 1% cysteine ​​5mL / L, sodium chloride 5g / L, disodium hydrogen phosphate 1g / L. The pH of the culture medium is 7.0-8.5, preferably 7-8.

[0026] The fermentation expansion culture in step (3) refers to culturing at 30-35°C, 120-150rpm shaking table for 2-3 hours, preferably culturing at 32°C, 150rpm shaking table for 2 hours; the addition of nickel-iron-based biochar fiber matrix to continue fermentation refers to continuing to culture at 30-35°C, 120-150rpm shaking table for 8-12 hours, preferably culturing at 32°C, 150rpm shaking table for 10 hours.

[0027] The volume ratio (V / V) of the activated bacteria to the fermentation medium in step (3) is 1 ml: 8-15 ml, preferably 1:10; the volume mass ratio (V:M) of the fermentation medium to the nickel-iron-based biochar fiber matrix is ​​1-2 mL: 1-2 g, preferably 2 mL: 1 g;

[0028] The centrifugation described in step (3) refers to centrifugation at 1000-1200 rpm and 4°C to obtain a precipitate.

[0029] The amounts of glycerol and cysteine ​​used in step (3) satisfy the following conditions: 8-12 g of glycerol is used for every 100 mL of fermentation medium used in step (3), and 8-12 mL of 1 wt% cysteine ​​is used for every 100 mL of fermentation medium used.

[0030] The drying in step (3) is preferably performed by wrapping the mixture of the precipitate, glycerol and cysteine ​​with plastic wrap, gauze or tin foil and piercing holes therein, and then placing the mixture in an oven at 35-37° C. and drying it with forced air for 2-3 days.

[0031] An oil removal bacterial agent loaded on a nickel-iron based biochar matrix prepared by the above method.

[0032] A bio-based flocculant is prepared from the above-mentioned oil removal bacterial agent loaded on a nickel-iron-based biochar matrix, and the specific steps are as follows:

[0033] (a) mixing an oil-removing bacterial agent loaded on a nickel-iron-based biochar matrix, a bacterial strain activator and sterile water, stirring and activating to obtain an activated oil-removing bacterial agent, and then adding the activated oil-removing bacterial agent to a fermentation medium for fermentation culture to obtain a fermentation product;

[0034] (b) The fermented product obtained in step (a) is subjected to heat treatment and then the pH value is adjusted to alkaline, followed by ultrasonic treatment and centrifugal filtration, and the resulting liquid is the bio-based flocculant.

[0035] The strain activator described in step (a) is at least one of the Shuizhiguo strain activator or the Fanxing biological strain activator; the amount ratio of the deoiling bacteria agent, the strain activator and the sterile water loaded on the nickel-iron based biochar matrix is ​​10-15g:1-2g:100-150mL, preferably 10g:1g:100mL; the stirring activation refers to stirring activation at 30-35°C for 2-4h, and the stirring speed is preferably 120-150r / min.

[0036] The formula of the fermentation medium in step (a) comprises D-glucose, yeast extract, sodium thiosulfate, sodium carbonate, cysteine ​​(mass fraction 1%), sodium chloride, disodium hydrogen phosphate and water.

[0037] Preferably, the formula of the culture medium includes 8-15 g / L D-glucose, 4-8 g / L yeast extract, 0.5-2 g / L sodium thiosulfate, 1-5 g / L sodium carbonate, 2-6 g / L cysteine, 2-8 g / L sodium chloride, 1-2 g / L disodium hydrogen phosphate, and water is added to make up the volume.

[0038] Further preferably, the medium formula is: D-glucose 10g / L, yeast extract 5g / L, sodium thiosulfate 1g / L, sodium carbonate 2g / L, 1% cysteine ​​5mL / L, sodium chloride 5g / L, disodium hydrogen phosphate 1g / L. The pH of the medium is 7.0-8.5, preferably 7-8.

[0039] In step (a), the amount of the activated deoiling bacteria agent and the fermentation medium is such that the volume ratio of the activated deoiling bacteria agent to the fermentation medium is 1-2:10-20, preferably 1:10.

