Abstract

The branch wastes of grape bushes as adsorbent for copper (II) ions removal from water solutions was
investigated. The equilibrium sorption data were fitted to Langmuir, Freundlich, Dubinin-Radushkevich (D-R)
and Temkin isotherms. The coefficient of determination value of Langmuir equation was the highest (0.9994). The
maximum monolayer sorption capacity is 3.47 mmol g−1. The mean of free energy was determined to be 3.26 kJ
mol−1. The calculated value of heat of adsorption has been obtained 0.627 J mol−1. The kinetic data are better
described by the pseudo-second model. The calculated values of the maximum sorption capacity from the pseudo-
second order equation (3.16 mmol g−1) and from the D-R isotherm (3.145 mmol g−1) are well agreements with its
experimentally found value (3.264 mmol g−1). The negative value of ΔH° (–46.767 kJ mol−1) indicates exothermic
nature of the adsorption process and the negative value of ΔS° (–0.15 kJ mol−1K−1) indicates a decreased disorder
during adsorption process.