Uday Sankar Roy

Combined cation-exchange and extraction chromatographic method of pre-concentration and concomitant separation of Cu(II) with high molecular mass liquid cation exchanger after its online detection

A selective method has been developed for the extraction chromatographic trace level separation of Cu(II) with Versatic 10 (liquid cation exchanger) coated on silanised silica gel (SSG-V10). Cu(II) has been extracted from 0.1M acetate buffer at the range of pH 4.0-5.5. The effects of foreign ions, pH, flow-rate, stripping agents on extraction and elution have been investigated. Exchange capacity of the prepared exchanger at different temperatures with respect to Cu(II) has been determined. The extraction equilibrium constant (K(ex)) and different standard thermodynamic parameters have also been calculated by temperature variation method. Positive value of ΔH (7.98 kJ mol⁻¹) and ΔS (0.1916 kJ mol⁻¹) and negative value of ΔG (-49.16 kJ mol⁻¹) indicated that the process was endothermic, entropy gaining and spontaneous. Preconcentration factor was optimized at 74.7 ± 0.2 and the desorption constants K(desorption)¹(1.4 × 10⁻²) and K(desorption)²(9.8 × 10⁻²) were determined. The effect of pH on R(f) values in ion exchange paper chromatography has been investigated. In order to investigate the sorption isotherm, two equilibrium models, the Freundlich and Langmuir isotherms, were analyzed. Cu(II) has been separated from synthetic binary and multi-component mixtures containing various metal ions associated with it in ores and alloy samples. The method effectively permits sequential separation of Cu(II) from synthetic quaternary mixture containing its congeners Bi(III), Sn(II), Hg(II) and Cu(II), Cd(II), Pb(II) of same analytical group. The method was found effective for the selective detection, removal and recovery of Cu(II) from industrial waste and standard alloy samples following its preconcentration on the column. A plausible mechanism for the extraction of Cu(II) has been suggested.

Solvent Extraction Behavior of Transitional Metals with Liquid Ion-Exchangers

Abstract A systematic study of the comparative extraction behavior of some transitional metals has been performed with the high molecular weight carboxylic acids, SRS-100 and Versatic-9, using benzene as diluent. The study includes the extraction behavior as a function of pH, effect of diluent, metal ion concentration, solvent concentration, salting-out agent, and finally interference of the associated elements. Exchange reaction for several systems are reported. In almost all cases nearly quantitative extraction has been achiaved. It has been found that the extraction is rapid and complete within 3–4 min but the optimum period of extraction is kept at 5 min. In some cases quantitative separations have also been carried out.

Role of river-derived algae on bioaccumulation in fixed bed reactors; a low-cost safe drinking water plant

Abstract River-derived algae, Phormidium luridum, Gloeothece rupestris and Chlorococcum infusionum a lowcost material were studied for its ability to remove water pollutants for safe drinking water at neutral pH. The algae were grown on naturally occurring gravels in a glass column of nutrient enriched with raw-water media. The effect of flow-rate and temperature on bioaccumulation was investigated. Sorption isotherm followed the Langmuir model with a high Q0 value (22.7 mg g−1) and the value is in well agreement with the break through capacity (16.8 mg g−1). Different physicochemical and bacteriological parameters were studied to investigate the purity of the effluent. The method effectively permits the quantitative removal (>95%) of both chemical (F−, AsO4 −3, PO4 −3, Fe+3, As+3) and bio-pollutants (total coli form, Faecal coli form, E. coli), from raw water.