Shahrood University of Technology Journal of Mining and Environment 2251-8592 14 3 2023 07 01 The Efficiency of Clay-Based Adsorbent in Fluoride Removal from Groundwater: Adsorption Process 839 851 2808 10.22044/jme.2023.12933.2348 EN Patrick MUHIZI Department of Civil Engineering, UIE Chandigarh University, Mohali, India Journal Article 2023 04 08 Excessive amounts of fluoride present in underground water sources are a major health concern worldwide. This study presents a new way to address the global health issue of high fluoride concentrations in groundwater using the abundantly available and cost-effective adsorbent material activated kaolinite clay “WR@KN”. The physical and chemical activation methods are employed to enhance its adsorption capacity. The optimum conditions for fluoride removal are determined through batch adsorption experiments, with a maximum adsorption capacity of 0.745 mg/g at pH 6, a particle size of 10 µm, a mixing speed of 210 rpm, a temperature of 24 °C, an initial fluoride concentration of 5.5 mg/L, a dose of 0.7 g activated WR@KN, and a contact period of 240 minutes. WR@KN successfully removes fluoride ions from 5.5 to 0.28 mg/L. The Langmuir isotherm model is found to be the most suitable for describing the adsorption behavior of fluoride on the WR@KN surface with an R² of 0.99984. The adsorption kinetic modeling shows that the pseudo-second-order model is the best fit with 0.754 mg/g, indicating that the fluoride adsorption process is chemisorption. The exothermic nature of the fluoride adsorption process is confirmed by a negative value of ΔH° (-77.08). The regenerated WR@KN adsorbent could remove fluoride effectively for the first four cycles but its performance deteriorated in the subsequent cycles. Increasing the ionic strength enhances the fluoride removal efficiency. Overall, the results suggest that the WR@KN adsorbent can be a promising material for cost-effective fluoride removal from groundwater. https://jme.shahroodut.ac.ir/article_2808_7500806fabfd865ec0d9d0b3adedd3f9.pdf