Development of an Anionic Exchange Gas Fiber Substrate POU Device to Remove Arsenic

Abstract

Arsenic poisoning is one of the most widespread water-related problems in the world (Cullen and Reimer, 1989). Arsenic in drinking water causes bladder, lung, and skin cancer. Even very low doses of arsenic may damage the central and peripheral nervous systems, heart, and blood vessels, and may also lead to serious skin problems. The U.S. Environmental Protection Agency (USEPA) has set a maximum contaminant level (MCL) for arsenic in drinking water at 10 micrograms per liter (µg/L). A National Academy of Sciences report (2001) has indicated that, even at levels as low as 3 µg/L, the risk of cancer is still ten times that of EPA’s acceptable value (0.1 per 1000 people). Thus the acceptable levels for arsenic may be further lowered in the future. Based on the best available data, it is conservatively estimated that more than 34 million Americans drink tap water from water supplies containing average levels of arsenic greater than 3 µg/L (Kartinen and Martin, 1995; National Academy of Sciences, 2001; Johnston and Heijnen, 2001; Wilson et al., 2004; Newcombe and Möller, 2006). Many millions more are at risk worldwide, most notably in Bangladesh and eastern India. In the Midwestern United States, numerous wells contain arsenic concentrations higher than 10 µg/L. A map showing public water supply wells in Illinois with arsenic concentrations > 10 µg/L is shown in Figure 1 (Wilson et al., 2004). The development of improved or new treatment technologies for removal of the two major arsenic ions, arsenate [As(V)] and arsenite [As(III)], is needed to help mitigate worldwide problems of arsenic-contaminated water and protect public health. </p><p>In this project, an iron oxide (Fe2O3) system supported on a glass fiber substrate developed at the Department of Materials Science at the University of Illinois at Urbana- Champaign was evaluated for removal of arsenic from water. Laboratory tests were performed to evaluate the effectiveness of these filters in removing arsenic to concentrations below the MCL and determine how long the filters remained effective. Both deionized (DI) water and natural groundwater spiked with arsenic were used in the laboratory tests to evaluate the rate of fouling and determine the significance of solute (i.e., anions such as bicarbonate, silicate, and phosphate) interference. Finally, a prototype of a point-of-use (POU) device was developed and tested in the homes of volunteers who had elevated arsenic concentrations in their well water.