Sorption of Cr(VI) onto hdtma modified zeolitic tuffs

The removal of Cr(VI) from aqueous solutions was investigated using clinoptilolite and phillipsite-chabazite rich tuffs. These minerals were modified using hexadecyltrimethyl – ammonium bromide (HDTMA-Br) and used for Cr(VI) ions removal. The physicochemical characteristics of zeolitic minerals were revealed by XRD, XRF, BET and FT-IR techniques. The uptake capacities of modified zeolites were compared in batch sorption experiments. To predict the sorption isotherms and to determine the characteristic parameters for process design, three isotherm models the Freundlich, the Langmuir, and the Bilangmuir, were applied to experimental data. The data obtained reveal homogeneous Cr(VI) sorption on one kind of active sites on PC-HDTMA surface and heterogeneous sorption on two kinds of active sites on CL-HDTMA surface.