The present disclosure relates generally to devices and systems for water treatment and, more particularly, to graphite structures or graphene three-dimensional array structures and related water-filtration membranes, devices, and manufacturing processes.
Desalination has received attention as an important technology because water scarcity is one of the most serious global challenges for humanity. Conventionally, desalination can be done by evaporation (or thermal distillation) or reverse osmosis (RO). However, both technologies require high energy consumption for operation. For example, RO, which uses a semipermeable membrane to remove molecules and ions from drinking water, uses an applied pressure to overcome osmotic pressure. A typical RO plant consumes 1.5 to 2.5 kilowatt-hours (kWh) of electricity to produce 1 m3 of freshwater from seawater. In a thermal distillation, the energy consumption goes up to 10 times that amount. Conventional semi-permeable membranes, which can effectively remove impurities such as ions, often suffer from poor water permeability. Development of high water-permeable membranes is needed for fresh water treatment.
Disclosed are devices and systems for water treatment. In one aspect, disclosed is a water-permeable device comprising: a supporting layer; and a water-permeable membrane, comprising graphene layers that are aligned to form interlayer hydrophobic channels between the graphene layers, wherein the interlayer hydrophobic channels are positioned to be aligned with the direction of water permeation.
In some cases, the graphene layers have an average angular spread of at least about 0.1°, about 0.5°, about 1°, about 2°, about 5°, about 10°, about 15°, or about 20°. In some cases, the graphene layers have an average angular spread of at most about 0.1°, about 0.5°, about 1°, about 2°, about 5°, about 10°, about 15°, or about 20°. In some cases, the graphene layers have an average angular spread of about 0.1° to about 20°. In some cases, the graphene layers have an average angular spread of about 0.1° to about 0.5°, about 0.1° to about 1°, about 0.1° to about 2°, about 0.1° to about 5°, about 0.1° to about 10°, about 0.1° to about 15°, about 0.1° to about 20°, about 0.5° to about 1°, about 0.5° to about 2°, about 0.5° to about 5°, about 0.5° to about 10°, about 0.5° to about 15°, about 0.5° to about 20°, about 1° to about 2°, about 1° to about 5°, about 1° to about 10°, about 1° to about 15°, about 1° to about 20°, about 2° to about 5°, about 2° to about 10°, about 2° to about 15°, about 2° to about 20°, about 5° to about 10°, about 5° to about 15°, about 5° to about 20°, about 10° to about 15°, about 10° to about 20°, or about 15° to about 20°. In some cases, the graphene layers have an average angular spread of about 0.1°, about 0.5°, about 1°, about 2°, about 5°, about 10°, about 15°, or about 20°. In some cases, the graphene layers have an average angular spread of less than 10°. In some cases, the graphene layers have an average angular spread of less than 1°.
In some cases, the graphene layers have an average size of at least about 0.1 μm, about 0.2 μm, about 0.5 μm, about 1 μm, about 2 μm, about 5 μm, about 10 μm, or about 20 μm. In some cases, the graphene layers have an average size of at most about 0.1 μm, about 0.2 μm, about 0.5 μm, about 1 μm, about 2 μm, about 5 μm, about 10 μm, or about 20 μm. In some cases, the graphene layers have an average size of about 0.1 μm to about 20 μm. In some cases, the graphene layers have an average size of about 0.1 μm to about 0.2 μm, about 0.1 μm to about 0.5 μm, about 0.1 μm to about 1 μm, about 0.1 μm to about 2 μm, about 0.1 μm to about 5 μm, about 0.1 μm to about 10 μm, about 0.1 μm to about 20 μm, about 0.2 μm to about 0.5 μm, about 0.2 μm to about 1 μm, about 0.2 μm to about 2 μm, about 0.2 μm to about 5 μm, about 0.2 μm to about 10 μm, about 0.2 μm to about 20 μm, about 0.5 μm to about 1 μm, about 0.5 μm to about 2 μm, about 0.5 μm to about 5 μm, about 0.5 μm to about 10 μm, about 0.5 μm to about 20 μm, about 1 μm to about 2 μm, about 1 μm to about 5 μm, about 1 μm to about 10 μm, about 1 μm to about 20 μm, about 2 μm to about 5 μm, about 2 μm to about 10 μm, about 2 μm to about 20 μm, about 5 μm to about 10 μm, about 5 μm to about 20 μm, or about 10 μm to about 20 μm. In some cases, the graphene layers have an average size of about 0.1 μm, about 0.2 μm, about 0.5 μm, about 1 μm, about 2 μm, about 5 μm, about 10 μm, or about 20 μm. In some cases, the graphene layers have an average size of less than 20 μm. In some cases, the graphene layers have an average size of less than 5 μm. In some cases, the graphene layers have an average size of about 1 μm.
