Fluoride removal from contaminated water using natural bio-adsorbents: A numerical and experimental investigation

The research work focused in this study is to develop and apply an economical, novel method for removal of fluoride content from contaminated water sources. Because the presence of fluoride content in water affects the human health adversely on bone, teeth, cancer, brain damage etc. This study explores the viability of four biomass-derived adsorbents that are cost effective namely: banana peels (BP), orange peels (OP), lemon peels (LP) and groundnut shell (GS) for defluorination of polluted water within the pH range where acidity and alkalinity are balanced. These adsorbents were assessed with products readily accessible in market and demonstrated significantly higher removal efficiencies, particularly at higher fluoride concentrations (20 mg/l) in industrial wastewater. The removal rates for LP, BP, GS and OP were 48.36 %, 79.8 %, 72.38 % and 39.19 % respectively. The optimal contact times for BP, GS, OP and LP were found to be 69 minutes, 44 minutes, 66 minutes and 76 minutes respectively, with doses of 14 mg/l, 12 mg/l, and 16 mg/l. The adsorption behaviour followed a pseudo second order (PSO) reaction, indicating a complex process of fluoride content removal (R2 - 0.9-0.98) involving both intra-particle diffusion, and surface adsorption, which collectively determine the rate of removal.