Bhim Chandra Mondal

Synthesis and characterization of a new resin functionalized with 2-naphthol-3,6-disulfonic acid and its application for the speciation of chromium in natural water

A polystyrene divinyl benzene (8%) copolymer has been functionalized by coupling it through NN group with 2-naphthol-3,6-disulfonic acid (NDSA). The resulting resin has been characterized by elemental analysis, thermogravimetric analysis and infrared spectra. The hydrogen ion, water regain and metal ion capacities of the resin have been determined. Two forms of chromium show different exchange capacities at different pH values, viz. Cr(III) selectively retained at pH 6.5 whereas Cr(VI) retained at pH 1.5. Hence complete separation of the two forms of chromium is possible. The kinetic studies show that the exchange of Cr(III) and Cr(VI) follows second-order kinetics. The metal ion concentration was measured by flame atomic absorption spectrometry. The method has been successfully applied for the speciation of chromium in natural water samples.

Microwave-assisted synthesis of a new chelating resin containing 2-aminothiophenyl S-acetic acid and its application to the determination of lead

Abstract Chloromethyl polystyrene has been functionalised with 2-aminothiophenyl S -acetic acid using microwave assisted reflux. The resulting chelating resin has been characterised by elemental analyses, infrared spectra, thermogravimetric analysis, hydrogen ion capacity and metal sorption capacity. It has been used for the preconcentration and separation of lead prior to its determination by flame atomic absorption spectrometry. The optimum conditions for both synthesis of the resin as well as the digestion of the road dust samples by microwave assisted treatment have been evaluated. Parameters such as the amount of the resin, effect of pH, equilibration rate, sorption and desorption of metal ions, and effect of diverse ions have been studied. The maximum sorption capacity for lead was found to be 0.03 mmol g −1 at the pH range 5.5–6.0. Recovery of Pb(II) was 98.9±3.5 at the 99% confidence level with a detection limit of 40.6 ng ml −1 . The proposed method has also been applied for the determination of lead in road dust.

Preconcentration and separation of copper, zinc and cadmium by the use of 6-mercapto purinylazo resin and their application in microwave digested certified biological samples followed by AAS determination of the metal ions.

6-Mercapto purinylazo resin has been used as solid phase extractor. Based on solid phase extraction, the present work describes the preconcentration and determination of copper, zinc and cadmium in certified biological samples after microwave-assisted digestion. The exchange capacity of the resin, the sorption and desorption of metal ions, and the effect of diverse ions have also been determined. The results show that the resin is highly selective for determination of these biologically significant metals. The method is simple, rapid and free from interferences and can be used routinely.

Low cost treatment of wastewater containing mercury salts

Removal of mercury from wastewater is of considerable significance from an environmental point of view. Treatment of wastewater containing mercury salts has been carried out with the help of modified fly-ash bed. The preparation of the bed material has been described. The effects of different parameters such as pH, exchange capacity and the presence of other constituents have been studied. Various mercury compounds, both mercury(I) and mercury(II), in synthetic mixtures as well as in actual wastewater samples containing mercury have been investigated. The removal of both mercury(I) and mercury(II) in different quantities has been investigated effectively utilising modified fly-ash bed. The recovery of mercury from the bed has also been studied. The use of modified fly-ash bed was found to be satisfactory and could be used as a low cost treatment method for the removal of mercury from wastewater.