A novel biochar-composed TiO2 (BC-Ti) for efficient photocatalytic degradation on arbidol

Abstract

Improper and inadequate treatment of Pharmaceutical and Personal Care Products (PPCPs) is currently a serious environmental problem, while photocatalysis is a rapidly developed and highly efficient treatment for PPCPs wastewater. A novel biochar-doped TiO2 photocatalyst (BC-Ti) prepared by the sol–gel method had exceptional activity and high photocatalytic performance on abidol (ABD) removal. The removal capacity of arbidol on the synthesized photocatalyst was up to 76 % shortly after 20 min UV lighting, which was 8 % and 52 % higher than that on commercial TiO2 and biochar, respectively (50 mg/L photocatalyst, pH = 6.77, ABD concentration = 20 mg/L). ABD removal rate increased continuously and could be over 90 % after 5 h irradiation. This reaction was well fitted to the Langmuir–Hinshelwood (L–H) kinetics model. The excellent reusability and stability were verified through six recycling experiments (only ca. 6 % removal reduction compared to the original one), which proved the economic viability of the catalyst. The analysis of SEM-EDS, BET, XRD, EIS, UV–vis DRS and PL verified an efficient biochar doping on the produced TiO2 and provided an explanation for the excellent photocatalytic performance of BC-Ti. ⋅O2– was proved to play important role on ABD removal through trapping test. The inferred structures of photocatalysis products and probable degradation pathways of arbidol were also analyzed via LC-MS and TOC which indicated a successful ABD decomposition. Partial ABD was converted into mineralized carbon (CO2) and the remaining photocatalysis products in solution were small molecule substances with low toxicity. This work paves the way for development a novel carbon-based photocatalyst and is conducive to PPCPs wastewater purification.