Tuning transport in graphene oxide membrane with single-site copper (II) cations

Mingzhan Wang; Xiang He; Eli Hoenig; Gangbin Yan; Guiming Peng; Fengyuan Shi; Julia Radhakrishnan; Grant Hill; David M Tiede; Hua Zhou; Chong Liu

doi:10.1016/j.isci.2022.104044

Tuning transport in graphene oxide membrane with single-site copper (II) cations

iScience. 2022 Mar 11;25(4):104044. doi: 10.1016/j.isci.2022.104044. eCollection 2022 Apr 15.

Authors

Affiliations

¹ Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL 60637, USA.
² Advanced Materials for Energy-Water Systems (AMEWS) Energy Frontier Research Center and Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, IL 60439, USA.
³ Electron Microscopy Core, University of Illinois Chicago, Chicago, IL 60607, USA.
⁴ X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA.

Abstract

Controlling the ion transport through graphene oxide (GO) membrane is challenging, particularly in the aqueous environment due to its strong swelling tendency. Fine-tuning the interlayer spacing and chemistry is critical to create highly selective membranes. We investigate the effect of single-site divalent cations in tuning GO membrane properties. Competitive ionic permeation test indicates that Cu²⁺ cations dominate the transport through the 2D channels of GO membrane over other cations (Mg²⁺/Ca²⁺/Co²⁺). Without/With the single-site M²⁺ modifications, pristine GO, Mg-GO, Ca-GO, and Cu-GO membranes show interlayer spacings of ∼13.6, 15.6, 14.5, and 12.3 Å in wet state, respectively. The Cu-GO membrane shows a two-fold decrease of NaCl (1 M) permeation rate comparing to pristine GO, Mg-GO, and Ca-GO membranes. In reverse osmosis tests using 1000 ppm NaCl and Na₂SO₄ as feeds, Cu-GO membrane shows rejection of ∼78% and ∼94%, respectively, which are 5%-10% higher than its counterpart membranes.

Keywords: Chemical engineering; Membranes; Separation science.