Ceramics-Silikáty 48 (2) 76-82 (2004)

THE SORPTION PROPERTIES OF TOBERMORITE MODIFIED WITH Na⁺ AND Al³⁺ IONS

R. Siauciunas, V. Janickis, D. Palubinskaite, R. Ivanauskas

The effect of Al₂O₃ and NaOH on the formation of 1.13 nm - tobermorite under hydrothermal conditions and ion exchange capacity of tobermorites with and without Al³⁺ as well as with double [Na⁺ + Al³⁺] substitution in relation to heavy metal ions (Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺) under static and dynamic conditions were studied. Ion exchange capacity of crystalline 1.13 nm tobermorite and that of Al - substituted tobermorites are insignificant. Insertion of Na⁺ ions into the crystalline lattice of tobermorite increases ten times ion exchange capacity of the sorbent. The ion exchange capacity of [Na⁺ + Al³⁺] - substituted tobermorite is 279 mg Cu²⁺, 230 mg Ni²⁺ and 206 mg Zn²⁺ per gram of the sorbent. The dynamic activity of this compound is highest for Ni²⁺ and Zn²⁺ ions, average for Cu²⁺ and lowest for Co²⁺ ions. Ion exchange capacity of the [Na⁺ + Al³⁺] - substituted tobermorite is only slightly related to the addition of NaOH and Al₂O₃.

Keywords: [Na⁺ + Al³⁺] - substituted tobermorite, Al³⁺ - substituted tobermorite, Ion exchange capacity, Wastewater cleaning