CFD modelling and simulation of oily-wastewater remediation using superhydrophobic-superoleophilic and superhydrophilic-superoleophobic membrane technologies coupled with the gravity separation (GS) technique

ABSTRACT Superhydrophobic-superoleophilic and superhydrophilic-superoleophobic (SHSO) membranes offer numerous advantages for removing oil from oily wastewater, due to their low maintenance costs, high energy efficiency, and ease of use. Membrane fouling is a key challenge to the practical application of SHSO in cleaning oily wastewater. This study designed and meshed a hybrid system that integrates SHSO membrane filtration with gravity separation via a hydrocyclone using ANSYS Fluent. The hydrocyclone performs a gravity separation on the initially produced water to break down and evict larger oil droplets from the mixture before passing it through the SHSO membranes. This assists significantly in reducing the fouling time of the SHSO membrane, hence contributing to the improved filtration efficiency of the membrane. The SHSO membranes developed were able to separate oil from water at an efficiency ranging from 97.55 to 99.65% for a membrane with one fluid outlet and 99.99% in the case of dual membranes with two fluid outlets. The hybrid system resulted in high separation efficiency and high anti-fouling abilities. For optimal performance by the SHSO membrane, the operating pressure at the SHSO inlet pipe should be maintained below 500 Pascal (gauge), and the inlet velocity should be kept at less than 4 m/s.