CNT/PDMS composite membranes for H_2 and CH_4 gas separation

摘要

Polydimethylsiloxane (PDMS) composites with different weight amounts of multi-walled carbon nanotubes (MWCNT) were synthesised as membranes to evaluate their gas separation properties. The selectivity of the membranes was investigated for the separation of H_2 from CH_4 gas species. Membranes with MWCNT concentrations of 1% increased the selectivity to H_2 gas by 94.8%. Furthermore, CH_4 permeation was almost totally blocked through membranes with MWCNT concentrations greater than 5%. Vibrational spectros-copy and X-ray photoelectron spectroscopy techniques revealed that upon the incorporation of MWCNT a decrease in the number of available Si-CH_3 and Si-O bonds as well as an increase in the formation of Si-C bonds occurred that initiated the reduction in CH_4 permeation. As a result, the developed membranes can be an efficient and low cost solution for separating H_2 from larger gas molecules such as CH_4.