The industrial waste, bauxite residue generated in the Bayer chemical process of alumina production, commonly known as red mud (RM) has been used as the adsorbent for selective removal of phosphate in aqueous solutions. RM collected from the storage area of alumina industry was characterized by chemical analysis and physical methods such as BET surface area, Scanning Electron Microscopy (SEM), particle size analysis, and X-ray diffraction (XRD) methods. Among the various red mud samples (0.2-200 ) studied, the samples treated with 1 M HCl for 2 h were found better for the selective adsorption of phosphate in comparison with untreated and heat treated RM samples. The presence of phosphate in the aqueous samples collected after adsorption studies with red mud was determined by standard spectrophotometric procedure using ammonium molybdate and ascorbic acid in nitrate medium at max 880 nm. The studies reported significant adsorption of phosphate on acid treated red mud in comparison with adsorption of phosphate on untreated and heat treated red mud, respectively. The adsorption of phosphate on raw red mud and activated red mud was further investigated with respect to stirring time, pH of the solution, dose of adsorbent, and varying phosphate concentration. Acid treated RM is observed as an efficient and cost-effective adsorbent for selective removal of phosphate in aqueous solutions.

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Thin layer chromatography ( TLC) of cobalt and nickel has been performed on silica gel layers induced with alkali mediated cellulose extract. A novel combination of 10% aqueous solutions of Tween-20 and potassium thiocyanate in 1∶ 1 ( v / v) was identified as the best mobile phase for the selective separation of Co 2 + from Ni 2 + on the impregnated Silica Gel G layers. The chromatographic characteristics of the cations were studied and the limits of detection as well as the limits of quantification for Co 2 + and Ni 2 + were determined. The quantitative estimation of the cations was achieved from the digital image analysis of respective chromatograms.The proposed quantitative method was successfully applied with 0 -0． 50% error for the determination of Co 2 + from Ni 2 + in spiked samples of bauxite, soil and rock containing common cations such as Al 3 + , Fe 2 + , Ti 4 + , Zn 2 + , Mn 2 + , Cu 2 + , Cr 6 + , Mg 2 + , etc. under the optimized chromatographic conditions.

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