Adsorption of lead ions by cow bones: Equilibrium and kinetics studies

In this work, Cow bone has been used as a low cost adsorbent to remove Pb(II) ions from aqueous solutions. This waste material is available easily. Optimal experimental conditions including pH, adsorbent dosage, temperature, salt concentration and contact time have been established. The lead ions was adsorbed at pH=4. The experiments showed that the adsorption process was quick and the equilibrium was attained within 5 min. The maximum equilibrium capacity of Cow bone from Langmuir model was 20.92 mg g^(-1) for Pb(II). It was seen that the increase in the salt concentration has no significant effect in removal of lead ions. Using the equilibrium concentration constants obtained at different temperatures, various thermodynamic parameters, such as ∆G^0 , ∆H^0 and ∆S^0 have been calculated. ∆H^0 and ∆S^0 were +54.50 kJ mol^(-1) and +202.91 J mol^(-1)K^(-1), respectively. The thermodynamics parameters system indicates spontaneous and endothermic process for removal of lead.

کلیدواژه ها:

Removal ، Lead ، Cow bone ، kinetics ، Equilibrium