Influence Of The Fe~0 Anode And CNTs/CoPc Modifyied Cathode On MFC Wastewater Treatment And Electricity Generation

The wastewater reclamation and energy consumption reduction of wastewater treatment are important issues for its practical application.The energy in wastewater can be partly converted to electricity by combining the wastewater treatment with Microbial Fuel Cells?MFCs?.The wastewater treatment efficiency and electricity generation were enhanced by optimizing the wastewater treatment system and the electrode materials in this study.???Combining MFC with Membrane Bioreactor?MBR?for high pollutant removal efficiency,the carbon felt anode modified by Fe0 in MFC contributed to flocculation and the electric field for membrane fouling control.The Fe0 oxidation accelerated the enrichment of electricigens on the anode surface and shortened the startup time.???To reduce the cost and increase the electricity generation,the air-cathode in single-chambered MFC wastewater treatment was studied.The structure of PVDF air-cathode was optimized and the cathode catalysts were studied.Based on the technologies mentioned above,following researches are conducted:?1?A novel three chambered MFC-MBR was developed with conductive stainless steel mesh membrane cathodes for wastewater treatment and electric energy production simultaneously.The carbon felt anode modified by Fer in MFC contributed to flocculation and the electric field for membrane fouling control,the membrane washing cycle was extended about 2 times compared to the control system.The average cell voltage of Fe0 MFC was about 1.5 times higher than the control system.The COD,NH₄⁺-N and total phosphate removal rate was about 95%,98%and 60%,respectively.?2?The three-chambered Iron Anode MFC-MBR wastewater treatment was developed with iron plates in the middle chamber served as the anode to enhance the electricity generation and flocculation.A synthetic wastewater containing triclosan?TCS?was treated by the system.The COD removal rate was about 95%and the highest triclosan removal rate reached 97.9%.The system generated a relatively stable power output?cell voltage?0.2 V?and the corrosion of iron plates contributed to electricity generation together with microbes on iron anode.The electricity generation was enhanced by-60%after TCS addition.Due to the electricity generation and flocculation,the membrane fouling was mitigated by approximately 30%,as compared with the control.?3?To reduce cost,polyvinylidene fluoride?PVDF?air-cathode in single-chambered MFC wastewater treatment was studied,the duration of power generation was extended by about 70%via optimizing the structure of air-cathode.Cheap PVDF was coated on the solution-side to replace expensive Nafion as a separator regardless of the ion exchange part.When PVDF was coated on the solution-side,the microbes were the main cathode foulant,when Nafion was the solution-side layer,the main foulant was cations.The maximum power density of solution-side Nafion MFC after soaked in HC1 was 338.1 MW m-2,which was 45%higher than that after ultraviolet light irradiation.?4?Efficient oxygen reduction reaction?ORR?catalysts-cobaltous phthalocyanine?CoPc?composited with carbon nanotubes?CNTs?were prepared for higher power generation in MFCs treating wastewater.The ORR activities of CoPc composited with CNTs were investigated and compared.The ORR on SMW-CNTs/CoPc proceeded in a dominant 2e-combined with 4e-pathway,while the others followed a dominant 4e-pathway.Cathodes modified with MW-CNTs/CoPc exhibited higher catalytic activity from CV results.The internal resistance of SMW-CNTs/CoPc cathode MFC?30-65 ??was lower than that of SSW-CNTs/CoPc?40-160??.SMW-CNTs/CoPc MFC cell voltage increased by 0.43%while SSW-CNTs/CoPc decreased by 8.31%in 20 days,suggesting a better performance of power generation by SMW-CNTs/CoPc.The Nafion layer either sank into the catalyst composite?SMW-CNTs/CoPc?or spread over it?SSW-CNTs/CoPc?,affecting internal resistance and MFC performance.In summary,the wastewater treatment efficiency of the Fe0 anode MFC was enhanced by combining MFC with MBR,while the membrane fouling can be reduced via the electrical force and electro-flocculation.The electricity generation and oxygen reduction reaction activity of MFC wastewater treatment system was increased by optimizing PVDF air-cathode structure and modifying it by the CNTs/CoPc catalyst.These results advocate progresses in developing sustainable/low-cost MFC wastewater treatment systems.