In some cases, the interlayer hydrophobic channels have an average thickness of at least about 1 Å, about 2 Å, about 3 Å, about 3.5 Å, about 4 Å, about 5 Å, about 6 Å, about 7 Å, about 8 Å, about 9 Å, about 10 Å, or about 20 A. In some cases, the interlayer hydrophobic channels have an average thickness of at most about 1 Å, about 2 Å, about 3 Å, about 3.5 Å, about 4 Å, about 5 Å, about 6 Å, about 7 Å, about 8 Å, about 9 Å, about 10 Å, or about 20 Å. In some cases, the interlayer hydrophobic channels have an average thickness of about 1 Å to about 20 Å. In some cases, the interlayer hydrophobic channels have an average thickness of about 1 Å to about 2 Å, about 1 Å to about 3 Å, about 1 Å to about 3.5 Å, about 1 Å to about 4 Å, about 1 Å to about 5 Å, about 1 Å to about 6 Å, about 1 Å to about 7 Å, about 1 Å to about 8 Å, about 1 Å to about 9 Å, about 1 Å to about 10 Å, about 1 Å to about 20 Å, about 2 Å to about 3 Å, about 2 Å to about 3.5 Å, about 2 Å to about 4 Å, about 2 Å to about 5 Å, about 2 Å to about 6 Å, about 2 Å to about 7 Å, about 2 Å to about 8 Å, about 2 Å to about 9 Å, about 2 Å to about 10 Å, about 2 Å to about 20 Å, about 3 Å to about 3.5 Å, about 3 Å to about 4 Å, about 3 Å to about 5 Å, about 3 Å to about 6 Å, about 3 Å to about 7 Å, about 3 Å to about 8 Å, about 3 Å to about 9 Å, about 3 Å to about 10 Å, about 3 Å to about 20 Å, about 3.5 Å to about 4 Å, about 3.5 Å to about 5 Å, about 3.5 Å to about 6 Å, about 3.5 Å to about 7 Å, about 3.5 Å to about 8 Å, about 3.5 Å to about 9 Å, about 3.5 Å to about 10 Å, about 3.5 Å to about 20 Å, about 4 Å to about 5 Å, about 4 Å to about 6 Å, about 4 Å to about 7 Å, about 4 Å to about 8 Å, about 4 Å to about 9 Å, about 4 Å to about 10 Å, about 4 Å to about 20 Å, about 5 Å to about 6 Å, about 5 Å to about 7 Å, about 5 Å to about 8 Å, about 5 Å to about 9 Å, about 5 Å to about 10 Å, about 5 Å to about 20 Å, about 6 Å to about 7 Å, about 6 Å to about 8 Å, about 6 Å to about 9 Å, about 6 Å to about 10 Å, about 6 Å to about 20 Å, about 7 Å to about 8 Å, about 7 Å to about 9 Å, about 7 Å to about 10 Å, about 7 Å to about 20 Å, about 8 Å to about 9 Å, about 8 Å to about 10 Å, about 8 Å to about 20 Å, about 9 Å to about 10 Å, about 9 Å to about 20 Å, or about 10 Å to about 20 Å. In some cases, the interlayer hydrophobic channels have an average thickness of about 1 Å, about 2 Å, about 3 Å, about 3.5 Å, about 4 Å, about 5 Å, about 6 Å, about 7 Å, about 8 Å, about 9 Å, about 10 Å, or about 20 Å. In some cases, the interlayer hydrophobic channels have an average thickness of less than 20 Å. In some cases, the interlayer hydrophobic channels have an average thickness of less than 5 Å. In some cases, the interlayer hydrophobic channels have an average thickness of about 3.4 Å.
In some cases, the water-permeable membrane has a thickness of at least about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, about 400 μm, about 450 μm, about 500 μm, about 1,000 μm, or about 2,000 μm. In some cases, the water-permeable membrane has a thickness of at most about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, about 400 μm, about 450 μm, about 500 μm, about 1,000 μm, or about 2,000 μm. In some cases, the water-permeable membrane has a thickness of about 50 μm to about 2,000 μm. In some cases, the water-permeable membrane has a thickness of about 50 μm to about 100 μm, about 50 μm to about 150 μm, about 50 μm to about 200 μm, about 50 μm to about 250 μm, about 50 μm to about 300 μm, about 50 μm to about 350 μm, about 50 μm to about 400 μm, about 50 μm to about 450 μm, about 50 μm to about 500 μm, about 50 μm to about 1,000 μm, about 50 μm to about 2,000 μm, about 100 μm to about 150 μm, about 100 μm to about 200 μm, about 100 μm to about 250 μm, about 100 μm to about 300 μm, about 100 μm to about 350 μm, about 100 μm to about 400 μm, about 100 μm to about 450 μm, about 100 μm to about 500 μm, about 100 μm to about 1,000 μm, about 100 μm to about 2,000 μm, about 150 μm to about 200 μm, about 150 μm to about 250 μm, about 150 μm to about 300 μm, about 150 μm to about 350 μm, about 150 μm to about 400 μm, about 150 μm to about 450 μm, about 150 μm to about 500 μm, about 150 μm to about 1,000 μm, about 150 μm to about 2,000 μm, about 200 μm to about 250 μm, about 200 μm to about 300 μm, about 200 μm to about 350 μm, about 200 μm to about 400 μm, about 200 μm to about 450 μm, about 200 μm to about 500 μm, about 200 μm to about 1,000 μm, about 200 μm to about 2,000 μm, about 250 μm to about 300 μm, about 250 μm to about 350 μm, about 250 μm to about 400 μm, about 250 μm to about 450 μm, about 250 μm to about 500 μm, about 250 μm to about 1,000 μm, about 250 μm to about 2,000 μm, about 300 μm to about 350 μm, about 300 μm to about 400 μm, about 300 μm to about 450 μm, about 300 μm to about 500 μm, about 300 μm to about 1,000 μm, about 300 μm to about 2,000 μm, about 350 μm to about 400 μm, about 350 μm to about 450 μm, about 350 μm to about 500 μm, about 350 μm to about 1,000 μm, about 350 μm to about 2,000 μm, about 400 μm to about 450 μm, about 400 μm to about 500 μm, about 400 μm to about 1,000 μm, about 400 μm to about 2,000 μm, about 450 μm to about 500 μm, about 450 μm to about 1,000 μm, about 450 μm to about 2,000 μm, about 500 μm to about 1,000 μm, about 500 μm to about 2,000 μm, or about 1,000 μm to about 2,000 μm. In some cases, the water-permeable membrane has a thickness of about 50 μm, about 100 μm, about 150 μm, about 200 μm, about 250 μm, about 300 μm, about 350 μm, about 400 μm, about 450 μm, about 500 μm, about 1,000 μm, or about 2,000 μm. In some cases, the water-permeable membrane has a thickness of less than 1,000 μm. In some cases, the water-permeable membrane has a thickness of between 100 to 500 μm. In some cases, the water-permeable membrane has a thickness of about 250 μm.
