Degradation of p-chloroaniline by FeO3−xH3−2x/Fe0 in the presence of persulfate in aqueous solution

Abstract

Sulfate radical based advanced oxidation processes are promising techniques for the removal of organic compounds in aqueous solutions. In this study, FeO_3−xH_3−2x/Fe⁰ catalyst was prepared and used to activate persulfate (S₂O₈²⁻) for the degradation of p-chloroaniline (PCA). The results showed that nearly complete degradation of PCA was observed within 1 h in the persulfate-FeO_3−xH_3−2x/Fe⁰ system under the following optimized reaction conditions: PCA concentration 0.05 mM, FeO_3−xH_3−2x/Fe⁰ 1 g L⁻¹, persulfate 2.5 mM and pH 7.0. The PCA degradation was higher under acidic conditions when compared to alkaline conditions. A complete removal of the added PCA (0.05 mM) was achieved within 5 min with the addition of 2.5 mM persulfate and 1 g L⁻¹ FeO_3−xH_3−2x/Fe⁰ at pH 3.0. FeO_3−xH_3−2x/Fe⁰ catalyst was prepared by the calcination of Fe⁰ at 200 °C. The morphology of the catalyst was investigated with X-ray diffraction patterns (XRD), Scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). The results demonstrated that the catalyst surface was mainly composed of hematite γ-Fe₂O₃ and goethite (α-FeOOH).