72 results about "Oxygen mass transfer" patented technology

A CMABR for running single-stage autotrophic biological nitrogen removal process belongs to the technical field of water treatment equipment. A membrane module of the CMABR is formed by vertically arranging multi-millipore carbon tube membranes at equal intervals; each carbon tube is wrapped by non-woven fabrics and microorganisms attach to filling of the non-woven fabrics; an air pump is adopted to pump air from bottom end of the membrane module into internal cavities of the carbon tube membranes and part of air enters the CMABR through walls of the carbon tube membranes and the rest air is vented from the other end; and the pressure of the internal cavities of the carbon tube membranes can be controlled by regulating a gas flow meter to regulate oxygen supply so as to further control dissolved oxygen inside the CMABR. The CMABR has the effects of high-effective oxygen mass transfer rate, huge biofilm carrier specific surface area and internal-external layered special biofilm structure, and easily achieves operation parameter required by the running of single-stage autotrophic biological nitrogen removal process. The CMABR is applicable to the single-stage autotrophic biological nitrogen removal process and is a novel biological nitrogen removal reactor with wide market application prospect.

The invention provides a bacterial agitation leaching experimental facility and a method for measuring and calculating oxygen mass transfer coefficients, bacterial oxygen consumption rate and saturated dissolved oxygen concentration. The experimental facility is suitable for bacterial agitation leaching in particular for the bacterial leaching at a high temperature, can provide online regulation control and measurement of temperature, pH, ORP and DO, and simultaneously has a real-time recording function. In the invention, a dynamic method in a fermentation technical research is used for measuring and calculating the oxygen mass transfer coefficients, the bacterial oxygen consumption rate and the saturated dissolved oxygen concentration. The bacterial agitation leaching experimental facility has the advantages of not only providing a bacterial agitation leaching device capable of performing online regulation control and recording correlation parameters, but also being suitable for researching the oxygen supply and consumption in the process of high temperature bacterial agitation leach, thereby providing a strong support for rate-limiting factors of high temperature bacterial leaching.

The invention relates to a microbial fuel cell and a method for treating wastewater by using the same. The microbial fuel cell comprises a main reaction zone 1, a biological selection and adjustment zone 2, an overflow water outlet trough 3, a perforated water distribution pipe 4, a biological positive electrode 5, an air negative electrode 6, an electrode support 6a, an electrode clamping slot 6b, an positive and negative electrode jack sealing ring 7, a reference electrode 8, PH and DO electrode jacks 9-I and II, an outer resistor 10, a water inlet pipe 11, a monitoring hole 12, evacuation pipes 13 and 14, and a water outlet pipe 15. According to the microbial fuel cell and the method disclosed by the invention, negative electrode aeration of the MFC (microbial fuel cell) is ingeniously avoided by using a capillary action, the energy consumption is reduced and the oxygen mass transfer efficiency of a negative electrode of the MFC is improved; stable and high-efficient denitrification and carbon removal can be realized, the COD (Chemical Oxygen Demand) removal rate can reach 75% to 94.4%, and the TN (total nitrogen) removal rate is 42% to 99.9%.

The invention discloses an offline cleaning method for removing pollutant of an SPG (shirasu porous glass) membrane used in biological wastewater treatment. The offline cleaning method includes steps of ultrasonically treating the polluted SPG membrane to remove a microbial polluted layer at first after the SPG membrane is used for treating domestic sewage; air-drying; performing heat treatment to remove organic pollutants; and performing acidic treatment to remove inorganic pollutants. After the pollutants of the SPG membranes are removed by the offline cleaning method, microbubble generating ability, oxygen mass transfer efficiency and dissolved oxygen concentration are comprehensively recovered, so that a smooth wastewater treatment process can be guaranteed.

