Sustainable Drinking Water Adsorptive Materials for Arsenic and Fluoride Removal in Emerging Regions

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1066425 Sabatini There is a global water crisis, as the United Nations University estimates that approximately 900 million people (nearly a seventh of the world's population) currently lack access to potable water. Naturally occurring contaminants such as arsenic and fluoride contribute to this crisis, causing severe health problems above World Health Organization (WHO) recommended levels. Treatment of arsenicand fluoride contaminated waters is especially challenging in the developing world since over 1.4 billionpeople live on less than $1.25 per day according to the WHO. Commercial water treatment materialsused for arsenic and fluoride treatment in the U.S. are expensive even by U.S. standards, putting them outof reach for remote villagers in low income countries. A great challenge thus exists to develop materialsthat approach the efficiency of commercial materials for arsenic and fluoride removal from drinking watersupplies, but that are much less expensive and that, ideally, are produced in the developing country. Anequal challenge is to develop materials that are sustainable in terms of both environmental impacts acrossthe life cycle and adoption and long term implementation in country.Intellectual Merit. The overall objective of this research is to utilize colloid and surfacechemistry principles to produce effective and sustainable water treatment materials for arsenic andfluoride removal in developing countries. Currently available materials suffer from high cost (e.g.,granular ferric oxide and activated alumina) or poor sorption capacity due to low surface area (e.g., ironcoated sand). To address these challenges, high surface area chars will be generated from organicbiomass (locally available plants and trees) and coated with iron and aluminum minerals that have highaffinities for arsenic and fluoride, thereby producing adsorbents with both high surface areas and highsorption affinities. Mineral coated chars will be characterized with respect to the size and distribution ofmineral particles in the chars, and the depth of penetration of mineral particles into char pores. Theseproperties will then be correlated with sorption performance. Batch and column sorption studies withmineral coated chars will be conducted, both in the presence and absence of potential competing anions,in order to identify those with the greatest sorption affinity for arsenic and fluoride under realisticconditions. Desorption and leaching studies will also be conducted to evaluate the suitability ofregeneration or permanent landfill disposal of spent mineral coated chars. These laboratory experimentswill be followed by comparative evaluation of the most promising mineral coated chars in terms ofenvironmental impacts across the life cycle using life cycle assessment, and development of a sustainableimplementation plan for local adoption of these materials using the principles of social entrepreneurship.The last component of the proposed work is to test, in collaboration with non-governmental organizationsand Dr. Feleke Zewge at the University of Addis Ababa, the most promising mineral coated chars forfluoride removal in a rural village in Ethiopia impacted by high fluoride in its water supply.Broader Impacts. The results of this research will be disseminated to the scientificcommunity through publications in refereed journals and to several governmental and non-governmentalorganizations. Research results will also be integrated into two senior/graduate engineering classes, aninterdisciplinary undergraduate honors class on water and sanitation in remote villages of developingcountries, and a business course focused on social entrepreneurship. Research students will presentpapers and undergraduate students in the multidisciplinary honors class will present posters at the biennialUniversity of Oklahoma (OU) International WaTER conference in order to further disseminate the resultsamong the international community of researchers and practitioners. Educational materials developed forthese classes will be submitted to the K-Gray Engineering Pathway Digital Library (a national repositoryfor K-gray educational materials in science and engineering) and their public availability to othereducators will be advertised widely. This research topic is popular for undergraduates, and, based onexperience at OU, attractive to underrepresented groups in science and engineering. By improving healthin the most impoverished regions of the world, the research results will enable education and developmentin regions historically plagued with unrest. Finally, developing novel water treatment materials andevaluating their use in terms of both adsorption efficiency and economic and environmental sustainability will lead to new applications appropriate not only for the developing world, but for the U.S. as well.This award is co-funded by the CBET/ENG Environmental Sustainability and Chemical and Biological Separations programs, and the NSF Office of International Science and Engineering.