A dual-carrier immobilized desulfurization bacteria microsphere and its preparation method and application

Abstract

The invention discloses a dual-carrier immobilized desulfurization bacteria microsphere and its preparation method and application. The dual-carrier immobilized desulfurization bacteria microsphere has a "core-shell" structure, with activated carbon loaded with desulfurization bacteria as the core and a gel formed by calcium ion cross-linking sodium alginate as the shell; its preparation method is: after the desulfurization bacteria are loaded on the activated carbon, they are immersed in the oil-water bag formed by the sodium alginate aqueous solution and liquid paraffin, and calcium chloride solution is added to react to form gel microspheres, the dual-carrier immobilized desulfurization bacteria microsphere improves the stability of the desulfurization bacteria through dual immobilization, and at the same time, the protective layer formed by calcium ion cross-linking sodium alginate is used to improve its salt resistance, and it can be recycled, and its preparation method is simple, low cost, and conducive to large-scale production. The desulfurization bacteria microsphere is applied to the removal of sulfide from the biogas alkali washing desulfurization liquid, and still has a high purification efficiency at a salt concentration of 0.2-0.8 mol / L, and its desulfurization rate is not less than 96%, and the sulfur oxidation rate is not less than 85%.

Description

Technical Field

[0001] The invention relates to a desulfurization bacteria microsphere, in particular to a dual-carrier immobilized desulfurization bacteria microsphere, and also to a preparation method and application of the dual-carrier immobilized desulfurization bacteria microsphere, belonging to the technical field of biological desulfurization. Background Art

[0002] As a renewable energy source, biogas has been paid attention to and developed by governments of various countries due to its advantages such as environmental friendliness and low cost. Biogas contains different concentrations of hydrogen sulfide (H2S) depending on the raw materials. 2 S), H 2 S not only corrodes transmission pipelines and power generation equipment, but also produces SO through the combustion process. x .

[0003] Currently, H 2 The main methods of removing sulfur include dry desulfurization, wet desulfurization, and biological desulfurization. Dry desulfurization is suitable for small-scale biogas purification projects and is only suitable for low-concentration H 2 Removal of S. Wet desulfurization is mainly used in southern my country. It has the advantages of high desulfurization efficiency and suitability for medium and large biogas projects. However, the elemental sulfur produced by this process is not easy to use and is mostly treated as hazardous waste. In addition, its operating cost is high and the degree of automation is low. Biogas biological desulfurization, as the main promotion technology for existing biogas purification, has the advantages of high automation, high treatment rate, low cost, and suitability for the removal of medium and high load hydrogen sulfide. Its basic reaction principle is as follows:

[0004] OH - +H 2 S→HS - +H 2 O

[0005] HS - +1 / 2O 2 →S↓+OH -

[0006] According to the process technology, biological desulfurization is divided into integrated and separated types. The integrated biological desulfurization occupies a small area and has high processing efficiency, but it is easy to cause clogging of the filler; the separated biological desulfurization separates the biogas purification from the alkali solution regeneration process, overcoming the defect of easy clogging of the integrated filler. In addition, the separated biological desulfurization has the advantages of large processing capacity and is suitable for biogas purification projects with high hydrogen sulfide concentrations. Therefore, the separated biological desulfurization is mainly used in the industry, and the most representative process is the shell-Paques process.

[0007] The separation biological desulfurization process mainly consists of three parts: 1. Alkali spray tower; 2. Biological regeneration pool; 3. Sulfur precipitation pool. After the biogas containing hydrogen sulfide is sprayed with alkali solution, the purified biogas is discharged from the upper end of the spray tower, and the desulfurized liquid containing sulfide flows into the biological regeneration pool for alkali solution regeneration; the desulfurized liquid is oxidized by microorganisms, and the regenerated circulating liquid is returned to the alkali spray tower, and the solid-liquid mixture is pumped to the sulfur precipitation pool for precipitation and impurity removal.

