Background: The contact process preferably used vanadium pentaoxide as catalyst to increase the rate of reaction of producing sulphuric acid. Sulfuric acid plants regularly require catalyst replacement in order to cope with process improvements. The spent catalyst is considered as hazardous solid waste and cannot be discarded untreated owing to presence of high amount of vanadium and other associated metals. Because of significant environment implications of spent catalyst wastes, it is imperative to recover valuable metals present in them. The recovery of precious materials or metals from waste will not only help in mitigating environment problem due to metal pollution but also help improve the economy of the country. The purpose of this research work is to develop method to recover vanadium from spent V 2 O 5 catalyst. Results: The detailed study of extraction, separation and recovery of vanadium from leached spent catalyst solution of composition; V, 3.6% ; Al, 2.1%; Fe, 1.3%; Ti, 0.8% and less than 1 % of Cr and Pb is reported in this paper. Cyanex 272 (bis (2, 4, 4-trimethylpentyl) phosphinic acid) has been explored for the recovery of vanadium from spent V 2 O 5 catalyst. The effects of different parameters like, pH, solvent concentration, organic to aqueous ratio etc. were optimised for the complete extraction and recovery of vanadium. Conclusions: The proposed procedure gives high purity vanadium with almost a quantitative yield (~99%) and of course free from closely associated metals. The extractants could be reused up to ten cycles with no significant change in the extraction capability.

Background. High arsenic levels in potable water are a threat to public health in India. About 85% of the water in India's rural areas comes from groundwater and roughly 27 million people are at risk of arsenic (As) contamination. Objectives. The present study was performed to examine the feasibility of providing an effective and affordable means for arsenic abatement in socio-economically poor and rural areas in India. This is the first report on the effectiveness of powder Nelumbo nucifera Gaertn (lotus) root biomass for As (III) eradication from aqueous solution. Methods. Batch experiments were conducted to determine the effects of various operating parameters, including pH, initial As (III) ion concentration, adsorbent dosages, and contact time for As (III) sorption onto lotus root. Discussion. The sorption efficiency of lotus root biomass for As (III) at pH 7 was found to be quantitative (96%) from 50 mg/L aqueous solution at a dose of 5gL −1 . Capacity of the biosorbent for As (III) ion adsorption and the interaction between adsorbate with biosorbents were studied using Langmuir and Freundlich isotherm models. In the present study, the equilibrium parameter values ranged between 0 and 1, indicating that the adsorption of the As (III) ion onto lotus root biomass was favorable. Conclusions. Lotus root powder biomass was found to be an effective adsorbent for As (III) and could be used as an efficient, cost-effective and environmentally safe biosorbent for the sorption of arsenic from aqueous solutions. Competing Interests. The authors declare no competing financial interests.

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