Selective interfacial oxidation of organic pollutants in Fenton-like system mediated by Fe(III)-adsorbed carbon nanotubes

In this study, we propose a heterogeneous Fenton-like system for selective oxidation towards target compounds based on the recognition of electrostatic attraction. The catalyst Fe-OCNT was fabricated by binding Fe ions onto the surface of oxidized carbon nanotubes, and the resultant Fe-OCNT/H2O2 system could oxidize methylene blue and chrysoidine G only among six test compounds, both of which are positively charged and could be adsorbed on the negatively charged surface of the catalyst. Also, the selective oxidation system features a broad pH suitability from 4.0 to 9.0, excellent resistance to traditional free HO quenching agents and halogen ions, and satisfactory reusability. After the exclusion of the contribution of various reactive species, e.g., free HO, FeIVO, 1O2, and surface-bound O*, we suggest that HO adsorbed on the CNT surface is responsible for such selective oxidation. This work presents a proof-of-concept design of highly selective Fenton-like system in water treatment.