Asymmetric surface interaction-induced in-situ demulsification boosts emulsion removal and near-full flux recovery with contracted carbon fiber filter

Recent membrane separation technologies have shown great potential in effective oil removal from wastewater. However, the performance of membrane filtration has been restricted by changes in membrane permeability and fouling caused by the passage of emulsified oil droplets through the membrane filtration layer. To avoid these problems, we developed a surfactant-modified contracted carbon fiber (CCF) filter to improve the filtration performance and removal efficiency of filter fouling. The CCF filter exhibited excellent filtration performance with a removal efficiency of up to 93.8 ± 2.0 % for emulsified oils under constant pressure conditions. A flux recovery of near 100 % was achieved by increasing pore size and using electrochemical backwashing. The surfactant-modified carbon fibers were able to demulsify oil-in-water (O/W) emulsions, thus increasing the size of oil droplets during filtration making it easier for their removal with in-situ cleaning. This sustainable filter and cleaning process provided effective oily wastewater treatment while reducing operational costs and the need for frequent membrane replacement. Overall, these findings offer valuable insights into fouling control strategies and potential applications of the carbon fiber filter in oily wastewater treatment.