Removal of Arsenic Through the Process of Biosorption

Abstract

Increase in human population and its need for its lifestyle improvisation leads to nature at risk. One of the natural source on which all live forms depends is water. Water pollution due to non- essential heavy metals is very common. Non- essential heavy metals are very toxic and are threats to human life and other life forms also. Arsenic is one of the non-essential heavy metal which is toxic as well as carcinogenic. Problem due to arsenic pollution is continuously increasing in Asian countries. Arsenic pollution in drinking water along with in paddy fields is global problem all around the world. In almost all regions of West Bengal, India concentration of arsenic in rice continuously increases. Arsenic toxicity is very serious for humans and causes various diseases. Hence, it is necessary to remove arsenic from aqueous solutions to protect human life from its toxic effect. This paper focuses on removal of arsenic using low cost adsorbents through process of biosorption. For removal of arsenic in this study a mixed biosorbent is prepared by mixing roots of Shatavari and Erandmool, leaves of Sadabahar, fruit of Nimbu and panchang of Brahmi. For removal of arsenic ultraviolet spectroscopy method is used here based on the principle of that arsenic when treated with acidified potassium iodate to liberate iodine. The Liberated iodine bleaches the violet colour of azure B which is measured at 644 nm. Results obtained show that maximum percentage of arsenic removal was obtained at 0.5 and 1.0 g of adsorbent dose at 3 mg/l and 5 mg/l of initial arsenic concentration in 3 hour contact time, pH of solution 7 and 8 and 40 rpm agitation speed. Maximum percentage removal obtained at pH 7 by 0.5 g adsorbent dose at 5 mg/l arsenic solution was 82 %. Adsorption isotherm model which supports arsenic removal was Freundlich model whose r2 value obtained was 0.99 and value of n is 1.78 and Kf is 2.53.