The Effect of Liquid Exposure on PTMSP/TiO2 Nanocomposite Membranes for Gas-Liquid Membrane Contactors for Removal of CO2 from Natural Gas

Abstract

This project concerns the development of membrane materials for use in gas-liquid membrane contactors for the removal of CO2 from natural gas. In this application, the membrane is primarily intended to prevent any phase dispersion and to secure a high gas flow across the gas-liquid interface. The CO2 selectivity is provided by the liquid absorbent, which is usually an amine solution. In addition to the importance of high permeability, the membrane-liquid compatibility is crucial to secure high performance and long-term stability.

Flat sheet nanocomposite membranes based on poly(1-trimethylsilyl-1-propyne) (PTMSP) have been prepared. Titanium dioxide (TiO2) nanoparticles are dispersed in the polymer matrix as a mean to disrupt the chain packing and thereby enhance the transport of gas.

The membranes were exposed to deionized water, 2 M MDEA and 4.2 M MDEA (aqueous solutions) for 1 day and up to about 9 weeks. After exposure, the membranes were characterized by means of gas permeation tests, SEM and contact angle measurements. As a result of liquid exposure, the permeability and the water contact angle decreased. Morphological changes were also observed. The morphological changes coincided with the reduction in permeability.

The nanocomposite membranes investigated in this work have shown poor performance at long-term exposure to MDEA solution.