The invention discloses an enhancing method of oxygen mass transfer efficiency of a microbial fuel cell cathode, comprising the following steps: arranging a guiding mechanism in the cathode chamber of a fuel cell; arranging the cathode of the fuel cell in the guiding mechanism or reducing the size of the cathode chamber of the fuel cell to achieve the function of the guiding mechanism; and arranging an aeration mechanism below the guiding mechanism and feeding oxidant bubbles in bubble flow or slug flow into the guiding mechanism through the aeration mechanism. The invention also discloses a microbial fuel cell designed according to the method. Due to the guiding mechanism used in the cathode, the cathode aeration intensity is enhanced, the catholyte oxygen solubility is increased, and simultaneously the purposes of stirring the catholyte, increasing the catholyte circular flow and increasing the mass transfer rate of proton to the electrode are realized, thereby effectively enhancingthe cathode reaction efficiency, ensuring the anaerobic condition of an anode chamber and increasing the electricity generating ability of the fuel cell.

The invention discloses a multi-dimensional multi-phase multi-process coupling analog method of activated sludge sewage treatment. According to the -dimensional multi-phase multi-process coupling analog method, based on a multi-phase flow theory, activated sludge used as a solid phase, a gas phase (bubbles) aerated in an activated sludge system and a liquid phase (sewage) form a three-phase composite system, a sludge-water-gas movement characteristic and an interphase physical function in a sewage treatment system are reasonably described by adopting a multi-phase flow movement equation; and meanwhile, an oxygen mass transfer equation and a pollutant migration and transformation equation are further combined, and a distribution characteristic of dissolved oxygen in a system, a migration and transformation characteristic of pollutants and an interphase biochemical action characteristic are accurately predicted. By adopting a coupling model disclosed by the invention, the part of an activated sludge system, at which sludge easily deposits, and effluent quality conditions under different working conditions can be quantitatively predicted, and the great significance is achieved for the maintenance of normal operation in a sewage treatment plant.

The invention discloses a system device for strengthening high-viscosity microbial polysaccharide fermentation. The system device comprises a tank body, a tank cover, a cooling interlayer, an air distributor, a first motor, a second motor, a supergravity revolving bed device and a high-temperature-resisting submerged pump. A rotary shaft is longitudinally arranged inside the tank body. The upper end of the rotary shaft penetrates through the tank cover to be in driven connection with the first motor, and the lower end of the rotary shaft extends into the tank body to be connected with the supergravity revolving bed device. The supergravity revolving bed device is transversely arranged at the center of the inside of the tank body. The air distributor is arranged at the lower end of the supergravity revolving bed device and is an annular pipeline. The high-temperature-resisting submerged pump is arranged on one side of the lower end of the inside of the tank body. One end of the high-temperature-resisting submerged pump is connected with the supergravity revolving bed device through a pipe, and the other end of the high-temperature-resisting submerged pump is connected with a rotary shaft of the second motor. The cooling interlayer is arranged outside the tank body. A fermentation period is greatly shortened by strengthening dissolved oxygen mass transfer, gas, liquid and solid phase mixing, rotating speed optimization, ventilatory capacity and other conditions, the yield and mass of high-viscosity polysaccharide are increased, and the cost is remarkably reduced.

The oxygen conveying system for patient includes one slender support with end part and capable of being fixed on head of the patient and extended from one side to the other; one support arm; one fixer to fix the support arm to one end of the support so as to make the support arm move relatively to the support direction and be located reliably in the required position; one oxygen conveying pipe; one oxygen conveying unit fixed to one end of the one oxygen conveying pipe; one detachable unit to fix the oxygen conveying pipe to the support arm; and one detachable unit to fix the second end of the oxygen conveying pipe to the oxygen supply source. When the slender support is set in place, the support arm supports the oxygen conveying pipe and the oxygen conveying unit in proper positions for supplying oxygen to the patient.

