MEMBRANE MATERIAL DEVELOPMENT FOR SELECTIVE Li+/Na+ SEPARATION

• Main Author: Aprilia, Nungky
• Format: Theses
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/34163
• Institution: Institut Teknologi Bandung

In this project, selective binding properties of crown ether polymer were investigated. DB15C5 was incorporated in polymer chain together withsebacic acid and PEG diacid. Based on the size-matching concept between the crown ether cavity and the ionic radius of metal ions, DB15C5 has selective binding with sodium ion (Na+). The presence of hydrophobic group was expected to increase the mechanical strength of the crown ether polymer. The hydrophilic group in this polymer was expected to increases the swelling as such the ions can reach the crown ether more easily. In a consequence of that, the binding ability of crown ether polymer with metal ions was increases. Synthesis procedure was developed to obtain the crown ether polymer with high molecular weight. GPC measurement wasdone to ensure the molecular weight. The chemical structures of synthesized polymer were validated by using 1H- NMR, XRD and FTIR. TGA and DSC measurements provided the data of the thermal properties of the synthesized polymer. Metal ions extractions wereconducted for three different samples: DB15C5, DB15C5 incorporated to sebacic acid, and DB15C5 incorporated to sebacic acid and PEG diacid. Sodium, lithium, potassium and calcium were used as the metal chlorides. Extraction tests were done by mixing the crown ether polymer in organic phase and metal chloride in aqueous phase. The effect of pH on the extraction results also discussed in this report. Competition between two ions was studied with mix-ions extraction tests. The incorporation of crown ether into polymer backbone, especially with hydrophilic units, increase the binding properties significantly. The change in selectivity of the crown ether was also observed. The crown ether polymer adsorbed K+ better than the other ions. It was concluded that, in addition to size matching concept between the crown ether cavity and the ionic radius of metal cations; the electronegativity of oxygen atoms and the hard-soft acid-base principle influenced the binding ability and selectivity.