Enhanced adsorption and photocatalytic activity of BiOI-MWCNT composites towards organic pollutants in aqueous solution.

BiOI-MWCNT composites, with high absorption and visible-light photocatalytic performance, were synthesized by a solvothermal process, in which ethylene glycol (EG) participated in the reaction. Synthesized BiOI-MWCNT composites were characterized by X-ray diffraction (XRD), diffuse reflectance spectra (DRS), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS). The results showed that the prepared BiOI-MWCNT composites exhibit strong adsorption ability with the increase of doped MWCNT amount. The efficiency of AOII degradation increased with the increase of MWCNT amount from 0.5 to 1.0% significantly. The photocatalytic degradation of AOII using BiOI-MWCNT composites under visible light (λ>400 nm) was almost completed within 180 min. BiOI-MWCNT composites maintained its degradation efficiency and durability after being reused for 5 batch runs. The high adsorption ability and degradation efficiency of BiOI-MWCNT for AOII was attributed to the sorption of doped MWCNT and the effective charge transfer from excited BiOI to MWCNTs, respectively. Moreover, organic compounds as intermediates of the degradation process were identified by LC/MS.