Fabrication of MoS2 nanopetals on honeycomb-like biochar with enhanced sonocatalytic activity for degradation of acid blue 7 and pharmaceutical pollutants

Abstract

Organic dyes constitute an integral part of industrial effluents. Advanced oxidation processes are efficient methods for the degradation of organic pollutants, one of the most promising of which is sonocatalysis. In this study, we aimed to immobilize MoS2 nanopetals on honeycomb-like biochar through a one-step hydrothermal method and evaluate its sonocatalytic performance in the degradation of acid blue 7 (AB7). The MoS2-Biochar composite demonstrated enhanced sonocatalytic activity, approved by its larger specific surface area (5.0 m2/g) and narrower bandgap (1.25 eV) compared with those of pure MoS2. Application of 1.5 g/L MoS2-Biochar (10:1) led to a 95 % decolorization of AB7 (20 mg/L) within 40 min of reaction time. Moreover, considerable degradation efficiencies were achieved for various organic pollutants, including hydroxychloroquine (96 %), levofloxacin (81 %), phenazopyridine (80 %), and tilmicosin (67 %) with initial concentration of 20 mg/L within 120 min of treatment. The synergy factor and degradation turnover value of the sonocatalytic process for decolorization of AB7 were calculated to be 4.88 and 27.37 µmol/h.gcat, respectively. Trapping experiments were conducted to determine the roles of various reactive species in the sonocatalytic degradation process, and holes were found to be the dominant species. Furthermore, the generated intermediates were identified using gas chromatography–mass spectrometry (GC–MS) analysis, which suggested a possible mechanism for the degradation process. A stable structure and acceptable reusability with a 16 % reduction in the decolorization efficiency after four consecutive sonocatalytic runs were observed for the 10:1 composite, suggesting a promising perspective for the application of the studied system in the efficient treatment of organic pollutants.