[0008] The circulating fluid contains a large amount of salt. After circulating spraying, the salt concentration in the biological regeneration pool increases. The activity of microorganisms decreases with the increase of salt in the regeneration pool. When the salt concentration is ≥0.4mol / L, the microorganisms are inactivated. To solve this problem, researchers screened and cultivated halophilic sulfur-oxidizing bacteria from saline-alkali lakes, mines, and textile wastewater to achieve the purpose of desulfurization and salt tolerance. CN111676716A uses halophilic and alkaliphilic sulfur microspirilla to oxidize H 2 S is elemental sulfur, and H 2 The S removal rate is 99%; CN104857842 screened out the salt-alkali lake mud in the Ordos area at pH = 11, c (Na + )=0.4mol / L Sulfur-oxidizing multifunctional sulfur alkaline vibrio, which can process H<3000mg / L 2 S, and the desulfurization rate is as high as 99%, but all of them are based on a single strain of bacteria, which is not only difficult to screen but also has poor resistance to environmental shock loads, and is not suitable for industrial use.

[0009] Immobilization technology is to fix microorganisms on a carrier, which can maintain a high density of moisture and maintain biological activity, and can reproduce rapidly under suitable conditions. It has the advantages of increasing the concentration of microorganisms, tolerating high concentrations of toxic substances, resisting shock loads, and being reusable. The main methods of immobilization are adsorption, embedding, cross-linking, and biological reaction. It has been widely used in the food-grade medical industry. Among them, the adsorption method uses van der Waals force, double layer force and polar force to fix microorganisms. It has the advantages of mild conditions, easy adsorption process, no damage to cell structure and low cost, but this force also has the defects of weak force and loose binding. Encapsulation immobilization technology is to embed microorganisms in a semipermeable carrier to support immobilized microorganisms, which can control the leakage of microbial cells and reduce the concentration of toxic pollutants in the immobilized internal environment, but its mass transfer performance is poor, the steric hindrance is large, and the carrier is non-renewable. Patent CN110964711A uses an embedding method to prepare an acid-resistant microbial capsule, using boric acid-calcium chloride as an embedding carrier, H 2The removal efficiency of S can reach 90-98%. However, boric acid has a certain inhibitory effect on microbial activity. Patent CN110452900A uses polyvinyl alcohol-sodium alginate composite immobilization carrier and uses embedding cross-linking method to reduce the toxicity of coking wastewater to microorganisms, increase the concentration of microorganisms, and give full play to the role of composite flora microorganisms. However, polyvinyl alcohol-sodium alginate immobilization has the disadvantages of poor biological activity, weak mechanical strength, and great influence by hydraulic shock.

[0010] In summary, in order to solve the problem of reduced microbial activity due to increased salt content in the biological desulfurization process, the existing technology has defects such as high production cost, poor microbial stability and low activity. Therefore, it is of great significance to develop a low-cost, high-stability and high-activity microbial composite material. Summary of the invention

[0011] In view of the defects of existing biological desulfurization technology such as high cost, poor microbial stability and low activity, the purpose of the present invention is to provide a dual-carrier immobilized desulfurization bacteria microsphere, which has activated carbon loaded with desulfurization bacteria as the core and a gel formed by calcium ion cross-linked sodium alginate as the shell, forming a "core-shell" structure, realizing the dual immobilization of desulfurization bacteria, having good stability, high desulfurization activity, high salt tolerance, and can be recycled.

[0012] The second object of the present invention is to provide a method for preparing dual-carrier immobilized desulfurization bacteria microspheres, which is simple and easy to operate, has low cost, and can meet the needs of large-scale production.

[0013] The third object of the present invention is to provide an application of dual-carrier immobilized desulfurization bacteria microspheres, which are used to remove sulfides from sulfur-containing wastewater. They have high biological activity, good stability, and are renewable. They also have strong salt tolerance and still show high biological activity in an environment with a salt concentration of 0.2 to 0.8 mol / L. The desulfurization rate is ≥96%, and the sulfur recovery rate is not less than 85%.

[0014] In order to achieve the above technical objectives, the present invention provides a method for preparing dual-carrier immobilized desulfurization bacteria microspheres, the method comprising the following steps:

[0015] 1) Loading desulfurization bacteria on activated carbon to obtain activated carbon pellets loaded with desulfurization bacteria;

[0016] 2) adding liquid paraffin into the sodium alginate aqueous solution and stirring to form oil-in-water;

[0017] 3) After the activated carbon balls loaded with desulfurization bacteria are immersed in oil-in-water, CaCl is slowly added under stirring conditions. 2 The solution reacts to form gel microspheres.

