Work

Improvement of vertically aligned carbon nanotube membranes: desalination potential, flux enhancement and scale-up

Year: 2016

Type: article

Abstract: Carbon nanotube (CNT) membranes are considered as next-generation membranes for desalination. Among the various types of CNT membranes, vertically aligned (VA) CNT membranes provide rapid water transport. However, when the water permeability of VA CNT membranes are compared with those of the commercial membrane, the VA CNT membranes only showed slightly higher water permeability due to their low pore densities. Additionally, the applicability of VA CNT membranes for desalination has been limited due to their larger pore sizes. Herein, we improved VA CNT membranes in terms of the desalination potential, flux enhancement, and scale-up. For the desalination potential, graphene oxide (GO) or polyamide (PA) were coated on a VA CNT membrane as a selective layer, which showed approximately 40–65% NaCl rejection, respectively. A pretreatment polyelectrolyte coating for a GO-coated VA CNT membrane increased the water permeability by approximately 50%. For the flux enhancement, the water permeability of a VA CNT membrane was nearly doubled when the VA CNT forest was mechanically densified by half. Finally, an enlarged VA CNT forest (2 × 2 cm2), sequential VA CNT forests (1 × 1 cm2) in a large cast, and an assembly of the VA CNT membrane were suggested as scale-up approaches.

Source: Desalination and Water Treatment

DOI: 10.1080/19443994.2016.1184188