In some cases, the water-permeable membrane comprises a synthetic graphene membrane. In some cases, the water-permeable membrane comprises a highly ordered pyrolytic graphite (HOPG) membrane. In some cases, the water-permeable membrane is fixed to the supporting layer. In some cases, the interlayer hydrophobic channels are positioned to be perpendicular to the supporting layer.
In some cases, the supporting layer comprises a membrane with an average pore size of at least about 1 μm, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, or about 20 μm. In some cases, the average pore size is at most about 1 μm, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, or about 20 μm. In some cases, the average pore size is about 1 μm to about 20 μm. In some cases, the average pore size is about 1 μm to about 2 μm, about 1 μm to about 3 μm, about 1 μm to about 4 μm, about 1 μm to about 5 μm, about 1 μm to about 6 μm, about 1 μm to about 7 μm, about 1 μm to about 8 μm, about 1 μm to about 9 μm, about 1 μm to about 10 μm, about 1 μm to about 20 μm, about 2 μm to about 3 μm, about 2 μm to about 4 μm, about 2 μm to about 5 μm, about 2 μm to about 6 μm, about 2 μm to about 7 μm, about 2 μm to about 8 μm, about 2 μm to about 9 μm, about 2 μm to about 10 μm, about 2 μm to about 20 μm, about 3 μm to about 4 μm, about 3 μm to about 5 μm, about 3 μm to about 6 μm, about 3 μm to about 7 μm, about 3 μm to about 8 μm, about 3 μm to about 9 μm, about 3 μm to about 10 μm, about 3 μm to about 20 μm, about 4 μm to about 5 μm, about 4 μm to about 6 μm, about 4 μm to about 7 μm, about 4 μm to about 8 μm, about 4 μm to about 9 μm, about 4 μm to about 10 μm, about 4 μm to about 20 μm, about 5 μm to about 6 μm, about 5 μm to about 7 μm, about 5 μm to about 8 μm, about 5 μm to about 9 μm, about 5 μm to about 10 μm, about 5 μm to about 20 μm, about 6 μm to about 7 μm, about 6 μm to about 8 μm, about 6 μm to about 9 μm, about 6 μm to about 10 μm, about 6 μm to about 20 μm, about 7 μm to about 8 μm, about 7 μm to about 9 μm, about 7 μm to about 10 μm, about 7 μm to about 20 μm, about 8 μm to about 9 μm, about 8 μm to about 10 μm, about 8 μm to about 20 μm, about 9 μm to about 10 μm, about 9 μm to about 20 μm, or about 10 μm to about 20 μm. In some cases, the average pore size is about 1 μm, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, or about 20 μm. In some cases, the average pore size is less than 10 μm. In some cases, the average pore size is about 3 μm. In some cases, the supporting layer can be any material that provides structure support for the water-permeable membrane. In some cases, the supporting layer comprises a polytetrafluoroethylene (PTFE) membrane.
In some cases, at least one edge plane of the water-permeable membrane is hydrophilic. In some cases, the at least one edge plane of the water-permeable membrane has a water contact angle of at most about 10°, about 20°, about 30°, about 40°, about 50°, about 60°, about 70°, about 80°, or about 90°. In some cases, the water contact angle is about 10° to about 90°. In some cases, the water contact angle is about 10° to about 20°, about 10° to about 30°, about 10° to about 40°, about 10° to about 50°, about 10° to about 60°, about 10° to about 70°, about 10° to about 80°, about 10° to about 90°, about 20° to about 30°, about 20° to about 40°, about 20° to about 50°, about 20° to about 60°, about 20° to about 70°, about 20° to about 80°, about 20° to about 90°, about 30° to about 40°, about 30° to about 50°, about 30° to about 60°, about 30° to about 70°, about 30° to about 80°, about 30° to about 90°, about 40° to about 50°, about 40° to about 60°, about 40° to about 70°, about 40° to about 80°, about 40° to about 90°, about 50° to about 60°, about 50° to about 70°, about 50° to about 80°, about 50° to about 90°, about 60° to about 70°, about 60° to about 80°, about 60° to about 90°, about 70° to about 80°, about 70° to about 90°, or about 80° to about 90°. In some cases, the water contact angle is about 10°, about 20°, about 30°, about 40°, about 50°, about 60°, about 70°, about 80°, or about 90°. In some cases, the water contact angle is smaller than 90°. In some cases, the water contact angle is smaller than 30°. In some cases, both edge planes of the water-permeable membrane are hydrophilic. In some cases, both edge planes of the water-permeable membrane have a water contact angle of at most about 10°, about 20°, about 30°, about 40°, about 50°, about 60°, about 70°, about 80°, or about 90°. In some cases, both edge planes of the water-permeable membrane have a water contact angle of about 10° to about 90°. In some cases, both edge planes of the water-permeable membrane have a water contact angle of less than 90°. In some cases, both edge planes of the water-permeable membrane have a water contact angle of less than 30°.
