This document discusses recent developments in graphene oxide (GO) based membrane technology. It begins with an introduction to GO and its advantages over polymeric membranes. It then describes methods for preparing and characterizing GO, as well as different approaches for fabricating GO membranes, including free-standing GO membranes, supported GO membranes, and GO-modified composite membranes. Specific examples are provided for each membrane type and their applications in water treatment and separation processes. The document concludes that GO is a promising nano-material for membrane applications due to its unique properties and that the membrane structure and performance depends on the fabrication method.

1. Recent Developments Of Graphene-
Oxide Based Membrane
Done By,
Kishan Kaunda(1DS16HCE03)
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2. CONTENTS:-
Introduction
Preparation of Graphene oxide
Characterization of Graphene oxide
Preparation methods for GO-based membrane
Types of GO membrane
References
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3. INTRODUCTION:
In the past few decades, membrane-based separation technology has attracted
considerable attention in many separation fields due to its advantages of easy-
operation, energy-efficiency and environmental friendliness.
Currently, polymeric membrane has governed the entire membrane market, owing
to its advantages of energy-efficiency, easy-operation, low-cost, and inherent
simplicity.
Restrictions of polymeric membranes still exist for most practical applications,
because most of them tend to foul, have low resistance to chlorine, strong
acids/alkaline, high temperature and organic solvents, and suffer from aperture
shrinkage under high pressure.
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4. These restrictions have urged membrane scientists to constantly seek new membrane
materials and develop novel membrane structures with superior chemical stability, thermal
stability, water permeability, as well as high selectivity.
Recently, carbon-based materials like carbon nanotubes (CNTs), Graphene, and its
derivative Graphene oxide (GO), have shown notable potential in membrane-based
separation fields because of their strong mechanical strength, high resistance to strong
acids/alkaline and organic solvents, and easy accessibility.
Among them, GO has served as one of the emerging nano-building materials for the
fabrication of novel separation membrane owing to its high mechanical strength, high
chemical inertness, nearly frictionless surface, good flexibility combined with large-scale
and cost-effective production in solution.
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5. PREPARATION OF GO(GRAPHENE OXIDE):
The synthetic process of GO mainly contains two steps: oxidation of graphite and
exfoliation of graphite oxide.
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6. Oxidant Method Acid Interlayer
Spacing
Reaction
Time
Note
KClO3 Brondie HNO3 5.95 Å 3-4 days Toxic gas ClO2
KClO3 Staudenmaier HNO3 , H2SO4 6.23 Å 1-10 days Toxic gas ClO2, NOx
KClO3 Hofmann HNO3 , H2SO4 6.48 Å 4 days Toxic gas ClO2, NOx
KMnO4 Hummers NaNO3, H2SO4 6.67 Å ~2 hour Toxic gas NOx, Mn2+ in GO
KMnO4 Modified Hummers K2S2O8, P2O5,
H2SO4
6.9 Å 8 hour Toxic gas NOx, Mn2+ in GO
KMnO4 Improved Hummers H2SO4 / H3PO4 9.3 Å ~12 hour Mn2+ in GO
K2FeO4 Iron-based green
method
H2SO4 9.0 Å 1 hour Fe3+ in GO
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7. As mentioned above, an approach which is highly oxidized, low-cost, safe,
simple and environmentally friendly will provide the possibility for large-scale
production of GO.
Therefore, continuous efforts are required to achieve this objective.
Additionally, it should be noted that the resultant GO produced with different
methods differs significantly in structure and physicochemical
property, which depends not only the species and dosage of oxidant, but also on
the reaction condition and initial graphite source.
So the method for GO preparation should be carefully designed in a practical
application.
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8. CHARACTERIZATION OF GO(GRAPHENE OXIDE):
In order to verify the successful synthesis of GO and identify its chemical
structure, a variety of characterization techniques have been employed.
SEM, TEM, and AFM are widely used to obtain the information of surface
morphology, size and thickness of GO.
With respect to the chemical composition of GO, quantitative XPS and
inductively coupled plasma mass spectrometry (ICP-MS) are usually utilized.
Additionally, Raman spectra, XRD, and FTIR spectra are extensively
applied to identify the chemical structure of GO.
To obtain more information about GO properties, TGA, and Zeta potential are
also employed to judge its thermal stability and electrochemical property.
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9. PREPARATION METHODS OF GO MEMBRANE:
Based on stable aqueous dispersity, GO membranes can be easily fabricated.
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10. TYPES OF GO-BASED MEMBRANES:
There are basically three types of GO-based membranes:
1) free-standing GO-based membrane
2) Supported-GO membrane
3) GO-modified composite membrane
Specifically, for the free-standing GO membrane, GO membrane is directly used
as a separation layer.
With respect to the supported-GO membrane, GO membrane is supported by a
polymeric or an inorganic substrate with GO layer as the active separation layer.
GO-modified composite membrane is referred to the GO-based membranes
obtained by directly incorporating GO nanosheets into polymer casting solutions
during membrane fabrication process.