[0040] The fermentation culture in step (a) refers to culturing at 30-35°C, 120-150 rpm shaking for 20-30 hours, preferably at 32°C, 150 rpm shaking for 24 hours;

[0041] The heating treatment described in step (b) refers to heating to 45-50°C and keeping warm for 15-20 minutes; the adjusting pH to alkalinity refers to adjusting the pH to 8-9; the ultrasound refers to ultrasound at a constant temperature of 50°C for 3-5 minutes; the centrifugation refers to centrifugation at 10000-12000rpm and 1-4°C for 15-20 minutes; the filtration refers to filtration with a 0.22um syringe microporous filter membrane.

[0042] The above oil removal bacteria agent and bio-based flocculant loaded on the nickel-iron-based biochar matrix are used in treating oily wastewater, wherein the oily wastewater is preferably wastewater containing petroleum hydrocarbons, more preferably printing and dyeing wastewater, and machining fluid wastewater.

[0043] A method for treating oily wastewater using an oil removal bacterial agent loaded on a nickel-iron based biochar matrix comprises the following steps:

[0044] The deoiling bacterial agent, bacterial activator and water loaded on the nickel-iron-based biochar matrix are stirred and mixed to obtain an activated bacterial agent, and then the activated bacterial agent is added to the oily wastewater to be treated (the pH of the wastewater is adjusted to 8-9), mixed evenly and then aerated;

[0045] The dosage ratio of the oil removal bacteria agent, bacteria activator and water loaded on the nickel-iron based biochar matrix is ​​10-15g:1-2g:100-150mL, preferably 10g:1g:100mL; the stirring activation refers to stirring activation at 30-35°C for 2-4h, and the stirring speed is preferably 120-150r / min.

[0046] The amount of the activated bacterial agent added is 1.5-5% of the volume of the oily wastewater to be treated, preferably 2%.

[0047] A method for treating oily wastewater using a bio-based flocculant comprises the following steps:

[0048] The pH of the oily wastewater to be treated is adjusted to alkaline, stirred for the first time, then a coagulant and a bio-based flocculant are added, stirred for the second time, and finally allowed to stand.

[0049] The pH value is adjusted to alkaline, that is, adjusted to pH=8-9;

[0050] The first stirring speed is 120-180 rpm, and the stirring time is 2-3 minutes; preferably, the first stirring speed is 140-150 rpm, and the stirring time is 2-3 minutes.

[0051] Preferably, the coagulant aid is a calcium salt, such as calcium chloride.

[0052] Preferably, the coagulant is added in the form of a solution with a concentration of 0.8-1.2 g / L, and the amount of the coagulant added is 2-3% of the weight of the oily wastewater.

[0053] Preferably, the amount of the bio-based flocculant added is 0.5-2% of the weight of the oily wastewater, preferably 2%. That is, even if a small amount of bio-based flocculant is added, the present invention has a good treatment effect on the oily wastewater.

[0054] Preferably, the second stirring is first stirring at a speed of 140-150 rpm for 1-2 min, and then stirring at a speed of 25-30 rpm for 8-10 min.

[0055] Preferably, the standing time is 20-30 minutes.

[0056] After standing, the wastewater is stratified, the turbidity removal rate can reach 80%-95%, and the COD removal rate can reach 60%-75%.

[0057] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0058] (1) The experimental parameters listed in the present invention are used to set the experimental conditions, and the nickel-iron-based biochar fiber matrix generated by the high-temperature coupling reaction has the advantages of large specific surface area and large total pore volume.

[0059] (2) The nickel-iron-based biochar fiber matrix has a large specific surface area and rich functional groups, which can provide more bacterial adsorption sites and electron shuttle channels to accelerate the electron transfer process. The effective live bacterial count of the oil removal agent prepared using the nickel-iron-based biochar fiber matrix is ​​greater than 5 billion / g.

[0060] (3) Compared with other common culture media, the improved fermentation culture formula enables faster bacterial growth, longer stable period, and greater bacterial count.

[0061] (4) The COD removal effect of the bacterial agent prepared by mixed strains is better than that of the bacterial agent prepared by a single pure strain.

