Investigation of Adsorption of Arsenic (V) Ions from Aqueous Solution Using Natural Clay/Fe-Mn Composite.

Naturally occurring elemental arsenic exists in both inorganic and organic forms and ranks twentieth in abundance in the earth’s crust, fourteenth in seawater and twelfth in the human body. The World Health Organization (WHO) has predicted that 200,000–270,000 people will die of cancer after drinking arsenic contaminated water in Bangladesh alone. TheWHO guideline for arsenic in drinking water has been decreased from 50 µg/L to 10 µg/L[1]. Many diseases such as lung cancer, skin cancer, bladder cancer, tummy bug, etc. may be caused by contacting with arsenic in aqueous or any other way. Typical concentration of arsenic in natural waters can rise up to 3 mg/L [2]. Various technologies are currently available to remove arsenic from water, such as ion exchange, coagulation (co-precipitation), reverse osmosis, bioremediation, and adsorption. Adsorption is a common practice for arsenic removal from drinking water due to technological and cost advantages [3]. In the adsorption method, the utilization of low- or no-cost agricultural and biological waste materials has been highly considered. Clay is considered as a main candidate in the decontamination and treatment of detrimental metal ions. The adsorption of metal ions on clay has been studied extensively in the last decade. The results suggested that the adsorption of metal ions increased with increasing pH values, and the adsorption was dominated by outer-sphere complexation or ion exchange at low pH and by inner-sphere complexation or precipitation at high pH. In this study, natural clay/ Fe-Mn composite was synthesized and used as adsorbent to remove ions of arsenic (V) from aqueous solutions. SEM and FTIR analysis was also used to study the properties of natural clay/Fe-Mn composite.