Removal of Cadmium from Aqueous Solutions Using Low Cost Sorbents

The pollution of water with heavy metals is a highly important environmental problem, first of all because of the propagation of the pollution and second, because of its unfavorable consequences on the aquatic life and different uses of water. Various agricultural waste could be potentially used as low cost adsorbents for biosorptive removal of heavy metal ions from aqueous solutions. This study presents the results of the adsorption process of Cd2+ on some adsorbents: clinoptillolite (CLP), carrot residue (CR) and green tea waste (TW). Removal efficiencies greater than 95% were achieved for clinoptillolite (CLP) and tea waste (TW), whereas carrot residue (CR) showed removal percentages between 80-90%. The suitability of the Freundlich, Langmuir and Temkin adsorption models to the equilibrium data were investigated for each heavy metal-adsorbent system. The results showed that the equilibrium data for these systems fitted the Freundlich model best within the concentration range studied, except for tea waste, for which the Temkin isotherm provides a better fit for the available data. The study points to the potential of use of low cost materials as effective sorbents for the removal of Cd2+ from aqueous solution.