Abstract
Exploring a new type of smart membrane with tunable separation performance is a promising area of research. In this study, new light-responsive metal–organic framework [Co(azpy)] sheets were prepared by a facile microwave method for the first time, and were then incorporated into a polymer matrix to fabricate smart mixed matrix membranes (MMMs) applied for flue gas desulfurization and decarburization. The smart MMMs exhibited significantly elevated SO2(CO2)/N2 selectivity by 184(166)% in comparison with an unfilled polymer membrane. The light-responsive characteristic of the smart MMMs was investigated, and the permeability and selectivity of the Co(azpy) sheets-loaded smart MMMs were able to respond to external light stimuli. In particular, the selectivity of the smart MMM at the Co(azpy) content of 20% for the SO2/N2 system could be switched between 341 and 211 in situ irradiated with Vis and UV light, while the SO2 permeability switched between 58 Barrer and 36 Barrer, respectively. This switching influence was mainly ascribed to the increased SO2 adsorption capacity in the visible light condition, as verified by adsorption test. The CO2 permeability and CO2/N2 selectivity of MMMs in the humidified state could achieve 248 Barrer and 103.2, surpassing the Robeson's upper bound reported in 2019.
Highlights
Azo-UiO-66 was incorporated into the polymer to form mixed matrix membranes (MMMs), and the results showed signi cantly increased CO2 permeability and CO2/N2 selectivity
The CO2 permeability and CO2/N2 selectivity of the humidi ed MMMs reach 293 Barrer and 103.2, respectively, which were signi cantly increased by 3.47-fold and 2.11-fold, respectively, both surpassing the upper bound reported in 2008 and 2019
The light-responsive metal–organic framework (MOF) sheets are incorporated into commercial polymer materials to fabricate MMMs
Summary
Several CO2 separation and MOF gas separation methods were investigated.[32,33] Peng et al prepared a lightresponsive metal–organic framework hybrid membrane with high on/off photo switchable proton conductivity.[34]. Apart from the MMM itself, the gas separation performance can be further improved by adopting an external stimulus.[41] Recently, external stimuli, such as temperature,[42] light, and electric eld,[43] have been used to elevate the gas separation performances. Among these external stimuli, light is thought to be the most promising one because of its ease of control, fastresponsiveness, and non-contact characteristics. Ladewig et al prepared light-responsive MOF (AzoUiO-66) for post combustion CO2 capture.[40] Azo-UiO-66 was incorporated into the polymer to form mixed matrix membranes (MMMs), and the results showed signi cantly increased CO2 permeability and CO2/N2 selectivity. The Co(azpy) is a photo agent capable of converting the structure under visible light and ultraviolet light illumination, which is being investigated
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