The invention belongs to the field of electrochemical energy, and provides a high-temperature proton exchange membrane fuel cell and a preparation method thereof. The preparation method comprises the following steps that a catalyst sizing agent with no adhesive is prepared and coats a gas diffusion layer, and drying is performed to obtain an electrode; phosphoric acid treatment is performed on the electrode; a PBI membrane is soaked into a phosphoric acid solution, and a soaking membrane is obtained; the electrode obtained after acid treatment and the soaking membrane form MEA, and the MEA is assembled into a high-temperature proton exchange membrane fuel cell. According to the preparation method of the high-temperature proton exchange membrane fuel cell, on one hand, the electric conductivity and oxygen mass transfer capability of the electrode can be improved with no adhesive; on the other hand, on the basis of phosphoric acid treatment, the electrode can obtain more proton transfer channels so that more reaction interfaces can be built, and then the performance of the cell is improved.

The invention discloses a high-stability direct methanol fuel cell membrane electrode based on a CNT material, and belongs to the technical field of proton exchange membrane fuel cells. The membrane electrode is composed of an anode diffusion electrode, a Nafion proton exchange membrane and a cathode diffusion electrode, wherein a diffusion layer of the cathode diffusion electrode is prepared from CNT material paper. According to the membrane electrode disclosed by the invention, the structure of a direct methanol fuel cell can be simplified; the volume of the fuel cell is reduced; meanwhile, the water logging problem on one side of the cathode in the direct methanol fuel cell is well solved, so that the oxygen mass transfer of the cathode is increased; the stability of the cell for lastingly working for a long period of time is improved; the contact resistance between a collector plate and the membrane electrode is significantly reduced; the problem of internal resistance increase caused by PTFE used as the mass transfer baffle layer in a traditional structure is avoided; and the performance of the battery is improved.

The invention discloses an aeration device for efficiently producing oxygen-enriched water, which is used for solving the problems that in the prior art, oxygen-enriched water preparation methods suchas a mechanical stirring method, an electrolytic method and dissolved gas release are generally adopted, the oxygen mass transfer driving force is insufficient, the oxygen mass transfer coefficient is low, and the transfer rate is low, and equipment investment cost is high, structure is complex, and yield or oxygen enrichment level cannot meet requirement of industrial production. The aeration device comprises a reaction kettle, an air compressor, an air conveying pipeline, an air filter, a regulating valve, a material distribution pipe, an air refining bubble generator, a multi-way valve, acheck valve, a filter, an input pipeline, an output pipeline and an exhale; according to the aeration device, a large number of micro-nano bubbles can be rapidly produced under the driving of certainpressure, and oxygen-enriched water is prepared through the gas-liquid mass transfer effect; the distribution pipe realizes uniform distribution of water and gas, the gas is crushed into tiny bubblesthrough the air refining bubble generator, and the bubbles are small in size, more uniform in distribution and more sufficient in contact with the water, so that the bubbles are better dissolved in the water to form oxygen-enriched water.

The invention discloses a fibrous membrane for aeration. The two ends of the fibrous membrane for aeration are arranged as a packaging end and an opening end. The manufacturing for the packaging end comprises the following steps: inserting one end of a hollow fibrous membrane into a solution of polyvinylidene fluoride and dimethylacetamide and then reacting in distilled water. The invention also discloses an alga type micro-nano aeration biological membrane component for in situ river control. The alga type micro-nano aeration biological membrane component comprises an aeration membrane unit, a biological membrane carrier and an end socket, wherein the aeration membrane unit comprises a packaging sleeve and a fibrous membrane beam composed of a plurality of fibrous membranes for aeration and fixed on the packaging sleeve; the aeration membrane unit is fixedly arranged on the end socket through the packaging sleeve; a vent hole which runs through the end socket is formed in the end socket; the biological membrane carrier is of bar shape and is fixed on the end socket. The fibrous membrane for aeration is capable of generating a large quantity of air bubbles at constant rate under lower air supply pressure, wherein the diameters of the air bubbles are within 60nm-200mum; the fibrous membrane for aeration has ultrahigh specific area; the fibrous membrane for aeration is capable of effectively increasing the contact surface area of water and air bubbles and increasing the oxygen mass transfer efficiency of aeration.

