Treatment of Heavy-Metal-Containing Oily Wastewater Using a Novel α-Zirconium-Phosphate/Polyacrylonitrile Ultrafiltration Membrane

Abstract

For most work on separation membrane for oily wastewater, heavy metals in oily wastewater may pollute the environment. Novel α-zirconium-phosphate-nanoparticle/polyacrylonitrile (α-ZrP-NP/PAN) mixed matrix membranes (MMMs) were prepared for effective oily wastewater treatment. The α-ZrP-NP contributed abundant –OH groups to the MMMs and enhanced their hydrophilicity. Meanwhile, the surface of the MMMs carried enhanced negative charges due to the α-ZrP-NP in the pH range of 3–10. Scanning electron microscopic analysis of the MMM morphology revealed that the macrovoid structure enhanced, the surface pore size, and the number of pores increased. The MMMs achieved a considerably improved flux and recovery rate of 175.91 L/m2·h and 75.66%, respectively, indicating improvements in filtration efficiency and anti-fouling performance. The purification effect (oil and COD removal rate) of the MMMs on oily wastewater remains above 90%, which reflects the decent purification ability of the membrane on oily wastewater. The removal rate of Pb2+, a representative heavy metal ion, reached 94.82%. The regeneration efficiency of the MMM contaminated with lead ions was more than 90%. These results demonstrated the tremendous potential of the treatment of heavy-metal-containing oily wastewater using the fabricated MMMs.