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

1066425 Sabatini全球性的水资源危机，据联合国大学估计，目前约有9亿人（近世界人口的七分之一）缺乏饮用水。砷和氟化物等自然产生的污染物助长了这一危机，造成严重的健康问题，超过了世界卫生组织（世卫组织）建议的水平。砷和氟污染的沃茨的处理在发展中国家尤其具有挑战性，因为根据世界卫生组织的数据，超过14亿人每天的生活费不到1.25美元。在美国，用于砷和氟化物处理的商业水处理材料即使按照美国的标准也很昂贵，这使得低收入国家的偏远村民无法获得。因此，存在着一个巨大的挑战，即开发接近商业材料的效率，用于从饮用水供应中去除砷和氟化物，但价格要便宜得多，理想情况下，在发展中国家生产。不平等的挑战是开发可持续的材料，无论是在整个生命周期的环境影响方面，还是在国家的采用和长期实施方面。本研究的总体目标是利用胶体和表面化学原理生产有效和可持续的水处理材料，用于发展中国家的砷和氟去除。目前可获得的材料具有高成本（例如，粒状氧化铁和活性氧化铝）或由于低表面积导致的吸附能力差（例如，涂铁砂）。为了应对这些挑战，将从有机生物质（当地可用的植物和树木）中产生高表面积的焦炭，并涂上对砷和氟化物具有高亲和力的铁和铝矿物，从而生产出具有高表面积和高吸附亲和力的吸附剂。矿物涂层炭的特征在于炭中矿物颗粒的尺寸和分布，以及矿物颗粒渗透到炭孔中的深度。这些特性将与吸附性能相关。在存在和不存在潜在竞争阴离子的情况下，将进行矿物涂层炭的批和柱吸附研究，以确定在实际条件下对砷和氟具有最大吸附亲和力的那些。还将进行解吸和沥滤研究，以评估再生或永久填埋处理用过的矿物涂层炭的适用性。在这些实验室实验之后，将使用生命周期评估对最有前途的矿物涂层炭在整个生命周期的环境影响进行比较评估，并使用社会企业家精神的原则制定当地采用这些材料的可持续实施计划。拟议工作的最后一个组成部分是测试，与非政府组织和阿迪斯大学的Feleke Zewge博士合作，在埃塞俄比亚一个受高氟供水影响的农村村庄使用最有前途的矿物涂层炭去除氟化物。这项研究的结果将通过在参考期刊上发表的出版物向科学界和一些政府和非政府组织传播。研究成果也将被纳入两个高级/研究生工程类，一个跨学科的本科生荣誉班在发展中国家偏远村庄的水和卫生设施，以及一个商业课程的重点是社会创业。研究生将提交论文，多学科荣誉班的本科生将在两年一度的俄克拉荷马州大学（俄克拉荷马州）国际水会议上提交海报，以进一步传播研究人员和从业者的国际社会的结果。为这些课程开发的教育材料将提交给K-Gray工程途径数字图书馆（K-Gray科学和工程教育材料的国家储备库），并将广泛宣传其对其他教育者的公开可用性。这一研究课题在本科生中很受欢迎，而且，根据在斯坦福大学的经验，对科学和工程领域代表性不足的群体很有吸引力。通过改善世界上最贫困地区的健康状况，研究结果将使历史上饱受动荡困扰的地区的教育和发展成为可能。最后，开发新型水处理材料，并从吸附效率、经济和环境可持续性两方面评估其使用，将导致不仅适合发展中国家，而且适合美国的新应用。该奖项由CBET/ENG环境可持续性和化学与生物分离项目以及NSF国际科学与工程办公室共同资助。

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.