The role of driving force directions of preparation in microstructure and performance of graphene oxide membranes. (December 2022)

• Record Type: Journal Article
• Authors: Kuang, B.; Su, J.; Tang, H.; Li, W.
• Is Part Of: Materials today chemistry. Volume 26(2022)
• Publication Date: 2022-12
• Subjects: Spin coating -- Vacuum filtration -- Nanofiltration -- Stability -- Transport pathway; Chemistry -- Periodicals; Materials -- Research -- Periodicals; Materials science -- Periodicals; Chemistry; Materials -- Research; Electronic journals; Periodicals; 660.282
• DOI: 10.1016/j.mtchem.2022.101177
• Languages: English
• ISSNs: 2468-5194

Abstract

Abstract: Graphene oxide (GO) membranes have been demonstrated with great potential for water treatment. For obtaining high-performance membranes, besides adjusting instinct GO characteristics and membrane modification parameters, controlling preparation processes is extremely crucial. In this study, we investigate the impact of driving force directions on microstructures and performance of GO membranes. Because of the misalignment between unidirectionality of driving forces and random orientations of anisotropic GO nanosheets, horizontal and vertical forces cause dramatically different deposition processes and membrane properties. Horizontal force parallel to GO nanosheets and substrates contributes to preparing membranes (GO-H) with uniform arrangements and homogeneous overlapping of oxidized and graphitic domains, due to the slow and orientated GO stacking and the balance between GO movements promoted by centrifugal force and GO migrations suppressed by oxygen-contained groups. Vertical force perpendicular to substrates facilitates the construction of membranes (GO-V) with relatively irregular orders, owing to the accelerated stacking and the direction inconsistency between GO nanosheets and driving force. Comparatively, the GO-H membranes exhibit better rejection, selectivity, and stability, while the GO-V ones have greater permeability. Relative to GO-V, the GO-H membranes show one order of magnitude higher ion sieving selectivity but one order of magnitude lower water permeability. Graphical abstract: Image 1 Highlights: The impact of driving force directions on GO membranes is investigated. Horizontal force contributes to uniform arrangements and homogeneous overlapping. Vertical force contributes to irregular orders and loose structures. Horizontal force membranes have better rejection, selectivity, and stability. Vertical force membranes have greater permeability.