Metal-Binding Silica Materials for Wastewater Cleanup

41242 TPL, Inc. A number of industrial processes generate wastewater with heavy metal contamination. Existing cleanup processes have difficulties in achieving low metal contamination levels, especially in the presence of competing nontoxic ions, high ionic strengths, and particulate matter; costs of cleanup can be prohibitively high. An effective and economical process to remove heavy metal ions prior to discharge is required. This project will examine two series of high-efficiency covalently modified silica materials, with metal ion capacities greatly exceeding those of commercial ion exchange resins. One series has high capacity for ¿soft¿ heavy metal ions such as mercury, lead, silver, and cadmium; the other has high capacity for anionic metal ions such as pertechnetate, arsenate, selenite, and chromate. Phase I will synthesize the materials and each will be evaluated for metal binding capacity, selectivity relative to nontoxic competing ions, efficiency in high ionic strength wastewaters, ease of regeneration for reuse of material and reclamation of metal, and cost and ease of production. The results will provide a foundation for Phase II, in which large-scale testing will be performed in actual industrial situations. Commercial Applications and Other Benefits as described by the awardee: The metal-binding silica materials should be effective in binding a broad range of toxic heavy metal ions, including mercury, lead, cadmium, silver, technetium, selenium, arsenic, and hexavalent chromium, from industrial wastewaters. Commercial applications include purification of wastewaters generated in nuclear processing, metal plating, battery recycling, and dentistry.