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

• Main Author: Hannah E. Siregar, Febri
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/83511
• Institution: Institut Teknologi Bandung

Heavy metals are one of the most common types of environmental pollutants found in water, especially in industrial wastewater. Heavy metals have the potential to be harmful to living organisms in these waters and to human health because they are toxic and not-degradable nature. Mercury is a metal with the highest level of toxicity to living things. Adsorption is the most commonly used method to remove metal ions. Carrageenan is a linear galactose sulfate (consisting of D-galactose and 3,6-anhydro-D-galactose) extracted from red seaweed class Rhodophyceae. The ability of carrageenan to adsorb metals is related to its functional groups, anionic properties, and polymer structure. In this study, ?-carrageenan cube adsorbent was used to adsorb Hg(II) ions. The adsorbent was prepared using the composition ?-carrageenan/KCl 0.05 M and dried using the freeze-dry method to form cavities. The ?-carrageenan cubes were characterized by swelling degree test, floating time test, and using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX). The adsorption ability was investigated by measuring the removal of Hg(II) ions from the solution using Cold Vapor Atomic Absorption Spectrometry (CVAAS). From the results, characterization using FTIR shows a typical peak of ?-carrageenan in the fingerprint area. SEM-EDX characterization shows changes in the adsorbent surface morphology and Hg(II) ion content before and after contact with Hg(II) ions. The optimum conditions for adsorption of Hg(II) ions by ?-carrageenan adsorbent was obtained at pH 4 using an adsorbent mass of 0,15 grams with a contact time of 45 minutes for an analyte concentration of 50 ppm. Adsorption of Hg(II) ions using ?-carrageenan cube adsorbent follows the pseudo second order adsorption kinetics model and Langmuir adsorption isotherm with a qm value of 804.89 mg.g?1 at 303 K. Thermodynamics of Hg(II) ion adsorption using floating ?-carrageenan cube adsorbent shows that adsorption takes place spontaneously, endothermic with a disordered system. The ?G values obtained at 303 K was ?19.31 kJ.mol?1, 313 K was ?20.53 kJ.mol?1, and 323 K was ?21.75 kJ.mol?1. At all three temperatures, ?H of 17.70 kJ.mol?1 and ?S of 122.15 J.K?1.mol?1 were obtained. The adsorption-desorption study of Hg(II) ions showed that the ?-carrageenan cube adsorbent could not be used repeatedly.