Biosorption of fluoride from aqueous medium by Indian sandalwood (Santalum Album) leaf powder

Sandalwood leaf powder prepared from mature, dried Indian sandalwood (Santalum album) leaves was investigated to assess its ability to remove fluoride from aqueous solutions using adsorption process. Effects of solution pH, contact time, adsorbent amount and solution temperature on fluoride sorption had been investigated. The biosorbent was effective at the pH range of 5.0-7.0 and its fluoride removal capacity was found to be above 75.0%. The kinetics of the interactions was measured with pseudo first order Lagergren equation (mean k1: 2.22 × 10−2 min−1), simple second order kinetics (mean k2: 4.43 × 10−1 g/mg/min), and intra-particle diffusion (mean ki: 8.31 × 10−2 mg/g/min0.5) mechanism. The adsorption data gave good fits with Langmuir, Freundlich and Temkin isotherms and yielded Langmuir monolayer capacity of 4.66 mg/g. The negative values of the thermodynamic parameters, ΔH, ΔS and ΔG showed the adsorption process to be exothermic in nature and thermodynamically favourable at lower temperature. These results indicated that Sandalwood leaf powder might be an effective adsorbent for treatment of water contaminated with fluoride.