The Study Of Conductive Membrane’s Fouling Suppression And E-Catalysis Effect With Electric Field Applied

The bio-fouling is always a limiting factor for the development and application of the membrane technology and the electric-membrane biological reactor (EMBR) has been proved an effective method to suppress the membrane fouling. By applying the electric field, the negative charge sludge can be moved away from the membrane surface by electric field force. Moreover, when the membrane was modified by the conductive organic polymer, the electrochemical property of membrane/electrode would be motivated and showed catalysis effect for water pollutants.In this paper, a novel conductive membrane/electrode was prepared, by modifying a polyester fabric membrane with impregnated graphene oxide (GO)/graphene (Gr) and coated polypyrrole (PPy) via vapor phase polymerization method (VPM) and liquid phase polymerization method (LPM). The better conductive modified membrane was employed in the simulate EMBR with low voltage and tested its anti-fouling property by filtrating the yeast solution. We found Gr/PPy modified membrane by VPM had the best comprehensive property with lower resistance (0.68±0.08k Ω/cm), more uniform colour and fix on the membrane firmly. With1V/cm electric field strength, an increase of20%in the short-term cumulative permeate volume was obtained for the Gr/PPy modified membrane and it was only10%for PPy modified membrane. Also the membrane fouling models were introduced to study the fouling mechanism, t/V-t and t/V-V curves are drawn, proving the classical cake filtration model can better describe the membrane fouling process.To confirm the electrochemistry-active membrane/electrode have an electro-catalysis effect on the water pollutants, methylene blue (MB) self-circulation degradation by Gr/PPy membrane in EMBR without the microorganism involvement was investigated. With stainless iron mesh as the anode, the membrane was used as the cathode for removing MB by E-Fenton reactions. Parameters affecting the E-Fenton reaction were investigated. It was found that appropriate dissolved oxygen, pH value, membrane flux and electric field strength all influenced this cathodic membrane performance in E-Fenton system. MB, the target pollutant, was significantly degraded by the in-situ generated hydrogen peroxide, and the combined function of membrane and catalysis on pollutants makes the effect even better. The membrane was stable with90%degradation efficiency in150min during serious tests and its performance was further promoted by doping with AQS (95%degradation rate in90min), which enabled more effective integration of membrane with electro-catalysis.As a result, the organic modified membrane in EMBR played the roles of both membrane fouling suppression and pollutants electro degradation. It integrated the membrane separation and electro catalysis technology as one entirety by the membrane with electro catalysis performance in EMBR. The wastewater decontamination of EMBR with electrochemistry-active membrane in it results from the comprehensive effect of biological degradation, electro catalysis and membrane separation, so better water-treating efficiency is obtained. Moreover, this modified membrane’s coupling with microbial fuel cell technology may hopefully realize the energy saving of wastewater treatment with high efficiency.