PIM-1/Holey Graphene Oxide Mixed Matrix Membranes for Gas Separation: Unveiling the Role of Holes

Abstract

PIM-1/holey graphene oxide (GO) mixed matrix membranes (MMMs) have been prepared and their gas separation performance for CO 2 /CH 4 mixtures assessed. Nanopores have been created in the basal plane of gas-impermeable GO by chemical etching reactions, and the resulting holey flakes have been further chemically functionalized, either with octadecylamine (ODA) or with PIM-1 moieties, to aid their dispersion in PIM-1. It is found that nanopores barely promote gas transport through the graphene-like nanofiller for fresh membranes (tested right after preparation); however, the prepared hybrid PIM-1/holey GO membranes exhibit higher CO 2 permeability and CO 2 /CH 4 selectivity than the pure polymer membrane 150 days after preparation and 13 and 15% higher CO 2 permeability for filler contents of 0.1% of octadecylaminefunctionalized holey GO and 1% of (PIM-1)-functionalized holey GO, respectively. The most significant improvement is observed for the mitigation of physical aging, as MMMs using 10% of (PIM-1)functionalized holey GO nanofillers are capable of maintaining up to 70% of their initial CO 2 permeability after 150 days, whereas only 53% is kept for pure PIM-1 after the same period. The gas permeability of the nanofiller has been rationalized with the aid of the Maxwell−Wagner−Sillars equation.

Thin film nanocomposite membranes of superglassy PIM-1 and amine-functionalised 2D fillers for gas separation

“…The density of PIM-1 was considered to be 0.948 g cm −3 , 12 and the density of GO was calculated as the two-dimensional mass density of a graphene single layer (7.63 × 10 −8 g cm −2 ) divided by the GO flake thickness (1 nm) as previously reported. 18 The n parameter was calculated for each TFN membranes using eqn (8) with P M (experimental gas permeability of the TFN membranes) and P p (experimental gas permeability of pure PIM-1), and the results are shown in Table S5 †. The n values results range between 0.943 and 1, which indicates that most of the rHGO flakes are parallel to each other and horizontally orientated to the gas flow.…”

“…26 The above mentioned model has been broadly used for the prediction of permeation performance in MMMs and reported by our group for 2D fillers-containing membranes. 18,27…”

“…Li et al reported an improvement in CO 2 permeability and CO 2 /N 2 selectivity of 21% (70 GPU) and 20.8% (130), respectively, by incorporating porous graphene oxide into thin-film composite (TFC) polyimide membranes through interfacial polymerization. 10 Recently, Luque-Alled and co-workers 18 reported mitigation of physical aging of MMMs when incorporating 10 wt% (PIM-1)-functionalised HGO into PIM-1 polymeric matrix. These retained 70% of the initial CO 2 permeability after 150 days.…”

Hydrogen deblending future and emerging technology watch

“…This includes GO MMMs made with PIMs to offer improved membrane lifespans and with CMSMs to improve CO2 and N2 separation. 47,48 4.3.3 Metal carbides, nitrides and carbonitrides.…”

A polyimide/poly(N-vinylimidazole) membrane for CO2/CH4 separation with high selectivity and permeability

“…[10][11][12] Due to the inherent properties, fillers can improve the compatibility and interfacial microstructure between filler and polymer matrix, effectively solving the problem of increasing the permeability and selectivity of separation membranes. To date, inorganic and organic materials including metal oxides, [13][14][15][16][17][18] carbon-based nanotubes and graphene oxide (GO), [19][20][21][22][23][24] and metal-organic frameworks (MOFs) [25][26][27][28][29][30][31][32] have been widely used for fabricating MMMs with enhancing CO 2 /CH 4 separation performance. Due to the good interphase compatibility with polymeric membrane, functional polymer-based fillers have received much attention.…”