Adsorption of Barium and Zinc Ions by Mesoporous TiO2 with Chemosorbed Carbonate Groups
In the present paper the mesoporous TiO2 with chemosorbed carbonate groups was investigated as an adsorbent for the removal of Zn2+ and Ba2+ cations from aqueous solutions. The dependence of the adsorption values of Zn2+ and Ba2+ on the agitation time, solution’s acidity, and modification of surface of TiO2 was determined. The process of Zn2+ and Ba2+ adsorption fit well by Lagergren’s pseudo-second-order kinetic model. The equilibrium adsorption was investigated in the concentration of heavy metal’s ranges 27.46 mg/L - 7809 mg/L. The experimental data was approximated by Langmuir and DubininRadushcevich adsorption theories. The energy of adsorption Zn2+ and Ba2+ onto modified TiO2 and unmodified TiO2 was calculated using Dubinin-Radushkevich equations, and was found to be 15.82 - 9.399 kJ/mol, which corresponds to the mechanism of physical adsorption. The application of Langmuir theory to experimental adsorption data gives high R2, close to unit. Separation factor RL indicates, that adsorption Zn2+ and Ba2+ onto modified TiO2 is very favorable. Modified mesoporous ТіО2 is very efficient adsorbent toward Zn2+ and Ba2+ cations from their individual solutions as well as from their mixture, and able to compete with the best world analogues.