Investigating Performance Properties of Three New Types of UF Membranes for Carwash Sector Applications

Abstract

Carwash facilities generate considerable amounts of wastewater, which presents both an environmental challenge and a potential alternative water source. To facilitate reuse, this wastewater must meet stringent quality standards. In this study, three novel ultrafiltration (UF) membranes were developed for the first time to treat carwash wastewater (CWW). These membranes were fabricated from postmodified (PM) polyvinyl chloride (PVC) derivatives: PVC modified with 4-tert-octylthiophenol (PP1), 4-tert-butylthiophenol (PP2), and thiophenol (PP3) using a mechanosynthesis approach. The membranes were synthesized by incorporating the respective modified polymers into a solvent mixture of tetrahydrofuran (THF) and N-methyl-2-pyrrolidone (NMP) via the casting solution technique. Structural characterization was performed using Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The membranes exhibited thicknesses of 143 μm (PP1), 178 μm (PP2), and 139 μm (PP3), porosity ranging from 64.67% to 73.33%, and average pore sizes between 23.41 and 28.81 nm. Performance testing revealed that PP1 demonstrated the highest rejection rates for suspended solids (99%), oil products (82.4%), and surfactants (79%), with a flux of 40.24 L/m2 h. Although PP3 achieved the highest water flux (61.82 L/m2 h), its rejection performance was slightly lower. Retentate underwent biological treatment, removing 85%–90% of organic matter, supporting sustainable wastewater reuse. © 2025 The Author(s). Journal of Applied Polymer Science published by Wiley Periodicals LLC.