A facile approach for the development of fine-tuned self-standing graphene oxide membranes and their gas and vapor separation performance

Romanos, George E.; Pastrana‐Martínez, Luisa M.; Tsoufis, Τheodoros; Athanasekou, Chrysoula; Galata, Evdokia; Katsaros, Fotios K.; Favvas, Evangelos P.; Beltsios, K.; Siranidi, E.; Falaras, Polycarpos; Psycharis, Vassilis; Silva, Adrián M.T.

doi:10.1016/j.memsci.2015.07.034

Cited by 33 publications

(10 citation statements)

References 27 publications

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“…The oxidized regions act as spacers to separate adjacent GO sheets and allow water molecules to intercalate between the GO sheets. 72,73 The instability of GO structures in water is the main challenge ahead of their application in aqueous media as separation membranes, as GO structures disintegrate over time. 74 For application to water treatment, GO membranes should be stabilized by reduction or chemical crosslinking.…”

Section: Multilayer Graphene Desalination Membranesmentioning

confidence: 99%

Graphene membranes for water desalination

2017

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Extensive environmental pollution caused by worldwide industrialization and population growth has led to a water shortage. This problem lowers the quality of human life and wastes a large amount of money worldwide each year due to the related consequences. One main solution for this challenge is water purification. State-of-the-art water purification necessitates the implementation of novel materials and technologies that are cost and energy efficient. In this regard, graphene nanomaterials, with their unique physicochemical properties, are an optimum choice. These materials offer extraordinarily high surface area, mechanical durability, atomic thickness, nanosized pores and reactivity toward polar and non-polar water pollutants. These characteristics impart high selectivity and water permeability, and thus provide excellent water purification efficiency. This review introduces the potential of graphene membranes for water desalination. Although literature reviews have mostly concerned graphene's capability for the adsorption and photocatalysis of water pollutants, updated knowledge related to its sieving properties is quite limited. NPG Asia Materials (2017) 9, e427; doi:10.1038/am.2017.135; published online 25 August 2017 INTRODUCTION Currently,~1.2 billion people around the world are suffering from a shortage of water and its adverse consequences on health, food and energy. 1,2 On one hand, population growth, increased industrialization and greater energy needs and, on the other hand, loss of snowmelt, shrinkage of glaciers and so on will worsen this situation in upcoming years. As estimated by the world water council, the number of affected people will rise to 3.9 billion in the coming decades. 2,3 One of the most promising approaches to alleviate the water shortage, desalination can increase the water supply beyond what is available from the hydrological cycle. 4 Seawater desalination indeed provides an infinite, steady supply of high-quality water that does not harm natural freshwater ecosystems.Seawater comprises a vast supply of water (97.5% of all water on the planet). Thus, the growth of the installation of seawater desalination facilities in the past decade to circumvent water shortage problems in water-stressed countries has progressed quickly. In 2016, the global water production by desalination was estimated to be 38 billion cubic meter per year, that is, two times higher than that in 2008. 5 So far, seawater desalination has been mainly performed via multistage flash distillation and reverse osmosis (RO). 6 Mostly in the arid Persian Gulf countries, desalination plants perform based on heating and then condensing seawater. This kind of desalination plant consumes large amounts of thermal and electric energy, thus emitting greenhouse gases extensively. 7 In addition to this non-economical and non-ecofriendly version of desalination plants, the main type of desalination plants constructed in the past two decades, as well as future planned ones, are based on RO technology (Figure 1). 8

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Section: Multilayer Graphene Desalination Membranesmentioning

confidence: 99%

Graphene membranes for water desalination

2017

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“…The most common oxidizing methods used to prepare GO flakes result in different total oxygen content and types of oxygen-containing functionalities. , For example, the Brodie oxidation method is known to result in a lower overall oxygen content than the more commonly employed Hummers method and favors the formation of conjugated epoxide and hydroxide functionalities . As a result, differences in water permeability have been observed , depending on whether the flakes were oxidized using the Hummers, Brodie, or Staudenmaier methods. The mechanical properties of GO membranes are also affected by changes in the degree and type of oxidation. ,, The total oxygen content of GO can also be controlled by chemical, thermal, and electrochemical reduction. ,, Reduced graphene oxide (RGO) membranes are chemically distinct and more hydrophobic , than their GO analogues, resulting in different transport properties, , including the possibility of improved salt rejection. , …”

