Adsorption study on orange peel: Removal of mercury (II) and chromium (III) from aqueous solution

摘要

The adsorption of Mercury (II) and Chromium (III) on orange peel has been studied in batch mode using flame atomic absorption spectroscopy for metal estimation. The effects of Mercury (II) and Chromium (III) ions concentration, agitation time and temperature on adsorption of heavy metals onto orange peel was investigated. The experimental isotherm results were fitted using Langmuir and Freundlich equations. The Langmuir and Freundlich model agrees very well with experimental data. The maximum amounts of Mercury (II) and Chromium (III) adsorbed (q_m), as evaluated by Freundlich isotherm, were 7.79 mg and 6.43 per gram of powder of orange peel, respectively. All adsorption processes can attain equilibrium within 30 min and kinetics was well fitted by psesudo-second order equation. It is proposed that the adsorption mechanism was com-plexation. Thermodynamic parameters (ΔG°, ΔS° and ΔH°) for sorption system was determined at five different temperatures.