Ion exchange of Cu2+, Ni2+, Pb2+ and Zn2+ in analcime (ANA) synthesized from Thai perlite

This work studied the ion exchange of Cu2+, Ni2+, Pb2+ and Zn2+ into an analcime (ANA) in the temperature range 298-333 K. The analcime was produced from an economically available Thai perlite. The selectivity sequence for ions entering analcime in its as-synthesized sodium form was Pb2+ > Cu2+ > Zn2+ > Ni2+, as indicated by values of ΔG0. The results demonstrated that the enthalpy of cation hydration determined the selectivity of the zeolite. ΔS0 values were related to changes in water content. A comparison of the selectivity series for Pb, Cu, Ni, and Zn cation uptake into analcime to those of other zeolites shows similar trends.