[0018] The present invention adopts double carriers to fix desulfurization bacteria microspheres. The desulfurization bacteria are first loaded onto activated carbon with a porous structure by adsorption, and the desulfurization bacteria can be stably fixed on the inner carrier of the activated carbon to reduce the free diffusion of microorganisms in the adverse external environment. The coating effect of the external carrier calcium alginate gel is then used to further improve the loading stability of the desulfurization bacteria. At the same time, the calcium alginate gel coated on the outside of the activated carbon is used to generate an ion exchange reaction in high-salt wastewater, and the Na in the liquid is attracted to the desulfurization bacteria. + or exclude Ca 2+ , to reduce Na + , Ca 2+ Ions enter the gel, reducing the impact of high salt concentration on microbial activity and achieving dual protection for desulfurization bacteria. Because the calcium alginate hydrogel is in a salt environment, the network structure will expand and release some Ca 2+ Ions, when there is Na + When Ca 2+ The release of -COO makes the -COO site vacant, and the gel is easier to interact with Na than microorganisms. + Reaction occurs, so Na + closer to the "shell", thus blocking the Na + Enter the core and inhibit microbial activity; when there is Ca in the environment 2+ When the gel “shell” excludes Ca to a certain extent, 2+ , making Ca 2+ Stay away from the gel, thereby protecting the "core".

[0019] In addition, the liquid paraffin used in the present invention forms an oil-water layer, further improving the stability of the desulfurization bacteria microspheres, and the material is cheap and easy to obtain; the calcium chloride used is very easy to form a gel with sodium alginate, which can be combined with Na + The exchange occurs and combines with the carboxyl group of sodium alginate, which has the effect of improving the mass transfer performance of the immobilized microspheres, enhancing the mechanical strength of the microspheres, and resisting impact loads. In the process of preparing microspheres, slowly adding the calcium chloride solution to the oil-water bag is beneficial to controlling the volume and shape of the microspheres. If calcium chloride is added directly at one time, it is easy to cause the microspheres to aggregate with each other.

[0020] As a preferred solution, the desulfurization bacteria include at least one of Pseudomonas, Desulfobacillus, Desulfurizing Rhodobacter and floccules thereof.

[0021] There is no strict restriction on the genus of desulfurizing bacteria in the present invention, and any bacteria species that can achieve the purpose of desulfurization can be used in the present invention.

[0022] As a preferred solution, the diameter of the activated carbon is 3 to 7 mm. If the diameter of the activated carbon is too small, it will cause a lot of dust, which is not conducive to the fixation of microorganisms; if the diameter of the activated carbon is too large, its specific surface area is reduced, and the amount of microbial adsorption is reduced.

[0023] As a preferred solution, the process of loading desulfurization bacteria on activated carbon is to immerse the activated carbon in a desulfurization bacteria liquid with a volume percentage concentration of 10 to 30%. The loading process can regulate the loading amount of activated carbon on desulfurization bacteria by controlling the volume content of desulfurization bacteria in the desulfurization bacteria liquid. If the amount of desulfurization bacteria added is too large, that is, the loading amount of activated carbon on desulfurization bacteria is too large, the density of desulfurization bacteria in the microspheres increases, causing the desulfurization bacteria close to the core to be unable to obtain sufficient nutrients and oxygen, and the microbial metabolism is reduced or even dead. On the contrary, if the amount of desulfurization bacteria added is too small, the number of desulfurization bacteria that can act is too small, which is not conducive to the desulfurization reaction.

[0024] As a preferred solution, the activated carbon is pre-treated by drying and sterilization; the drying time is 20 to 28 hours. As a more preferred solution, the sterilization treatment is a high-temperature treatment at 121°C. In order to prevent contamination by other microorganisms and ensure the purity of microorganisms during the biological immobilization process, the activated carbon can be dried and sterilized at high temperature.

[0025] As a preferred solution, the mass concentration of the sodium alginate aqueous solution is 1-5%. The mass concentration of the liquid paraffin in the sodium alginate aqueous solution is 2-5%. 2 The mass concentration of the solution is 2-6%. 2 CaCl in solution 2 The mass of sodium alginate is 20-300% of that of sodium alginate.