In some cases, at least one surface of the interlayer hydrophobic channels is hydrophobic. In some cases, the at least one surface of the interlayer hydrophobic channels has a water contact angle of at most about 90°, about 100°, about 110°, about 120°, about 130°, about 140°, about 150°, about 160°, about 170°, or about 180°. In some cases, the water contact angle is about 90° to about 180°. In some cases, the water contact angle is about 90° to about 100°, about 90° to about 110°, about 90° to about 120°, about 90° to about 130°, about 90° to about 140°, about 90° to about 150°, about 90° to about 160°, about 90° to about 170°, about 90° to about 180°, about 100° to about 110°, about 100° to about 120°, about 100° to about 130°, about 100° to about 140°, about 100° to about 150°, about 100° to about 160°, about 100° to about 170°, about 100° to about 180°, about 110° to about 120°, about 110° to about 130°, about 110° to about 140°, about 110° to about 150°, about 110° to about 160°, about 110° to about 170°, about 110° to about 180°, about 120° to about 130°, about 120° to about 140°, about 120° to about 150°, about 120° to about 160°, about 120° to about 170°, about 120° to about 180°, about 130° to about 140°, about 130° to about 150°, about 130° to about 160°, about 130° to about 170°, about 130° to about 180°, about 140° to about 150°, about 140° to about 160°, about 140° to about 170°, about 140° to about 180°, about 150° to about 160°, about 150° to about 170°, about 150° to about 180°, about 160° to about 170°, about 160° to about 180°, or about 170° to about 180°. In some cases, the water contact angle is about 90°, about 100°, about 110°, about 120°, about 130°, about 140°, about 150°, about 160°, about 170°, or about 180°.
In some cases, the water-permeable device has a low ion permeation rate when applying an ion solution of 1 M (e.g., K+, Na+, Cl−, Mg2+ or [Fe(CN)6]3−). For example, the ion permeation rate is about 0.001 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2. In some cases, the ion permeation rate is at least about 0.001 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2, about 0.05 mol per h per m{circumflex over ( )}2, about 0.1 mol per h per m{circumflex over ( )}2, about 0.5 mol per h per m{circumflex over ( )}2, or about 1 mol per h per m{circumflex over ( )}2. In some cases, the ion permeation rate is at most about 0.001 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2, about 0.05 mol per h per m{circumflex over ( )}2, about 0.1 mol per h per m{circumflex over ( )}2, about 0.5 mol per h per m{circumflex over ( )}2, or about 1 mol per h per m{circumflex over ( )}2. In some cases, the ion permeation rate is about 0.001 mol per h per m{circumflex over ( )}2 to about 0.005 mol per h per m{circumflex over ( )}2, about 0.001 mol per h per m{circumflex over ( )}2 to about 0.01 mol per h per m{circumflex over ( )}2, about 0.001 mol per h per m{circumflex over ( )}2 to about 0.05 mol per h per m{circumflex over ( )}2, about 0.001 mol per h per m{circumflex over ( )}2 to about 0.1 mol per h per m{circumflex over ( )}2, about 0.001 mol per h per m{circumflex over ( )}2 to about 0.5 mol per h per m{circumflex over ( )}2, about 0.001 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2 to about 0.01 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2 to about 0.05 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2 to about 0.1 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2 to about 0.5 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2 to about 0.05 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2 to about 0.1 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2 to about 0.5 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2, about 0.05 mol per h per m{circumflex over ( )}2 to about 0.1 mol per h per m{circumflex over ( )}2, about 0.05 mol per h per m{circumflex over ( )}2 to about 0.5 mol per h per m{circumflex over ( )}2, about 0.05 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2, about 0.1 mol per h per m{circumflex over ( )}2 to about 0.5 mol per h per m{circumflex over ( )}2, about 0.1 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2, or about 0.5 mol per h per m{circumflex over ( )}2 to about 1 mol per h per m{circumflex over ( )}2. In some cases, the ion permeation rate is about 0.001 mol per h per m{circumflex over ( )}2, about 0.005 mol per h per m{circumflex over ( )}2, about 0.01 mol per h per m{circumflex over ( )}2, about 0.05 mol per h per m{circumflex over ( )}2, about 0.1 mol per h per m{circumflex over ( )}2, about 0.5 mol per h per m{circumflex over ( )}2, or about 1 mol per h per m{circumflex over ( )}2. In some cases, the ion permeation rate is less than 0.001 mol·h−1·m−2. In some cases, the ion comprises K+, Na+, Cl−, Mg2+ or [Fe(CN)6]3−.
In some cases, the water-permeable device has an ion rejection rate of about 50% to about 99%. In some cases, the ion rejection rate is at least about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 99%. In some cases, the ion rejection rate is at most about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 99%. In some cases, the ion rejection rate is about 50% to about 60%, about 50% to about 70%, about 50% to about 80%, about 50% to about 90%, about 50% to about 95%, about 50% to about 99%, about 60% to about 70%, about 60% to about 80%, about 60% to about 90%, about 60% to about 95%, about 60% to about 99%, about 70% to about 80%, about 70% to about 90%, about 70% to about 95%, about 70% to about 99%, about 80% to about 90%, about 80% to about 95%, about 80% to about 99%, about 90% to about 95%, about 90% to about 99%, or about 95% to about 99%. In some cases, the ion rejection rate is about 50%, about 60%, about 70%, about 80%, about 90%, about 95%, or about 99%. In some cases, the water-permeable device has an ion rejection rate of more than 80%. In some cases, the water-permeable device has an ion rejection rate of more than 95%. In some cases, the ion comprises K+, Na+, Cl−, Mg2+ or [Fe(CN)6]3−. In some cases, the water-permeable device has Na+ rejection rate of more than about 90%. In some cases, the water-permeable device has Na+ rejection rate of more than about 95%. In some cases, the water-permeable device has Na+ rejection rate of about 90% to 99%. In some cases, the water-permeable device has Na+ rejection rate of about 98%.
