PENGARUH KESETIMBANGAN ADSORPSI MANGAN OKSIDA BIRNESSITE TERHADAP ION LOGAM Pb(II)

Abstract

Lead is one of the non-essential heavy metals which is toxic to environment. If accumulated beyond the threshold value, this metal ions may cause problems for the survival of organisms and the environment. One effort developed to reduce levels of Pb metal ions in the environment is through adsorption method. In this study, the adsorbent used is birnessite with has been synthesized using the ceramic method (Astria, 2012). Birnessite has been proven to be useful in reducing heavy metals found in the environment as well as solid waste waters. This can occur because the birnessite can exchange cations in its frameworks with cations in solution. The objective of this research is to study the adsorption capacity and adsorption equilibrium birnessite towards metal ions Pb(II). The effect of time, concentration, temperature and pH on the adsorption of Pb in the birnessite has also been studied. The result showed that the maximum adsorption of Pb in birnessite is 95% with the condition at the contact time of 5 minutes, concentration adsorption capacity of 95,30 %, temperature of 60°C, and pH 6. The process of adsorption in birnessite follows Freundlich isotherm types. Adsorption type used in this study is physical adsorption (fisisorpsi) which is characterized by a low value of ΔH (+1.678 kJ/mol) which indicates the reaction is endothermic. The value of Gibbs free energy (ΔG) is positive, ie 0.399 kJ/mol and can be concluded that reaction was not spontaneous