Abstract: Liquid solution separation (e.g., concentration and/or desalination) methods and related systems involving membrane separators having at least one-semipermeable membrane are provided. In some instances, at least some of the membrane separators permit a portion of solute in a retentate side input stream to pass through the semi-permeable membrane. In some instances, multiple membrane separators are employed, with the membrane separators having different solute permeabilities (e.g., due to varying pore size and/or molecular weight cutoffs). The methods and systems may be configured such that the ratio of mass flow and/or concentration of solute entering the retentate sides of the membrane separators are relatively high compared to the mass flow and/or concentration of solute exiting the retentate sides of the membrane separators.

Abstract: A thin-film-composite hollow-fiber membrane includes a phase-inversion layer, which is in the form of a hollow fiber, and an active layer coated on the phase-inversion layer. The active layer selectively allows passage of water molecules but rejects at least some dissolved ions. The thin-film-composite hollow-fiber membrane can have an internal burst pressure of at least 4 MPa. In a method for forming the membrane, the polymer concentration in the spinning dope from which the hollow-fiber substrate is formed can have a polymer concentration no greater than 5% below the critical concentration.

Abstract: Condensing apparatuses and their use in various heat and mass exchange systems are generally described. The condensing apparatuses, such as bubble column condensers, may employ a heat exchanger positioned external to the condensing vessel to remove heat from a bubble column condenser outlet stream to produce a heat exchanger outlet stream. In certain cases, the condensing apparatus may also include a cooling device positioned external to the vessel configured and positioned to remove heat from the heat exchanger outlet stream to produce a cooling device outlet stream. The condensing apparatus may be configured to include various internal features, such as a vapor distribution region and/or a plurality of liquid flow control weirs and/or chambers within the apparatus having an aspect ratio of at least 1.5. A condensing apparatus may be coupled with a humidifier to form part of a desalination system, in certain cases.

Abstract: Liquid solution concentration methods and related systems involving osmosis units and energy recovery are generally described. In some embodiments, an osmotic system has a pump, a first reverse osmosis unit, a second reverse osmosis unit, and one or more energy recovery devices. Various embodiments are directed to features such as balancing streams, recirculation streams, and/or valving that alone or in combination may afford improved energy efficiency and/or system performance. Some embodiments may improve performance of certain types of energy recovery devices in combination with osmosis units, such as isobaric or turbine energy recovery devices.

Abstract: Liquid solution concentration methods and related systems involving osmosis units and energy recovery are generally described. In some embodiments, an osmotic system has a pump, a first reverse osmosis unit, a second reverse osmosis unit, and one or more energy recovery devices. Various embodiments are directed to features such as balancing streams, recirculation streams, and/or valving that alone or in combination may afford improved energy efficiency and/or system performance. Some embodiments may improve performance of certain types of energy recovery devices in combination with osmosis units, such as isobaric or turbine energy recovery devices.

Abstract: Liquid solution concentration systems, and related methods, are generally described. In some embodiments, the system is an osmotic system comprising a plurality of osmotic modules. For example, the osmotic system can comprise a feed osmotic module configured to produce an osmotic module retentate outlet stream having a higher concentration of solute than the retentate inlet stream transported to the feed osmotic module. The osmotic system can also comprise an isolation osmotic module fluidically connected to the feed osmotic module. The osmotic system can also optionally comprise a purification osmotic module fluidically connected to the feed osmotic module and/or the isolation osmotic module. Certain embodiments are related to altering the degree to which the feed osmotic module retentate outlet stream is recycled back to the retentate-side inlet of the feed osmotic module during operation.

Abstract: Methods and systems directed to recovery of lithium (e.g., lithium salts) from liquid streams are provided. In some embodiments, methods relate to obtaining lithium (e.g., as a solid lithium salt) by removing at least a portion of liquid from a feed stream to form a concentrated stream with respect to solubilized lithium cations. Liquid removal may include transporting at least a portion of the feed stream to an osmotic unit and/or a humidifier. Some methods include removing impurities (e.g., non-lithium cations) from the concentrated stream (e.g., via precipitation and/or crystallization). In some embodiments, solutions containing solubilized lithium cations and anions are electrochemically-treated such that first solubilized anions are replaced with second, different anions. In some embodiments, solid lithium salt containing at least a portion of the lithium cations and the second anions is obtained (e.g.