In some cases, the water-permeable device has a water permeability of about 20 LMH bar to about 200 LMH bar. In some cases, the water permeability is at least about 20 LMH bar, about 30 LMH bar, about 40 LMH bar, about 50 LMH bar, about 60 LMH bar, about 70 LMH bar, about 80 LMH bar, about 90 LMH bar, about 100 LMH bar, about 150 LMH bar, or about 200 LMH bar. In some cases, the water permeability is at most about 20 LMH bar, about 30 LMH bar, about 40 LMH bar, about 50 LMH bar, about 60 LMH bar, about 70 LMH bar, about 80 LMH bar, about 90 LMH bar, about 100 LMH bar, about 150 LMH bar, or about 200 LMH bar. In some cases, the water permeability is about 20 LMH bar to about 30 LMH bar, about 20 LMH bar to about 40 LMH bar, about 20 LMH bar to about 50 LMH bar, about 20 LMH bar to about 60 LMH bar, about 20 LMH bar to about 70 LMH bar, about 20 LMH bar to about 80 LMH bar, about 20 LMH bar to about 90 LMH bar, about 20 LMH bar to about 100 LMH bar, about 20 LMH bar to about 150 LMH bar, about 20 LMH bar to about 200 LMH bar, about 30 LMH bar to about 40 LMH bar, about 30 LMH bar to about 50 LMH bar, about 30 LMH bar to about 60 LMH bar, about 30 LMH bar to about 70 LMH bar, about 30 LMH bar to about 80 LMH bar, about 30 LMH bar to about 90 LMH bar, about 30 LMH bar to about 100 LMH bar, about 30 LMH bar to about 150 LMH bar, about 30 LMH bar to about 200 LMH bar, about 40 LMH bar to about 50 LMH bar, about 40 LMH bar to about 60 LMH bar, about 40 LMH bar to about 70 LMH bar, about 40 LMH bar to about 80 LMH bar, about 40 LMH bar to about 90 LMH bar, about 40 LMH bar to about 100 LMH bar, about 40 LMH bar to about 150 LMH bar, about 40 LMH bar to about 200 LMH bar, about 50 LMH bar to about 60 LMH bar, about 50 LMH bar to about 70 LMH bar, about 50 LMH bar to about 80 LMH bar, about 50 LMH bar to about 90 LMH bar, about 50 LMH bar to about 100 LMH bar, about 50 LMH bar to about 150 LMH bar, about 50 LMH bar to about 200 LMH bar, about 60 LMH bar to about 70 LMH bar, about 60 LMH bar to about 80 LMH bar, about 60 LMH bar to about 90 LMH bar, about 60 LMH bar to about 100 LMH bar, about 60 LMH bar to about 150 LMH bar, about 60 LMH bar to about 200 LMH bar, about 70 LMH bar to about 80 LMH bar, about 70 LMH bar to about 90 LMH bar, about 70 LMH bar to about 100 LMH bar, about 70 LMH bar to about 150 LMH bar, about 70 LMH bar to about 200 LMH bar, about 80 LMH bar to about 90 LMH bar, about 80 LMH bar to about 100 LMH bar, about 80 LMH bar to about 150 LMH bar, about 80 LMH bar to about 200 LMH bar, about 90 LMH bar to about 100 LMH bar, about 90 LMH bar to about 150 LMH bar, about 90 LMH bar to about 200 LMH bar, about 100 LMH bar to about 150 LMH bar, about 100 LMH bar to about 200 LMH bar, or about 150 LMH bar to about 200 LMH bar. In some cases, the water permeability is about 20 LMH bar, about 30 LMH bar, about 40 LMH bar, about 50 LMH bar, about 60 LMH bar, about 70 LMH bar, about 80 LMH bar, about 90 LMH bar, about 100 LMH bar, about 150 LMH bar, or about 200 LMH bar. In some cases, the water-permeable device has a water permeability of more than about 50 LMH bar. In some cases, the water-permeable device has a water permeability of more than about 90 LMH bar.
