@article{30185,
  author = {Katya Cherukumilli and Caroline Delaire and Susan Amrose and Ashok J Gadgil},
  title = {Factors Governing the Performance of Bauxite for Fluoride Remediation of Groundwater},
  abstract = {<p>Globally, 200 million people drink groundwater contaminated with fluoride concentrations exceeding the World Health Organization{\textquoteright}s recommended level (WHO-MCL = 1.5 mg F<sup>{\textendash}</sup>/L). This study investigates the use of minimally processed (dried/milled) bauxite ore as an inexpensive adsorbent for remediating fluoride-contaminated groundwater in resource-constrained areas. Adsorption experiments in synthetic groundwater using bauxites from Guinea, Ghana, U.S., and India as single-use batch dispersive media demonstrated that doses of \~{}10{\textendash}23 g/L could effectively remediate 10 mg F<sup>{\textendash}</sup>/L. To elucidate factors governing fluoride removal, bauxites were characterized using X-ray fluorescence, X-ray diffraction, gas-sorption analysis, and adsorption isotherms/envelopes. All ores contained gibbsite, had comparable surface areas (\~{}14{\textendash}17 m<sup>2</sup>/g), had similar intrinsic affinities and capacities for fluoride, and did not leach harmful ions into product water. Fluoride uptake on bauxite -primarily through ion-exchange- was strongly pH-dependent, with highest removal occurring at pH 5.0{\textendash}6.0. Dissolution of CaCO<sub>3</sub>, present in trace amounts in India bauxite, significantly hindered fluoride removal by increasing solution pH. We also showed that fluoride remediation with the best-performing Guinea bauxite was \~{}23{\textendash}33 times less expensive than with activated alumina. Overall, our results suggest that bauxite could be an affordable fluoride-remediation adsorbent with the potential to improve access to drinking water for millions living in developing countries.</p>},
  year = {2017},
  booktitle = {Environmental Science \& Technology},
  journal = {Environmental Science \& Technology},
  series = {Environmental Science \& Technology},
  volume = {51},
  pages = {2321 - 2328},
  month = {01/2017},
  issn = {0013-936X},
  doi = {10.1021/acs.est.6b04601},
  language = {eng},
}