Nanoparticulate Apatite-Coated-Calcite/Limestone Filter Materials for Removing Contaminants From Contaminated Water

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Docket# 14-3027-1


Fluorosis, a disease caused by chronic excessive ingestion of fluoride (F-) primarily through drinking contaminated groundwater, is a major health challenge particularly in developing countries. Excess fluoride may produce several health problems such as dental fluorosis, skeletal fluorosis and various neurological manifestations. Several remediation strategies currently exist, but they suffer from high operation and maintenance costs and/or production of secondary pollutants.

Researchers at Princeton University have invented a novel apatite-based sorbent for defluoridation via synthesis and sorption of nano-micro crystalline hydroxyapatite-coated limestone. The nano-micro crystalline apatite, tested under several chemical conditions, has very high fluoride removal efficiency and does not affect water quality by any other means.

Apatite is well known to remove fluoride, cadmium and lead from water. However, naturally occurring forms of apatite are relatively inefficient in terms of cost and their sorption capacity. This new method of making nano-micro crystalline apatite on calcite/ limestone surfaces is much more efficient than raw apatite in terms of cost, sorption, capacity and usage. The nanoparticulate apatite crystals can be made on locally and cheaply available limestone/calcite substrates, and are highly reactive due to their surface structure and high surface area. This rapid reaction ensures a high degree of reduction of fluoride and does not require a complex or expensive device. The granular hydroxyapatite-coated filter material may be used by itself to treat water or form part of a filtration apparatus.



•       Removal of fluoride from water

•       Removal of cadmium, lead and other heavy chemicals from water


•       Low cost

•       Does not require complex device

•       Raw materials available locally

•       No harmful residue after filtration

•       No secondary byproducts in water

•       Can be used along with other filtration materials and apparatus



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.


      Myneni SC and Jaffe P (2015, October 29). Nanoparticulate Apatite Coated Calcite/Limestone Filter Materials for Removing Contaminants from Contaminated Water. Google Patents. Retrieved from


      Princeton University is currently looking for Industry collaborators to further develop and commercialize this technology.



      Chris Wright

      Princeton University Office of Technology Licensing • (609) 258-5579•




Patent Information:
For Information, Contact:
Chris Wright
Licensing Associate
Princeton University
Satish Myneni
Peter Jaffe
civil engineering
earth science
green tech
polymer chemistry
wastewater management