Polymeric, Catalytic, Conductive, Porous Hollow Fiber Membrane Cathode for Water and Energy Recovery from Wastewater Treatment

Polymeric porous hollow fiber membrane (HFM) is regarded as revolutionary solution in the wastewater industry for recovery of clean water at low cost. Further advancing research towards the energy recovery using microbial electrochemical principle has been conceptualized by precisely modifying polymeric porous HFMs to become catalytic and electrically conductive. The polymeric catalytic conductive HFMs were used as a cathode in anaerobic electrochemical membrane bioreactor (AnEMBR) for recovery of both water/energy from low organic strength wastewaters (such as sewage). In turn this mechanism also reduces biofouling by membrane scouring through the generation of H₂ bubbles on the surface of the membrane and/or generation of electrical field. The advantage of such membranes in biological waste water treatment has been reported for polymeric flat sheet [1] and inorganic HFM [2].

In this study, we have investigated the development of multilayer polymeric catalytic and conductive porous HFM cathodes using atomic layer deposition (ALD) technique. These fibers were compared with the benchmark Pt-coated (0.5 mg Pt/cm²) carbon cloth cathodes (control reactor) generally used in microbial electrochemical systems research. They were used as cathode in AnEMBR and operated in electrolysis mode under applied potential (-0.1V vs Ag/AgCl). The e^- and H⁺ generated at the anode ultimately get reduced to H₂ on the surface of cell cathode. The performance of the AnEMBR in terms of fouling propensity was compared with a control reactor, which was operated as an anaerobic MBR (AnMBR). The AnEMBr fouled significantly less than that of AnMBR due to the indigenous H₂ evolution on the conductive fibers surface. Their dual functionality and architecture open the window for sustainable harnessing of resources from wastewaters (i.e. pollution to purification) and mitigating the unavoidable phenomenon of biofouling in membrane processes.

References

[1] L. Malaeb, K.P. Katuri, B.E. Logan, H. Maab, S.P. Nunes, P.E. Saikaly, A Hybrid Microbial Fuel Cell Membrane Bioreactor with a Conductive Ultrafiltration Membrane Biocathode for Wastewater Treatment, Environmental Science & Technology, 47 (2013) 11821-11828.

[2] K.P. Katuri, C.M. Werner, R.J. Jimenez-Sandoval, W. Chen, S. Jeon, B.E. Logan, Z. Lai, G.L. Amy, P.E. Saikaly, A novel anaerobic electrochemical membrane bioreactor (AnEMBR) with conductive hollow-fiber membrane for treatment of low-organic strength solutions, Environmental Science and Technology, 48 (2014) 12833-12841.