Description:
Princeton Docket # 14-3027
Elevated levels of fluoride in groundwaters of granitic and basaltic terrains pose a major environmental problem and are affecting millions of people all over the world. Everyday many people, especially in the developing world, are exposed to elevated levels of fluoride, which has been found to be well above the World Health Organization drinking water limits. Fluoride at these levels is also shown to cause mental dementia, dental and skeletal fluorosis. Several remediation strategies are currently employed; however, many of them require significant maintenance and are expensive to operate.
To address this issue, researchers in the Department of Geosciences and Civil & Environmental Engineering at Princeton University have developed novel, less expensive materials using hydroxyapatite, a mineral common in bones and teeth. Although hydroxyapatite has been shown previously to be a strong sorbent for fluoride, low permeability of synthetic hydroxyapatite results in overall limited flow regimes, and hence volume of water processed in filters.
This novel method of synthesizing nano- to micrometer sized hydroxyapatite on the surfaces of granular limestone improves the sorption efficiency of the hydroxyapatite-based filters. Larger limestone grains act as templates for nanometer sized apatite crystals. The best conditions for producing complete coating and coverage of limestone grains have been identified in the studies. In laboratory conditions, the rate and magnitude of fluoride sorption by the novel hydroxyapatite-coated-fine limestone are comparable to those of pure hydroxyapatite, and the fluoride levels dropped to below the World Health Organization’s drinking water limit of 79 μM for fluoride concentrations commonly encountered in contaminated potable waters, suggesting that these materials could be used as effective filters.
Also examined was the application of these novel hydroxyapatite-coated limestone filter materials in the sorption of other contaminants, such as lead and cadmium. It was discovered that these heavy metal contaminants react strongly, and the metal concentrations dropped to below detection levels upon exposure to the new synthetic filter materials.
The novel hydroxyapatite-coated limestone filter materials synthesized using this new process are ideal for removing fluoride and several heavy metal contaminants from drinking or wastewater at a very low cost, and do not introduce other contaminants into water.
Applications:
· Removal of fluoride from drinking water
· Removal of lead, cadmium, and other heavy metals from drinking water
Advantages:
· Easy process to manufacture filter particles
· Utilizes locally available limestone
· Cost-effective
· Efficient
Publications
Kanno, Cynthia M, et al. “A Novel Apatite-Based Sorbent For Defluoridation: Synthesis And Sorption Characteristics Of Nano-Micro Crystalline Apatite On Limestone”. Environmental Science And Technology (2014).
ElBishlawi, Hagar, E., “Immobilization of Inorganic Species by Reactive Porous Media: Control of Trace Metals in a Constructed Urban Marsh and Fluoride Removal Via Novel Calcite Hydroxyapatite,” Princeton University Ph.D. Dissertation, Department of Civil and Environmental Engineering, 2014.
Faculty Inventors
Satish Myneni is Associate Professor of Environmental Geochemistry in the Department of Geosciences at Princeton University. He is also affiliated with the Departments of Chemistry and Civil & Environmental Engineering. He obtained his Ph.D. from The Ohio State University and conducted post-doctoral research at the Lawrence Berkeley National Laboratory before joining Princeton University in 1999. His research focuses on molecular environmental geochemistry, and studies interfacial processes involving minerals and aquatic pollutants, and chemistry of organic carbon and organochlorine compounds in soils.
Peter R. Jaffé is Professor of Civil and Environmental Engineering and Associate Director for Research of the Andlinger Center for Energy and the Environment at Princeton University. He was Chair of the department of Civil and Environmental Engineering from 1999 to 2005. His background is in chemical engineering, and he obtained a Ph.D. in Environmental and Water Resources Engineering from Vanderbilt University in 1981. He held the position of Research Associate in the Department of Civil Engineering at Princeton University from 1982 to 1983, and was a faculty member at the Universidad Simón Bolívar in Venezuela from 1983 to 1985. He joined the faculty of the Department of Civil Engineering at Princeton University in 1985, and was department chair from 1999 to 2005. He held visiting positions at the Venezuelan Research Institute and the International Institute for Applied Systems Analysis in Austria. He has served on numerous committees and panels, including the National Research Council, EPA, NIH, NSF, and DOE.
His research interests relate to the physical, chemical, and biological processes that govern the transport and transformation of pollutants in the environment, and their application towards the remediation of contaminated systems. Areas of current emphasis include: (1) biological and chemical processes in porous media; (2) simulation and analysis at the watershed scale of soil contamination processes; and (3) dynamics of trace metals and radionuclides in sediments, wetland soils, and groundwater.
Intellectual Property Status
Patent protection is pending.
Princeton is seeking to identify appropriate partners for the further development and commercialization of this technology.
Contact
Michael Tyerech
Princeton University Office of Technology Licensing • (609) 258-6762• tyerech@princeton.edu
Laurie Bagley
Princeton University Office of Technology Licensing • (609) 258-5579• lbagley@princeton.edu