Saragih, O.ErmanAmri, T. A.2013-08-012013-08-012013-08-01Rangga Dwijunanda Putrahttp://repository.unri.ac.id:80/handle/123456789/4880Copper (Cu) is one pollutant that becomes a problem because it is toxic and is classified as a hazardous waste material so that the presence of this metal in the aquatic environment should be reduced by adsorption. Adsorbent used commonly is activated carbon, seaweed , sugar cane waste and other materials. Clay is a natural mineral which is cheap and readily available as well as a porous material with a large surface area and cation in it that can be interchanged so that it can be used as an adsorbent. Power low adsorption of natural clays can be improved by physical and chemical activation. In this study, use of natural clays from Palas activated with NaOH 2M soaked for 8 hours at a temperature of 105 ± 4oC and calcined at 400o C for 3 hours. Clay activation results were used to adsorb Cu based on the influence of contact time, concentration, temperature, pH and adsorbent weight to study the adsorption equilibrium. The method used is a batch reactor and the filtrate obtained was analysed with Atomic Absorption Spectroscopy (AAS). The results showed that the model can represent equlibrium Langmuir adsorption of Cu (II) on clay which is activated with NaOH. It can be seen from the coefficient of determination (R2), that models Langmuir is higher (0.950) than Freundlich (0.931. Exothermic reaction occurs on adsorption clay activation by the value of ΔH = -7,851kJ / mol and ΔS = -42,85J / mol K. Gibss free energy (ΔG) which is positive value 5,131 kJ /mol hence it can be concluded that the reaction is not spontaneous.otherActivationAdsorptionIon Cu (II)Other