The invention discloses a fixed bed type cell bioreactor which comprises a stirring device, a ventilation device, an exhaust device, a supplementing device, a fixed bed device, a water jacket interlayer and a controller. The fixed bed device is composed of an outer ring cylindrical shell, a middle ring cylindrical shell, an inner ring cylindrical shell, a hollow cylindrical flow guiding tube, an upper cover plate, a lower cover plate and a hollow flow guiding tubule; the defect that an existing fixed bed type cell bioreactor is not sufficient in cell density and mass transfer efficiency is overcome, the bioreactor is applicable to the adherent cell cultivation mode, the nutrient solution and oxygen mass transfer efficiency can be better improved, and the higher cell density and product concentration are achieved.

The invention relates to a method for testing oxygen mass transfer resistance of ordered electrodes. The method comprises the steps of firstly preparing ordered electrodes through magnetron sputtering; preparing a membrane electrode and then testing limited current density of the membrane electrode at different oxygen concentrations through optimizing test conditions; and calculating the oxygen mass transfer resistance according to the tested limited current density. According to the method, the internal oxygen mass transfer resistance of low-platinum ordered electrodes after being prepared into the membrane electrode (MEA) is successfully tested, and the method is of great significance for study on oxygen transfer of the low-platinum ordered electrodes and is especially suitable for testing of the oxygen mass transfer resistance of the low-platinum ordered electrodes in the field of proton exchange membrane fuel cells.

The invention discloses a PTFE composite membrane for MABR. The PTFE composite membrane comprises a hydrophobic hollow fiber porous support tube membrane and a hydrophilic polytetrafluoroethylene porous flat membrane wrapping layer arranged on the surface of the hydrophobic hollow fiber porous support tube membrane; the contact angle of the hydrophobic hollow fiber porous support tube membrane isgreater than 130 DEG; the instantaneous contact angle of the hydrophilic polytetrafluoroethylene porous flat membrane wrapping layer is less than 60 DEG, and is reduced to 0 DEG within 30 s. The surface of the hydrophobic microporous membrane is wrapped with the thin hydrophilic PTFE membrane layer through ultrasonic spot welding, the internal main body of the prepared PTFE composite membrane hasthe super-hydrophobic characteristic and has the excellent oxygen mass transfer performance, and the surface thin layer of the PTFE composite membrane has the super-hydrophilic characteristic and hasthe excellent microbial affinity performance.

Belonging to the field of sewage denitrification treatment, the invention discloses a membrane aerated biofilm micro-aerobic sludge bed process and a wastewater treatment method thereof. The membraneaerated biofilm micro-aerobic sludge bed process adopts a biofilm micro-aerobic sludge bed, a sludge bed water inlet pipe, a sludge bed water outlet pipe, a sludge discharge pipe, a biofilm aeration component, an air pump, a circulating pump, a peristaltic pump, air flow meters and pressure gauges. The treatment method realizes the mutualism and collaborative metabolism of aerobic bacteria, anaerobic bacteria and facultative anaerobes in a micro-aerobic environment, at the same time utilizes the efficient oxygen mass transfer efficiency of the membrane aeration component and enables wastewaterto flow on the outer surface of the biofilm to form back diffusion of oxygen and pollutants, and can realize effective removal of pollutants in a bioreactor. The process and the treatment method provided by the invention are suitable for denitrification treatment of urban sewage and industrial wastewater, and have the advantages of high treatment efficiency, high energy utilization rate, stable effluent effect, fast start-up speed, etc.

