Adsorption studies of zinc ions on barium titanate from aqueous solution

Adsorption of Zn(II) ions on barium titanate has been studied as a function of concentration of Zn(II) (1.0 x 10(-5)-5.0 x 10(-7) M), temperature (281-313 K) and pH (4-8) of the adsorptive solution using Zn-65 tracer and gamma-ray spectroscopy. The adsorption process was found to obey the first order rate law and the Freundlich adsorption isotherm for the range of concentration studied. The uptake increases from 32 to 70% with the increase in dilution (from 1.0 x 10(-5) to 5.0 x 10(-7) M). The extent of adsorption also increases with increasing temperature and pH of solution. The activation energy for the process was determined to be 12.3 kJ mol(-1). The removal of Zn(II) ions by barium titanate appears to be endothermic and irreversible.