Fe-Cu binary oxide loaded zeolite as heterogeneous Fenton catalyst for degradation of carbamazepine at near-neutral pH

Abstract

In this study, Fe-Cu binary oxide was loaded on zeolite (Fe/Cu/zeolite) to be used as heterogeneous Fenton catalyst, and the catalytic degradation of carbamazepine (CBZ) were optimized at near-neutral pH. The results showed that the Fe and Cu oxide, mainly Fe₂O₃, Fe₃O₄, and CuO nanoparticles, were uniformly distributed on the surface of zeolite particles. Under the optimized conditions, Fe/Cu/zeolite could completely degrade CBZ when initial pH ranged from 3 to 7, and the removal efficiency of CBZ still remained above 74% even though the initial pH increased to near 10. After 8 times' repeated use, the Fe/Cu/zeolite exhibited an over 95% removal efficiency of CBZ. The hydroxyl radicals (•OH) were verified to be the main active oxidants by quenching experiments and ESR testing. The XPS of the materials revealed that the high catalytic efficiency was attributed to the synergistic effect of Fe(III)/Fe(II) and Cu(II)/Cu(I) redox cycles. This catalyst can be used for the efficient degradation of organic pollutants in heterogeneous Fenton systems.

Keywords: Carbamazepine; Fe/Cu/zeolite; Heterogeneous Fenton; Hydroxyl radicals; Neutral pH.