Preparation of barium ferrate from mill scale and degradation study of aqueous Eriochrome black – T

Abstract

This present study involves the utilization of mill scale, an iron rich steel industry waste, to synthesize barium ferrate. Ferrate with iron in +(VI) oxidation state is a green chemical with promising oxidation, disinfection and coagulation properties. The X-Ray diffraction(XRD) analysis of mill scale indicates the presence of iron in three forms hematite, magnetite and wustite. Mill scale was dissolved in concentrated HCl. The metallic composition of dissolved mill scale was determined by Inductively Couple Plasma Mass Spectroscopy(ICP-MS). Barium ferrate was synthesized using the dissolved mill scale by the wet oxidation method. The resulting crude ferrate was washed with different organic solvents to remove the impurities. The product thus obtained was analyzed by chromite method and characterized by Fourier Transform Infrared Spectroscopy(FTIR). Degradation of aqueous Eriochrome Black – T(EBT) with barium ferrate was studied at different pH, time and concentration. The degradation of the dye was monitored by UV-Visible spectroscopy and chemical oxygen demand. The degradation products of the aqueous EBT were characterized by Gas Chromatography-Mass Spectroscopy(GC-MS) and Proton Nuclear Magnetic Resonance (1H-NMR). Computational studies were performed to compare the stability of barium ferrate with that of potassium ferrate. The 1H-NMR calculations were performed to compare the degradation products obtained experimentally.