Industrial wastewater treatment using PES UF membranes containing hydrophilic additives: Experimental and modeling of fouling mechanism

Abstract

In order to acquire preferred structure and performance, the effects of different hydrophilic additives, including triethylene glycol (TEG), polyethylene glycol (PEG), polyvinylpyrrolidone ( PVP ) at various concentrations, and coagulation bath temperature (CBT) on the morphology and performance of polyethersulfone (PES) ultrafiltration (UF) membranes were studied. The PES membranes were fabricated via non-solvent induced phase separation (NIPS) technique, and their performances were measured in terms of pure water flux (PWF), the flux of synthetic oil/water (O/W) emulsion, and industrial oily and textile wastewater, and oil rejection. Additionally, the morphology and hydrophilicity of the membranes were characterized by the SEM and water contact angle (CA) tests, respectively. The results revealed that the morphology and structure of the PES membranes depend on the type and concentration of the additive in the casting solution, as PES/PVP membranes had a denser structure than the PES/TEG and PES/PEG membranes. Besides, increasing CBT from 25 °C to 45 °C leads to the formation of a membrane with higher porosity, larger pores, higher water permeability, and lower oil rejection. The membrane containing 5%wt of TEG showed the best separation performance for treating synthetic and industrial wastewaters. Moreover, modeling of the flux decline using Hermia’s model and second kind standard blocking indicated the gel layer formation is the dominant fouling mechanism of the UF process of the oily wastewaters. • Effect of hydrophilic additives on morphology of PES UF membrane was investigated. • Effect of different CBTs on microstructure and performance of PES membranes was examined. • Optimal membrane exhibited an appropriate performance for treating refinery and textile industrial wastewaters. • Hermia’s model was applied to ascertain the governing fouling mechanisms.