[0062] (5) The method of preparing oil removal agent microbial flocculant by heating alkalinization and ultrasonic extraction can extract more oil removal agent than other extraction methods.

[0063] (6) The raw materials for the preparation of microbial agents are agricultural solid waste, which can realize the resource utilization of solid waste. The use of microbial agents to prepare microbial flocculants has simple operation steps and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is the appearance of the nickel slag raw material in the embodiment.

[0065] Figure 2This is a photo of the prepared nickel-iron based biochar fiber matrix.

[0066] Figure 3 It is a growth curve diagram of the mixed bacterial agent of the present invention in the improved fermentation medium of Example 1, LB medium and nutrient broth medium.

[0067] Figure 4 This is a comparison chart of the COD removal effects of the oil removal agents prepared with the mixed strains in Example 1 and the single strains in Comparative Examples 7-10.

[0068] Figure 5 This is the thermogravimetric analysis diagram of bio-based flocculant. DETAILED DESCRIPTION

[0069] The present invention is further described in detail below in conjunction with the examples and drawings, but the embodiments of the present invention are not limited thereto. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0070] Unless otherwise specified, the embodiments are carried out at room temperature, which is 25-35°C.

[0071] Example 1

[0072] 1.1 Preparation of modified nickel-iron-based biochar fiber matrix

[0073] Required raw materials: banyan tree whiskers, urea, nickel slag

[0074] Nickel slag: Nickel slag is taken from a nickel industry company in Guangdong Province. The company uses wet laterite ore as raw material. The red nickel ore is dried in a rotary kiln, reduced and roasted, and smelted in an ore-heating furnace to produce nickel alloy products. The slag produced by the ore-heating furnace enters the slag flushing pool for water quenching. The nickel slag used in this experiment is the nickel slag obtained from the slag flushing pool. The nickel slag in the slag flushing pool is scooped out of the water quenching pool by a slag grabber and placed in a slag bin beside the pool to drain the water. When the slag water does not leak, it is scooped out by an excavator and transported. The appearance of the nickel slag raw material can be seen. Figure 1 , the raw material ingredients are shown in Table 1 below.

[0075] Table 1 Main components of nickel slag

[0076] Element Ni Fe <![CDATA[Cr2O3]]> <![CDATA[SiO2]]> MgO CaO <![CDATA[Al2O3]]> ％ 0.038～0.068 8～9.31 1.01～1.12 47.28～48.41 29.43～30.546 1.36～1.39 3.77～3.87

[0077] (1) Raw material pretreatment

[0078] Crushing the banyan tree: crush the banyan tree using a crusher (model YDC-QLFSJ) and pass through a 100-mesh sieve for later use;

[0079] Nickel slag pretreatment: Nickel slag is placed in an oven at 105°C and dried for 24 hours. Nickel slag is preliminarily crushed to pass through a 100-mesh sieve before mixing.

[0080] (2) Mix the raw materials in proportion

[0081] The synthetic modified biochar fiber matrix was prepared by mixing the banyan tree beard crushed material + urea + nickel-iron slag. The mass ratio of the banyan tree beard crushed material: urea: nickel-iron slag was 100:10:1.

[0082] (3) High temperature coupling reaction to generate nickel-iron-based biochar fiber matrix

[0083] After mixing the raw materials, they were placed in a well-sealed quartz tube furnace and calcined at 800°C in a CO2 atmosphere. The heating rate was 20°C / min and the holding time was 2h. The obtained samples were washed with sterile water, dried at 80°C, ground, sieved (100 mesh), and collected for use. The photo of the prepared nickel-iron-based biochar fiber matrix is ​​shown in Figure 2. Figure 2 shown.

[0084] 1.2 Bacteria Activation

[0085] Oil removal bacteria name: Achromobacter sp. strain number: CCTCC AB 2013198, original number HZ01;

[0086] Pseudomonas sp. strain number: CCTCC DB 20082423;

[0087] Candida lipolytica strain number: CCTCC KY 2008677;

[0088] Microbacterium oleivorans strain number: CCTCC AB 205290.

