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recent developments on Graphene oxide based membranes

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Introduction
Preparation of Graphene oxide
Characterization of Graphene oxide
Preparation methods for GO-based membrane
Types of GO membrane

Publié dans : Ingénierie
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recent developments on Graphene oxide based membranes

  1. 1. Recent Developments Of Graphene- Oxide Based Membrane Done By, Kishan Kaunda(1DS16HCE03) 1
  2. 2. CONTENTS:- Introduction Preparation of Graphene oxide Characterization of Graphene oxide Preparation methods for GO-based membrane Types of GO membrane References 2
  3. 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. 3
  4. 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. 4
  5. 5. PREPARATION OF GO(GRAPHENE OXIDE): The synthetic process of GO mainly contains two steps: oxidation of graphite and exfoliation of graphite oxide. 5
  6. 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 6
  7. 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. 7
  8. 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. 8
  9. 9. PREPARATION METHODS OF GO MEMBRANE: Based on stable aqueous dispersity, GO membranes can be easily fabricated. 9
  10. 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. 10
  11. 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. 11
  12. 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. 12
  13. 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 13
  14. 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. 14
  15. 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 15
  16. 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. 16
  17. 17. REFERENCES: Lee, K.P.; Arnot, T.C.; Mattia, D. A review of reverse osmosis membrane 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. 17
  18. 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. 2017, 307, 643–649. 18
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