Composite hybrid membrane of chitosan-silica in pervaporation separation of MeOH/DMC mixtures.
Chitosan-silica hybrid membranes (CSHMs) were prepared by cross-linking chitosan (CS) with 3-aminopropyl-triethoxysilane (APTEOS). The dynamic behaviors of the CS membrane and the CSHM were investigated in pervaporation (PV) of methanol/dimethyl carbonate (MeOH/DMC) mixtures. The membranes were characterized by X-ray diffraction (XRD), contact angle meter, scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). The transition state of PV processes were studied. During the PV processes, the amorphous region of the membranes increases and the contact angle between MeOH and the membrane decreases within a range of operating time and then remains almost constant implying a reconstruction occurred on the membrane surface. The silica is well distributed in the CSHM matrix and the thermal stability of the CSHM is enhanced. The time for a PV process to reach a steady state decreases with increasing MeOH concentration or feed temperature, and it is longer for the CSHM than the CS membrane under the same operating condition. Swelling experiments show that the degree of swelling (DS) is greatly depressed by cross-linking CS with APTEOS. Sorption data indicate that the selectivity of solubility and diffusion of the CSHM are greatly improved over the CS membrane. The CSHM presents superior separation behaviors over other membranes with a flux of 1265 g/(hm(2)) and separation factor of 30.1 in PV separation of 70 wt% MeOH in feed at 50 degrees C.
Chen
Jian Hua
JH
Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China.
Liu
Qing Lin
QL
Fang
Jun
J
Zhu
Ai Mei
AM
Zhang
Qiu Gen
QG
D000327:Adsorption; D048271:Chitosan / Q000737:chemistry*; D004058:Diffusion; D005561:Formates / Q000737:chemistry*; D008567:Membranes, Artificial; D000432:Methanol / Q000737:chemistry*; D015394:Molecular Structure; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014835:Volatilization
D005561:Formates; D008567:Membranes, Artificial; D012822:Silicon Dioxide; D048271:Chitosan; C023025:methyl carbonate; D000432:Methanol