Fenton-like degradation of diclofenac in water using iron-impregnated mussel shell biochar (Fe@MSBC)

Abstract

Emerging pollutants such as diclofenac (DFC) are a cause of concern worldwide due to their persistence in the environment. Advanced oxidation processes (AOPs), such as Fenton-like processes, are among the emerging technologies for wastewater treatment due to their capability to completely degrade even recalcitrant pollutants. However, previously-investigated catalysts are expensive. Here, we report the performance of the synthesized iron-impregnated biochar derived from mussel shells (Fe@MSBC) as a catalyst for DFC degradation in water using sodium percarbonate (SPC) as an oxidant. SEM, EDX, FTIR, DSC, and TGA confirmed the successful synthesis of Fe@MSBC. A Box-Behnken design of experiments was used to investigate the effects of Fe@MSBC catalyst loading, initial DFC concentration, and SPC concentration on the removal of DFC. Here, we found that a reduced cubic model can adequately model these effects. Lower Fe@MSBC catalyst loadings, higher initial DFC concentrations, and SPC concentrations near 1.5 mmol L-1 SPC yielded higher DFC degradation. Maximum DFC removal can be achieved at 15.1831 mg L-1 Fe@MSBC catalyst loading, 60 mg L-1 initial DFC concentration, and 1.5228 mmol L-1 SPC concentration. 98.2872 % ± 0.0278 % DFC can be degraded under these conditions. These results show the exceptional degradation efficiency of Fe@MSBC in degrading DFC. These findings could help our search for novel materials to degrade emerging pollutants in wastewater, leading to a safer wastewater effluent to be released into the environment.