The influences of the initial pH, temperature, contact time and dosage of the adsorbent on adsorption performance have been experimentally verified by a batch method. The adsorbent used in this study exhibited a good adsorption potential at initial pH 4.5 for temperatures 28, 35 and 45 ºC. The removal efficiency and distribution coefficient have also been determined for the adsorption system as a function of dosage of the adsorbent. The experimental results are described by Langmuir, Freundlich and Dubinin-Kaganer-Radushkevich (DKR) isotherm models. Experimental results show that the kinetic model of pseudo-second order provided a good description of the whole experimental data more than the kinetic of the Lagergren-first order.
Based upon the experimental results of this study, the following conclusions can be drawn:
1. The maximum removal efficiency of Fe(III) ions occurs at initial pH of 4.5 and solution temperature of
28 ºC.
2. The removal efficiency of Fe(III) ions increases as the dosage of the adsorbent increases.
3. The isotherm study indicates that the Langmuir, Freundlich and Dubinin–Kaganer–Radushkevich
(DKR) isotherms models can adequately model sorption data.
4. The equilibrium removal of Fe(III) ions decreases as
the temperature of solution increases.
5. The removal of Fe(III) ions by this olive cake is an exothermic process.
6. It is found that the pseudo-second order model is applicable for whole the range of contact time while
not for the pseudo-first order.