Biphenyl-based covalent triazine framework-incorporated polydimethylsiloxane membranes with high pervaporation performance for n-butanol recovery

Biphenyl-based covalent triazine framework (CTF) particles, as a new class of organic porous materials, were incorporated into polydimethylsiloxane (PDMS) for the fabrication of a high performance pervaporation membrane for n-butanol (n-BtOH) recovery. Increasing the CTF loading remarkably enhanced both the flux and the separation factor of the membrane. This was ascribed to the strongly hydrophobic, highly porous and mesoporous structure of CTF providing highly permeable and preferential pathways for n-BtOH. Importantly, compared to other reported PDMS-based mixed matrix membranes containing conventional microporous particles, our CTF-incorporated PDMS (CTF/PDMS) membrane exhibited a significantly higher flux and excellent separation factor. Increasing feed temperature and n-BtOH concentration further enhanced pervaporation performance. As a result, the maximum n-BtOH recovery performance (total permeate flux: 2816 ± 118 g m−2 h−1, separation factor: 62.8 ± 1.5 and permeate n-BtOH concentration: 71.5 ± 2.7 wt%) was attained when the CTF/PDMS membrane containing 12.5 wt% CTF was operated with a 4 wt% n-BtOH feed solution at 60 °C. Our proposed strategy provides an effective method to prepare high performance membranes for pervaporation and gas and organic solvent separation.