RARE EARTH ELEMENTS ADSORPTION BY PYRAZOLONE LOADED CALCIUM ALGINATE MICROCAPSULES

• Main Author: (NIM : 30507004); Ketua tim promotor : Prof. Dr. Buchari; Anggota tim pembimbing : Dr. M. B, RUSNADI
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/17117
• Institution: Institut Teknologi Bandung

Rare earth elements (REEs) have some unique properties and wide range of applications. REEs are used in industry for the production of glass additives, fluorescent materials, catalysts, ceramics, lasers, supraconductors, or magnets. The wide use of REEs in many industrial activities results in the increasing demand for them and has led to enhance REEs release to aquatic environment. Extraction method, preconcentration and recovery technique of REEs are absolutely important, not only from the view of their limited resource availability, but also for the environmental issues. It can be forecast that the introduction rare earth ions in very large quantities to the environment through various pathways will result in environmental problems in the next few decades. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Solvent extraction is the major technique for removal, recovery and separation metal ions from aqueous solution because the process is well-suited for large-scale continuous operations, its inherent high selectivity and fast kinetics. Unfortunately, the large amount of organic solvent and extractant may adversely affect the environment and harm human health. Ion exchange can be performed in a single-stage operation within a simple packed column but not as selective as the extractants. Adsorption is commonly used because of ease in operation, good performance and relatively low cost. Microcapsule containing an extractant can be used as an adsorbent in adsorption process to combine the mutual advantages of solvent extraction and ion exchange methods. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Alginate is a natural polysaccharide extracted from various species of brown seaweed. The carboxylate groups of the polymer reveal its ability to undergo a sol-gel transition in the presence of calcium ions. Alginate ability to form microcapsule calcium alginate has been used for the encapsulation of an organic extractant. 4-Acyl-5-pyrazolone is a type of Beta-diketone, which have been extensively used as extractants for hard ions such as trivalent lanthanoid ions. Because of their increased acidity and various synthetic modifications, which can be made to the basic structure, these extractants present some possibilities to improve the separation procedures for lanthanoids. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> In the present work, new adsorbent were developed by encapsulating 4-Acyl-5-pyrazolone, 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (HPMBP) and 4-sebacoyl -bis(l-phenyl-3-methyl-5-pyrazolone) (H2SbBP), within calcium alginate gel. The adsorption behaviour of cerium, lanthanum and gadolinium with HPMBP loaded calcium alginate microcapsules (CAHP) and H2SbBP loaded calcium alginate microcapsules (CAH2) have been investigated in detail. The effect of various parameters such as lanthanoid ions concentration, contact time, adsorbent dose and pH on the adsorption was determined. Adsorption isotherm, kinetics and the adsorption mechanism also have been studied. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> From the analysis of pH, FTIR and AAS, it could be concluded that the uptake of Ln3+ by CAHP and CAH2 microcapsules were governed mainly by complexation with the ligands and electrostatic interaction with carboxylate functional groups on alginate, and just a little contribution from ion-exchange reaction in the calcium alginate matrices.