The Efficiency of Clay-Based Adsorbent in Fluoride Removal from Groundwater: Adsorption Process

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 ۰.۷۴۵ mg/g at pH ۶, a particle size of ۱۰ µm, a mixing speed of ۲۱۰ rpm, a temperature of ۲۴ °C, an initial fluoride concentration of ۵.۵ mg/L, a dose of ۰.۷ g activated WR@KN, and a contact period of ۲۴۰ minutes. WR@KN successfully removes fluoride ions from ۵.۵ to ۰.۲۸ 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 R۲ of ۰.۹۹۹۸۴. The adsorption kinetic modeling shows that the pseudo-second-order model is the best fit with ۰.۷۵۴ 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° (-۷۷.۰۸). 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.

کلیدواژه ها:

Ceramic clay ، Drinking water ، Remediation technology ، Reuse ، Water treatment