[0089] Source of strains: China Center for Type Culture Collection.

[0090] Activator: Bacteria Activator (BioNutrition H1 bacteria activator from Wuhan Water Country Environmental Protection Technology Co., Ltd.)

[0091] (1) Preparation of mixed bacterial strains: 4 bacterial strains were mixed in a volume ratio of Achromobacterium: Pseudomonas: Candida lipolytica: Microbacterium petrophagens = 2:2:1:1;

[0092] (2) Mix the bacteria: activator: sterile water in a ratio of 10:1:100. Take 100 ml of sterile water, add 1 g of the bacteria activator, and mix 10 ml of the bacteria. Stir and activate at 35°C for 2 h.

[0093] 1.3 Preparation of inoculants

[0094] (1) Preparation of improved fermentation medium

[0095] The improved 1L fermentation medium formula: D-glucose 10g / L, yeast extract 5g / L, sodium thiosulfate 1g / L, sodium carbonate 2g / L, 1% cysteine ​​5mL / L, sodium chloride 5g / L, disodium hydrogen phosphate 1g / L, fixed to volume with water. The pH of the medium is 8.

[0096] (2) Fermentation and expansion

[0097] After the bacterial liquid seeds were activated, 10 mL was added to 100 mL of fermentation medium and cultured in a shaking incubator at 32°C and 150 rpm for 2 h; then 50 g of the modified nickel-iron-based biochar fiber matrix prepared in step 1.1 was added (fermentation medium V: modified nickel-iron-based biochar fiber matrix m = 2 mL: 1 g), and the fermentation culture was continued at 32°C and 150 rpm for 10 h.

[0098] (3) Preparation of degreasing agent

[0099] ① After fermentation is completed, centrifuge at 1200 rpm and 4°C to obtain a precipitate; put the precipitate into a glass dish, and add 8 g of glycerol and 12 mL of 1% cysteine.

[0100] ② Add plastic wrap or gauze or tin foil to make holes on the surface of the glass dish, put it in a 37°C oven, and blow dry it for 3 days to obtain the oil-removing bacterial agent loaded on the nickel-iron-based biochar matrix.

[0101] (4) Preparation of bio-based flocculants

[0102] 2.1 Preparation of fermentation medium

[0103] Improved 1L fermentation medium formula: D-glucose 10g / L, yeast extract 5g / L, sodium thiosulfate 1g / L, sodium carbonate 2g / L, 1% cysteine ​​5mL / L, sodium chloride 5g / L, disodium hydrogen phosphate 1g / L, fixed to volume with water. The pH of the medium is 7.5.

[0104] 2.2 Activation of bacterial agents

[0105] The degreasing bacterial agent prepared in step 1.3: activator (BioNutritionH1 bacterial strain activator from Wuhan Water Country Environmental Protection Technology Co., Ltd.): sterile water = 10g: 1g: 100mL, take 100ml of sterile water, add 1g of bacterial strain activator, 10g of the degreasing bacterial agent prepared in step 1.3, and activate with stirring at 35°C for 2h.

[0106] 2.3 Fermentation culture of bacterial agents

[0107] After the bacterial liquid seed is activated, 10 mL is added to 100 mL of the fermentation medium prepared in step 2.1. The culture is shaken at 32°C and 150 rpm for 24 hours to obtain a fermentation bacterial suspension;

[0108] 2.4 Heating-alkalization-ultrasonic extraction of bio-based flocculants

[0109] The specific process of the heating-alkalization-ultrasound method is: heat 100mL of the fermentation bacterial suspension in step 2.3 to 50°C, keep warm for 20 minutes, adjust the pH to 9, ultrasonicate for 5 minutes at a constant temperature of 50°C, and centrifuge at 10000rpm and 4°C for 20 minutes. After centrifugation, filter with a 0.22um syringe microporous filter membrane. The resulting liquid is the bio-based flocculant. The thermogravimetric analysis of the bio-based flocculant is shown in the figure below: Figure 5 shown.

