Performance evaluation of double stage process using nano hybrid PES/SiO2-PES membrane and PES/ZnO-PES membranes for oily waste water treatment to clean water

Membrane-based separation is a technology that recently developed by researchers, especially in wastewater treatment. Implementation of membrane technology in oil wastewater treatment is limited due to its low productivity as a result of fouling on the membrane surface. The introduction of nanomaterials has been developed to the produced nano-hybrid membrane with better performance. In this paper, nano-hybrid polyethersulfone (PES) membranes contained nano SiO2 and ZnO are fabricated and evaluated for produced water treatment in a double stages configuration. The nano-hybrid PES membranes are fabricated using dry-wet phase inversion to form flat sheet membranes. The membrane filtration cell is set in double stages configuration with nano-hybrid PES membrane in the first stage and neat PES membrane in the second stage. In this study, separation performance of nano-hybrid PES-nano SiO2 and PES-nano ZnO is compared and discussed. Fouling behaviour of the membranes is also revealed. Experimental results show that the nano-hybrid PES-nano SiO2 membrane has 25% higher permeate flux than the nano-hybrid PES-nano ZnO. Comparing overall improvements of double stages performance with single stage confirmed that the final flux enhanced by 200%, mineral rejection efficiency improved by 16–18%, and the lower foulant deposition on the membrane. The performance enhancement of nano-hybrid membrane is restricted by the loading concentration where the agglomeration doesn’t occur. It is expected that this study can provide guidance for improving new strategies to facilitate PES membrane-based separation as an effective and efficient technology for produced water treatment.