Bentonite and montmorillonite nanoparticles effectiveness in removal of fluoride from water solutions

The aim of this study was to evaluate the effectiveness of montmorillonite and bentonite nanoparticles in removal of fluoride from water solutions. This experimental study has been conducted in batch condition in which the effects of different parameters such as contact time, pH, initial concentration of fluoride and amount of adsorbent mass have been investigated. Finally thermodynamics, isotherm and kinetics of the both adsorbents have been studied. The maximum adsorption capacity for both adsorbents occurred at fluoride concentration of 20 mg/L, contact times of 60 minutes, pH = 3 and adsorbent mass of 0.25 g/L. The adsorption process was exothermic and the result of the Langmuir and Freundlich isotherm study show that bentonite nanoparticles behave more similar to the Langmuir isotherm model and montmorillonite nanoparticles behave according to the both isotherms. Furthermore, the adsorption of fluoride by bentonite in all studied fluoride concentrations and montmorillonite in higher fluoride concentrations followed pseudo second-order kinetics.