[0110] Comparative Example 1

[0111] Comparative Example 1 is basically the same as Example 1, except that the temperature of the high-temperature coupling reaction in Example 1 to generate the nickel-iron-based biochar fiber matrix is ​​replaced from 800°C to 400°C.

[0112] Comparative Example 2

[0113] Comparative Example 2 is basically the same as Example 1, except that the temperature of the high-temperature coupling reaction in Example 1 to generate the nickel-iron-based biochar fiber matrix is ​​replaced from 800°C to 600°C.

[0114] Comparative Example 3

[0115] Comparative Example 3 is substantially the same as Example 1, except that the raw material in Example 1 is replaced by a mixture of banyan tree beard crushed material + urea + nickel-iron slag with banyan tree beard powder of the same total mass.

[0116] Comparative Example 4

[0117] Comparative Example 4 is basically the same as Example 1, except that the raw materials in Example 1 are replaced by a mixture of banyan tree beard crushed material + urea + nickel-iron slag with an equal total mass of banyan tree beard crushed material and urea, and the mass ratio of banyan tree beard crushed material: urea is 100:10.

[0118] Comparative Example 5

[0119] Comparative Example 5 is basically the same as Example 1, except that the heating-alkalization-ultrasonic extraction of bio-based flocculant in step 2.4 of Example 1 is replaced by centrifugal extraction. The specific operation is as follows: 100 mL of bacterial suspension is centrifuged at 10000 r / min and 4°C for 30 min.

[0120] Comparative Example 6

[0121] Comparative Example 6 is basically the same as Example 1, except that the heating-alkalization-ultrasonic extraction of bio-based flocculant in step 2.4 of Example 1 is replaced by EDTA extraction, and the specific operation is as follows: 100 mL of bacterial suspension is added with 10 mL of 2% EDTA, and the reaction is carried out for 2 hours. After the reaction, centrifuge at 12000 r / min for 30 minutes. After centrifugal extraction, the centrifugal extraction is filtered with a 0.22 um syringe microporous filter membrane.

[0122] Comparative Example 7

[0123] Comparative Example 7 is substantially the same as Example 1, except that the "10 ml mixed bacteria" in step (2) of "1.2 Activation of bacteria" in Example 1 is replaced with "10 ml Colorless Bacillus".

[0124] Comparative Example 8

[0125] Comparative Example 8 is substantially the same as Example 1, except that the "10 ml mixed bacteria" in step (2) of "1.2 Activation of bacteria" in Example 1 is replaced by "10 ml Pseudomonas".

[0126] Comparative Example 9

[0127] Comparative Example 9 is substantially the same as Example 1, except that the "10 ml mixed strains" in step (2) of "1.2 Activation of strains" in Example 1 is replaced by "10 ml Candida lipolytica".

[0128] Comparative Example 10

[0129] Comparative Example 10 is substantially the same as Example 1, except that the "10 ml mixed bacteria" in step (2) of "1.2 Activation of bacteria" in Example 1 is replaced with "10 ml Microbacterium petrolatum".

[0130] The specific surface area and total void volume of the nickel-iron-based biochar fiber matrix prepared in Example 1 and Comparative Examples 1 and 2 are specifically shown in Table 2 below:

[0131] Table 2 Specific surface area and total void volume of nickel-iron based biochar fiber matrix prepared in Example 1 and Comparative Examples 1-2

[0132] <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Total void volume (cm 3 / g)]]> Comparative Example 1 30.28 0.0527 Comparative Example 2 90.73 0.0873 Example 1 170.35 0.1290

[0133] As can be seen from Table 2, by setting the experimental conditions using the experimental parameters of Example 1, the nickel-iron-based biochar fiber matrix generated by the high-temperature coupling reaction has the advantages of large specific surface area and large total pore volume.

[0134] The effective live bacterial counts of the oil removal bacteria agent loaded on the nickel-iron based biochar matrix prepared in Example 1 and Comparative Examples 3 and 4 are shown in Table 3 below. It can be seen from Table 3 that the effective live bacterial count of the oil removal bacteria agent loaded on the nickel-iron based biochar matrix prepared in Example 1 is greater than 5 billion / gram.