The invention discloses an MABR and CH4MBfR combined device for treating p-nitrophenol-containing wastewater. The device comprises a wastewater storage device, an MABR device and a CH4-MBfR device which sequentially communicate with one another, and an intermediate water outlet tank is connected between the MABR device and the CH4-MBfR device. According to the invention, the advantages of the twomembrane reactors are fully combined, p-nitrophenol can be effectively degraded, deep denitrification is realized, and the effluent is discharged after reaching the standard. As the MABR adopts bubble-free aeration, the oxygen utilization rate is high and can reach 100%, the oxygen mass transfer range is relatively small, the toxicity is reduced under the action of hydrolytic acidification and thelike of anaerobic layer florae, and then metabolism mineralization degradation is conducted through aerobic and facultative layer florae; and a denitrification type methane anaerobic oxidation florabiological membrane in the CH4-MBfR main body reactor can be used for effective and deep denitrifying, a large amount of methane flora exists in the microbial membrane, part of methane can be suppliedto the biological membrane, the adding cost of a carbon source is saved, and the emission of methane greenhouse gas is reduced.

The invention discloses a breathing bottle for measuring the breathing rate of a biofilm, comprising a bottle body, a carbon dioxide absorbing tube and a perforated separator arranged inside the bottle body; a perforated partition plate divides the inside of the bottle body into an oxygen mass transfer stirring zone provided with a stirring device and a biofilm reaction zone used for placing MBBRfillers; the carbon dioxide absorbing tube is provided with a permeable hole and contains a solution capable of absorbing CO<2>; a perforated separator has a first hole corresponding to a middle portion and a lower portion of the perforated separator and serving as a liquid exchange channel and a second hole corresponding to an upper portion of the perforated separator and serving as a gas exchange channel, and the oxygen transfer stirring zone is communicated with the biofilm reaction zone through the liquid exchange channel and the gas exchange channel. On the one hand, the fact that gas-liquid exchange of the oxygen transfer stirring zone and the biofilm reaction zone is fully processed is ensured. On the other hand, the stirring device can avoid the destruction of biofilm on MBBR packing, so the respiratory kinetic characteristics of biofilm on MBBR packing can be measured in situ. The determination process is simpler, quicker, and the determination results are more accurate and effective.

The invention discloses a culture medium added with a surfactant and application thereof. The culture medium added with the surfactant is composed of glycerinum or glucose which is taken as a major carbon source, a yeast extract and / or sodium glutamate which are / is taken as a major nitrogen source, inorganic salt components comprising Na2SO4, KH2PO4, K2HPO4, K2SO4 and MgSO4.7H2O, vitamins VB1, VB6 and VB12, and Tween 20, Tween 40, Tween 60 or Tween 60 added separately, wherein the concentration of the glycerinum or the glucose is 10-120g / L, and the concentration of the yeast extract and / or the sodium glutamate is 5-50g / L. The surfactant of an appropriate concentration is added to the culture medium so that the cell membrane permeability of microorganisms is changed, mass transfer of a substrate and oxygen is strengthened and growth is promoted; due to the adopted technical scheme, the conversion rate of the substrate can be increased without extra labor or equipment investment, and therefore, the fermentation of schizochytrium limacinum is effectively reduced.

The invention discloses an activated carbon cathode electro-Fenton system which comprises a well casing which is divided into an upper section, a middle section and a lower section, wherein the middle section is a water filter pipe, and the lower section is a precipitation pipe; a plurality of cathodes and a plurality of anodes which are fixed to form a comb tooth structure, wherein the cathodes are stainless steel mesh filled activated carbon cathodes, and the anodes are ruthenium-iridium / iridium-tantalum electrodes; the cathodes and the anodes are arranged in a crossed mode, and the cathode located at the uppermost position is located on the anode located at the uppermost position. The invention also provides a method for removing halogenated hydrocarbon in underground water by using the activated carbon cathode electro-Fenton system. The underground water is repaired by adopting the stainless steel mesh filled activated carbon cathode electro-Fenton technology, the system is used for enhancing the degradation of halogenated hydrocarbon in the underground water, the system has the characteristics of environmental friendliness and simplified operation, and on the basis, the placement mode of the electrode is improved, the oxygen mass transfer effect is enhanced, and external oxygen supply is not needed.

