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

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.