Highly Permeable Graphene Oxide/Polyelectrolytes Hybrid Thin Films for Enhanced CO2/N2 Separation Performance

Jiwoong Heo,Dahye Ji,Jinkee Hong,Jungyun Chang,Sang Wook Kang,Moonhyun Choi

doi:10.1038/s41598-017-00433-z

Jiwoong Heo, Dahye Ji + Show 4 more

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https://doi.org/10.1038/s41598-017-00433-z

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Journal: Scientific Reports	Publication Date: Mar 28, 2017
Citations: 37	License type: open-access

Affiliation: Chung-Ang University, Sangmyung University

Abstract

Separation of CO2 from other gasses offers environmental benefits since CO2 gas is the main contributor to global warming. Recently, graphene oxide (GO) based gas separation membranes are of interest due to their selective barrier properties. However, maintaining selectivity without sacrificing permeance is still challenging. Herein, we described the preparation and characterization of nanoscale GO membranes for CO2 separation with both high selectivity and permeance. The internal structure and thickness of the GO membranes were controlled by layer-by-layer (LbL) self-assembly. Polyelectrolyte layers are used as the supporting matrix and for facilitating CO2 transport. Enhanced gas separation was achieved by adjusting pH of the GO solutions and by varying the number of GO layers to provide a pathway for CO2 molecules. Separation performance strongly depends on the number of GO bilayers. The surfaces of the multilayered GO and polyelectrolyte films are characterized by atomic force microscopy and scanning electron microscopy. The (poly (diallyldimethylammonium chloride) (PDAC)/polystyrene sulfonate (PSS)) (GO/GO) multilayer membranes show a maximum CO2/N2 selectivity of 15.3 and a CO2 permeance of 1175.0 GPU. LbL-assembled GO membranes are shown to be effective candidates for CO2 separation based on their excellent CO2/N2 separation performance.

Highlights

Among the various separation methods, membrane techniques utilizing graphene oxide (GO) show great potential in CO2 separation
The CO2 separation performance of GO membranes results from the interlayer spaces in stacked GO sheets[26,27,28]
CO2 permeance declines as the thickness of the GO layers increases because of the longer diffusion pathway that CO2 molecules must traverse to pass through the membrane

Summary

Introduction

Among the various separation methods, membrane techniques utilizing graphene oxide (GO) show great potential in CO2 separation. Park et al reported selective gas transport through a few-layer GO membrane by adjusting centrifugal force and electrostatic repulsion during the adsorption process of GO sheets[16]. GO membranes have been prepared mostly in aqueous solution and processed using spin coating, drop casting, and filtration methods. We propose a spray-assisted layer-by-layer (LbL) self-assembly method for precisely controlling the preparation of GO sheets to be used as CO2 separation membranes. The most important advantage of the method is that it offers precise control of film thickness and internal structure without limitation by substrates and materials through complementary interactions (i.e., electrostatic interactions, covalent interactions, and hydrogen bonding)[18,19,20,21,22,23,24]. We adopted a spray method to deposit a stable nanofilm on the flexible substrate[25]

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