Removal of Cd(II), Co(II) and Ni (II) ions from aqueous solutions using eucalyptus leaves ash

In this study، eucalyptus leaves ash (ELA) was used as a low cost adsorbent for simultaneous removal of Cd (II)، Ni (II) and Co (II) ions from aqueous solutions. The adsorption parameters، such as initial pH of the solution، contact time، adsorbent dose and temperature، were studied and optimized. Evaluation of the obtained data with isotherm studies indicated that the adsorption process was matched well with the Langmuir model. The maximum capacity of adsorbent for Cd (II)، Co (II) and Ni (II) ions were 166. 7، 27. 03 and 23. 8 mg g−1، respectively. Kinetic studies were carried out on various kinetic models and the pseudo-second order kinetic model was fitted very well with experimental data. Moreover، base on thermodynamic studies the adsorption process was both endothermic and spontaneous.