Enhanced separation performance of coal-based carbon membranes coupled with an electric field for oily wastewater treatment

• Coal-based carbon membrane coupled with an electric field is designed.
• The electric field has a positive effectiveness on suppressing membrane fouling.
• Improved separation properties are achieved due to anodic oxidation.
• Carbon membrane possess good fouling resistance to oil droplets under acidic condition.
• Fouling analysis confirms enhanced antifouling ability by applying an electric field.

Coal-based carbon membrane coupled with an electric field is designed to achieve enhanced separation performance for oily wastewater treatment in this study. Effect of electric field intensity, concentration and pH of oily wastewater, rotate speed of peristaltic pump, electrolyte concentration, and electrode distance on separation performance of carbon membrane are investigated. The morphologies of carbon membranes are examined using scanning electron microscope (SEM). Fouling analysis is also carried out for further evaluating the antifouling ability of coal-based carbon membrane. The results demonstrate that coal-based carbon membranes integrated with an electric field show improved permeate flux and removal efficiency for oily wastewater treatment due to anodic oxidation. No obvious oil foulants are observed on carbon membrane by SEM images. Low total fouling ratio (TFR) and high flux recovery (FR) imply that exerting an electric field can significantly improve antifouling ability of carbon membrane. Acidic condition is benefit for carbon membrane to possess good fouling resistance to oil droplets. An decrease in electrode distance improves the separation performance of the treatment system. The optimum operation conditions of 0.31 V/cm electric field intensity, 7.5 r/min pump rotate speed, and 5 g/L electrolyte concentration are recommended. After cleaning, carbon membrane coupled with an electric field still demonstrates great potential in oily wastewater treatment.