CN-122010282-A - Microbial electrolytic cell device for purifying phosphorus pollution by utilizing agricultural waste biochar

CN122010282ACN 122010282 ACN122010282 ACN 122010282ACN-122010282-A

Abstract

The invention discloses a microbial electrolytic cell device and a method for purifying phosphorus pollution by utilizing agricultural waste biochar. The device comprises an electrolytic cell body (1) and a circulation system. The electrolytic cell main body (1) is of a single-chamber structure, and the constant-voltage power supply (12) is connected with the anode rod (2) and the cathode rod (3). The cathode rod (3) adopts a composite structure of a permeable electrode shell (31) and a biochar electrode (32), so that the replacement and recovery of the electrode are facilitated. The device can also be configured with a monitoring system and a reaction maintaining system to realize automatic regulation and control. The method comprises the steps of microorganism inoculation film formation, pretreatment feeding, calcium source supplementing, electrolytic adsorption coupling dephosphorization, calcium phosphate recovery and the like, and realizes efficient dephosphorization and phosphorus resource recovery through the synergistic effect of electrochemistry and biological adsorption under the condition of low voltage (0.5-1.5V). The invention is suitable for the treatment of multi-source phosphorus-containing wastewater in agriculture, industry, life and the like.

Inventors

LI TIAN
MA YUXUAN
LIU CHEN
BAI YIFENG
Mao Gexiang
WANG GUOLIANG
LI RUIXIANG

Assignees

南开大学

Dates

Publication Date: 20260512
Application Date: 20260318

Claims (10)

1. A microbial electrolytic cell device for purifying phosphorus pollution by utilizing agricultural waste biochar comprises an electrolytic cell main body (1) and a circulating system, and is characterized in that the electrolytic cell main body (1) is of a single-chamber structure, an anode rod (2) and a cathode rod (3) are arranged in the electrolytic cell main body, a constant-voltage power supply (12) is respectively connected with the anode rod (2) and the cathode rod (3), the cathode rod (3) is of a composite structure and comprises a permeable electrode shell (31) and an internally filled biochar electrode (32), the biochar electrode (32) can be taken out from the permeable electrode shell (31) for replacement, and the circulating system comprises a feed pipe (4), a water inlet pipe (5), a water outlet pipe (6), an exhaust pipe (7) and a blow-down pipe (21) and is used for inputting raw materials and waste water and outputting treated waste water and waste materials to maintain the normal working state of the electrolytic cell.
2. The device according to claim 1, wherein the anode rod (2) adopts a titanium-based coating electrode, and comprises a titanium substrate and a metal oxide coating coated on the surface of the titanium substrate, wherein the coating is one or a combination of IrO 2 -Ta 2 O 5 and RuO 2 -IrO 2 , and has high oxygen evolution overpotential and catalytic selectivity.
3. The device according to claim 1, wherein the permeable electrode housing (31) is made of porous metal mesh or porous ceramic, the aperture is 50-500 μm, the biochar electrode (32) is prepared by pyrolysis of agricultural waste in an oxygen-limited environment at 400-700 ℃, the specific surface area is not less than 300m 2 /g, and the waste biochar electrode (32) can be directly used as a soil conditioner.
4. The device according to claim 1, further comprising a monitoring system comprising a barometric pressure sensor (8), a barometric pressure control valve (9), an electrochemical workstation (13), a pH sensor (14), a temperature sensor (15) and a level gauge (16) for monitoring and controlling in real time the barometric pressure, electrochemical parameters, pH, temperature and level in the reactor.
5. The device according to claim 4, wherein the air pressure sensor (8) is connected with an air pressure control valve (9) to control the opening and closing states of the exhaust pipe (7) by monitoring the air pressure in the reactor, and the electrochemical workstation (13) is respectively connected with the anode rod (2) and the cathode rod (3) to monitor the current, the voltage and the electrode reaction efficiency in the electrolytic process in real time.
6. The device of claim 1, further comprising a reaction maintaining system, wherein the reaction maintaining system comprises a stirring device (10), a baffle plate (11), a constant-temperature water bath sleeve (17), a circulating water inlet pipe (18), a circulating water outlet pipe (19) and a circulating heating pump (20), the stirring device (10) comprises a stirring motor (101) and a stirring rotating shaft (102), the stirring paddles are arranged in 2-4 groups and uniformly arranged on the stirring rotating shaft (102), the baffle plate (11) is vertically or obliquely arranged for 2-4 blocks, the baffle plate is circumferentially and uniformly distributed on the inner wall of the reactor, and cooperates with the stirring device (10) to form a forced circulating flow field, the mass transfer efficiency is enhanced, the constant-temperature water bath sleeve (17) is wrapped on the outer side of the electrolytic cell main body (1), and the circulating water is driven to flow between the circulating water inlet pipe (18) and the circulating water outlet pipe (19) through the circulating heating pump (20), so that the reaction temperature is accurately controlled.
7. The device according to claim 4 or 6, further comprising a PLC controller electrically connected to the air pressure sensor (8), the air pressure control valve (9), the stirring motor (101), the constant voltage power supply (12), the electrochemical workstation (13), the pH sensor (14), the temperature sensor (15), the liquid level meter (16) and the circulating heat pump (20), respectively, and performing automatic regulation and control on the stirring speed, the heating power, the water inflow and the voltage of the device by real-time monitoring.
8. A phosphorus pollution purification method is based on the device of claim 1, and the device further comprises a monitoring system of claim 4 and a reaction maintaining system of claim 6, and is characterized by comprising the following steps of (1) inoculating and hanging a film of microorganisms, namely inoculating electrogenic microorganism flora into an electrolytic cell main body (1), carrying out biofilm mount culture by taking a biochar electrode (32) as a carrier, wherein the hanging film culture time is 7-21 days until stable electrogenic current is monitored; the method comprises (2) pre-treating and feeding, injecting the wastewater to be treated into an electrolytic tank main body (1) through a water inlet pipe (5), controlling the liquid level to a preset range, detecting the concentration of calcium ions in the wastewater, supplementing a calcium source through a water inlet pipe (4) when the concentration of Ca 2+ is insufficient, enabling the concentration of Ca 2+ in the reaction solution to reach 30-100 mg/L, (3) regulating the environment, regulating the reaction temperature to 25-35 ℃, regulating the pH of the reaction solution to 6.5-8.0, (4) carrying out electrolysis and adsorption reaction, starting a constant voltage power supply (12), controlling the voltage to 0.5-1.5V, starting a stirring device (10), carrying out electrolysis and adsorption reaction for 2-8 hours, generating oxygen evolution reaction at an anode, oxidizing organic matters by microorganisms in a cathode region, generating a reduction environment, lifting the local pH value, promoting the combination of phosphate ions and calcium ions to generate calcium phosphate precipitates, depositing on the surface of a biochar electrode (32), standing the precipitate after the reaction is completed, recovering the calcium phosphate precipitates, discharging the wastewater reaching the standard after the treatment, the solid waste is discharged from the blow-down pipe (21).
9. The method of claim 8, wherein the phosphorus-containing wastewater to be treated comprises one or more of agricultural wastewater, industrial wastewater, or domestic wastewater.
10. The method of claim 8, wherein the step (4) further comprises a multi-stage operation mode control, wherein the adsorption stage is to turn off the constant voltage power supply (12), start the stirring device (10) only, adsorb phosphorus by using the biochar electrode (32) for 0.5-2 hours, the electrolysis stage is to turn on the constant voltage power supply (12), maintain the set voltage for electrochemical conversion for 2-6 hours, and the precipitation stage is to turn off the stirring device (10) and the constant voltage power supply (12) and to stand for 0.5-1.5 hours.