[0026] In the process of using sodium alginate to fix the activated carbon beads loaded with desulfurization bacteria, the concentration of sodium alginate is directly related to the ball formation and mechanical strength of the bacteria balls. The low-concentration sodium alginate gel balls are easy to make, but the cross-linking degree is low, it is not easy to form balls, and the mechanical lightness is low; on the contrary, the high-concentration sodium alginate gel balls have high mechanical strength, but poor mass transfer, and the bacteria balls are not easy to form balls due to tailing. Therefore, in order to ensure that the formed desulfurization bacteria microspheres have good mechanical strength and ball formation, the mass concentration of sodium alginate needs to be controlled within the range of 1-5%.

[0027] The concentration of calcium chloride directly affects the mass transfer performance, mechanical strength and impact load resistance of the microspheres. When the mass concentration of calcium chloride is lower than 2%, the coagulation ability of the microspheres is too weak, the cortex is too thin, the impact load resistance is small, and the cross-linking time is too long, resulting in Ca 2+ Diffusion into the gel is not conducive to microbial reproduction; when the mass concentration of calcium chloride is higher than 5%, a dense cross-linked structure is quickly formed on the contact surface with sodium alginate, making the overall microspheres uneven in size, and also adversely affecting the mechanical strength and mass transfer of the entire gel ball. At the same time, if the amount of calcium chloride added is too little, it cannot fully react with the oil-water bag, and the amount of microspheres formed is small; if the amount added is too much, it will waste resources and increase costs.

[0028] As a preferred solution, the diameter of the gel microspheres is 3 to 10 mm. The diameter of the desulfurization bacteria microspheres obtained by the preparation method of the present invention is 5 to 10 mm, but the desulfurization bacteria microspheres are too small to be collected and processed.

[0029] The present invention also provides a dual-carrier immobilized desulfurization bacteria microsphere, which is prepared by the above method. The desulfurization bacteria microsphere has high biological activity, strong stability, good salt tolerance, and still exhibits high biological activity in an environment with a salt concentration of 0.2 to 0.8 mol / L. The salt components mainly include sodium salt and calcium salt.

[0030] The present invention also provides an application of dual-carrier immobilized desulfurization bacteria microspheres, which is applied to the removal of sulfide in sulfur-containing waste liquid.

[0031] The desulfurization bacteria microspheres can be applied to any high-salinity waste desulfurization treatment field, including sulfur-containing waste gas or wastewater.

[0032] As a preferred solution, the sulfur-containing waste liquid is biogas alkali-washed desulfurized waste liquid; the salt concentration in the sulfur-containing waste liquid is 0.2-0.8 mol / L; and the hydrogen sulfide content in the biogas is 50-4000 ppm.

[0033] When the desulfurization bacteria microspheres are applied to the removal of sulfide from the biogas alkaline desulfurization liquid, the desulfurization rate is not less than 96%, and the sulfur recovery rate is not less than 80%. When the salt concentration in the alkaline desulfurization liquid exceeds 0.8 mol / L, the gel microspheres will dissolve, resulting in a decrease in the desulfurization efficiency. In addition, when the hydrogen sulfide content in the biogas exceeds 4000 ppm, it will cause a large microbial treatment load, which is not conducive to microbial reproduction. Therefore, it is necessary to control the concentration of hydrogen sulfide in the original biogas not to be too high. In addition, the use of the dual-carrier immobilized desulfurization bacteria microspheres in the present invention in the desulfurization process of the alkaline desulfurization liquid not only solves the poor stability of the adsorption method, but also solves the defect of poor mass transfer of the embedding method. Sodium alginate-calcium chloride has a certain adsorption effect on microorganisms at the same time, which increases the stability of microorganisms in the carrier load. The encapsulation of activated carbon by sodium alginate solves the problem of difficult collection and regeneration of activated carbon at the same time. The inner core of activated carbon is mainly composed of microporous structures, which has a certain adsorption capacity for sulfur anions, thus facilitating the rapid adsorption and enrichment of sulfides, improving the contact efficiency with desulfurization bacteria, and greatly increasing the sulfur oxidation rate.

[0034] As a preferred solution, in the process of removing hydrogen sulfide from biogas, the biogas containing hydrogen sulfide first reacts with a desulfurizing agent, and the obtained desulfurized liquid is oxidized into elemental sulfur or sulfate by desulfurizing bacteria microspheres. As a more preferred solution, the desulfurizing agent is Na 2 CO 3 , NaOH, Ca(OH) 2 At least one mixed solvent with PDS.

