Aqueous Phase Removal of Fluoride as Fluorosis agent Using Montmorillonite Clay as Natural Nanoadsorbent

A natural nanomaterial, montmorillonite clay, was collected, purified, and then applied in the removal of fluoride. To obtain the activated montmorillonite clay, 150 g of the grounded montmorillonite clay was weighed and refluxed in 500 mL of 1M HCl at 120 °C for one hour thirty minutes. Fluoride was determined with the aid of SPADNS reagent (2-parasulfophenylazo)-1,8-dihydroxy-3,6-naphthalene disulfanate) using UV/visible spectrophotometer (Model JENWAY 6300) at the wavelength of 570 nm. Adsorption parameters studied were adsorbent dose, contact time, and pH effect. Fluoride was removed with a maximum percentage of 83.5% at optimum pH of 2 with contact time of 50 minutes and adsorbent dose of 2.0 g as well as temperature of 25°C. Two most used kinetic models were employed in this research, pseudo-first order and pseudo-second order. The experimental data were found to follow pseudosecond kinetic than pseudo-first order. Thus, montmorillonite clay as a natural nanoadsorbent could be used to remove fluoride which could help in the prevention of dental fluorosis.