Description

Microbial electrolytic cell device for purifying phosphorus pollution by utilizing agricultural waste biochar Technical Field The invention belongs to the technical field of wastewater treatment and resource recovery, and particularly relates to a device and a method for purifying phosphorus pollution by utilizing common agricultural waste biochar, which can be applied to purification of various phosphorus-containing low-carbon sewage and recovery of phosphorus resources. Background With the continuous increase of agricultural intensive production, industrial pollution discharge and urban and rural domestic sewage discharge, a large amount of phosphorus-containing pollutants enter natural water bodies, and the phosphorus-containing pollutants become one of main causes for inducing water body eutrophication. Eutrophication not only damages the balance of the aquatic ecosystem, but also can cause the problems of blue algae bloom, dissolved oxygen reduction, water quality deterioration and the like, and seriously affects the safety of drinking water and the health of the aquatic ecological environment. Therefore, the development of efficient, economical and sustainable phosphorus-containing wastewater treatment technology has important practical significance. At present, common phosphorus-containing wastewater treatment technologies mainly comprise a chemical precipitation method, an adsorption method, a biological method, an electrochemical method and the like. The chemical precipitation method has the advantages of high chemical consumption, high sludge yield, high running cost, simple and convenient operation of the adsorption method, difficult regeneration after the saturation of the adsorbent, easy secondary pollution generation, suitability for low-concentration phosphorus-containing wastewater, sensitivity to water quality fluctuation, long treatment period, difficult realization of efficient recovery of phosphorus, high reaction speed, flexible control, good environmental compatibility and the like, and the electrochemical method has the advantages of high reaction speed, high control flexibility, high environmental compatibility and the like, and is widely paid attention in recent years, and the problems of high energy consumption, high electrode material cost and the like limit the large-scale application of the electrochemical method. In order to reduce the processing cost and realize the resource recovery, researchers have recently tried to combine the recycling of agricultural wastes with electrochemical technology. Agricultural wastes such as straw, rice husk, corncob and the like are wide in sources and huge in yield, but the recycling utilization rate of the agricultural wastes is generally low, and the agricultural wastes are often burnt or discarded, so that resource waste and environmental pollution are caused. Researches show that the biochar prepared by pyrolyzing agricultural wastes under the oxygen limiting condition has rich pore structure, larger specific surface area and good surface functional group activity, and can be used as an excellent adsorption material for removing phosphorus and heavy metals in water. Meanwhile, the biochar has good conductivity and biocompatibility and has potential of being used as an electrode material or electrode filler. In recent years, microbial cell technology has received attention for its ability to drive contaminant conversion and achieve energy or resource recovery under low voltage conditions. The biochar is introduced into a microbial electrolytic cell system, so that the adsorption and electrochemical activity of the biochar can be cooperatively exerted, and the fixation and conversion of phosphorus are enhanced. However, the existing microbial electrolytic cell device has the problems of complex structure, poor universality, difficult electrode replacement, insufficient reaction environment regulation precision and the like. For example, the traditional cathode is mostly of a fixed structure, the biochar is difficult to replace and recycle after being filled, the sustainability of the biochar in actual wastewater treatment is limited, key parameters such as temperature, pH, air pressure and the like in the reaction process lack effective monitoring and regulating means, the microbial activity and the reaction stability are difficult to ensure, and meanwhile, the traditional device is designed for single type of wastewater, and is difficult to adapt to the treatment requirements of multi-source phosphorus-containing wastewater such as agriculture, industry, life and the like. In summary, when the prior art is used for treating multi-source phosphorus-containing wastewater, the problems of low treatment efficiency, poor operation stability, difficult resource recovery, inconvenient device maintenance and the like still exist, and development of a novel treatment device which has the advantages of optimized structure, precise regulation and cont