Simultaneous removal of aniline, antimony and chromium by ZVI coupled with H2O2: Implication for textile wastewater treatment

Aniline, antimony (Sb) and chromium (Cr) are typical and regulated co-contaminants in textile wastewater, but their removal was often investigated individually. In this work, simultaneous removal of aniline, Sb and Cr by ZVI coupled with H2O2 was studied. With the dosage of 0.5 g L-1 ZVI and 2 mM H2O2, aniline, Sb and Cr can be removed completely at pH 3. Experiment with iso-propanol as the radical scavenger confirmed that (OH)-O-center dot derived from Fenton reaction accounts for aniline degradation, but not for Sb and Cr removal. H2O2 accelerated Fe(0) corrosion and generated the nanoscale iron(hydro)oxides. Aniline was degraded by (OH)-O-center dot first and then the degradation products were removed by iron(hydro)oxides via adsorption and co-precipitation. Both Fe(0) and iron (hydro)oxides were responsible for Sb and Cr removal, yet iron(hydro)oxides were identified as the major contributor. X-ray photoelectron spectroscopy analysis demonstrated that Sb and Cr were removed mainly as the states of Sb(III) and Cr(III). The real textile wastewater investigation confirmed that ZVI coupled with H2O2 can eliminate aniline, Sb and Cr effectively, which has important implications for the advanced treatment of textile wastewater.