Kinetics and equilibrium studies of heavy metal ions removal by use of natural zeolite

The efficiency of zeolite as an adsorbent for the removal of heavy metals namely, Cd(II), Cu(II), and Ni(II) from aqueous solution at different initial concentration, zeolite amount, agitation speed and pH was determined. The sorption kinetics was tested for the first order reaction, intra-particle diffusion, pseudo-first order, and pseudo-second order reaction at different experimental conditions. Adsorption of Cd(II), Cu(II), and Ni(II) by zeolite was dependent significantly on the pH, adsorbent amount and initial adsorbate concentration. Studies on the rate of uptake of heavy metal ions by zeolite indicated that the process was quite rapid and maximum adsorption occurred within the first one hour of contact. The results showed that clinoptilolite is an effective and inexpensive adsorbent for Cd(II), Cu(II), Ni(II) removal from aqueous solutions.