Membranes comprising of alkanolamines incorporated into poly(vinyl alcohol) matrix for CO2/N2 separation

This study is concerned with facilitated transport membranes comprising of alkanolamines entrapped in poly(vinyl alcohol) matrix for CO2/N2 separation. Representative primary, secondary and tertiary alkanolamines (i.e., monoethanolamine (MEA), 2-amino-2-methyl-1-propanol (AMP), diethanolamine (DEA) and N-methyldiethanolamine (MDEA)) were examined for their suitability as the facilitating agent for CO2 permeation. Among the amines tested, DEA was found to be most effective in improving the CO2/N2 permselectivity. The effects of amine content, feed pressure and temperature on the membrane performance were evaluated. The membrane permeance to CO2 increased initially with an increase in the amine content but then decreased when the amine content was sufficiently high. Unlike the permeance of nitrogen, which was only slightly affected by the transmembrane pressure differential, the permeance of CO2 gradually decreased as CO2 pressure increased. The facilitation in CO2 transport is more significant at lower CO2 pressures.