Columbia Technology Ventures

Arsenic removal filter for high-phosphate water based on binding with sulfide

Lead Inventor: Alexander F. Van Geen, Ph.D. Early Saturation of Filter for Arsenic in Drinking Water The Environmental Protection Agency (EPA) and World Health Organization (WHO) have set a limit of 10 parts per billion (10 µg/L) for arsenic (As), an odorless, tasteless contaminant, in drinking water. Both in the US and in many regions throughout the world, people do not have access to arsenic-free water, and therefore require purification systems. A drawback of currently used filtration systems is the lack of selectivity of the filter, which leads to early saturation with competing materials. Sulfide Material Filter Selectively Binds Arsenic in the Presence of Phosphate This invention describes a filter composed of a sulfide material, which shows selective binding of arsenic in the presence of phosphate (P). It can be used to remove arsenic in phosphate-rich water supplies. Field evidence supporting this selectivity has been collected in regions of Bangladesh where groundwater exhibits a loss of arsenic (group-III), with conservation of phosphate (group-V) in the presence of the sulfide. Applications: • Filter for arsenic found in water that is phosphate-rich • Potential use for removal of other heavy metals or contaminants from water, depending on results testing for the material’s affinity • Removal of arsenic contamination from other materials, for example oil shale, which is processed for production of fossil fuels Advantages: • No early saturation of the filter by phosphate, or other competing material in the water • Can be produced locally at a low cost • Easy to maintain and monitor Patent Status: Know-how / Copyright Licensing Status: Available for Licensing and Sponsored Research Support Publications: A. van Geen, Y. Zheng, M. Stute, and K. M. Ahmed, Comment on ""Arsenic Mobility and Groundwater Extraction in Bangladesh"" (II), Science 300 (5619), 584c, 2003 Joseph H. Graziano and Alexander van Geen, Reducing Arsenic Exposure from Drinking Water: Different Settings Call for Different Approaches, Environmental Health Perspectives, 113 (6), 2005, A360 Alexander van Geen, K.M. Ahmed, A. A. Seddique, M. Shamsudduha, Community wells to mitigate the arsenic crisis in Bangladesh, Bull World Health Organ, 81 (9), Genebra, 2003, 632