Research subject: Oil-based wastewater treatment is essential to prevent environmental harm and comply with regulations. Membrane processes are ideal for this due to their efficiency, low energy use, and ability to handle complex emulsions effectively.
Research approach: The primary goal of this study is to employ an ultrafiltration membrane separation process for the treatment of wastewater containing oil compounds (e.g., diesel fuel). To achieve this, polyethersulfone/sulfonated-polyethersulfone (PES/SPES) blend membranes with various SPES loadings were fabricated using the nonsolvent-induced phase separation (NIPS) method. The effects of SPES loading on the membrane morphology, surface roughness, surface hydrophilicity, mechanical strength, porosity, and water and wastewater flux were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle measurement, mechanical strength testing, and filtration performance tests, respectively.
Main results: The results showed that adding SPES to PES and increasing the loading of SPES led to the formation of macrovoids in the membrane cross-section, enhanced surface roughness and hydrophilicity, increased porosity, improved water and wastewater flux, and increased the pure water flux recovery ratio. However, these benefits came with reduced mechanical strength and increased membrane compaction. Among the prepared membranes, the PES/SPES (60/40 wt./wt.) blend membrane exhibited the best filtration performance, achieving a final wastewater flux of 34.78 L/m²·h, compared to 11.35 L/m²·h for the neat PES membrane. Meanwhile, the PES/SPES (40/60 wt./wt.) composite demonstrated the highest surface roughness, hydrophilicity, and flux recovery ratio. Notably, all membranes synthesized in this study achieved over 99% rejection efficiency for the diesel fuel-water emulsions, which is significant for practical and industrial applications.