Immobilizing nanocatalyst onto polyvinyl alcohol cross-linked by sodium alginate: a new strategy to degrade high amount of chloramphenicol and amitriptyline

Abstract

Drug contamination is one of the most dangerous categories of impurities, which can be mitigated by photocatalysis reaction. Despite the unignorable advantage of nanophotocatalyst, their separation from batch reaction is challenging. Herein, a developed equipment is presented based on immobilizing a nanocatalyst onto the surface of a non-soluble polymeric substrate to degrade high amounts of chloramphenicol and amitriptyline under UV radiation. At first, polyvinyl alcohol plates were prepared through cross-linking by C₆H₉NaO₇ in the presence of C₅H₈O₂ and then characterized according to the water uptake amount and measuring water contact angle. The nanocatalyst was prepared by mixing two separate core–shell suspensions of Fe₃O₄@SiO₂ and WO₃@TiO₂; afterward, Fe₃O₄@SiO₂–WO₃@TiO₂ was sprayed onto the surface of the plates. The materials were characterized by X-ray diffraction spectroscopy, FTIR analysis, scanning electron microscopy, energy dispersive X-ray spectrometry, elemental mapping analysis, thermogravimetric analysis, Brunauer−Emmett−Teller and diffuse reflectance spectroscopy. The degradation recovery was optimized with respect to pH, UV radiation time and nanocatalyst amount. The adsorption efficiency, degradation efficiency, reusability, reproducibility, durability, effect of interference ions, adsorption isotherm, adsorption kinetic, photocatalytic kinetic and degradation mechanism were studied and explained. Analytical greenness metric approach is reported. Four different water samples were successfully employed as real samples.