Abstract: A serial filtration system for liquid purification includes a preliminary-stage reverse-osmosis (RO) module and a first-stage, high-permeability, reverse-osmosis (HiRO) module. Both modules include (a) a chamber including an inlet, a retentate outlet, and a permeate outlet, and (b) at least one membrane separating the chamber into a retentate side on an upstream side of the membrane and a permeate side on a downstream side of the membrane. The membrane in the preliminary stage is an RO membrane, while the membrane in the first stage is an oxidized membrane. The first-stage inlet is in fluid communication with the preliminary-stage, retentate outlet; and the oxidized membrane in the first stage, comprises an oxidized polyamide active layer coated on a porous support, wherein the oxidized polyamide active layer has an atomic oxygen/nitrogen ratio of at least 1.5.

Abstract: A serial filtration system for liquid purification includes a preliminary-stage reverse-osmosis (RO) module and a first-stage, high-permeability, reverse-osmosis (HiRO) module. Both modules include (a) a chamber including an inlet, a retentate outlet, and a permeate outlet, and (b) at least one membrane separating the chamber into a retentate side on an upstream side of the membrane and a permeate side on a downstream side of the membrane. The membrane in the preliminary stage is an RO membrane, while the membrane in the first stage is an oxidized membrane. The first-stage inlet is in fluid communication with the preliminary-stage, retentate outlet; and the oxidized membrane in the first stage, comprises an oxidized polyamide active layer coated on a porous support, wherein the oxidized polyamide active layer has an atomic oxygen/nitrogen ratio of at least 1.5.

Abstract: Liquid solution concentration methods and related systems involving osmosis units and energy recovery are generally described. In some embodiments, an osmotic system has a pump, a first reverse osmosis unit, a second reverse osmosis unit, and one or more energy recovery devices. Various embodiments are directed to features such as balancing streams, recirculation streams, and/or valving that alone or in combination may afford improved energy efficiency and/or system performance. Some embodiments may improve performance of certain types of energy recovery devices in combination with osmosis units, such as isobaric or turbine energy recovery devices.

Abstract: Turbines and associated components, systems, and methods are described. In some embodiments, the turbine blades and turbines are configured to convert kinetic energy present in fluid (e.g., water) to other forms of energy (e.g., in a hydrokinetic energy system in a river or ocean) relatively efficiently and/or at relatively low cut-in speeds. The turbine blades may have a shape and/or include structural features that contribute at least in part to relatively high efficiency and/or relatively low cut-in speeds. In some embodiments, the turbine blades have a geometry similar to the geometry of a maple seed.

Abstract: Provided herein are osmotic desalination methods and associated systems. According to certain embodiments, multiple osmotic membranes may be used to perform a series of osmosis steps, such that an output stream having a relatively high water purity—compared to a water purity of an aqueous feed stream—is produced. In some embodiments, multiple draw streams can be used to produce aqueous product streams having sequentially higher purities of water. Certain embodiments are related to osmotic desalination systems and methods in which forward osmosis is used to produce a first product stream having a relatively high water purity relative to an aqueous feed stream, and reverse osmosis is used to perform a second step (and/or additional steps) on the first product stream. In some embodiments, multiple reverse osmosis steps can be used in series to perform a net desalination process.

Abstract: Turbines and associated components, systems, and methods are described. In some embodiments, the turbine blades and turbines are configured to convert kinetic energy present in fluid (e.g., water) to other forms of energy (e.g., in a hydrokinetic energy system in a river or ocean) relatively efficiently and/or at relatively low cut-in speeds. The turbine blades may have a shape and/or include structural features that contribute at least in part to relatively high efficiency and/or relatively low cut-in speeds. In some embodiments, the turbine blades have a geometry similar to the geometry of a maple seed.