The invention provides a mobile green roof type anti-blocking wastewater treatment technology, which comprises the following steps: removing suspended solids from wastewater through a grating chamberC1 and homogenizing through a regulating reservoir C2; guiding wastewater to flow by an aerobiotic pond O1, an anoxic pond A1, an anaerobic pond A2 and an aerobiotic pond O2 in turn, for performing enhanced OAAO treatment; guiding wastewater to pass by a denitration filter chamber B1 and a phosphorous removing filter chamber B2 in turn, for deeply treating; adopting a real-time fine regulation system for monitoring nitrogen and phosphorus removal effects and remotely adjusting internal running state of the technology. According to the invention, the enhanced OAAO treatment is adopted, so thatbackflow of mixed liquor can be avoided; a special structure of biological film filler in the aerobiotic pond O1 is beneficial to promoting oxygen mass transfer efficiency and use ratio of oxygen; anti-blocking structures in the denitration filter chamber and the phosphorous removing filter chamber can effectively solve the blocking problem of filter chambers; a mobile constructed wetland is arranged on the top of pond; due to the combination of biological, chemical and ecological treatment, the treated water can reach level A; the technology has the advantages of impact load resistance, excellent treatment effect, running stability, low cost, and the like, and is suitable for treating domestic wastewater.

The invention provides a method for determining a size of bubbles in a system for preparing TA through PX oxidation. The method comprises the following steps: (A) establishing a reaction equation for preparing TA through PX liquid phase oxidation; (B) when other reactions in which oxygen participates are not considered, obtaining the following mass transfer equilibrium equation according to the relationship that the oxygen mass transfer rate is equal to a reaction consumption rate; (C) establishing an EA mathematical expression; (D) establishing a liquid phase component concentration CB-CE mathematical relation; and (E) establishing an E-infinity mathematical relation. According to the method for determining the size of the bubbles in the system for preparing the TA through the PX oxidation, the design and operation of a micro-interface enhanced reactor are optimized by discussing the method for determining the optimum size of the bubbles in the system for preparing the TA through the PX oxidation.

The invention relates to a semi-submersible embedded aeration pipe. The semi-submersible embedded aeration pipe comprises a breather pipe and a micro-nano aerator pipe sleeved on the outer side of thebreather pipe. A plurality of air holes are sequentially formed in the breather pipe along the length direction of the breather pipe. Each air hole is radially formed in the pipe wall of the breatherpipe. The breather pipe is sequentially defined as a first section air pipe, a second section air pipe and a third section air pipe along the length direction. Each section of air pipes is respectively provided with air holes which accord with respective rules, so that the whole aeration pipe can generate micro-nano bubbles which are approximately uniformly distributed from the front section to the rear section, and the problem that the existing aeration pipe cannot simultaneously meet the requirements of higher oxygen mass transfer efficiency and underwater water dissolved oxygen concentration is solved.

The invention provides a tubular aeration tank type high-temperature aerobic composting system. The system comprises a fermentation tank and air pipes located at the bottom of the fermentation tank, the air pipes are connected with a tubular micro-hole aerator, and a grating plate covers the upper surface of the tubular micro-hole aerator; water permeable bricks are arranged under the air pipes and the tubular micro-hole aerator, water collection tanks are formed under the water permeable bricks, a turning machine used for uniformly mixing materials in the fermentation tank is arranged on thefermentation tank, and the air pipes are connected with an aeration fan and output oxygen to the tubular micro-hole aerator through the aeration fan. According to the system, the adopted tubular micro-hole aerator can make gas uniformly distributed and improve the oxygen mass transfer efficiency and the fermentation efficiency, through the water permeable bricks and the water collection tanks, moisture in the materials and moisture generated from fermentation can be collected and treated uniformly, and secondary pollution is avoided.

