Effect of Temperature on Sequestration of Cu(ll) from Aqueous Solution onto Turmeric Powder

Abstract

In this work effect of temperature on adsorption of Cu(II) onto turmeric powder was investigated in order to understand sequestrating behavior of turmeric powder. Langmuir, Freundlich and D-R equilibrium models were employed and changes in equilibrium parameters with changing temperature have been discussed. Various thermodynamic parameters such as ?Hº, ?Gº and ?Sº have been calculated. It was found that with increase in temperature maximum adsorption capacities of Cu(II) increase which showed that the adsorption of Cu(II) onto turmeric powder is endothermic. ?Hº and Ea values also confirmed the same trend. Entropy values showed increased in randomness with increasing temperature. Gibbs free energies were non spontaneous at all the temperatures studied. E values were in the range of 2.89-3.53KJmol⁻¹, which indicated that adsorption is essentially of physical nature. The value of S* is much less than 1 indicating favourable sticking of adsorbate to adsorbent with physiosorption mechanism predominant.