Enhancing the degradation of bisphenol A by dioxygen activation using bimetallic Cu/Fe@zeolite: Critical role of Cu(I) and superoxide radical

Abstract

Copper-iron bimetallic material shows a high reactive activity in dioxygen activation processes (DOAs) but presents a significant challenge for enhancing superoxide radical (•O2−) generation. In this study, a practical strategy was developed to enhance •O2− generation for BPA degradation using a zeolite-supported Cu-Fe bimetallic system (called Cu/Fe@zeolite), which was simply prepared by impregnation method. The results verified that the Cu(I) regeneration at the zeolite surface contributes •O2− generation and the H2O2 that is further generated induces •OH production via a further Fenton reaction. In the reaction process, the initial generation of •O2− was primarily enhanced by the Cu(I) loaded onto the zeolite surface and the adsorbed BPA was easily degraded by the •OH. Under optimal operating conditions (i.e., Cu/Fe@zeolite = 3 g/L, Cu:Fe = 1:2, pH = 5, t = 120 min), it was found that 87% of BPA can be removed from wastewater. It is also important to note that the weak alkali buffering property of zeolite not only provides BPA adsorption sites under acidic conditions but also accelerates the precipitation efficiency for metallic ions and reduced the adverse effect of metallic residue on the effluent quality.