In some cases, the water-permeable device has a water permeability/pore size (e.g., average thickness of the interlayer hydrophobic channels) of about 1,000 LMH/nm to about 10,000 LMH/nm. In some cases, the water permeability/pore size is at least about 1,000 LMH/nm. In some cases, the water permeability/pore size is at most about 10,000 LMH/nm. In some cases, the water permeability/pore size is about 1,000 LMH/nm to about 1,500 LMH/nm, about 1,000 LMH/nm to about 2,000 LMH/nm, about 1,000 LMH/nm to about 2,500 LMH/nm, about 1,000 LMH/nm to about 3,000 LMH/nm, about 1,000 LMH/nm to about 3,500 LMH/nm, about 1,000 LMH/nm to about 4,000 LMH/nm, about 1,000 LMH/nm to about 4,500 LMH/nm, about 1,000 LMH/nm to about 5,000 LMH/nm, about 1,000 LMH/nm to about 8,000 LMH/nm, about 1,000 LMH/nm to about 10,000 LMH/nm, about 1,500 LMH/nm to about 2,000 LMH/nm, about 1,500 LMH/nm to about 2,500 LMH/nm, about 1,500 LMH/nm to about 3,000 LMH/nm, about 1,500 LMH/nm to about 3,500 LMH/nm, about 1,500 LMH/nm to about 4,000 LMH/nm, about 1,500 LMH/nm to about 4,500 LMH/nm, about 1,500 LMH/nm to about 5,000 LMH/nm, about 1,500 LMH/nm to about 8,000 LMH/nm, about 1,500 LMH/nm to about 10,000 LMH/nm, about 2,000 LMH/nm to about 2,500 LMH/nm, about 2,000 LMH/nm to about 3,000 LMH/nm, about 2,000 LMH/nm to about 3,500 LMH/nm, about 2,000 LMH/nm to about 4,000 LMH/nm, about 2,000 LMH/nm to about 4,500 LMH/nm, about 2,000 LMH/nm to about 5,000 LMH/nm, about 2,000 LMH/nm to about 8,000 LMH/nm, about 2,000 LMH/nm to about 10,000 LMH/nm, about 2,500 LMH/nm to about 3,000 LMH/nm, about 2,500 LMH/nm to about 3,500 LMH/nm, about 2,500 LMH/nm to about 4,000 LMH/nm, about 2,500 LMH/nm to about 4,500 LMH/nm, about 2,500 LMH/nm to about 5,000 LMH/nm, about 2,500 LMH/nm to about 8,000 LMH/nm, about 2,500 LMH/nm to about 10,000 LMH/nm, about 3,000 LMH/nm to about 3,500 LMH/nm, about 3,000 LMH/nm to about 4,000 LMH/nm, about 3,000 LMH/nm to about 4,500 LMH/nm, about 3,000 LMH/nm to about 5,000 LMH/nm, about 3,000 LMH/nm to about 8,000 LMH/nm, about 3,000 LMH/nm to about 10,000 LMH/nm, about 3,500 LMH/nm to about 4,000 LMH/nm, about 3,500 LMH/nm to about 4,500 LMH/nm, about 3,500 LMH/nm to about 5,000 LMH/nm, about 3,500 LMH/nm to about 8,000 LMH/nm, about 3,500 LMH/nm to about 10,000 LMH/nm, about 4,000 LMH/nm to about 4,500 LMH/nm, about 4,000 LMH/nm to about 5,000 LMH/nm, about 4,000 LMH/nm to about 8,000 LMH/nm, about 4,000 LMH/nm to about 10,000 LMH/nm, about 4,500 LMH/nm to about 5,000 LMH/nm, about 4,500 LMH/nm to about 8,000 LMH/nm, about 4,500 LMH/nm to about 10,000 LMH/nm, about 5,000 LMH/nm to about 8,000 LMH/nm, about 5,000 LMH/nm to about 10,000 LMH/nm, or about 8,000 LMH/nm to about 10,000 LMH/nm. In some cases, the water permeability/pore size is about 1,000 LMH/nm, about 1,500 LMH/nm, about 2,000 LMH/nm, about 2,500 LMH/nm, about 3,000 LMH/nm, about 3,500 LMH/nm, about 4,000 LMH/nm, about 4,500 LMH/nm, about 5,000 LMH/nm, about 8,000 LMH/nm, or about 10,000 LMH/nm. In some cases, the water-permeable device has a water permeability/pore size of more than about 2,000 LMH/nm. In some cases, the water permeability/pore size is more than about 4,400 LMH/nm.
In another aspect, disclosed is a method for permeating water, comprising: (a) applying water to a water-permeable device comprising: a supporting layer; and a water-permeable membrane, comprising graphene layers that are aligned to form interlayer hydrophobic channels between the graphene layers, wherein the interlayer hydrophobic channels are positioned to be aligned with the direction of water permeation; and (b) collecting water permeated from the water-permeable device.
In another aspect, disclosed is a method for permeating water, comprising: (a) applying water to the water-permeable device disclosed herein; and (b) collecting water permeated from the water-permeable device.
In another aspect, disclosed is a method for removing ions from water, comprising: (a) applying water to a water-permeable device comprising: a supporting layer; and a water-permeable membrane, comprising graphene layers that are aligned to form interlayer hydrophobic channels between the graphene layers, wherein the interlayer hydrophobic channels are positioned to be aligned with the direction of water permeation; (b) removing ions from the water; and (c) collecting permeated water, wherein the permeated water has a lower ion concentration than the water before being applied to the water-permeable device.
In another aspect, disclosed is a method for removing ions from water, comprising: (a) applying water to the water-permeable device disclosed herein; (b) removing ions from the water; and (c) collecting permeated water, wherein the permeated water has a lower ion concentration than the water before being applied to the water-permeable device.
In another aspect, disclosed is a method for manufacturing a water-permeable device, comprising: fixating a water-permeable membrane on a supporting layer, wherein the water-permeable membrane comprises graphene layers that are aligned to form interlayer hydrophobic channels between the graphene layers, wherein the interlayer hydrophobic channels are positioned to be aligned with the direction of water permeation. In some cases, the method further comprises treating a surface of the water-permeable membrane using reactive-ion etching (RIE).
In another aspect, disclosed is a method for manufacturing the water-permeable device disclosed herein, comprising fixating the water-permeable membrane on the supporting layer. In some cases, the method further comprises treating a surface of the water-permeable membrane using reactive-ion etching (RIE).
It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the disclosure.
