ADSORPTION OF HG(II) IONS USING FLOATING ?-CARRAGEENAN BEADS ADSORBENT

• Main Author: Nabila Putri, Annisa
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/82785
• Institution: Institut Teknologi Bandung

Mercury is one of the heavy metals that is carcinogenic and can accumulate in human cells. Mercury in the environment comes from gold mining activities, the battery industry, and the thermometer industry. These industrial activities produce mercury waste that can pollute the environment. One way to reduce mercury levels is by adsorption method. Adsorbents that can be used for the adsorption of Hg(II) ions are ?-carrageenan with an anionic surface of sulfate ester groups that can attract Hg(II) ions. In this study, floating ?-carrageenan beads adsorbent was used to adsorb Hg(II) ions. Floating beads will facilitate the retrieval of the adsorbent after contact. Floating ?-carrageenan beads were prepared using a mixture of ?-carrageenan and CaCO3 with a mass ratio of 8:2. CaCO3 solution will react with the acid to form cavities in the ?-carrageenan beads. Characterization of the adsorbent was carried out by determining the swelling degree, flotation test, functional group analysis using Fourier Transform Infrared (FTIR) spectroscopy, morphological analysis, and elemental composition on the adsorbent surface using Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy (SEM EDS). FTIR results showed shifts in the absorption peaks of O-H and O=S=O vibrations of ?-carrageenan moieties. SEM results showed changes in adsorbent morphology before and after contact. EDS results showed the presence of Hg(II) ions on the adsorbent surface after contact. The adsorption ability of floating ?-carrageenan beads was carried out by measuring the residual Hg(II) ions after the adsorption process using Cold Vapor-Atomic Absorption Spectrometry (CV-AAS). The optimum conditions for adsorption of Hg(II) ions by floating ?-carrageenan beads were obtained at pH 3, contact time for 120 minutes, and adsorbent mass of 0,1 gram. Adsorption of Hg(II) ions using floating ?-carrageenan beads followed the pseudo second-order adsorption kinetics and Langmuir adsorption isotherm model with qmax of 29,56 mg.g?1 obtained at 50 °C. Thermodynamic study of adsorption of Hg(II) ions showed that the adsorption was spontaneous and endothermic as judged from the ?G values at temperatures of 303 K, 313 K, 323 K of ?25,84 kJ.mol?1, ?26,94 kJ.mol?1, and ?28,03 kJ.mol?1 respectively and the ?H and ?S values of 7,32 kJ.mol?1 and 109,45 J.K?1.mol?1 respectively.