Steel wastes as versatile materials for treatment of biorefractory wastewaters.

Recent research on novel cost-effective adsorbent materials suggests potential use of industrial wastes for effluent treatment, with the added benefit of reuse of the wastes. Waste steel materials, including blast oxygen furnace sludge (BOFS), blast furnace sludge (BFS), and blast furnace dust (BFD), were investigated as low-cost adsorbents for removal of an oil emulsion and RR195 dye. The residues were characterized by X-ray diffraction, Brunauer-Emmett-Teller area, volume and distribution of pore diameters, Mössbauer spectroscopy, X-ray fluorescence, granulometry, scanning electron microscopy/energy dispersive spectroscopy, and pHpzc. Adsorption kinetics data were obtained by UV-vis spectrophotometry at the maximum absorption wavelength of the dye solution and crude oil emulsion. The use of waste as an adsorbent was more efficient for treatment of the oil emulsion than the dye solution. BOFS had higher total organic carbon (TOC) removal efficiency than the other waste materials. For the RR195 dye, good color removal was observed for all adsorbents, >90 % within 24 h. TOC removal was poor, <10 % for BFD and BFS and a maximum of 37 % for BOFS. For the oil emulsion, 97 % TOC removal was obtained by adsorption onto BOFS and 87 % onto BFS.