Graphene oxide membranes and related methods

A technology of graphene and graphene sheets, applied in chemical instruments and methods, membranes, membrane technology, etc., can solve problems such as hindering technical limitations or economic constraints, not suitable for a wide range of chemical environments, and time-consuming

Active Publication Date: 2018-12-21
MASSACHUSETTS INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Despite their utility, many existing ultrafiltration and nanofiltration membranes have technical or economic limitations that prevent their use
For example, many ultrafiltration and nanofiltration membranes are expensive to manufacture and / or maintain, require complex and / or time-consuming fabrication techniques, and are not suitable for use in a wide range of chemical environments

Method used

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  • Graphene oxide membranes and related methods
  • Graphene oxide membranes and related methods
  • Graphene oxide membranes and related methods

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0162] This example describes the formation and properties of cross-linked graphene oxide (ie, GO) films.

[0163] The structure of GO was studied. From these experiments, two key features were identified: first, graphene oxide films are unstable in water when the flakes are held together only by van der Waals forces; It also serves as a size exclusion mechanism for GO membranes. The interlayer spacing of GO films is determined by the attractive van der Waals forces between flakes and is affected by the humidity of the environment during film formation. For graphene oxide, the interlayer distance as measured by the 2θ peak of X-ray diffraction is typically to Unoxidized graphite exhibits ABA stacking of graphene layers and associated lower ca. layer spacing. Reduced graphene oxide also shows lower-order 2-theta peaks, but not necessarily packing as ABA. In all cases, there are no chemical bonds, either horizontally or vertically, between the individual flakes. When h...

Embodiment 2

[0180] This example describes the compatibility of cross-linked graphene oxide films in a variety of environments. Crosslinked graphene oxide films were found to be compatible with chlorinated solvents, elevated temperatures in aqueous solvents, elevated temperatures in non-polar solvents, oxidizing agents, and high pH.

[0181] Durable graphene oxide films can be prepared using chemically durable linking groups. For example, these graphene oxide films can be soaked overnight in pure dichloromethane (DCM). In contrast, commercial polyethersulfone membranes degrade immediately upon contact with only a few drops of DCM.

[0182] Even in water, today's polymeric NF membranes are typically rated at 25°C with a reported maximum operating temperature of 50°C. However, the temperature and solvent tolerance of the robustly cross-linked graphene oxide films was demonstrated at elevated temperatures. Briefly, X-ray diffraction data is used to give the interplanar spacing between shee...

Embodiment 3

[0190] This example describes the formation in Example 1 and is shown in Figure 14 Highly cross-linked foam in .

[0191] Highly cross-linked foams were formed by functionalizing GO sheets with acid chlorides. Briefly, 20 mg of GO, 20 mL of dimethylformamide and 1 mL of oxalyl chloride were reacted for 4 hours. The resulting solution was dried by rotary evaporation for 30 minutes of some hydrochloric acid by-product and further diluted with 80 mL of DMF. Add 1 mL of NEt while stirring 3 to induce cross-linking. After 3 minutes, the mixture was vacuum filtered through a polyvinylidene fluoride or polytetrafluoroethylene filter and washed with methanol to remove residue and precipitate triethylammonium hydrochloride (white salt). The layered GO films have macropores.

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Abstract

Membranes comprising graphene oxide sheets and associated filter media and methods are provided. In some embodiments, a membrane may comprise graphene oxide sheets that have undergone one or more chemical treatments. The chemical treatment(s) may impart beneficial properties to the membrane, such as a relatively small d-spacing, compatibility with a broad range of environments, physical stability,and charge neutrality. For example, the graphene oxide sheets may undergo one or more chemical treatments that form chemical linkages between at least a portion of the graphene oxide sheets in the membrane. Such chemical linkages may impart a small d-spacing, broad compatibility, and / or allow relatively thick membranes to be formed. In certain embodiments, the graphene oxide sheets may undergo one or more chemical treatment that imparts relative charge neutrality to the membrane by altering the ionizability of certain functional groups. Graphene oxide membranes, described herein, can be usedfor a wide range applications.

Description

[0001] Related applications [0002] This application requires a US provisional patent entitled "Cross-linked Graphene Oxide Films for Separation Processes", filed on May 11, 2016, under 35 U.S.C § 119(e) Priority to application Serial No. 62 / 334,567, the disclosure of which is incorporated herein by reference in its entirety for all purposes. technical field [0003] Embodiments of the present invention relate generally to graphene oxide membranes, and in particular to graphene oxide membranes used in separation processes. Background technique [0004] Membranes provide partial or complete barriers to solids, liquids and / or gases. A semipermeable membrane allows certain molecules (eg, permeate) to pass through, while restricting the passage of other molecules (eg, retentate). Recently, research has focused on the use of semipermeable membranes for ultrafiltration (UF) and nanofiltration (NF). Ultrafiltration membranes are used to separate higher molecular weight molecule...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/02B32B3/26B32B9/00C02F1/44
CPCB01D67/0093B01D2323/30B32B7/10B32B9/007B32B9/041B32B15/082B32B15/085B32B15/09B32B27/283B32B27/285B32B27/286B32B27/302B32B27/304B32B27/308B32B27/32B32B27/322B32B3/26B32B3/266B32B2307/20B32B2307/308B32B2307/732C01B32/198B01D71/021B01D61/02B01D69/02B01D2325/04B01D71/024B32B2313/04
Inventor 施雷亚·H·戴夫杰弗里·C·格罗斯曼戈奇·代乌尔·韩布兰特·凯勒
Owner MASSACHUSETTS INST OF TECH
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