Desalination membrane comprising hydroxyl-rich graphene oxide or hydroxyl-rich reduced graphene oxide

Reusable Desalination Membrane Using Hydroxyl-Rich Graphene Oxide with Expanded Interlayer Spacing

This technology involves a desalination membrane, its manufacturing process, and a desalination method using a layer of hydroxyl-rich graphene oxide (HGO) or hydroxyl-rich reduced graphene oxide (HRGO) with expanded interlayer spacing, formed via vacuum filtration on an inorganic alumina membrane support. It features a double-membrane structure where two single membranes are stacked with their graphene layers facing each other, enclosed by a copper foil perimeter.

As demand for seawater desalination grows, there is a need for membranes that efficiently filter out salts like NaCl. However, conventional graphene oxide membranes are difficult to reuse because contaminants adsorbed during use are hard to remove. Standard reduced graphene oxide has short interlayer spacing, making it difficult to achieve both high water permeability and effective ion rejection.

This technology uses an HRGO layer with an interlayer spacing of 4Å to 10Å to filter out salts while allowing water to pass through. The conductivity of the graphene, restored during the reduction process, allows for the easy removal of adsorbed contaminants via an applied voltage. By using a porous alumina support, the membrane achieves both structural integrity and ion permeability, making it suitable for seawater desalination, brine purification, and industrial water treatment, enabling reusable modules that extend membrane replacement cycles.

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Key Features:

• Desalination membrane featuring a hydroxyl-rich graphene oxide or hydroxyl-rich reduced graphene oxide layer formed on an inorganic alumina membrane support with a uniform capillary pore structure
• Structure that removes salts such as NaCl, which have a hydration radius of 3.3 to 5.9Å, using a hydroxyl-rich reduced graphene oxide layer with an interlayer spacing of 4Å to 10Å
• Double-membrane configuration consisting of two single membranes stacked with their graphene oxide layers facing inward, enclosed by a copper foil perimeter
• Method of desalination by inserting the membrane into the center of a U-tube to divide it into feed and permeate compartments, allowing water to pass from the feed to the permeate side

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This invention was developed with support from the Ministry of Education, Science and Technology for the development of graphene-based biosensors.

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