Parametric Study of CO₂ Fixed Carrier Facilitated Transport through Swollen Chitosan Membranes

Abstract

Swollen and dry chitosan membranes were used to separate carbon dioxide from a feed gas composed of 10% CO2, 10% H2, and 80% N2 in a temperature range of 20−150 °C for a feed pressure of 1.5 atm. Swelling increased CO2 permeabilities (barrers) of chitosan membranes from 0.381 to 213 at 20 °C, 9.50 to 482 at 110 °C, and 26.1 to 399 at 150 °C, accompanied with similar trends for the separation factors: CO2/H2 and CO2/N2. The total water levels of the membranes were controlled to be the same at all temperature conditions by manipulating the relative humidities of the feed and sweep gases. This permitted direct comparison of the levels of bound and free water to carbon dioxide permeability and selectivity factors. CO2 transport in swollen chitosan membranes is mainly dominated by water-facilitated reactions of CO2 with primary amine groups of chitosan. Cussler’s model was modified to incorporate facilitated reactions caused by both free and bound water. The values of the model’s kinetic and transport parameters were consistent with the reaction chemistry of the facilitated process and the physical chemistry of the polymer.

Anionic surfactant-doped Pebax membrane with optimal free volume characteristics for efficient CO 2 separation

“…The content of total water (W t , %), free water (W f , %) and bound water (W b , %) of membrane was determined following the reported procedure [30]. Each membrane was firstly weighed to determine the "humidified" weight (m 1 , mg) after gas permeation test, and then was heated in a 100°C vacuum oven for 6 h to remove free water.…”

Synergistic Effect of Combining Titanosilicate and 1-Ethyl-3-Methylimidazolium Acetate in Mixed Matrix Membranes for Efficient C02 Separation

“…High hydrophilicity makes CS prone to effective barriers against O 2 , CO 2 and aromas, but their barrier properties against water are poorer which makes CS membrane effective for CO 2 separation due to the high CO 2 solubility in water (Liu et al 2008). Furthermore, CS membranes have been well studied for CO 2 separation (Ito et al 1997;El-Azzami and Grulke 2008;El-Azzami and Grulke 2009). Its mechanical stability has nevertheless been tried to improve by coating on a porous polysulfone support (Kai et al 2008), organic chemical crosslinking (Xiao, Feng and Huang 2007), and physical mixing with zeolite particles .…”

Synthesis and Characterisation of ETS-10/Acetate-based Ionic Liquid/Chitosan Mixed Matrix Membranes for CO2/N2 Permeation

“…The high hydrophilicity of chitosan makes it prone to hydrate and form water-swollen membranes with enhanced CO 2 :N 2 perm-selectivity because of the high CO 2 solubility in water [12]. Swollen CS-based membranes have been studied for CO 2 separation, usually by humidifying the feed gas prior to entering the membrane module [13] for CO 2 :N 2 50:50 (vol %) mixtures and recently the influence of free and bound water on separation performance was analysed, for diluted CO 2 :N 2 :H 2 mixtures simulating flue gas streams [14,15]. Its mechanical stability has, nevertheless, been tried to improve by coating on a porous polysulfone support [16], organic chemical crosslinking [17], and physical mixing with zeolite particles [18].…”