Removing arsenic from water using a natural, inexpensive filter

CHED 1143

Tina M. Nagel, tmnagel@stthomas.edu and J. Thomas Ippoliti, jtippoliti@stthomas.edu. Department of Chemistry, University of Saint Thomas, 2115 Summit Ave, St. Paul, MN 55105
Arsenic in drinking water is a significant problem in India and other developing countries, causing multiple types of cancer. Using a corn cob soaked in 50/50 sodium hypochlorite/water solution for one day, rinsed in 5% sodium bicarbonate, and dried, water contaminated with arsenic can be filtered to meet the international standard, less than 10 µg As/L, for an extremely low cost in non-renewable parts. Standard arsenic solutions were prepared in 20 µg As/L and 40 µg As/L. These solutions were filtered through this novel filtering system, and the resulting water was analyzed using the Hach EZ Arsenic Test Kit®. The test uses a mixture of salts and zinc that reacts with the arsenic to create a gas that discolors a mercury coated strip. This discoloration corresponds to a standard color to concentration comparison guide. The filter successfully removed all of the arsenic from the test solutions to the detection limits of the kit, under 10 µg/L.