Study on the Separation Property of Mixing Gas with Chemical-Modified Chitosan

• Main Authors: pei-Ju Jao, 饒佩如
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/95239834078193740692

碩士 === 國立雲林科技大學 === 工業化學與災害防治研究所 === 91 === This thesis addresses the modification of chitosan (CS) with a chemical method (sulfonation), which was intended to improve the solubility in water, reduce the use of organic solvent, and be applied to CO2/CH4 separation process (purification of natural gas). Chitosan is prepared by hot alkali deacetylation from purchased chitin, then different degree of deacetylation (DD) chitosans were obtained by different alkali deacetylation reaction time. Several DDs chitosans were modified by 1,3-propane sultone to form sulfonated chitosans(SCS). By dry-method, we got dense films, which were applied to separate the main gases CO2/CH4 of natural gas. The degree of deacetylation of chitosan was confirmed by colloid titration method. The structures of chitosan and sulfonated chitosan were characterized by FTIR. The results are shown from colloid titration method that the DD of chitosan is between 73%~95%, and the characteristic adsorption peak of sulfonation in the chitosan is also shown in the FTIR. From element analysis, the degree of sulfonation of sulfonated chitosan is estimated between 56%~87%. The separation efficiency had been measured by gas permeability analyzer. The experimental results show that the selectivity coefficients for mixture (CO2/CH4) increase with increasing DD, and decrease while the sulfonation effect exists. From BET, the exist of hydrogen bonding between CO2 and chitosan results inCO2 had higher solubility to the film. Relationship among solubility coefficiency, diffusivity coefficiency and permeability coefficiency were described by solution-diffusion model. And also, we can control the correlation between material design and separation efficiency. In addition, the synthesis of polydimethylsiloxane-contained polyurethane were described herein. The structure of PDMS-contained PU was characterized by FTIR and 29Si-NMR. From gas permeability analyzer, the permeability increase certainly resulted from the addition of PDMS. Because of its poor film forming properties of sulfonated polyurethane, there were few data about its physical properties up to now.