title: Equilibrium, kinetic and thermodynamic studies of mercury adsorption on almond shell.
abstract: The application of almond shell as a low cost natural adsorbent to remove Hg(2+) from aqueous solution was investigated. Batch experiments were carried out to evaluate the adsorption capacity of the material. The chemical and physical parameters such as pH, sorbent amount, initial ion concentration, and contact time were optimized for the maximum uptake of mercury onto the solid surface. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models, and the experimental data were found to fit the Langmuir model rather than the Freundlich. The maximum adsorption capacity obtained from the Langmuir isotherm was 135.13 mg/g. A kinetic study was carried out with pseudo-first-order and pseudo-second-order reaction equations and it was found that the Hg(2+) uptake process followed the pseudo-second-order rate expression. The thermodynamic values, ΔG(0), ΔH(0) and ΔS(0), indicated that adsorption was an endothermic and spontaneous process. The potential of this material for mercury elimination was demonstrated by efficient Hg(2+) removal from a synthetic effluent.
authors.affiliation: Department of Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran. sh_khaloo@sbmu.ac.ir
authors.forename: Shokooh Sadat
authors.initials: SS
authors.lastname: Khaloo
authors.forename: Amir Hossein
authors.initials: AH
authors.lastname: Matin
authors.forename: Sahar
authors.initials: S
authors.lastname: Sharifi
authors.forename: Masoumeh
authors.initials: M
authors.lastname: Fadaeinia
authors.forename: Narges
authors.initials: N
authors.lastname: Kazempour
authors.forename: Shaghayegh
authors.initials: S
authors.lastname: Mirzadeh
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008628:Mercury / Q000302:isolation & purification*; D027861:Prunus / Q000737:chemistry*; D013816:Thermodynamics; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D008628:Mercury