Cd(II) and Pb(II) separation from aqueous solution using clinoptilolite and Opuntia ectodermis.

This work presents the conditions for Pb(II) and Cd(II) removal from aqueous solution using two different sorbent materials, namely, clinoptilolite and Opuntia ectodermis, which were characterized before and after entering into contact with the metal-containing aqueous media, using scanning electron microscopy (SEM), thermal analysis (TGA) and surface area (BET). Metal removal was found to depend on the initial metal concentration in aqueous solution, pH and the mass/volume ratio. The Pb(II) and Cd(II) uptake process was maximum at pH 4 for both sorbents, which showed an adsorption capacity that was adequately described by the Freundlich adsorption isotherm. The Thomas model was used to describe the adsorption data from column studies, the sorption capacity was 12.21 Pb(II) mg per gram of Opuntia ectodermis, while 7.71 Pb(II) mg per gram of clinoptilolite were adsorbed; lower values were obtained for Cd(II) removal. It was demonstrated that the use of low cost materials for the treatment of Pb(II), and Cd(II), containing wastewater is an effective and economical alternative method.