The invention discloses an optimizing operation method for an isothermal layer aerator. The optimizing operation method comprises the following steps: firstly, according to a double-membrane oxygen mass transfer theory, establishing an aeration indoor oxygenation dynamic model and an integral solution method thereof, wherein gas volume fraction and water flow speed related in the aeration dynamic model are calculated by adopting an aeration room water dynamic model, an overall oxygen transfer rate KLa is calculated by adopting a formula associated with the gas volume fraction and gas bubble property; utilizing the aeration dynamic model to calculate vertical distribution of concentration of dissolved oxygen in the aeration door under different aeration conditions; establishing a representing method for the aeration room oxygen mass transfer rate; establishing an aeration efficiency representing method according to the oxygen mass transfer rate and the energy efficiency of the isothermal layer aerator; respectively drawing relationship curves of the oxygen mass transfer rate and the aeration efficiency under different aeration amount conditions according to the calculated dissolved oxygen concentration and represented water flow speed in an inlet and an outlet of the aeration room, wherein the aeration amount corresponding to the junction of the relationship curves is the optimal aeration amount of the isothermal layer aerator.

The invention discloses a microelectrode system and method for testing an oxygen mass transfer coefficient of a proton exchange membrane. The system comprises an electromagnetic shielding box, an on-off type temperature controller and an environment cavity formed in the electromagnetic shielding box; atmosphere can be continuously introduced into the environment cavity, and humidity can be monitored; a high-temperature-resistant clamping device, a platinum disc microelectrode with the effective diameter being 10 micrometers, a platinum sheet electrode, a silica gel heating plate and a temperature sensor are arranged in the environment cavity; the clamping device is used for sequentially superposing and clamping the proton exchange membrane to be detected, the platinum sheet electrode and the silica gel heating plate; the on-off temperature controller is connected with the silica gel heating plate, the temperature sensor is used for monitoring the temperature of the silica gel heating plate, the platinum disc microelectrode serves as a working electrode, and the platinum sheet electrode serves as a counter electrode and a reference electrode and is connected to the electrochemical workstation. According to the system and the method disclosed in the invention, the mass transfer coefficient of oxygen in various polymer electrolytes can be quantitatively and accurately characterized, and quantitative guidance is provided for optimization of a catalytic layer structure.

A system for aerobic fermentation includes a vessel, an aeration system including a gas sparger fluidly coupled to the vessel to introduce a compressed gas to an internal volume of the vessel, and a recirculation loop fluidly coupled to an outlet of the vessel. The recirculation loop includes an eductor fluidly coupled to an oxygen-containing gas source, a static mixer downstream of the eductor, aheat exchanger downstream of the eductor, and a distributor downstream of the heat exchanger. The distributor is fluidly coupled to the vessel. The aeration system provides mixing and oxygen mass transfer to the fermentation composition in the vessel. The fermentation composition passes through the eductor, static mixer, heat exchanger, and distributor of the recirculation loop, and back into thevessel. Oxygen is transferred from an oxygen containing gas to the fermentation composition and heat is removed from the fermentation composition in the recirculation loop.

The invention discloses a preparation method of a green heteroatom modified integrated biochar cathode, and relates to a preparation method of a biochar cathode. The invention aims to solve the technical problem of low H2O2 accumulation amount caused by the fact that an existing electro-Fenton cathode cannot cooperatively regulate and control oxygen mass transfer and electron transfer. The method comprises the following steps: 1, polishing the surface of a wood biomass material; 2, dipping the material in a phosphoric acid solution; 3, conducting freeze drying; and 4, conducting pre-carbonization and carbonization to obtain the green heteroatom modified integrated biochar cathode. According to the green heteroatom modified integrated biochar cathode, the H2O2 yield reaches 5-6.5 mg*L<-1> when the current density is 25 mA*cm<-2>, and the green heteroatom modified integrated biochar cathode can be applied to the field of electro-Fenton.