Abstract :
Devdaru (Polyalthia longifolia) leaf powder, DLP, prepared from mature, dried Polyalthia longifolia (Devdaru) leaves was used as biosorbent for removal of fluoride from aqueous solutions using the batch adsorption process. The biosorbent was first characterized with respect to surface area, surface functional groups by FTIR, cation and anion exchange capacities, surface topography by SEM technique and then effects of pH, agitation time and fluoride concentration, adsorbent amount and temperature on adsorption of fluoride were investigated to determine optimum adsorption properties.
The biosorbent was found to be effective around psH 7.0 and the maximum fluoride removal capacity of this adsorbent was about 77 % at 303 K. Kinetic study showed that the fluoride sorption on DLP was predominantly chemical in nature and its mechanism was a complex one involving both surface adsorption and intra-particle diffusion. Thermodynamic study showed that sorption process was exothermic in nature and was found to be favourable at lower temperature. The results showed that the biosorbent, DLP may be used as cost-effective adsorbent for treating fluoride bearing water.
Keyword :
Fluoride biosorption, Kinetic study, Thermodynamic study.