Table 5.

Permeation properties of selected Pebax-based MMMs filled with carbon materials.

Pebax Type	Filler Type	Filler Amount (wt%)	Test Conditions	CO2 (Barrer 1)	Selectivity (-)	Ref.
3000	Carboxyl-functionalized single-wall carbon nanotubes (CSWCNTs) (length 30 nm; outer d 1–2 nm; inner d 0.8–1.6 nm)	10	25 °C, 6 bar	53.2	106.4 (CO2/N2) 31.3 (CO2/CH4)	[35]
1657/PEG200	CNT	8 CNT 50 PEG	25 °C, 14 bar mixed CO2/CH4 (50/50 vol%) 25 °C, 12 bar 40 °C, 12 bar	302 (pure) 138 (mixed) 193 (mixed)	45 CO2/CH4 (pure) 19 CO2/CH4 mixed 15.7 CO2/CH4 mixed	[36]
1657	MWCNT-NH2 (outer diameter 8–15 nm, length ∼50 µm, 0.45 wt% NH2) NMP as solvent	6	30 °C, 3.5 bar	174	32 (CO2/N2)	[37]
		6	45 °C, 3.5 bar	285	57 (CO2/N2)
		6	60 °C, 3.5 bar	405	51 (CO2/N2)
1657	Carbon nanospheres (CNs-600) (650 nm)	0.5	25 °C, 4 bar mixed CO2/N2 (10/90 vol%)	100 (pure gas) 97 (mixed gas)	76 (pure gas) 64 (mixed gas)	[39]
1657	Nanodiamonds (ND) 5–10 nm	0.5	35 °C, 2 bar feed pressure and 0.015 bar downstream	46	35.5	[40]
	Nanodiamonds (ND) decorated with polyethyleneimine (PEI) (5–10 nm)	0.5	35 °C, 2 bar feed pressure and 0.015 bar downstream	50	51
1657 on PES support	Graphene nanoplatelets (GNP)	0.7	25 °C and 4 bar	45 (+68%)	112 CO2/N2 (+50%), 9.9 O2/N2 (+28%)	[43]
1657 on PVDF support	N-doped few-layer graphene (N-FLG) (thickness ~4 nm, ~10 layers)	4	Room T, 1–2 bar	239.8	95.5 (CO2/N2)	[44]
1657/ PEG-MEA	Graphene oxide (GO)	0.3 GO 50 PEG-MEA	35 °C, 1 bar	600	55.8 (CO2/N2)	[47]
1657	GO sheets Medium-lateral sized (GO-M) (1–2 μm, d-spacing of 0.8 nm)	0.1	single: 25 °C, 3 bar mixed: 25 °C, 1 bar CO2/N2 (50/50 vol%)	95 Single gas 75 Mixed dry 110 Mixed humid	85 Single gas (CO2/N2) 72 Mixed dry 80 Mixed humid	[46]
1657	GO (sheet size: 500–1000 nm, thickness: 1.5–2.0 nm)	1	30 °C, 2 bar (dry)	110	67 (CO2/N2)	[83]
		10	30 °C, 2 bar (humidified)	420	64 (CO2/N2)
1657	Imidazole-functionalized graphene oxide (ImGO) (0.5–1 μm)	0.8	25 °C, 8 bar	76.2	105.5 (CO2/N2) (+46.0%)	[49]
1657 on PVDF support	Ionic-Liquid-functionalized graphene oxide (GO-IL)	0.2	25 °C, 4 bar	143	79.4 (CO2/N2) 13.8 (CO2/H2)	[50]
1657 on PSf support	Aminated partially reduced GO nanofiller (A-prGO)	0.1	Room T, 4 bar	47.5	105.6 (CO2/N2) 23.75 (CO2/CH4)	[52]
1657	Aminosilane-functionalized GO Nanosheets (f-GO)	0.9	35 °C, 2 bar, humidified mixed CO2/N2 (20/80 vol%) mixed CO2/CH4 (30/70 vol%)	934.3	71.1 (CO2/N2) 40.9 (CO2/CH4)	[53]
1657	GO nanosheets	0.1	25 °C	107 (4 bar) 117 (10 bar)	104 (4 bar), 77 (10 bar) (CO2/N2) 22 (4 bar), 26 (10 bar) CO2/CH4	[54]
1657	GO nanosheets modified by polypyrrole (GO-PPy) (100 to 200 nm)	0.1	25 °C	100 (4 bar) 122 (10 bar)	107 (4 bar), 123 (10 bar) CO2/N2 (+62%) 22.5 (4 bar), 30 (10 bar) CO2/CH4 (+51%)	[54]
1657	GO nanosheets modified by polypyrrole and zinc cations (GO-PPy-Zn)	0.1	25 °C	118 (4 bar) 131 (10 bar)	83 (4 bar), 119 (10 bar) CO2/N2 (+58%) 24 (4 bar), 30 (10 bar) CO2/CH4 (+56%)	[54]
1657	Covalently grafted polyetheramine (M2070)-carbon nanotube solvent-free hybrid nanofluids (CNTs NF)	30	25 °C, 1.0 bar Dry mixed CO2/N2 (20/80 vol%)	225 (pure 2 bar) 180 (mixed 2 bar) 332 (mixed 1 bar) (+442%)	61 (pure 2 bar) 60 (mixed 2 bar) 72 (mixed 1 bar) (+77%) CO2/N2	[38]
	Covalently grafted polyetheramine (M2070)-graphene oxide solvent-free hybrid nanofluids (GO NF)	15	25 °C, 1.0 bar Dry mixed CO2/N2 (20/80 vol%)	150 (pure 2 bar) 140 (mixed 2 bar) 248 (mixed 1 bar)	52 (pure 2 bar) 48 (mixed 2 bar) 56 (mixed 1 bar) CO2/N2
1657	Graphite oxide flakes functionalized with iron oxide (Fe3O4–GO) magnetic alignment/vertical	3	25 °C, 2 bar Mixed gas CO2/CH4 or CO2/N2 (10/90 vol%)	538	75 (CO2/N2) 47 (CO2/CH4)	[55]
2533	GO	0.02	35 °C, 1 bar	371.39	24.00 (CO2/N2)	[48]
	Porous (PGO)	0.02	35 °C, 1 bar	397.35	23.75 (CO2/N2)
	Polyetheramine-functionalized graphene oxide (PEAGO)	0.02	35 °C, 1 bar	380.44	24.19 (CO2/N2)

¹ Barrer = 10⁻¹⁰ cm³ (STP) cm cm⁻² s⁻¹ cmHg⁻¹.