Surface Modification of Carbon Nanotubes Using Acid Treatment to Enhance Gas Separation Performance of Hybrid Nanocomposite Mixed Matrix Membrane

Recently, many researchers have explored the idea of hybrid mixed matrix membranes. Membrane separation processes based on hybrid mixed matrix membrane comprising inorganic material such as zeolite and carbon nanotubes (CNTs) embedded in polymer matrix have become one of the emerging technologies and extensively discussed in membrane separation literature. The present study is performed primarily to investigate the effect of chemical modification on carbon nanotubes surface towards gas separation performance of mixed matrix membrane. Polyethersulfone (PES)-carbon nanotubes mixed matrix membrane for modified and unmodified carbon nanotubes were casted using dry/wet phase inversion technique. The modified carbon nanotubes were prepared by treating the carbon nanotubes with acid treatment to allow PES chains to be attached to carbon nanotubes surface. The results of FESEM, DSC and FTIR analysis confirmed that chemical modification on carbon nanotubes surface had taken place. Meanwhile, the nanogaps in the interface of polymer and carbon nanotubes were appeared in the PES mixed matrix membrane with unmodified of carbon nanotubes. The modified carbon nanotubes mixed matrix membrane increases the mechanical properties, the productivity and purity of gas mixture compare to neat PES and unmodified carbon nanotubes mixed matrix membrane. For PES-modified carbon nanotubes mixed matrix membrane the maximum selectivity achieved for CO2/CH4 are 32.59.