A	membrane area (m2)
D	diffusion coefficient (10−8 cm2/s)
J	permeation flux (g/m2h)
l	membrane thickness (μm)
P	permeability (g m/m2h kPa)
P/l	permeance (g/m2h kPa)
S	sorption coefficient (cm3(STP)/cm3 atm)
x	weight percent of components in the feed
y	weight percent of components in the permeate
Greek Letter
α	selectivity
β	separation factor
δ	solubility parameter (MPa1/2)
Abbreviations
2D	two-dimensional
BTESE	1,2-bis(triethoxysilyl)ethane
COF	covalent-organic framework
CS	chitosan
DMC	dimethyl carbonate
ECN	Energy Research Centre of the Netherlands
GO	graphene oxide
MMM	mixed-matrix membrane
MOF	metal-organic framework
MTBE	methanol/methyl tert-butyl ether
NF	nanofiltration
PA	polyamide
PAN	poly(acrylonitrile)
PBI	polybenzimidazole
PDC	3,5-pyrazoledicarboxylic acid
PDMS	polydimethylsiloxane
PE	polyether
PEBA	poly(ether-block-amide)
PEC	polyelectrolyte complex
PES	poly(ether sulfones)
PI	polyimide
PIMs	polymers of intrinsic microporosity
PMPS	polymethylphenysiloxane
POMS	polyoctylmethylsiloxane
POSS	polyhedral oligomeric silsesquioxanes
PTMSP	poly(1-trimethysilyl-1-propyne)
PU	polyurethane
PVA	polyvinyl alcohol
SA	sodium alginate
SNW-1	schiff base network framework
TDC	2,5-thiophenedicarboxylic acid
TEOS	tetraethylorthosilicate
TFC	thin-film composite
TMS	glycidyloxypropyltrimethoxysilane