Abstract
Iron nano-impregnated adsorbent was synthesized, characterized and applied for fluoride subtraction from the water. Maximum fluoride removal (90%) was at 4.0mg/L concentration, 25.0min. contact time, 7.0 pH, 2.5g/L dose and 293K temperature. Iron nanocomposite adsorbent was selective for fluoride removal. The experimental data obeyed Langmuir, Freundlich and Temkin models. The values ΔG° were −1.89, −0.86 and −0.74kJ/mol at 293, 298 and 303K temperatures. ΔH° value was −7.61kJ/mol; indicating exothermic adsorption. ΔS° value was −2.30 x 10−2kJ/molK; a signal of entropy decrease during adsorption. The adsorption process was in the order of 293>298>303K. Kinetic modeling confirmed pseudo-first-order and liquid film diffusion mechanisms. The mechanism of adsorption is also determined.
•Green synthesis of iron nanocomposite material- eco-friendly method•Fast and selective fluoride removal from water•Economic removal due to low contact time and dose•Eco-friendly method due to capability to work at natural pHs of water bodies