Heterogeneous activation of persulfate by ZnCo_xFe_2−xO₄ loaded on rice hull carbon for degrading bisphenol A

Abstract

A new low-cost composite of ZnCo _<i>x</i> Fe_2-<i>x</i> O₄ loaded on rice hull carbon (ZnCo _<i>x</i> Fe_2-<i>x</i> O₄-RHC) was synthesized <i>via</i> waste ferrous sulfate (the industrial waste produced in the process of producing titanium dioxide) and rice hull as raw materials, which was applied for the degradation of bisphenol A (BPA) by heterogeneous activated peroxodisulfate (PS). A series of characterizations including XRD, SEM, FTIR, and BET analysis were carried out to analyze the structure and morphology of the materials. It is confirmed that the ZnCo _<i>x</i> Fe_2-<i>x</i> O₄-RHC composites show better catalytic activity and performance than other control samples, which can be attributed to the synergistic effect of Fe and Co, ZnCo _<i>x</i> Fe_2-<i>x</i> O₄ and RHC based on these analyses. The degradation rate of BPA by ZnCo_1.3Fe_0.7O₄-50%RHC reached 100% within 15 min, and it can still maintain good catalytic efficiency after 5 cycles. ESR test and XPS results showed that free radical and non-free radical processes were involved in BPA degradation. These findings offer a novel, low cost and simple strategy for rational design and modulation of catalysts for the industrial degradation of organic pollutants, and provide a new idea for the utilization of waste ferrous sulphate in titanium dioxide industry.