Zeolitic imidazolate framework-8 nanoparticle: a promising adsorbent for effective fluoride removal from aqueous solution

Fluoride removal from living entities is the foremost task as it is a non-biodegradable and harmful pollutant mostly found in groundwater. Nowadays, the application of nanoparticles as an adsorbent of fluoride is becoming an intense research due to its high surface area. In the present study, zeolitic imidazolate framework-8 (ZIF-8) nanoparticles adsorption behavior and its efficiency in fluoride removal from an aqueous phase were studied. Various structures, sizes and morphologies of nanoparticles were investigated by Fourier-transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscope, transmission electron microscopy, Raman spectroscopy and zeta seizer. By varying process parameters such as contact time, adsorbent dosage, stirring rate, temperature, and pH, batch adsorption was carried out. The optimum conditions for fluoride removal by ZIF-8 nanoparticles were found as contact time 15 min, adsorbent dosage 0.06 g/L, agitation rate 400 rpm, temperature 20 °C, pH 8. Pseudo-second order in kinetic study showcases that the regression coefficient was found to be 0.99. The experimental data of Langmuir isotherm model of adsorption system reveal the adsorption capacity of 90 mg/g which has better adsorption capacity than other adsorbents. The isothermal multistage adsorption was also studied to understand the mechanism of adsorption of ZIF-8 nanoparticles for fluoride removal. The result in the present work gives a promising adsorbent for the fluoride removal.