Photocatalytic activity of ZnO coated magnetic crosslinked chitosan/ polyvinyl alcohol microspheres

摘要

ZnO coated magnetic chitosan/polyvinyl alcohol microspheres (ZMChi/PVA) were synthesized by crosslinking of Chi/PVA mixture in the presence of hydrothermally synthesized magnetite nanoparticles and then immersion in basic Zn(NO)_3 solution for 24 h. Chemical structure of the synthesized materials was elucidated by Fourier Transform infrared (FT-IR) spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray (EDX). The effect of different ZnO loadings upon Brunauer-Emmett-Teller (BET) surface area, band gap energy (E_g), Photoluminescence (PL) spectra intensity and saturation magnetization (M_s) was investigated. Visible light photocatalytic decolorization of Rhodamine B (RB) dye solution by ZMChi/PVA under various operational conditions was carried out. It was regarded that 98% of 3mg/L RB solution can be decolorized by 1 g/L of ZMChi/PVA at Ph 10.0 after 40min. Kinetic studies indicated that photodegradation results can be analysed according to Langmuir-Hinshelwood model. Active species trapping experiment showed that positive holes (h~+) and hydroxyl radicals (OH) are responsible for photodegradation of RB. Moreover, recycling of ZMChi/PVA for six cycles indicated its high efficiency and photostability.