The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
Disclosed are devices and systems for water treatment. For example, devices and systems can comprise a membrane for water treatment. For example, the membrane can be a highly oriented pyrolytic graphite (HOPG) membrane. In other cases, the membrane can be a synthetic graphene membrane. These membranes can act as a high flux reverse osmosis (RO) membrane system. Water can flow through the pores of the membranes or interstices between layers of graphene (e.g., formed by vertically aligned graphenes in HOPG membranes). The surfaces of the membranes can be treated and/or optimized to have a hydrophilic membrane surface and a hydrophobic membrane channel, and/or to act as high flux RO membranes. In some cases, the membranes can be treated by reactive ion etching (RIE), such as oxygen RIE. The treated membranes can produce a purified water that is higher than any reported for commercial RO membranes by more than an order of magnitude, reaching a water flux of 100 LMH·bar. The membranes can also have pores and/or graphene that is well defined and ordered, and can be used as materials for separation and templates at the atomic scale.
The membranes can have a layered structure that comprises stacked graphene layers. In some cases, the membranes can have an average angular spread of less than 10° between the graphene layers, for example, less than 10°, 9°, 8°, 7°, 6°, 5°, 4°, 3°, 2°, 1°, or 0.5° between the graphene layers. In some cases, the membranes can have an average angular spread of from 10° to 0.1° between the graphene layers, for example, from 10° to 5°, from 5° to 3°, from 4° to 2°, from 3° to 1°, from 2° to 0.5°, or from 1.5° to 0.1° between the graphene layers.
In some cases, the membranes can have an average interlayer spacing of less than 20 Å between the structure materials, for example, less than 18 Å, 16 Å, 14 Å, 12 Å, 10 Å, 8 Å, 6 Å, 4 Å, 2 Å, or 1 Å between the structure materials. The membranes can be a high purity carbon material and/or have a highly flat surface.
The ion permeation rates, J, can be calculated as:
wherein D is the diffusion coefficient for small ions in water, at about 10−5 cm2/s. AC is the concentration gradient across the membrane. ΔC is 23 g/L in the case of a 1 M solution of Na+. Aeff is the effective area of the water column through the membranes (e.g., the effective pore area of the membranes) and Leff is the effective length of the water column (e.g., the penetration length of ions through the membranes). Aeff and Leff can be expressed as:
wherein A, L, h, and d are the membrane area, the size of graphene sheets consisting of HOPG, the thickness of the membrane, and the interlayer spacing, respectively. Here, A is 4.45 cm2, L is 1 μm, h is 250 μm, and d is 3.4 Å.
The slip length can be calculated with an indirect method using the following equation:
where V(λ) and VNS are the flow velocity with slip and no-slip boundary conditions, respectively; λ is the slip length; and h is the distance between the two sheets (e.g., interlayer spacing). V(λ) can be estimated from the experimentally observed flow velocity when choosing the slip length. The size of the interlayer space can be determined by XRD measurement for the interlayer spacing, h. VNS can be calculated using the Poiseuille flow between two stationary plates with no slip [VNS=(h2Δp)/(12 μL) from the Stokes equation]. Poiseuille flow V(λ) between two stationary plates with slip boundary condition can be expressed as:
wherein Δp/dx, μ, and L are pressure drop, viscosity, and channel length, respectively.
The following examples are included to more clearly demonstrate the overall nature of the disclosure. These examples are exemplary, not restrictive, of the disclosure.
As illustrated in
The orientation of graphene 16 in the HOPG membrane 1 was observed with X-ray diffraction (XRD). See
The XRD pattern on the basal plane 18 of the HOPG showed a typical graphite pattern. A peak at 20=24.6° signified the (002) crystal plane, which means the basal plane 18 of graphene, and the interlayer spacing between graphenes was 3.4 Å. The (002) plane at 24.6° and the (004) plane at 54.7° were parallel. A peak at 42.3° was observed in the pattern on the edge plane 20 (cutting plane) of the HOPG which signifies the (100) crystal plane. The (001) peak signified that the graphene was vertically aligned because the (100) plane was perpendicular to the (002) plane. Therefore, the mechanically cut HOPG was vertically aligned graphene membrane when the edge plane 20 (cutting plane) of the HOPG was used as a membrane surface for water permeation.
The top and bottom edge planes 20 of the HOPG slices were plasma-treated by an RIE etcher with oxygen (e.g., plasma finish, V15-G) to make the edge planes 20 hydrophilic. The RIE etcher was equipped with microwave power, set at about 300 W. The work pressure was set at about 0.1 Torr in the chamber. During the RIE process, the flow rate of oxygen was set at 300 standard cubic centimeter per minute (sccm) for an etch time of 120 s.
The modification can make water molecules 10 easily permeate through the surface of the HOPG membrane 1. An oxygen plasma treatment in the form of oxygen reactive ion etching (RIE) was carried out on both surfaces of the HOPG membrane 1.
The transformation of both the top and bottom surfaces of the HOPG membrane 1 to hydrophilic surfaces after oxygen RIE treatment was observed by contact angle measurement. See
The formation of hydrophilic functional groups on the surface was confirmed by Raman spectroscopy. See
The formation of hydrophilic functional groups on the surface was also confirmed by X-ray photoelectron spectroscopy (XPS) by deconvolution of the C 1 s spectrum (PHI 5000 versaProbe II; Al Kα source).
The mechanically cut HOPG slice was positioned on a PTFE membrane with an average pore size of about 3 μm, which was treated with ethanol. The HOPG slice on the PTFE membrane was surrounded by the high-viscous epoxy 22 to clamp the HOPG slice under high test pressure. The HOPG slice surrounded by the epoxy 22 was then cured at room temperature for 24 hours. The resultant membrane is the HOPG membrane 1.
