Vertically aligned carbon nanotube membrane: synthesis, characterization and application in salt water desalination

Previous studies used molecular dynamics simulation to assess the feasibility of applying the vertically aligned carbon nanotube membranes (VA-CNT) for salt water desalination. The presented report experimentally determined the potential of salt water desalination by VA-CNT membrane. The VA-CNT membranes were synthesized through the templated-assisted pyrolysis of polybenzimidazole-Kapton inside the pores of anodized aluminium oxide (AAO) and were characterized by several techniques. The permeability, salt rejection, and biofouling tendency of VA-CNT membranes were measured in various operating conditions and the results were compared with performance of commercial reverse osmosis (RO) membrane (BW30). The VA-CNT membranes permeability was about two-fold higher than permeability of RO membrane. Furthermore, VA-CNT membranes had higher stability against biofouling phenomena and, also showed antibacterial activity so that about 70% of adsorbed cells on VA-CNT membranes were killed by CNTs tips which were vertically aligned on the membrane surface. The rejection efficiency of the VA-CNT membrane was comparable to the commercial RO membrane. Finally, chlorine stability studies showed that strong hypochlorite exposure (48000 ppm.h) did not significantly fail the flux and rejection of the VA-CNT membranes confirming their chemical stability. This study shows the high capability of the VA-CNT membrane in the water treatment process.