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11. 1) Free standing GO-membranes:
At present, a variety of approaches have been employed to fabricate free-
standing GO membrane, such as vacuum filtration, evaporation-driven self-
assembly, self-assembly process under ambient conditions, drop casting, and
pressurized ultra filtration (UF) method.
The sodium salts could be effectively separated from the heavy-metals salts and
organic contaminants through these free-standing GO membranes via drop-
casting method.
For dehydration of ethanol, free-standing GO thin films are fabricated via a
pressurized filtration method.
for oil/water separation, Zhao fabricated a free-standing GO-polygorskite (GOP)
nanohybrid membrane. It has outstanding separation performance and anti-fouling
property for various oil-in-water emulsion systems.
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12. 2) Supported-GO membranes:
Although free-standing GO membranes have achieved great progresses in
membrane separation applications, a GO membrane supported on desired
mechanical support for high-pressure application is rather necessary.
For separation of Isopropyl alcohol (IPA) from water mixture, GO-modified PAN
composite membranes are developed via PASA (pressure-assisted self-
assembly)technique.
For efficient carbon capture in separating the CO2/CH4 mixture, a highly
permeable and borate cross-linked GO/PES composite membrane was
developed via vacuum filtration method.
For humic acid (HA) removal GO-coated PES UF membranes are used via a
simple vacuum filtration process.
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13. Types of GO
membrane
Name of GO
membrane
Fabrication method Application
GO/PES Spin-casting Gas separation
GO/mPAN Pressure-assisted self-
assembly
Pervaporation separation of
70 wt% IPA/water mixture
GO/PAN LbL assembly Water purification
Supported GO/Nylon Shear-alignment method Water treatment
GO/PES Vacuum filtration Humic acid removal
GO/ceramic Dip-coating Pervaporation separation of
water/ethanol mixtures
GO/PES Vacuum filtration Gas separation
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14. 3) GO-modified composite membrane:
various GO-modified polymeric composite membranes have been developed and
presented improved water permeability, selectivity,
and anti-microbial performances.
Specifically, based on the modified methods of GO, two strategies have been
developed to modify the polymeric membranes.
For the first method, the GO nanosheets were directly incorporated into polymeric
casting solutions during membrane fabrication process.
For the other one, GO nanosheets were utilized to functionalize polymeric
membranes via surface modification technique.
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15. Types of GO
membrane
Name of GO
membrane
Fabrication method Application
GO/PSF Phase inversion Water purification(Rejection: Na2SO4
(95.2%); MgSO4 (91.1%); NaCl
(59.5%))
GO/PSF Phase inversion Water treatment
GO-modified GO/PESc LbL self-assembly Water treatment (Rejection: Mg2+
(92.6%) Na+ (43.2%))
Pebax/GO/PVDF Dip-coating Gas separation
GO/H-PAN Electrospinning Oil/water separation
GO/PEI/DPAN Dip-coating Solvent resistant NF
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16. CONCLUSIONS:
In summary, based on the unique single-atomic-thick and two-dimensional
structure, together with excellent physicochemical property, GO as an emerging
star nano-building material has attracted great interest in the membrane-based
separation field.
An approach which is highly oxidized, low-cost, safe, simple, and
environmentally friendly will provide the possibility for massive production of GO.
The structure and separation performance of GO membrane significantly depend
on the fabrication method and corresponding
fabrication conditions.
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17. REFERENCES:
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materials for desalination—Development to date and future potential. J. Membr.
Sci. 2011, 370, 1–22
Geise, G.M.; Park, H.B.; Sagle, A.C.; Freeman, B.D.; McGrath, J.E. Water
permeability and water/salt selectivity tradeoff in polymers for desalination. J.
Membr. Sci. 2011, 369, 130–138.
Nair, R.R.;Wu, H.A.; Jayaram, P.N.; Grigorieva, I.V.; Geim, A.K. Unimpeded
permeation of water through helium-leak-tight graphene-Based Membranes.
Science 2012, 335, 442–444.
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18. Wang, J.; Wang, Y.; Zhu, J.; Zhang, Y.; Liu, J.; Bruggen, B.V.D. Construction of
TiO2@graphene oxide incorporated antifouling nanofiltration membrane with
elevated filtration performance. J. Membr. Sci. 2017,
533, 279–288.
Qin, D.; Liu, Z.Y.; Bai, H.W.; Sun, D.D. Three-dimensional architecture
constructed from a graphene oxide nanosheet-polymer composite for high-flux
forward osmosis membranes. J. Mater. Chem. A. 2017, 24,
12183–12192.
Zhang, J.Q.; Xue, Q.Z.; Pan, X.L.; Jin, Y.K.; Lu,W.B.; Ding, D.G.; Guo, Q.K.
Graphene oxide/polyacrylonitrile fiber hierarchical-structured membrane for
ultra-fast microfiltration of oil–water emulsion. Chem. Eng. J.
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