[0035] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0036] (1) The desulfurization bacteria microspheres are fixed by dual carriers and have a "core-shell" structure. They have both high biological activity and high stability, as well as strong salt resistance. The microspheres can be recycled.

[0037] (2) The desulfurization bacteria microspheres are less dependent on the quality of microorganisms, and the desulfurization bacteria microspheres commonly used in industry and their combinations can be used to obtain the desulfurization bacteria microspheres.

[0038] (3) When the desulfurization bacteria microspheres are used to remove hydrogen sulfide from biogas, they occupy a small area, have low energy consumption, and have high desulfurization efficiency, wherein the desulfurization rate is not less than 96%, and the sulfur recovery rate is not less than 85%. They are particularly suitable for purifying biogas with a hydrogen sulfide content of 50 to 4000 ppm. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Process flow chart for biogas desulfurization DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0041] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0042] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0043] Example 1

[0044] The following is a method for preparing dual-carrier immobilized desulfurization bacteria microspheres, comprising the following steps:

[0045] (1) Use 5 mm activated carbon as the adsorption carrier, dry it for 24 h, and then sterilize it at 121 °C for 30 min;

[0046] (2) adding activated carbon to a bacterial suspension formed by desulfurization red bacteria and desulfurization bacillus and physiological saline and soaking for 14 hours, wherein the volume content of desulfurization red bacteria and desulfurization bacillus in the physiological saline is 20%, and obtaining activated carbon pellets loaded with desulfurization red bacteria and desulfurization bacillus for use;

[0047] (3) preparing a 3 wt % sodium alginate aqueous solution, adding 2 wt % liquid paraffin thereto, and stirring to form a milky white oil-water bag;

[0048] (4) The activated carbon pellets loaded with desulfurizing red bacteria and desulfurizing bacillus were immersed in the oil-water bag for 30 min, and then 4 wt% CaCl was gradually added. 2 The solution was 50 mL, stirred for 2 h, and then centrifuged. The turbid liquid below was taken and washed with anhydrous ethanol 2-3 times to obtain desulfurization bacteria microspheres with a diameter of 5 mm and a smooth surface.

[0049] Example 2

[0050] (1) Use 5 mm activated carbon as the adsorption carrier, dry it for 24 h, and then sterilize it at 121 °C for 30 min;

[0051] (2) adding activated carbon to a bacterial suspension formed by desulfurization red bacteria and desulfurization bacillus and physiological saline and soaking for 14 hours, wherein the volume content of desulfurization red bacteria and desulfurization bacillus in the physiological saline is 20%, and obtaining activated carbon pellets loaded with desulfurization red bacteria and desulfurization bacillus for use;

[0052] (3) preparing a 3 wt % sodium alginate aqueous solution, adding 2 wt % liquid paraffin thereto, and stirring to form a milky white oil-in-water solution;

[0053] (4) The activated carbon pellets loaded with desulfurizing red bacteria and desulfurizing bacillus were immersed in the oil-water bag for 30 min, and then 3 wt% CaCl was gradually added. 2 The solution was 50 mL, stirred for 2 h, and then centrifuged. The turbid liquid below was taken and washed with anhydrous ethanol 2-3 times to obtain desulfurization bacteria microspheres with a diameter of 5 mm and a smooth surface.

[0054] Example 3

[0055] The dual-carrier immobilized desulfurization bacteria microspheres prepared in Example 1 were applied to remove hydrogen sulfide from biogas. Figure 1 As shown, it contains 1500ppm hydrogen sulfide; the biogas is sprayed with alkaline solution from the bottom to the top of the desulfurization tower, and the purified biogas is discharged from the top of the desulfurization tower, and the desulfurization liquid is pumped out from the bottom into the biological regeneration pool, where the pH of the desulfurization tower is 9-10, the filler is PP ball, the desulfurizer is a mixed solvent of NaOH and PDS, the biological regeneration pool contains desulfurization bacteria microspheres, and Na + The concentration is 0.4mol / L, and flow pushers are installed on both sides of the bottom of the pool to stir the desulfurization bacteria microspheres. Under the oxidation action of immobilized microorganisms, the desulfurization liquid is oxidized from sulfide to elemental sulfur or sulfate. The upper alkali liquid is returned to the desulfurization tower through a pipeline pump, and the solid-liquid mixture in the lower layer is pumped into the sulfur precipitation tank through a self-priming pump. After gravity sedimentation, the solid sulfur is discharged, and part of the liquid enters the subsequent treatment system, and part is returned to the biological regeneration tank for recycling.

