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The objective of the present work was to investigate the removal of Ni(II) by the fresh biomass (FBM) and chemically treated leached biomass (LBM) of Calotropis procera. The scope of the work included screening of the biosorbents for their metal uptake potential, batch equilibrium, column mode removal studies and kinetic studies at varying pH (2–6), contact time, biosorbent dosages (1–25 g/L) and initial metal ion concentration (5–500 mg/L). The development of batch kinetic model and determination of order, desorption studies, column studies were investigated. It was observed that pH had marked effect on the Ni(II) uptake. Langmuir and Freundlich models were used to correlate equilibrium data on sorption of Ni(II) metallic ion by using both FBM and LBM at 28°C and pH 3 and different coefficients were calculated. It was found that both biomasses were statistically significant fit for Freundlich model. The biomass was successfully used for removal nickel from synthetic and industrial effluents and the technique appears industrially applicable and viable.

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Laboratory measurements of water samples from a range of environments in the Bhilai region demonstrated the ability to identify characteristic features of groundwater quality. This study focusses on geology and hydrology of the studied site to evaluate the ability to locate the source of contamination, either geological or concentration of mine drainage or industrial pollution causing adverse quality of potable water in some areas of this region. Monitoring the groundwater at periodic intervals over a two-year period provided information on the production and transport of pollutant. During analysis of the water samples concentration of redox species such as Fe 2+ and S 2were found significantly above their detection limits. Anomalous high concentration of ferrous iron Fe 2+ (65 ppm) and sulphide S 2-(24 ppm) witnessed in various areas are indicative of the reducing conditions of the ground water. The majority of bore wells and hand-pump samples clustered towards the Ca-Mg-HCO 3 regime of the phase diagram. In contrast to increased concentrations of Fe 2+ , an increased alkalinity up to 700 ppm has been observed which makes the study significant. A correlation study indicated that the iron and sulphide anomaly is primarily related to point source contamination.

Iron is essential heavy metal in trace quantities, but its excessive concentration as Fe2+ is present in effluents from steel mills, iron ore mines, and metal processing industries, which pollute the groundwater. Among other conventional methods, sorption by natural biomass is a low-cost alternative for iron sequestration from an aqueous solution. The root of a native weed plant Calotropis Procera was used to optimize the adsorption parameters like pH, contact time, sorbent dose, and initial adsorbate concentration. Competitive adsorption of Fe2+ in the presence of cations (Ni2+, Cd2+, Cr3+, Zn2+, Ca2+, Mg2+, As3+) and anions (Cl-, SO42- , F-) was also studied. Batch adsorption studies were carried out to evaluate adsorption isotherm by Langmuir and Freundlich isotherm models. Leaching of biomass significantly improved iron uptake capacity from 15 mg g-1 to 80 mg g-1. The kinetics of the reaction was fast, with equilibrium conditions attaining in 30 minutes. FTIR study of the biomass revealed the presence of -COOH, -NH groups responsible for the metal binding mechanism. The biomass could be regenerated with 0.1 M HNO3 for further use. Iron removal from simulated acidic water was done under optimum conditions and absorbance was measured by a UV-Visible spectrophotometer.