[0135] Table 3 Effective viable bacteria count of the deoiling bacteria agent loaded on the nickel-iron-based biochar matrix prepared in Example 1 and Comparative Examples 3-4

[0136] Effective viable count (dilution plate test results) Comparative Example 3 <![CDATA[2*10 8 pcs / g]]> Comparative Example 4 <![CDATA[6*10 8 pcs / g]]> Example 1 <![CDATA[5*10 9 pcs / g]]>

[0137] The growth curve of the mixed bacterial agent of the present invention (mixed in a volume ratio of Achromobacter sp.: Pseudomonas sp.: Candida lipolytica: Microbacterium oleivorans = 2:2:1:1) in the improved fermentation medium prepared in step (1) of "1.3 Preparation of Bacterial Agent" of Example 1, as well as LB medium (manufacturer: Shanghai MacLean Biochemical Technology Co., Ltd.) and nutrient broth medium (manufacturer: Guangdong Huankai Biological) is shown in the figure below. Figure 3 As shown, from Figure 3 It can be seen that compared with other common culture media, the improved fermentation culture formula can make bacteria grow faster, have a longer stable period, and have a larger number of bacteria.

[0138] The extraction amount of the microbial flocculants prepared in Example 1 and Comparative Examples 5 and 6 is shown in Table 4, wherein the extraction amount refers to the weight of the freeze-dried bioflocculant measured by using an analytical balance after freeze-drying the liquid after centrifugation in a -40°C freeze dryer for 24 hours. It can be seen from Table 4 that the extraction amount of the microbial flocculant prepared in Example 1 is greater than that of Comparative Examples 5 and 6.

[0139] Table 4 Extraction amount of microbial flocculants prepared in Example 1 and Comparative Examples 5 and 6

[0140] Microbial flocculant extraction amount (g / 100mL culture medium) Example 1 0.25-0.40 Comparative Example 5 0.01-0.13 Comparative Example 6 0.05-0.15

[0141] Application Examples

[0142] (1) Treatment of oily wastewater with deoiling bacteria loaded on nickel-iron-based biochar matrix

[0143] The oil removal bacterial agent loaded on the nickel-iron based biochar matrix was activated by the step of "2.2 Activation of Bacterial Agent" in Example 1, and then the activated bacterial agent was added to the printing and dyeing wastewater at 2% of the volume of the printing and dyeing wastewater (the wastewater was taken from a textile factory in Gaoming District, Foshan, and the physical and chemical properties of the wastewater were initial COD = 1200 mg / L, turbidity of 4000 NUT, initial pH = 10.25 ± 0.5, and its pH was adjusted to 8), mixed evenly and aerated, and then samples were taken at different times (days) to determine the COD removal rate in the oily wastewater.

[0144] For comparison, the oil removal bacterial agent loaded on the nickel-iron based biochar matrix prepared in Comparative Examples 7-10 was also activated according to the steps of "2.2 Activation of Bacterial Agent", and then the activated bacterial agent was added to the printing and dyeing wastewater at 2% of the volume of the printing and dyeing wastewater, mixed evenly and aerated, and then samples were taken at different times (days) to determine the COD removal rate in the oily wastewater.

[0145] The removal effects of the oil removal agents prepared by the mixed strains in Example 1 and the single strains in Comparative Examples 7-10 on COD are as follows: Figure 4 As shown, from Figure 4 It can be seen that the oil removal agent prepared by the mixed strains has a better COD removal effect than the oil removal agents prepared by the four single pure strains, indicating that there is a synergistic effect between the four pure strains, resulting in the oil removal strain prepared by the mixed strain in Example 1 having an excellent COD removal effect.

