@article{21e8b6e83d0544138f979b0b55b57955,
title = "Internalization of fluoride in hydroxyapatite nanoparticles",
abstract = "Hydroxyapatite (HAP) is a cost-effective material to remove excess levels of fluoride from water. Historically, HAP has been considered a fluoride adsorbent in the environmental engineering community. This paper substantiates an uptake paradigm that has recently gained disparate support: assimilation of fluoride to bulk apatite lattice sites in addition to surface lattice sites. Pellets of HAP nanoparticles (NPs) were packed into a fixed-bed media filter to treat solutions containing 30 mg-F/L (1.58 mM) at pH 8, yielding an uptake of 15.97 ± 0.03 mg-F/g-HAP after 864 h. Solid-state 19F and 13C magicangle spinning nuclear magnetic resonance spectroscopy demonstrated that all removed fluoride is apatitic. A transmission electron microscopy analysis of particle size distribution, morphology, and crystal habit resulted in the development of a model to quantify adsorption and total fluoride capacity. Low- and high-estimate median adsorption capacities were 2.40 and 6.90 mg-F/g-HAP, respectively. Discrepancies between experimental uptake and adsorption capacity indicate the range of F- that internalizes to satisfy conservation of mass. The model was developed to demonstrate that F- internalization in HAP NPs occurs under environmentally relevant conditions and as a tool to understand the extent of F- internalization in HAP NPs of any kind. ",
author = "Mosiman, {Daniel S.} and Andre Sutrisno and Riqiang Fu and Marin~as, {Benito J.}",
note = "Funding Information: This work was supported by the Institute for Sustainability, Energy, and Environment at the University of Illinois at Urbana-Champaign. The authors acknowledge the Materials Research Laboratory at the University of Illinois at Urbana-Champaign (MRL-UIUC). XRD and conventional TEM experiments were performed at MRL-UIUC; we acknowledge the scientific and technical assistance of Dr. Mauro Sardela and Dr. Wacek Sweich, respectively. The authors acknowledge the facilities of the Australian Centre for Microscopy and Microanalysis Facility (ACMM) at the University of Sydney. High-resolution TEM was conducted at the ACMM, and we acknowledge the scientific and technical assistance of Dr. Hongwei Liu and Dr. Magnus Garbrecht. The authors acknowledge the School of Chemical Sciences Microanalysis facility at UIUC where ICP-MS and CH analyses were conducted. The F and C NMR portions of this work were conducted at the National High Magnetic Field Laboratory in Tallahassee, FL, which is supported by National Science Foundation Cooperative Agreement DMR-1644779 and the State of Florida. The H DP NMR portion of this work was conducted at UIUC{\textquoteright}s SCS NMR/EPR laboratory. This material is based upon work supported by the National Science Foundation{\textquoteright}s Graduate Research Fellowship Program under Grant DGE–1746047. D.S.M. also acknowledges funding from the American Water Works Association{\textquoteright}s Larson Aquatic Research Support Doctoral Scholarship. 19 13 1 Publisher Copyright: {\textcopyright} 2020 American Chemical Society.",
year = "2021",
month = feb,
day = "16",
doi = "10.1021/acs.est.0c07398",
language = "English (US)",
volume = "55",
pages = "2639--2651",
journal = "Environmental Science and Technology",
issn = "0013-936X",
publisher = "American Chemical Society",
number = "4",
}