RETRACTED: Amazon silicates modified by organofunctionalization for use in removing Hg(II) from aqueous medium: A thermodynamic approach (Retracted article. See vol. 14, pg. 1987, 2011)

Smectite and zeolite samples have been used for chemical modification process with 1,4-bis(3-aminopropyl)piperazine reacted with methyl acrylate to yield the new inorganic-organic chelating materials. The resulting matrices have been characterized through carbon and silicon nuclear magnetic resonance in the solid-state. The natural (S and Z) and modified silicate (S-APPMA and Z-APPMA) samples have been tested as potential adsorbents for the removal of to Hg(II) from aqueous solution at pH 2.0 and 298 +/- 1 K. The adsorption process was fitted to Sips model for non-linear regression method. The adsorption experiments performed under batch process with pH and mercury concentration as variables. These interactions were calorimetrically followed and the thermodynamic data showed the following exothermic enthalpy (-8.0 to -7.5 kJ mol(-1)), negative Gibbs free energy (-22.0 to -23.6 kJ mol(-1)), and positive entropy (47.0-54.0 J K-1 mol(-1)). These thermodynamic data confirmed the energetically favorable condition of such interaction solid/liquid for all systems. (c) 2009 Published by Elsevier B.V.