The surface modification of the edge plane 20 of the HOPG membrane 1 can lead to a dramatic increase in permeability. See
Ion rejection rate was determined by measuring the conductivity of the permeate solution 36 through the HOPG membrane 1. The conductivity of the feed solution 34 and the permeate solution 36 before and after filtration of ion solutions was measured with a Mettler Toledo SevenCompact™ conductivity meter. The concentration of positive and negative ions in the solution was measured with Shimdzu JP/ICPS-750 (inductively coupled plasma, ICP) and Dionex ICS-3000 (Ion chromatograph, IC), respectively. The NaCl rejection rate was measured to 98%.
The hydrophobic channel wall and the hydrophilic entrance and exit were optimal conditions to realize fast mass transport through the HOPG membrane 1. Water molecules 10 that pass through the entrance can form water chains through hydrogen bonding into the HOPG interior, i.e., graphene channels. The water chains can ballistically pass through the HOPG interior because of frictionless flow between the hydrophobic graphene wall and the water chains. The fast mass transport phenomena result in high permeability. The HOPG membrane 1 realized the phenomena through oxygen RIE treatment.
The existence of water intercalated into the interlayer spaces was observed with a terahertz wave, defined as an electromagnetic wave within the band of frequencies from 0.3 to 3 terahertz. (THz=1012 Hz). Terahertz waves can penetrate a wide variety of non-conducting materials such as paper, wood, plastic, and ceramic materials but cannot penetrate liquid water or metal. In the case of HOPG, terahertz waves can pass through interlayer spaces because the HOPG has a well-aligned graphene structure in spite of conducting materials.
To evaluate the ion sieving ability of the HOPG membrane 1, the ion permeation rate was measured with a hydrostatic pressure driven test cell. The ion concentration of the permeate solution was measured by inductively coupled plasma (ICP) and ion chromatograph (IC) to measure ion concentration into the permeate. The permeation rates observed for five ions (K+, Na+, Cl−, Mg2+, and [Fe(CN)6]3−) are shown in
The HOPG membrane 1 showed low permeation rates on small-sized ions such as K+, Na+, and Cl−. The permeation rates approached theoretical limits (cross-hatched area). The permeation rates of K+ and Na+ ions were lower than an order of 10−3. The Cl− amount was measured with NaCl. Cations and anions moved through the HOPG membrane 1 in stoichiometric amounts so that charge neutrality within the permeate was preserved. Cl− was similar to Na+ in the permeation rate. The HOPG membrane 1 showed no detectable permeation on large-sized [Fe(CN)6]3−. The theoretical permeation rate of the HOPG membrane 1 was calculated as 3×10−6 on Na +(lowest dotted line in
The permeation rate of the HOPG membrane 1 for sodium ions was compared with other membranes: graphene oxide (GO)-based membranes (reported in R. Joshi et al., “Precise and ultrafast molecular sieving through graphene oxide membranes,” Science 343, 752-54 (2014)), a commercial RO membrane, crosslinked GO membranes (reported in Z. Jia & Y. Wang, “Covalently crosslinked graphene oxide membranes by esterification reactions for ions separation,” Journal of Materials Chemistry A 3, 4405-12 (2015)), and ultrathin reduced graphene (rGO) membranes (reported in H. Liu, H. Wang, & X. Zhang, “Facile fabrication of freestanding ultrathin reduced graphene oxide membranes for water purification,” Advanced Materials 27, 249-54 (2015)). All publications mentioned in this specification are incorporated by reference to the same extent as if each individual publication were specifically and individually indicated to be incorporated by reference. The permeation rate of the commercial RO membrane (LFC-1) for sodium ions was estimated by the rejection rate measured with the dead-end filtration system 30.
The permeation rates of the GO-based and ultrathin rGO membranes, which was in the form of buckypaper, were measured with osmotic pressure caused by the concentration difference between ion and non-ion solutions without external pressure. The permeation rates of GO-based and ultrathin rGO membranes shown in
The two data points grouped in the middle circle of
Conventional RO membranes made of a polyamide active layer showed poor permeability in spite of a high rejection rate to ions. The carbon nanomaterial membranes were shown to have a low ion rejection rate relative to the conventional RO membrane because the pore size is much larger than the size of the ions. The HOPG membrane 1 showed superior properties when compared to conventional RO membranes and carbon nanomaterial membranes.
The slip length of the HOPG membrane 1 was as long as that of the CNT membranes. Hydrophobic CNT walls can lead to a frictionless flow and thus to a high flow velocity as a consequence of the weak interfacial force between water molecules and atomically smooth, hydrophobic CNT inner walls in the case of the open-ended membrane. For the HOPG membrane 1, water molecules 10 can be surrounded by graphene 16; therefore, the same reasoning as for the flow inside of the HOPG membrane 1 would apply, which results in the high slip length.
The average pore size of the conventional polyamide thin-film composite (TFC) membrane is about 4 Å. The normalized permeability of carbon nanomaterial membranes including HOPG, vertically aligned CNT, and graphene membranes is higher than that of conventional membranes, thin film nanocomposite membranes (or mixed membranes) including polyamide zeolite, polyamide-GO-CNT and mLBL (molecular Layer-by-Layer) polyamide although carbon nanomaterial membranes are much thicker than conventional membranes. The HOPG membrane 1 showed very high normalized permeability.
Although illustrated and described above with reference to certain specific embodiments and examples, the present disclosure is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the disclosure. It is expressly intended, for example, that all ranges broadly recited in this document include within their scope all narrower ranges which fall within the broader ranges. It is also expressly intended that the steps of the methods of using the various devices disclosed above are not restricted to any particular order.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/041204 | 7/10/2019 | WO | 00 |
Number | Date | Country | |
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62696636 | Jul 2018 | US |