Topic: Chemistry
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Adsorption Kinetics of Cadmium and Lead by Chitosan
An evaluation of the kinetics and capacity of chitosan to trap lead and cadmium ions in aqueous solution was carried out at 25oC using concentration and contact time as parameters. The experiments were done as batch process. Our results show that the adsorption process is concentration-driven with high capacity of chitosan for the adsorption of these metal ions
The Infra red spectroscopic study on the chitosan and the metal-chitosan complexes reveal a metal coordination based on the observed characteristic band changes. At initial lead concentrations of 1000, 500, 400, 250 and 100 mg/L, the adsorbed lead ion concentrations are 557, 265, 218, 132 and 65 mg/L, respectively. However, for the cadmium, the adsorbed concentrations are 263, 165, 152, 78 and 45 mg/L, respectively at the same initial concentrations. The lead and cadmium adsorption kinetic behavior could not be described using the Langmuir isotherm over the whole concentration range but Freundlich isotherm conforms to the experimental data.
This study showed that chitosan absorbs heavy metals, in particular, lead and cadmium ions, and hence can be used to remove not only lead and cadmium but also other heavy metals from aqueous effluents. Chitosan as a result of its bioavailability would be economically useful for the treatment of wastewater containing heavy metals. Generally, the adsorption process for both metals is concentration driven.
Source: www.academicjournals.org
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