Abiotic reduction of p-chloronitrobenzene by sulfate green rust: influence factors, products and mechanism

The reduction of p-chloronitrobenzene (p-CNB) by sulfate green rust (GR(SO(4))) was systematically studied. The results revealed that GR(SO(4)) has a good removal effect on p-CNB. The removal efficiencies of p-CNB by GR(SO(4)) improved with the increase of the pH value. The removal efficiencies in the presence of ions were better than that of GR(SO(4)) alone, while natural organic matter (NOM) could adsorb p-CNB, which competed with GR(SO(4)). The reductions of p-CNB by GR(SO(4)) under different conditions followed pseudo-first-order reaction kinetics except for the reactions in the presence of NOM. p-CNB was converted into p-chloroaniline (p-CAN), which produced p-nitrosochlorobenzene and p-chlorophenylhydroxylamine as the intermediate products. The results of the X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed GR(SO(4)) was gradually transformed into goethite. Fe(ii) in the GR(SO(4)) structure was the main electron donor involved in the reaction.