Abstract: The present disclosure is related to hybrid desalination systems and associated methods. The hybrid desalination system can comprise a first desalination unit comprising a reverse osmosis unit and a second desalination unit fluidically connected to the first desalination unit, wherein the second desalination unit comprises a humidification-dehumidification desalination apparatus. The present disclosure is also related to systems and methods for the formation of solid salts using a humidifier. According to certain embodiments, the flow velocity of a gas in the humidifier can be relatively high during the formation of the solid salt. In some embodiments, the humidifier comprises a multi-stage bubble column humidifier.

Abstract: Turbines and associated components, systems, and methods are described. In some embodiments, the turbine blades and turbines are configured to convert kinetic energy present in fluid (e.g., water) to other forms of energy (e.g., in a hydrokinetic energy system in a river or ocean) relatively efficiently and/or at relatively low cut-in speeds. The turbine blades may have a shape and/or include structural features that contribute at least in part to relatively high efficiency and/or relatively low cut-in speeds. In some embodiments, the turbine blades have a geometry similar to the geometry of a maple seed.

Abstract: Systems and methods related to desalination systems are described herein. According to some embodiments, the desalination systems are transiently operated and/or configured to facilitate transient operation. In some embodiments, a liquid stream comprising water and at least one dissolved salt is circulated through a fluidic circuit comprising a desalination system. In some embodiments, a portion of the desalination system (e.g., a humidifier) is configured to remove at least a portion of the water from the liquid stream to produce a concentrated brine stream enriched in the dissolved salt. In certain cases, the concentrated brine stream is recirculated through the fluidic circuit until the concentrated brine stream reaches a relatively high density (e.g., at least about 10 pounds per gallon) and/or a relatively high salinity (e.g., a total dissolved salt concentration of at least about 25 wt %).

Abstract: A counter-flow simultaneous heat and mass exchange device is operated by directing flows of two fluids into a heat and mass exchange device at initial mass flow rates where ideal changes in total enthalpy rates of the two fluids are unequal. At least one of the following state variables in the fluids is measured: temperature, pressure and concentration, which together define the thermodynamic state of the two fluid streams at the points of entry to and exit from the device. The mass flow rate of at least one of the two fluids is changed such that the ideal change in total enthalpy rates of the two fluids through the device are brought closer to being equal.

Abstract: Liquid solution concentration systems, and related methods, are generally described. In some embodiments, the system is an osmotic system comprising a plurality of osmotic modules. For example, the osmotic system can comprise a feed osmotic module configured to produce an osmotic module retentate outlet stream having a higher concentration of solute than the retentate inlet stream transported to the feed osmotic module. The osmotic system can also comprise an isolation osmotic module fluidically connected to the feed osmotic module. The osmotic system can also optionally comprise a purification osmotic module fluidically connected to the feed osmotic module and/or the isolation osmotic module. Certain embodiments are related to altering the degree to which the feed osmotic module retentate outlet stream is recycled back to the retentate-side inlet of the feed osmotic module during operation.

Abstract: Described herein are systems and methods for treating an aqueous input stream comprising at least one suspended and/or emulsified immiscible phase (e.g., oil, grease) and, in some cases, one or more additional contaminants, such as solubilized bicarbonate (HCO3?) ions, solubilized divalent cations (e.g., Ca2+, Mg2+), solubilized trivalent cations (e.g., Fe3+, Al3+), organic material (e.g., humic acid, fulvic acid), hydrogen sulfide (H2S), and/or suspended solids. According to certain embodiments, the aqueous feed stream is supplied to a water treatment system comprising a chemical coagulation apparatus and a suspended solids removal apparatus (e.g., a clarifier). Within the chemical coagulation apparatus, an amount of an inorganic coagulant (e.g., aluminum chlorohydrate, polyaluminum chloride), an amount of a strong base (e.g., sodium hydroxide), and an amount of a polyelectrolyte (e.g., polyacrylamide) may be added to the aqueous input stream to form a chemically-treated stream.

Abstract: Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).