A water treatment system with a vessel that contains saline water and a membrane module with a first planar semi-permeable membrane, a second planar semi-permeable membrane substantially parallel to the first planar semi-permeable membrane, and at least one elongated membrane with an elongated cavity sandwiched between the first and the second planar semi-permeable membranes, wherein water molecules in the saline water are permeated through said membranes when a draw solution is passed through the elongated cavity; and a method of forming a purified water stream with the water treatment system.

A method and system of generating electrical power or hydrogen from thermal energy is disclosed. The method includes separating, by a selectively permeable membrane, a first saline solution from a second saline solution, receiving, by the first saline solution and/or the second saline solution, thermal energy from a heat source, and mixing the first saline solution and the second saline solution in a controlled manner, capturing at least some salinity-gradient energy as electrical power as the salinity difference between the first saline solution and the second saline solution decreases. The method further includes transferring, by a heat pump, thermal energy from the first saline solution to the second saline solution, causing the salinity difference between the first saline solution and the second saline solution to increase. The method may include a process of membrane distillation, forward osmosis, evaporation, electrodialysis, and/or salt decomposition for further energy efficiency and power generation.

A method is provided for using forward osmosis to remove impurities dissolved in an aqueous-based feed solution, where the method includes directing a solvent past a first side of a forward osmosis membrane and the feed solution is directed past a second side of the forward osmosis membrane, the solvent having a higher osmotic pressure than the feed solution so as to draw water across the membrane thereby diluting the solvent and concentrating the impurities in the feed solution, where the solvent is an amine-terminated branched PEG, such as amine-terminated glycerol ethoxylate, amine-terminated trimethylolpropane ethoxylate, or amine-terminated pentaerithritol ethoxylate, for example. The method further includes regenerating the solvent by exposing the diluted solvent to a gas containing CO2, whereby the CO2 is absorbed by the solvent, facilitating substantial separation of the solvent from water.

A forward osmosis process is provided, which includes separating a feed part and a draw solution part by a semi-permeable film. An ionic liquid is introduced into the draw solution part, and brine is introduced into the feed part. The brine has an osmotic pressure lower than that of the ionic liquid, so that pure water of the brine permeates through the semi-permeable film, enters the draw solution part, and mixes with the ionic liquid to form a draw solution. The draw solution was obtained out of the draw solution part to be left to stand at room temperature, so that the draw solution separated into a water layer and an ionic liquid layer. The ionic liquid includes

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A method for treating produced water from a fraccing source is disclosed. The method first mixes nitrogen and produced water and feeds the mixture to a forward osmosis unit containing a semi-permeable membrane; carbon dioxide gas is then fed to the forward osmosis unit, therein creating a pressurized nitrogen side and a pressurized carbon dioxide side of the forward osmosis unit; concentrated produced water is recovered from the pressurized nitrogen side of the forward osmosis unit and fresh water is recovered from the pressurized carbon dioxide side of the forward osmosis unit.

A system and method for generating power from waste heat, the system including (1) a forward osmosis module having an FO membrane a water inlet, a water outlet, a draw solution solute inlet and a diluted draw solution outlet; (2) a hydro-turbine using the diluted draw solution for generating power; (3) a CO.sub.2 absorption reactor to permit the introduction of compressed CO.sub.2 into the diluted draw solution to cause substantial separation of draw solution solute from the water, which water can be processed for subsequent recycling to the FO module, the CO.sub.2 absorption reactor configured to discharge a mixture of separate draw solution solute and absorbed CO.sub.2; and (4) a heat exchanger for transferring waste heat from an incoming heated fluid to the mixture of draw solution solute and CO.sub.2.

A process for separating solvent from a feed solution, said process comprising contacting the feed solution with one side of a semi-permeable membrane, applying hydraulic pressure to the feed solution, such that solvent from the feed solution flows through the membrane by reverse osmosis to provide a permeate solution on the permeate-side of the membrane, separating solvent from the permeate solution to provide a stream comprising the solvent and a residual solution having an increased osmotic pressure than the permeate solution, and recycling the residual solution to the permeate-side of the semi-permeable membrane, whereby the osmotic pressure on the permeate-side of the semi-permeable membrane is lower than the osmotic pressure of the feed solution.

Disclosed herein is a use of an inorganic salt to form and regenerate a draw solute for forward osmosis, wherein the inorganic salt is selected from one or more of the group selected from sodium sulfate, calcium lactate, disodium phosphate, tetrasodium pyrophosphate, and hydrates thereof. Also disclosed herein is a method of forward osmosis using said inorganic salt.

An embodiment provides a working medium to be used in a circular osmotic pressure electric power generation system. The working medium comprises water and an inducing-liquid. The working medium, under conditions of a temperature of 5? C. to 35? C. and a pressure of 1 atmosphere, is in (1) a state of a liquid-liquid mutually dissolved two-component mixed solution when a concentration of the water or the inducing-liquid in the total amount of the water and the inducing-liquid is 10% by weight or lower, and (2) a state of being separated into the water phase and the inducing-liquid phase when the concentration of the water or the inducing-liquid in the total amount of the water and the inducing-liquid is higher than 10% by weight.

Methods and systems for filtering of biological particles are disclosed. Filtering membranes separate adjacent chambers. Through osmotic or electrokinetic processes, flow of particles is carried out through the filtering membranes. Cells, viruses and cell waste can be filtered depending on the size of the pores of the membrane. A polymer brush can be applied to a surface of the membrane to enhance filtering and prevent fouling.