Sorption characteristics of economically viable silicate sorbents for sequestration of lead ions from aqueous solutions

Abstract

The adsorption of Pb²⁺ from aqueous solutions by sorbents based on calcium silicates, obtained in multi-component systems CaCl₂–Na₂SiO₃–H₂O (sorbent I) and CaSO₄·2H₂O–SiO₂·nH₂O–KOH–H₂O (sorbent II), was studied. Surface area of the two sorbents was found to be 100 and 40 m²/g respectively. The sorption capacities of the adsorbent materials were found to be 3.6 l/mmol and 8.4 l/mmol respectively. Characterization of the sorbent materials was carried out. The equilibrium data was fitted in Langmuir's isotherm and the adsorption capacity of the adsorbent materials was determined. The distribution coefficients at Pb²⁺ ions for the sorbents were determined at different ratios of solid and liquid phases.