elimination of cd2+ and mn2+ from wastewaters using natural clinoptilolite and synthetic zeolite p

this study deals with the uptake of cd2+ and  mn2+ ions from contaminated water using two iranian natural clinoptilolite-rich tuffs from meyaneh (z-m), and semnan (z-s) regions , and a synthetic zeolite-p from z-m sample (z-p) under static (batch operation) and dynamic (column operation) conditions. to investigate the selectivity of the zeolites toward cd2+ and mn2+ cations, the ion exchange isotherms were constructed at 298k. according to the data obtained for both cations, the following general trend in distribution coefficient (kd) and consequently in selectivity was achieved for the investigated exchangers: z-p>>z-m> z-s.