Abstract: A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.

Abstract: An apparatus for enhanced anti-fouling of a submerged surface includes a bath of a feed liquid that includes water; a fouling structure in contact with the feed liquid; and a gas feed configured to introduce a gas into contact with the fouling structure and the feed liquid to separate the fouling structure from the feed liquid with a gas layer.

Abstract: A multi-effect membrane distillation system includes first and second membrane distillation effects. Each effect (stage) includes a feed channel, a gap, and a vapor-permeable membrane separating the feed channel from the gap. A liquid feed is fed into the feed channel of the first effect via a feed inlet, and the liquid feed is extracted from the first-stage feed channel via a first feed-transfer conduit that delivers the liquid feed to the second-stage feed channel. The feed is extracted from the second-stage feed channel via a second feed-transfer conduit. At least one permeate-extraction conduit is coupled with the first-stage and second-stage gaps and is configured to extract permeate (e.g., pure water) therefrom.

Abstract: A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.

Abstract: A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.

Abstract: Apparatus for energy-efficient conductive-gap membrane distillation includes a feed-liquid source and a distillation module. The distillation module includes a feed-liquid chamber in fluid communication with the feed-liquid source. The feed-liquid chamber includes a selectively porous material that allows a component of the feed liquid to pass through the selectively porous material and exit the feed-liquid chamber in vapor form but not in liquid form. The distillation module also includes a conductive-gap chamber adjacent to the selectively porous material on an opposite side of the selectively porous material from the feed-liquid chamber; a heat-transfer surface maintained at a lower temperature than the feed liquid in the feed-liquid chamber, wherein the heat-transfer surface is in thermal contact with the conductive-gap chamber; and a thermally conductive material extending across the conductive-gap chamber.

Abstract: An energy-efficient liquid-gap distillation apparatus includes a source of a feed liquid; a distillation module comprising: (a) a feed-liquid chamber n fluid communication with the feed-liquid source to establish a flow of the feed liquid there through, wherein the feed-liquid chamber includes a selectively porous material that allows a component of the feed liquid to pass through the selectively porous material and exit the feed-liquid chamber in vapor form but not in liquid form; (b) a condensing surface maintained at a lower temperature than the feed liquid in the feed-liquid chamber, wherein the condensing surface is sufficiently hydrophobic to produce a contact angle with water of at least 150; and (c) a gap between the selectively porous material and the condensing surface. Vapor passing through the membrane can be condensed as jumping droplets at the condensing surface.

Abstract: A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.

Abstract: A source liquid including a solvent with a dissolved impurity flows into a reservoir. The source liquid or a concentration of the source liquid is pumped from the reservoir through a pressure exchanger into an upstream side of a liquid-separation module. The module includes a membrane that at least partially purified solvent as filtrate to a permeate side of the liquid-separation module while diverting the impurity in a feed retentate on the upstream side of the liquid-separation module. The substantially pure water is extracted from the permeate side of the liquid-separation module, while the feed retentate is passed from the upstream side of the liquid-separation module through the pressure exchanger, where pressure from the feed retentate is transferred to the feed from the reservoir. The feed retentate is then passed from the pressure exchanger to the reservoir and recirculated as a component of the feed via the above steps.

Abstract: A multi-effect membrane distillation system includes first and second membrane distillation effects. Each effect (stage) includes a feed channel, a gap, and a vapor-permeable membrane separating the feed channel from the gap. A liquid feed is fed into the feed channel of the first effect via a feed inlet, and the liquid feed is extracted from the first-stage feed channel via a first feed-transfer conduit that delivers the liquid feed to the second-stage feed channel. The feed is extracted from the second-stage feed channel via a second feed-transfer conduit. At least one permeate-extraction conduit is coupled with the first-stage and second-stage gaps and is configured to extract permeate (e.g., pure water) therefrom.

Abstract: An apparatus for enhanced anti-fouling of a submerged surface includes a bath of a feed liquid that includes water; a fouling structure in contact with the feed liquid; and a gas feed configured to introduce a gas into contact with the fouling structure and the feed liquid to separate the fouling structure from the feed liquid with a gas layer.

Abstract: An energy-efficient liquid-gap distillation apparatus includes a source of a feed liquid; a distillation module comprising: (a) a feed-liquid chamber n fluid communication with the feed-liquid source to establish a flow of the feed liquid there through, wherein the feed-liquid chamber includes a selectively porous material that allows a component of the feed liquid to pass through the selectively porous material and exit the feed-liquid chamber in vapor form but not in liquid form; (b) a condensing surface maintained at a lower temperature than the feed liquid in the feed-liquid chamber, wherein the condensing surface is sufficiently hydrophobic to produce a contact angle with water of at least 150; and (c) a gap between the selectively porous material and the condensing surface. Vapor passing through the membrane can be condensed as jumping droplets at the condensing surface.

Abstract: Apparatus for energy-efficient conductive-gap membrane distillation includes a feed-liquid source and a distillation module. The distillation module includes a feed-liquid chamber in fluid communication with the feed-liquid source. The feed-liquid chamber includes a selectively porous material that allows a component of the feed liquid to pass through the selectively porous material and exit the feed-liquid chamber in vapor form but not in liquid form. The distillation module also includes a conductive-gap chamber adjacent to the selectively porous material on an opposite side of the selectively porous material from the feed-liquid chamber; a heat-transfer surface maintained at a lower temperature than the feed liquid in the feed-liquid chamber, wherein the heat-transfer surface is in thermal contact with the conductive-gap chamber; and a thermally conductive material extending across the conductive-gap chamber.