RESUMO
Sorption properties of natural zeolite-containing tripolite from the Khotynetsky deposit (Russia, Oryol region) were studied to evaluate their possibility to purify ground waters contaminated by technogenic Ni2+ and Zn2+. According to experimental data the total ion-exchange capacity of the natural tripolite sample equaled to 1.79 mg-eq/g. The kinetic experiments showed that equilibrium in the studied rock-solution system took place after 500 h of interaction. In the range of the used Ni2+ and Zn2+ concentrations (2-10 mg/L) after 21 days of interaction with natural tropolite suspension, the sorption of the studied ions can be approximated by a linear isotherm, zinc being sorbed much better than nickel: the average values of distribution coefficients (Kd) obtained for 0.003 N CaCl2 aquatic solution equaled to 2.7 × 103 ml/g for Ni2+ and 6.7 × 103 ml/g for Zn2+. Therefore, natural zeolite-containing tripolite of the Khotinetsky deposit can be used for extraction of technogenic Ni2+ and Zn2+ from natural surface and ground waters contaminated by these ions and can be considered as an effective natural sorbent for solving environmental problems.