Catalytic ozonation with disilicate-modified nZVI for quinoline removal in aqueous solution: Efficiency and heterogeneous reaction mechanism

Abstract

• Innovative disilicate-modified nZVI catalyst with unique functional groups was prepared. • The optimal Si-nZVI catalyst (Si15-nZVI) showed excellent catalytic ozone performance. • The Si15-nZVI material displayed good ozone tolerance and satisfactory reusability. • The [Si O Fe] OH functional groups on Si15-nZVI played an essential role to activate ozone. • Magnetic recyclability of Si-nZVI/O 3 system is conducive to its practical application. Nanoscale zero-valent iron (nZVI) was not considered as an ideal candidate for catalytic ozonation process in aqueous media because of its drawbacks of rapid passivation, self-agglomeration and consequent loss of reactivity. In this study, a novel disilicate-modified nZVI (Si-nZVI) material, was prepared through a liquid-phase reducing method with hydrosoluble disilicate as a modifier. The optimal Si-nZVI catalyst (Si15-nZVI), with negligible iron leaching and a good tolerance in ozone water, showed favorable water-dispersibility to achieve a highly efficient ozonation catalysis for removing quinoline (91.9% removal efficiency). Compared to the nZVI, the Si-nZVI displayed satisfactory catalytic stability and benign reusability as well. It was revealed that [Si O Fe] OH groups on Si15-nZVI, as the dominating active centers, played an essential role to boost the adsorption and catalytic decomposition of O 3 in aqueous solution. This study demonstrates the suitability of Si-nZVI to catalytic ozonation process, and provides a prospective oxidation technology for decontamination.