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confidence: 99%

“…As a result, differences in water permeability have been observed , depending on whether the flakes were oxidized using the Hummers, Brodie, or Staudenmaier methods. The mechanical properties of GO membranes are also affected by changes in the degree and type of oxidation. ,, The total oxygen content of GO can also be controlled by chemical, thermal, and electrochemical reduction. ,, Reduced graphene oxide (RGO) membranes are chemically distinct and more hydrophobic , than their GO analogues, resulting in different transport properties, , including the possibility of improved salt rejection. , …”

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confidence: 99%

“…15,16 For example, the Brodie oxidation method 17 is known to result in a lower overall oxygen content than the more commonly employed Hummers method 18 and favors the formation of conjugated epoxide and hydroxide functionalities. 15 As a result, differences in water permeability have been observed 19,20 depending on whether the flakes were oxidized using the Hummers, 18 Brodie, 17 or Staudenmaier 21 methods. The mechanical properties of GO membranes are also affected by changes in the degree and type of oxidation.…”

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In Silico Design and Characterization of Graphene Oxide Membranes with Variable Water Content and Flake Oxygen Content

2019

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Graphene oxide (GO) membranes offer exceptional promise for certain aqueous separation challenges, such as desalination. Central to unlocking this promise and optimizing performance for a given separation is the establishment of a detailed molecular-level understanding of how the membrane’s composition affects its structural and transport properties. This understanding is currently lacking, in part due to the fact that, until recently, molecular models with a realistic distribution of oxygen functionalities and interlayer flake structure were unavailable. To understand the effect of composition on the properties of GO membranes, models with water contents and oxygen contents, varying between 0% and 40% by weight, were prepared in this work using classical molecular dynamics simulations. The change in membrane interlayer distance distribution, water connectivity, and water diffusivity with water and oxygen content was quantified. Interlayer distance distribution analysis showed that the swelling of GO membranes could be controlled by separately tuning both the flake oxygen content and the membrane water content. Water-molecule cluster analysis showed that a continuous and fully connected network of water nanopores is not formed until the water content reaches ∼20%. The diffusivity of water in the membrane was also found to strongly depend on both the water and the oxygen content. These insights help understand the structure and transport properties of GO membranes with sub-nanometer interlayer distances and could be exploited to enhance the performance of GO membranes for aqueous separation applications. More broadly, the high-throughput in silico approach adopted could be applied to other nanomaterials with intrinsic non-stoichiometry and structural heterogeneity.

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“…In general, one of the most common approaches in multi-layer graphene membrane fabrication is the vacuum filtration method. In the study by Romanos et al [ 81 ], the membrane performance was investigated while varying several parameters, such as the filtration rate (controlling the downstream pressure), volume of GO suspension (thickness of the selective layer) and surface chemistry (GO and rGO). From the gas permeation data, a slower filtration rate led to a membrane showing molecular sieving characteristics.…”

Section: Performance Of a Graphene-based Membranementioning

confidence: 99%

Graphene-based Membranes for H2 Separation: Recent Progress and Future Perspective

2020

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Hydrogen (H2) is an industrial gas that has showcased its importance in several well-known processes such as ammonia, methanol and steel productions, as well as in petrochemical industries. Besides, there is a growing interest in H2 production and purification owing to the global efforts to minimize the emission of greenhouse gases. Nevertheless, H2 which is produced synthetically is expected to contain other impurities and unreacted substituents (e.g., carbon dioxide, CO2; nitrogen, N2 and methane, CH4), such that subsequent purification steps are typically required for practical applications. In this context, membrane-based separation has attracted a vast amount of interest due to its desirable advantages over conventional separation processes, such as the ease of operation, low energy consumption and small plant footprint. Efforts have also been made for the development of high-performance membranes that can overcome the limitations of conventional polymer membranes. In particular, the studies on graphene-based membranes have been actively conducted most recently, showcasing outstanding H2-separation performances. This review focuses on the recent progress and potential challenges in graphene-based membranes for H2 purification.

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A facile approach for the development of fine-tuned self-standing graphene oxide membranes and their gas and vapor separation performance

Cited by 33 publications

References 27 publications

Graphene membranes for water desalination

Graphene membranes for water desalination

In Silico Design and Characterization of Graphene Oxide Membranes with Variable Water Content and Flake Oxygen Content

Graphene-based Membranes for H2 Separation: Recent Progress and Future Perspective

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