Journal of Geoscience and Environment Protection, 2022, 10, 224-241 https://www.scirp.org/journal/gep ISSN Online: 2327-4344 ISSN Print: 2327-4336 DOI: 10.4236/gep.2022.1012013 Dec. 29, 2022 224 Journal of Geoscience and Environment Protection Adsorption of Fluoride from Water Using Aluminum Coated Sand: Kinetics, Equilibrium, Effect of pH, and Coexisting Ions Kiana Modaresahmadi, Amid P. Khodadoust * , James Wescott Department of Civil, Materials, and Environmental Engineering, University of Illinois Chicago, Chicago, IL, USA Abstract An aluminum coated sand (AlCS) was evaluated as a metal oxide adsorbent for adsorption and removal of fluoride from water using a low-cost adsorbent with potential application in continuous flow adsorber systems. Surface cha- racterization of the AlCS sorbent was performed using TEM, SEM/EDX, XRD and BET. The AlCS sorbent contained mostly amorphous aluminum oxides based on adsorbent characterization results. Favorable adsorption of fluoride onto the AlCS sorbent occurred according to the Langmuir and Freundlich adsorption equations, while physical adsorption of fluoride onto the AlCS sorbent was observed based on results from the Dubinin-Radushkevich equa- tion. Fluoride adsorption onto the AlCS sorbent followed pseudo-second or- der kinetics, while surface charge analysis indicated a pH PZC of 7.1 for the AlCS sorbent. Effective fluoride removal occurred over a broad pH range from 3 to 11 with a maximum fluoride removal observed at pH 4 to 5. The effect of co-existing ions in water resulted in a decrease in fluoride uptake in the presence of bicarbonate, while resulting in an increase in fluoride uptake in the presence of calcium. The AlCS sorbent was a low-cost and sustainable adsorbent for effective adsorption and rapid removal of fluoride from water within an hour. Keywords Fluoride, Removal, Adsorption, Coated Sand, Aluminum 1. Introduction Fluoride levels in groundwater and surface water are elevated due to geological causes such as slow dissolution of fluoride minerals and industrial discharge like semiconductor production (between 10 mg/L and 1000 mg/L release) (Bhatna- How to cite this paper: Modaresahmadi, K., Khodadoust, A. P., & Wescott, J. (2022). Adsorption of Fluoride from Water Using Aluminum Coated Sand: Kinetics, Equili- brium, Effect of pH, and Coexisting Ions. Journal of Geoscience and Environment Protection, 10, 224-241. https://doi.org/10.4236/gep.2022.1012013 Received: October 26, 2022 Accepted: December 26, 2022 Published: December 29, 2022 Copyright © 2022 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access