REMOVAL OF ARSENIC FROM SYNTHETIC WASTEWATER

Abstract

Arsenic contamination in wastewater, even in drinking water has been recognized as a worldwide problem. It affects human health severely if the limit of toxicity is crossed. There are several treatment methods capable of this level of performance - membranes, coagulation, anion exchange, disposable iron media, softening, adsorption etc. But adsorption is the cheaper and easier as well as efficient method compared to other methods for removal of metal ions. The present study has been carried out using two different raw bioadsorbents like rice husk and maize leaves. Several work has been done on these bio-adsorbents and it has been already reported that rice husk and maize leaves are one of the cheap and effective bioadsorbents for removal of arsenic from industrial wastewater. But the removal efficiency has been increased when adsorbents are impregnated by zirconium and zinc. Different analysis such as FESEM, EDAX, TGA, DTA, FTIR has been done to characterize the adsorbent. FESEM can be able to capture the images of the adsorbents with high resolution. EDAX determines metals and elements presence on the rice husk.DTA/TGA shows the loss of the moisture with respect to temperature. SDDC method was applied for analysis of arsenic. Batch experiments were conducted by varying various process parameters such as pH, contact time and temperature. At optimum treatment conditions (pH 8, contact time of 5 hrs and temperature of 35°C, adsorbent dose 10 g/l) 89.5% As was removed from aqueous solution. Langmuir and Freundlich isotherms were used for equilibrium studies. Freundlich isotherm was better fitted with experimental data. As well as adsorption biological methods are promising field due to cost-effectiveness and in this method possibility of sludge production is nil. In this study immobilization of P. putida MTCC 1194 on zirconium impregnated rice husk has been done in order to increase arsenic removal capacity.