title: Adsorption of Ag, Cu and Hg from aqueous solutions using expanded perlite.
abstract: The aim of the present work was to investigate the ability of expanded perlite (EP) to remove of silver, copper and mercury ions from aqueous solutions. Batch adsorption experiments were carried out and the effect of pH, adsorbent dosage, contact time and temperature of solution on the removal process has been investigated. The optimum pH for the adsorption was found to be 6.5. Adsorption of these metal ions reached their equilibrium concentration in 120, 240 and 180 min for Ag (I), Cu (II) and Hg (II) ions, respectively. Experimental data were also evaluated in terms of kinetic characteristics of adsorption and it was found that adsorption process for these metal ions followed well pseudo-second-order kinetics. Using Langmuir isotherm model, maximum adsorption capacity of EP was found to be 8.46, 1.95 and 0.35 mg/g for Ag (I), Cu (II) and Hg (II) ions, respectively. Finally, the thermodynamic parameters including, the change of free energy (DeltaG degrees ), enthalpy (DeltaH degrees ) and entropy (DeltaS degrees ) of adsorption were calculated for each metal ion. The results showed that the adsorption of these metal ions on EP was feasible and exothermic at 20-50 degrees C.
authors.affiliation: Department of Chemical Engineering, Tarbiat Modarres University, PO Box 14115-143, Tehran, Iran. h.ghassabzadeh@gmail.com
authors.forename: Hamid
authors.initials: H
authors.lastname: Ghassabzadeh
authors.forename: Ahmad
authors.initials: A
authors.lastname: Mohadespour
authors.forename: Meisam
authors.initials: M
authors.lastname: Torab-Mostaedi
authors.forename: Parisa
authors.initials: P
authors.lastname: Zaheri
authors.forename: Mohammad Ghannadi
authors.initials: MG
authors.lastname: Maragheh
authors.forename: Hossein
authors.initials: H
authors.lastname: Taheri
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D003300:Copper; D007700:Kinetics; D008628:Mercury; D019216:Metals, Heavy / Q000302:isolation & purification*; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver; D012996:Solutions; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods
chemical_list: D019216:Metals, Heavy; D012996:Solutions; D014874:Water Pollutants, Chemical; C003076:Perlite; D012834:Silver; D012822:Silicon Dioxide; D003300:Copper; D008628:Mercury; D000537:Aluminum Oxide