[0056] In the biogas hydrogen sulfide removal process, the desulfurization rate reaches 98% and the sulfur recovery rate reaches 90%.

[0057] Comparative Example 1

[0058] On the basis of Example 1, the concentration of the sodium alginate aqueous solution was controlled to be 0.5 wt %, and other conditions remained unchanged.

[0059] Under this preparation condition, it is difficult to form balls, and the solid particles obtained are rough surface. This is because the low concentration of sodium alginate aqueous solution makes the cross-linking degree low during the preparation of the fungus balls, making it difficult to form a regular sphere, and the surface of the formed agglomerated material is rough.

[0060] Comparative Example 2

[0061] Based on Example 1, control CaCl 2 The solution concentration was 7 wt %, and other conditions remained unchanged.

[0062] Under the preparation conditions, microspheres with a diameter of 5 mm were obtained. The desulfurization efficiency was tested under the conditions of Example 3, and it was found that the sulfide removal rate was only 76%, which was mainly because the high concentration of calcium chloride reduced the mass transfer of the microspheres.

[0063] Comparative Example 3

[0064] On the basis of Example 3, the content of hydrogen sulfide in the original biogas was controlled to be 6000 ppm, and other conditions remained unchanged.

[0065] The results showed that under this hydrogen sulfide load, the aeration volume of the biological regeneration pool had to be increased, causing the liquid surface to churn violently, the wetness of the microorganisms to decrease, and the activity to drop, resulting in the system being unable to operate continuously and stably.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing dual-carrier immobilized desulfurization bacteria microspheres, characterized in that: The following steps are involved: 1) Loading desulfurization bacteria on activated carbon to obtain activated carbon pellets loaded with desulfurization bacteria; 2) Add liquid paraffin into the sodium alginate aqueous solution and stir to form oil-in-water; 3) After immersing the activated carbon beads loaded with desulfurization bacteria in oil-in-water, slowly add CaCl2 solution under stirring conditions to react and form gel microspheres; The mass concentration of the sodium alginate aqueous solution is 1-5%; The mass concentration of the liquid paraffin in the sodium alginate aqueous solution is 2-5%; The mass concentration of the CaCl2 solution is 2-6%; The mass of CaCl2 in the CaCl2 solution is 20-300% of the mass of sodium alginate.

2. The method for preparing a dual-carrier immobilized desulfurization bacteria microsphere according to claim 1, characterized in that: The desulfurizing bacteria include at least one of Pseudomonas, Desulfobacillus, and Desulfurizing Rhodobacter.

3. The method for preparing a dual-carrier immobilized desulfurization bacteria microsphere according to claim 1, characterized in that: The activated carbon has a diameter of 3-7 mm.

4. A method for preparing a dual-carrier immobilized desulfurization bacteria microsphere according to any one of claims 1 to 3, characterized in that: The process of loading desulfurization bacteria on activated carbon is to immerse the activated carbon in a desulfurization bacteria liquid with a volume percentage concentration of 10-30%.

5. A method for preparing a dual-carrier immobilized desulfurization bacteria microsphere according to claim 1 or 3, characterized in that: The activated carbon is pre-treated by drying and sterilization; The drying process time is 20 to 28 hours.

6. The method for preparing a dual-carrier immobilized desulfurization bacteria microsphere according to claim 1 or 2, characterized in that: The diameter of the gel microspheres is 3-10 mm.

7. A dual-carrier immobilized desulfurization bacteria microsphere, characterized in that: Prepared by the method described in any one of claims 1 to 6.

8. The use of a dual-carrier immobilized desulfurization bacteria microsphere according to claim 7, characterized in that: Used for removing sulfide from sulfur-containing wastewater.

9. The use of a dual-carrier immobilized desulfurization bacteria microsphere according to claim 8, characterized in that: The sulfur-containing waste liquid is biogas alkaline desulfurization liquid; the salt concentration in the biogas alkaline desulfurization liquid is 0.2-0.8 mol / L; the hydrogen sulfide content in the biogas is 50-4000 ppm.

Images