| Conductive membranes play the role of anti-pollution,energy recovery,selective regulation and other functions in the field of water treatment technology.The development of high-efficiency conductive membrane reactors is the top priority to promote the development of conductive membranes to the practical application of industrialization,and realize conductive membrane water treatment The key to further technological breakthroughs lies in the high conductivity and high stability of the membrane.The MWCNTs/PVDF conductive membrane studied in this paper realizes the stable load of the conductive functional layer on the commercial PVDF flat membrane.The MFC/MBR system coupled with the conductive membrane can operate stably in a high-salt environment.Under the action of the micro-electric field generated by the MFC,The membrane fouling has been alleviated.The coupling system provides a new idea for the scientific,environmentally friendly,and efficient treatment of high-salt wastewater with conductive membranes,and has good application prospects.This research is based on carboxylated multi-walled carbon nanotubes（MWCNTs-COOH）,adding cross-linked polymer polyvinyl alcohol to improve the dispersion of carbon nanotubes to construct a uniformly distributed conductive functional layer,and prepare MWCNTs/PVDF conductive membrane by vacuum filtration.Analyze the surface morphology and chemical changes of the conductive membrane by field emission scanning electron microscopy（FESEM）and X-ray photoelectron spectroscopy（XPS）.Investigate the effects of cross-linked polymer and cross-linking time on the stability,hydrophilicity,and conductivity of the conductive membrane.The results showed that the pure water contact angle of the modified MWCNTs/PVDF conductive membrane was decreased from 87°to 25°;the average mass loss rate of the conductive functional layer of the conductive membrane in the 30-min ultrasonic oscillation experiment was 1.22%,and the mass loss was as low as 10-4g,excellent stability;the average conductivity of the modified MWCNTs/PVDF conductive membrane was 1.15 S·cm-1,and the conductivity was good.Set up an electrically-assisted membrane filtration device to conduct electrically-assisted anti-membrane fouling experiments on yeast suspension,bovine serum protein solution,polyacrylamide solution and activated sludge,and explore the operating performance of conductive membranes under different external electric field conditions.The results showed that the MWCNTs/PVDF conductive membrane exhibited good filtering performance and anti-fouling performance for pollutants with different particle sizes and properties under the condition of applying a cathode potential on the surface of the membrane.The filter cake layer model and the pore blockage model were used to analyze the membrane fouling mechanism of the conductive membrane during the electrical-assisted filtering of pollutant solutions.The curve fitting results and the fitting slope value both indicated that the external electric field has an effect on the formation of the filter cake layer and the membrane pores.Clogging was playd a role in improving,and the conductive membrane has excellent anti-membrane fouling performance under electric assist conditions.The MWCNTs/PVDF conductive membrane was used as the cathode membrane to treat high-salt wastewater in a new baffled MFC/MBR coupling system.The coupling system realized the good growth of halophilic electricity-producing microorganisms.In the actual operation process,the removal rate of COD was 90%,and the average removal rate of ammonia nitrogen was greater than 95%.With an external resistance of 500Ω,the coupling system has a power generation voltage of 0.36 V,and the system has a good power generation capacity;the maximum power density generated during system operation was 76.74m W·m-2.Through three-dimensional fluorescence and infrared spectroscopy analysis,it was known that the conductive membrane coupled MFC/MBR system has achieved a certain effect in mitigating membrane pollution. |
