Experiments were conducted to investigate influence of different factors on the adsorption of Zn2+ and Cd2+ ions from aqueous solution onto vermiculite. The ratio of the initial concentration of ions, C0, to the adsorbent concentration, W0, was shown to be the key factor determining the equilibrium ion adsorption density, qe. Subject to the magnitude of C0/W0, the value of qe could either attain its maximum level, qm (the maximum adsorption density), when the solid surface was fully saturated, or approach its critical limit, qc (the C0/W0 ratio...
