Optimization of nanocomposite conductive membrane formulation and operating parameters for electrically-enhanced palm oil mill effluent filtration using response surface methodology

Electrically-enhanced membrane filtration with the application of electric field across the conductive membrane was proved as an effective method in reducing membrane fouling through the enhancement of electrostatic repulsion between foulants and the membrane surface. In this study, nanocomposite conductive membranes were fabricated by blending graphene oxide (GO) and multi-walled carbon nanotubes (MWCNTs) into polyvinylidene fluoride (PVDF) membrane matrix via phase inversion method. Response surface methodology (RSM) was employed to establish the optimum nanocomposite conductive membrane formulation and operating parameters for the electrically-enhanced filtration process in palm oil mill effluent (POME) treatment. The optimum process variables for continuous mode study are the use of nanocomposite conductive membrane with carbon nanomaterials concentration of 4.22 wt% and electric field of 221.00 V/cm. Whereas, interval time of 32.00 min and application time of 6.00 min are suggested for intermittent mode study in achieving high normalized flux. The corresponded experimental normalized flux for optimum continuous study mode and intermittent study mode were 0.7778 and 0.7983, with low percentage of error 9.94% and 11.20%, respectively. Optimization with the use of RSM is satisfactory to improve the performance of nanocomposite conductive membrane in electrically-enhanced filtration process through the reduction of membrane fouling propensity. (C) 2019 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.