Experimental Investigation of the Effect of Implanting TiO2-NPs on PVC for Long-Term UF Membrane Performance to Treat Refinery Wastewater

Faris H Al-Ani; Qusay F Alsalhy; Rawia Subhi Raheem; Khalid T Rashid; Alberto Figoli

doi:10.3390/membranes10040077

Experimental Investigation of the Effect of Implanting TiO₂-NPs on PVC for Long-Term UF Membrane Performance to Treat Refinery Wastewater

Membranes (Basel). 2020 Apr 21;10(4):77. doi: 10.3390/membranes10040077.

Authors

Faris H Al-Ani¹, Qusay F Alsalhy², Rawia Subhi Raheem¹, Khalid T Rashid², Alberto Figoli³

Affiliations

¹ Civil Engineering Department, University of Technology, Alsinaa Street 52, Baghdad 10066, Iraq.
² Membrane Technology Research Unit, Chemical Engineering Department, University of Technology, Alsinaa Street 52, Baghdad 10066, Iraq.
³ Institute on Membrane Technology, National Research Council (ITM-CNR), 87030 Rende (CS), Italy.

Abstract

This study investigated the impact of implanting TiO₂-NPs within a membrane to minimize the influence of long-term operation on the membrane characteristics. Four poly vinyle chloride-titanium oxide (PVC-TiO₂-NPs) membranes were prepared to create an ultrafiltration membrane (UF) that would effectively treat actual refinery wastewater. The hypothesis of this work was that TiO₂-NPs would function as a hydrophilic modification of the PVC membrane and excellent self-cleaning material, which in turn would greatly extend the membrane's lifetime. The membranes were characterized via Fourier transforms infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy dispersive X-ray (EDX), atomic force microscope (AFM), and scanning electron microscope (SEM). The removal efficiency of turbidity, total suspended solid (TSS), oil and grease, heavy metals and chemical oxygen demand (COD) were investigated. Contact angle (CA) reduced by 12.7% and 27.5% on the top and bottom surfaces, respectively. The PVC membrane with TiO₂-NPs had larger mean pore size on its surface and more holes with larger size inside the membrane structure. The addition of TiO₂-NPs could remarkably enhance the antifouling property of the PVC membrane. The pure water permeability (PWP) of the membrane was enhanced by 95.3% with an increase of TiO₂ to 1.5 gm/100gm. The PWP after backwashing was reduced from 22.3% for PVC to 10.1% with 1.5 gm TiO₂-NPs. The long-term performance was improved from five days for PVC to 23 d with an increase in TiO₂-NPs to 1.5 gm. The improvements of PVC-TiO₂-NPs long-term were related to the enhancement of the hydrophilic character of the membrane and increase tensile strength due to the reinforcement effect of TiO₂-NPs. These results clearly identify the impact of the TiO₂-NPs content on the long-term PVC/TiO₂-NPs performance and confirm our hypothesis that it is possible to use TiO₂-NPs to effectively enhance the lifetime of membranes during their long-term operation.

Keywords: PVC; TiO2NPs; composite membranes; crossflow filtration; oily wastewater; ultrafiltration application.