Controlled Nanorod-like Structure of Iron Tetrapolyvanadate for Enhanced Heterogeneous Fenton-like Catalysis

Abstract

In this study, a heterogeneous Fenton-like system was developed based on Fe2V4O13 composite oxide material with the aim of decomposing some hazardous organic compounds present in industrial wastewater (e.g., methylene blue, ciprofloxacin, etc.). The research results have shown that this composite oxide material was synthesized via a simple hydrothermal method with controlled conditions optimized for hydrothermal temperature and structure aging temperature. Characterization methods indicated that the optimal hydrothermal condition was at 180°C for 12 hours and the structure aging temperature was at 80°C for 12 hours. Under these synthesis and structure aging conditions, a characteristic nano-rod structure of the material with dimensions of 500 × 40 × 20 nm (in length × width × height) was formed. This structure exhibited the best catalytic activity for organic compound decomposition compared to other material structures synthesized under different conditions in this study. The catalytic activity in decomposing of methylene blue and ciprofloxacin was high, reaching > 99% and > 77 %, respectively, after 14 minutes. This was achieved following the Fenton system mechanism in the presence of H2O2 at pH 7 and 9. The mechanism followed the mixed homogeneous and heterogeneous Fenton process, in which the presence of leached vanadium ions accelerated the =Fe2+/=Fe3+ redox couple regeneration, consequently enhancing the degradation efficiency. In the mechanism, the formation of the highly active free radicals •OH and •OOH is observed and demonstrated by using specific competitive inhibitors (quinhydrone, ascorbic acid). These findings suggest the potential of the Fe2V4O13-based nanomaterial for the efficient treatment of organic compounds in wastewater, particularly under neutral to alkaline media.