Note from Fluoride Action Network:
“Since all methods [to remove fluoride] produce a sludge with very high concentration of fluoride that has to be disposed of, only water for drinking and cooking purposes should be treated, particularly in the developing countries.”
Reference: Fluorosis (see Interventions), World Health Organization

Abstract

This data was decisive on the adsorption of fluoride by microwave assisted carbonized Azadirachta indica bark (MACAIB) adsorbent material from aqueous solution. Azadirachta indica bark is a plant-based effortlessly available item which is transformed into a carbonaceous adsorbent material and utilized for the removal fluoride from aqueous solution. Characterization of the MACAIB adsorbent material demonstrated that it was porous and extremely effective in the removal of fluoride. The operating parameters such as pH, adsorbent dose, agitation speed, initial fluoride concentration, contact time and temperature were efficient on the adsorption ability of fluoride. The maximum removal efficiency of fluoride with an initial fluoride concentration 2 mg/L was found to be 83.50%. Experimental adsorption isotherm equilibrium data furnished was the best with Langmuir adsorption isotherm model, showing monolayer adsorption on a homogenous surface (most extreme monolayer adsorption capacity was 0.923 mg/g at 303 K). The adsorption kinetics experiment was followed by pseudo second-order kinetic model that indicated chemisorptions process. Intra-particle diffusion mechanism was not the sole rate-controlling factor. Thermodynamic analysis proposes that removal of fluoride from aqueous solution by MACAIB material was an exothermic and spontaneous process. Characterization of the MACAIB carbon material before and after adsorption through FTIR, SEM, EDX and XRD techniques confirmed the fluoride adsorption on the adsorbent surface. It could be accomplished that MACAIB is an effective adsorbent material for successful removal of fluoride from aqueous solution.

*Read full study at http://fluoridealert.org/wp-content/uploads/telkapalliwar-2019.pdf