Study of operating conditions on fabrication of a kaolin hollow fibre membrane

• Main Author: Zykamilia Kamin
• Format: Thesis
• Language: English; English
• Published: 2011
• Subjects: TA401-492 Materials of engineering and construction. Mechanics of materials
• Online Access: https://eprints.ums.edu.my/id/eprint/40573/1/24%20PAGES.pdf; https://eprints.ums.edu.my/id/eprint/40573/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/40573/

A high surface to volume ratio and harsh environments stability of a ceramic hollow fibre membrane attracts its current use. Currently, it is produced using expensive advanced ceramics (Al2O3, Ti2O, ZrO2 etc.). In this research, the inexpensive kaolin was proposed as hollow fibre membrane material. However, available spinning condition for hollow fibre membrane (HFM) preparation of the existing materials is not suitable for kaolin. Therefore this study reveals the fundamental knowledge to prepare kaolin HFM. Morphology study is important as an indicator for ceramic HFM applications either in separation or deposition of catalyst. In this study, various suspensions were prepared containing kaolin, polyethersulfone (PESf) and n-methyl-2-pyrrolidone (NMP) as ceramic powder, polymer binder and solvent respectively, spun at 0, 3 and 6 cm air gaps and later sintered between 1100 and 1600 °C. The results showed that suspensions viscosity between 1.280 x 103 and 3.310 x 105 cp were obtained. Fibres with regular cross-section were achieved at 3 and 6 cm air gaps. Subsequently, an increased in spinneret dimension required for a higher air gap to form a continuously nascent fibre. By scanning electron microscopy, asymmetric fibres were obtained; with outer finger-like voids and inner finger-like voids dominated the fibre cross-section at a low viscosity and a low air gap respectively. At increasing viscosity and air gap heights, the voids growth were inhibited by their respective contrast voids, due to the increased of kaolin particles amount at distributed particle size coupled with the gravitational effect and a retention time for particles orientation. Sponge region were seen to dominate the fibre cross-section in the most viscous (ratio of kaolin/PESf 3.5 (S6)) fibres spun at 6 cm (the longest air gap). After sintering, fibres asymmetric structures were retained; however, the S6 fibre outer finger-like voids sintered at 1600 °C were eliminated. The kaolin fibre morphology showed versatile structures depending on the process condition used.