[0146] (2) Bio-based flocculants for treating oily wastewater

[0147] The printing and dyeing wastewater to be treated was regulated (the wastewater was taken from a textile factory in Gaoming District, Foshan, and the physical and chemical properties of the wastewater were initial COD = 1200 mg / L, turbidity of 4000 NUT, and initial pH = 10.25 ± 0.5), and the pH range was adjusted to 8-9. The first stirring speed was 120 rpm, and the stirring time was 3 minutes. Then calcium chloride solution (0.8-1.2 g / L, the mass of calcium chloride solution was 2% of the mass of printing and dyeing wastewater) and microbial flocculant (the amount of microbial flocculant added was 0.5-2% of the weight of printing and dyeing wastewater) were added, and the second stirring was first stirred at a speed of 150 rpm for 1 minute, and then stirred at a speed of 30 rpm for 10 minutes. Let it stand for 30 minutes. After the standing period, the wastewater was layered, and the turbidity and COD removal rate in the water layer were tested (the turbidity and COD were measured using a water quality rapid detector (Tianjin Shengaohua Environmental Protection Technology Co., Ltd.)).

[0148] Table 5 Turbidity of water layer and COD removal rate after treatment under different parameter conditions

[0149]

[0150] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing an oil removal bacterial agent loaded on a nickel-iron based biochar matrix, characterized in that The following steps are involved: (1) crushing banyan tree whiskers, mixing them with urea and nickel-iron slag, and then subjecting them to a high-temperature coupling reaction to generate a nickel-iron-based biochar fiber matrix; (2) mixing the bacterial strain, bacterial strain activator and water, stirring and activating the mixture, and obtaining an activated bacterial strain; (3) adding the activated bacteria to the fermentation medium for fermentation and expansion, and then adding the nickel-iron-based biochar fiber matrix of step (1) to continue fermentation. After the fermentation is completed, centrifugation is performed to obtain a precipitate, glycerol and cysteine ​​are added to the precipitate, the mixture is mixed evenly, and then dried to obtain an oil removal bacterial agent loaded on the nickel-iron-based biochar matrix.

2. The method for preparing the degreasing bacterial agent loaded on the nickel-iron-based biochar matrix according to claim 1, characterized in that: The mass ratio of the crushed banyan tree roots, urea and nickel-iron slag in step (1) is 200-100:20-10:2-1; The high temperature coupling described in step (1) refers to heating to 750-850°C at a heating rate of 30-15°C / min and keeping the temperature for 1.5-2.5h in a CO2 atmosphere.

3. The method for preparing the degreasing bacterial agent loaded on the nickel-iron-based biochar matrix according to claim 1, characterized in that: The bacterial species in step (2) is at least one of Achromobacter, Pseudomonas, Candida lipolytica, and Microbacterium petrolatum, preferably a mixture of the four bacterial species, more preferably a mixture of Achromobacter, Pseudomonas, Candida lipolytica, and Microbacterium petrolatum in a volume ratio of 2:2:1:1; The ratio of the bacterial strain, bacterial strain activator, and water in step (2) is 25-10 g: 5-1 g: 200-100 mL; The stirring activation described in step (2) refers to stirring activation at 30-35° C. for 2-4 hours.

4. The method for preparing the degreasing bacterial agent loaded on the nickel-iron-based biochar matrix according to claim 1, characterized in that: The formula of the fermentation medium described in step (3) includes D-glucose, yeast extract, sodium thiosulfate, sodium carbonate, cysteine, sodium chloride, disodium hydrogen phosphate, and water; The fermentation expansion culture in step (3) refers to culturing at 30-35°C, 120-150rpm shaking for 2-3h; the addition of nickel-iron-based biochar fiber matrix to continue fermentation refers to continuing to culture at 30-35°C, 120-150rpm shaking for 8-12h; The volume ratio of the activated bacteria to the fermentation medium in step (3) is 1 ml: 8-15 ml; the volume mass ratio of the fermentation medium to the nickel-iron-based biochar fiber matrix is ​​1-2 mL: 1-2 g; The centrifugation in step (3) refers to centrifugation at 1000-1200 rpm and 4° C. to obtain a precipitate; The amounts of glycerol and cysteine ​​used in step (3) satisfy the following conditions: 8-12 g of glycerol is used for every 100 mL of fermentation medium used in step (3), and 8-12 mL of 1 wt% cysteine ​​is used for every 100 mL of fermentation medium used; The drying in step (3) is to wrap the mixture of the precipitate, glycerol and cysteine ​​with plastic wrap, gauze or tin foil and pierce holes, and then put it in an oven at 35-37° C. and dry it with forced air for 2-3 days.

