Abstract
In continuation of our efforts to explore the application of a modified natural polymer to remove toxic heavy metals from aqueous solutions, Gum Arabic (Gum acacia [GA]) dialdehyde phenylthiosemicarbazone (GAD-PTSC) chelating resin was prepared through the oxidation of GA followed by a reaction with 4-phenylthiosemicarbazide (PTSC). The structural functionalities, surface morphologies, and thermal stabilities of the resultant adsorbent resin were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermo-gravimetric analysis. The chelating behavior of the obtained resin with mercury (Hg (II)) in aqueous solution was studied using the batch technique. The adsorption and the kinetic models were adopted to calculate the kinetic and thermodynamic parameters of the adsorption process. The removal percentage of Hg (II) ions on GAD-PTSC reached 97% at pH 5.5, and the maximum adsorbed amount of Hg (II) was found to be 120 mg g(-1) at pH 5.5. The experimental results complied with the second-order kinetic model supporting chemical adsorption with calculated maximum adsorption capacity of 122.10 mg g(-1). The Langmuir isotherm model showed good fitting with the experimental results with maximum adsorption capacity of 133.33 mg g(-1).