Investigation of Removal of Cu(II) Ions by Commercial Activated Carbon: Equilibrium and Thermodynamic Studies

Abstract

The present study deals with the application of activated carbon for the adsorptive removal of Cu(II) from its aqueous solutions. This paper incorporates the effects of pH, adsorbent dose, contact time, concentration and temperature. Equilibrium adsorption isotherms are usually used to determine the capacity of an adsorbent. The adsorption behavior of the Cu(II) has been studied using Langmuir and Freundlich adsorption isotherm models. The monolayer adsorption capacity determined from the Langmuir adsorption equation has been found as 13.7 mg g^–1. Adsorption of Cu(II) on adsorbent was found to increase on decreasing initial concentration, increasing pH up to 7 and increasing temperature. The paper discusses the thermodynamic parameters of the adsorption (the Gibbs free energy, entropy and enthalpy). Our results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions. SPSS software was employed for prediction and investigation of factor importance in determining of reminded Cu(II) after adsorption. According to Beta-value the importance order of factors is: concentration, adsorbent dose, time, pH and temperature respectively. Also, the obtained results from this study show the good adaptation between experimental and prediction values of % Cu(II).