5. An oil removal bacterial agent loaded on a nickel-iron based biochar matrix prepared according to the method according to any one of claims 1 to 4.

6. A bio-based flocculant, which is prepared from the degreasing bacterial agent loaded on the nickel-iron-based biochar matrix according to claim 5, the specific steps are as follows: (a) mixing an oil-removing bacterial agent loaded on a nickel-iron-based biochar matrix, a bacterial strain activator and sterile water, stirring and activating to obtain an activated oil-removing bacterial agent, and then adding the activated oil-removing bacterial agent to a fermentation medium for fermentation culture to obtain a fermentation product; (b) The fermented product obtained in step (a) is subjected to heat treatment and then the pH value is adjusted to alkaline, followed by ultrasonication and centrifugal filtration, and the resulting liquid is the bio-based flocculant.

7. The bio-based flocculant according to claim 6, characterized in that: The amount ratio of the degreasing agent, activator and sterile water loaded on the nickel-iron-based biochar matrix described in step (a) is 10-15g:1-2g:100-150mL; the stirring activation refers to stirring activation at 30-35°C for 2-4h; The formula of the fermentation medium in step (a) comprises D-glucose, yeast extract, sodium thiosulfate, sodium carbonate, cysteine, sodium chloride, disodium hydrogen phosphate, and water; In step (a), the amount of the activated degreasing bacterial agent and the fermentation medium is such that the volume ratio of the activated degreasing bacterial agent to the fermentation medium is 1-2:10-20; The fermentation culture in step (a) refers to culture at 30-35°C and 120-150 rpm on a shaking table for 20-30 hours; The heating treatment described in step (b) refers to heating to 45-50°C and keeping warm for 15-20 minutes; the adjusting pH to alkalinity refers to adjusting the pH to 8-9; the ultrasound refers to ultrasound at a constant temperature of 50°C for 3-5 minutes; the centrifugation refers to centrifugation at 10000-12000rpm and 1-4°C for 15-20 minutes; the filtration refers to filtration with a 0.22um syringe microporous filter membrane.

8. Use of the oil removal bacterial agent loaded on the nickel-iron based biochar matrix according to claim 5 and the bio-based flocculant according to claim 6 or 7 in the treatment of oily wastewater.

9. A method for treating oily wastewater using the oil removal bacteria agent supported on a nickel-iron based biochar matrix according to claim 5, characterized in that The following steps are involved: The deoiling bacterial agent, the activator and water loaded on the nickel-iron-based biochar matrix are stirred and mixed to obtain an activated bacterial agent, and then the activated bacterial agent is added to the oily wastewater to be treated, mixed evenly and then aerated; The oil removal agent, activator and water loaded on the nickel-iron-based biochar matrix are used in a ratio of 10-15 g: 1-2 g: 100-150 mL; the stirring activation refers to stirring activation at 30-35° C. for 2-4 hours; The pH of the oily wastewater to be treated is 8-9; The added amount of the activated bacterial agent is 1.5-5% of the volume of the oily wastewater to be treated.

10. A method for treating oily wastewater using a bio-based flocculant according to claim 6 or 7, characterized in that The following steps are involved: The pH of the oily wastewater to be treated is adjusted to alkaline, stirred for the first time, then a coagulant and a bio-based flocculant are added, stirred for the second time, and finally allowed to stand; The pH being adjusted to alkaline refers to adjusting to pH=8-9; The first stirring speed is 120-180 rpm, and the stirring time is 2-3 minutes; The coagulant is a calcium salt; the coagulant is added in the form of a solution with a concentration of 0.8-1.2 g / L, and the amount of the coagulant added is 2-3% of the weight of the oily wastewater; The bio-based flocculant is added in an amount of 0.5-2% of the weight of the oily wastewater; The second stirring is first stirring at a speed of 140-150 rpm for 1-2 min, and then stirring at a speed of 25-30 rpm for 8-10 min; The standing time is 20-30 minutes.

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