Enhanced nevirapine degradation via cellulose acetate-based photocatalytic membrane

Abstract

• Novel cellulose acetate photocatalytic membrane (V 2 CT x @WO 3 /ZnIn 2 S 4 /CA) via phase inversion. • Nanocomposite cellulose acetate membranes have improved hydrophilicity and antifouling properties. • 0.5 VWZ@CA demonstrated 76.6 % degradation efficiency towards nevirapine. • Superoxide emerged as the dominant reactive species governing the degradation process, nevirapine was degraded to butane (less harmful product). Membrane technology is one of the widely used technologies in water remediation owing to its high efficiency and ease of operation. Nonetheless, fouling stands out as the major drawback in membrane application resulting in reduced flux and efficiency. Owing to excellent hydrophilic and optical properties of WO 3 , ZnIn 2 S 4 , WO 3 /ZnIn 2 S 4 , and V 2 CT x @WO 3 /ZnIn 2 S 4 (VWZ), the nanoparticles were used as fillers during the fabrication of cellulose acetate photocatalytic membranes via the phase invasion method. The fabricated membranes were characterized using XRD, SEM, contact angle, and streaming potential. Compared to pristine cellulose acetate (CA), the composite membrane exhibited improved surface hydrophilicity with 0.5 VWZ@CA recording the lowest contact angle of 38.4° which was 2.13 times lower than that of pristine cellulose acetate (82°). There was a significant enhancement of membrane porosity from 11.8% for pristine CA to 80.1% for 0.5 VWZ@CA. The 0.5 VWZ@CA registered remarkable antifouling properties with a flux recovery ratio of 76.2% compared to 54.8% for pristine CA. The highest photodegradation efficiency (76.6%) towards 10 ppm nevirapine solution was achieved by 0.5 VWZ@CA at pH 7. The enhanced degradation efficiency in 0.5 VWZ@CA was attributed to the presence of superoxide produced during the photocatalytic activity. The membrane demonstrated high stability after 5 cycles with a 9.1% decline in efficiency and no structural distortion, as shown by XRD spectra of used and unused membranes. Liquid chromatography–mass spectrometry (LC–MS) analysis confirmed the transformation of nevirapine (NVP) (m/z 266) into its less toxic final degradation product, butane (m/z 58). The ability to degrade nevirapine from synthetic water confirms potential application of prepared membrane in real wastewater systems.