A membrane apparatus including a housing, a forward osmosis membrane dividing an internal space of the housing into an inlet region and a mixing region, and a pervaporation membrane dividing the internal space of the housing into the mixing region and a discharge region. The forward osmosis membrane separates a preliminary filtration liquid from an inlet liquid and provides the separated preliminary filtration liquid to the mixing region, the preliminary filtration liquid is mixed with a forward osmosis draw solution to make a mixed solution, the pervaporation membrane separates a final filtration liquid from the mixed solution and provides the separated final filtration liquid to the discharge region, the final filtration liquid is vaporized in the discharge region to make vapor, and an amount of the vapor is adjusted by at least one of a temperature of the mixed solution and a degree of vacuum of the discharge region.

Method and apparatus are disclosed for maximizing the generation of large-scale renewable energy (LSRE) by pressure-enhanced osmosis (PEO) and synergistic effects, in which a PEO module is designed by increasing the maximum power generation by increase of the dilution factor β to enhance a power output beyond ten times of the conventional PRO method, and even more power can be generated by the PEO method by incorporation with synergistic effects to form two types of PEO systems: (1) a surficial PEO system, in which the synergistic effects are achieved through combined effects of FO and nanofiltration (NF) or ultrafiltration (UF), and application of an energy exchange and fluid recovery device for re-concentration and reuse of the draw solution, (2) a subsurface PEO system, synergistic effects are achieved through application of the gravitational potential, application of waste heat from power generation, and application of an uplift chamber.

According to one embodiment, a working medium is provided. The working medium includes a first amine compound and a second amine compound. The first amine compound is a tertiary amine compound which consists of a carbon atom, a nitrogen atom and a hydrogen atom, and in which a ratio (C/N ratio) of a carbon atom number to a nitrogen atom number included in one molecule is in a range of 7 or more to 9 or less. The second amine compound is a tertiary amine compound which consists of a carbon atom, a nitrogen atom and a hydrogen atom, and in which a ratio (C/N ratio) of a carbon atom number to a nitrogen atom number included in one molecule is in a range of 5 or more to less than 7.

A system for reverse osmosis, RO, and for pressure retarded osmosis, PRO, includes: a RO subsystem (10) with a high-pressure RO chamber (11) and a low-pressure RO chamber (12) separated by a RO membrane (13), the high-pressure RO chamber (11) having a RO feed inlet (14) and a brine outlet (15) and the low-pressure RO chamber (12) having a permeate outlet (16); a PRO subsystem (20) with a high-pressure PRO chamber (21) and a low-pressure PRO chamber (22) separated by a PRO membrane (23), the high-pressure PRO chamber (21) having a draw inlet (24) and a draw outlet (25) and the low-pressure PRO chamber (22) having PRO feed inlet (26) and a PRO feed outlet (27); an induction motor (30) having a stator and a rotor, wherein the rotor is mechanically connected to an input shaft of a hydraulic pump (31) configured for providing a feed solution to the RO feed inlet (14) and to an output shaft of a hydraulic motor (32) configured for receiving a draw solution from the draw outlet (25). The invention further discloses a method for operating such system for RO/PRO and to the use of such system.

A process and system for indirect seawater, and other contaminated waters, electrolysis are provided. The system includes a pressure retarded osmosis unit including a semipermeable membrane, and a high pressure electrolyzer unit including an anode and a cathode, with an osmotic agent solution being circulated at high pressure between the draw side of the pressure retarded osmosis unit and the electrolyzer unit. The osmotic agent solution is diluted in the PRO unit as molecular water is drawn into it from the feed solution side through the semipermeable PRO membrane, and it is concentrated in the electrolyzer unit as molecular water is removed by electrolysis. The PRO process supplies the electrolyzer with the required molecular water for electrolysis and maintains a high pressure of the electrolyzer feed.

A draw solute may have a low viscosity, and can be circulated during a forward-osmosis water treatment, and has a sedimentation under heating and a higher osmotic pressure than that of seawater, when used as a draw solution. A draw solute may include at least one of vinyl ether polymer containing an oxyethylene chain in a side chain and having a number average molecular weight (Mn) of 13,000 or less.

An ionic liquid and a forward osmosis process employing the same are provided. The ionic liquid has a structure represented by Formula (I)

AB.sub.n   Formula (I)

, wherein A is

##STR00001##

n is 1 or 2; m is 0, or an integer from 1 to 7; R.sup.1 and R.sup.2 are independently methyl or ethyl; k is an integer from 3 to 8; B is

##STR00002##

i is independently 1, 2, or 3; and j is 5, 6, or 7. The forward osmosis process employing the ionic liquid is used to desalinate a brine via a forward osmosis (FO) model.

An extracted material for forward osmosis is provided. The extracted material includes a first ionic compound, a second ionic compound and a third ionic compound, which are represented by formula {K[A.sup.+(R.sup.1)(R.sup.2)(R.sup.3)].sub.p}(X.sup.−).sub.c(Y.sup.−).sub.d. X.sup.− is the same as Y.sup.− in the first ionic compound. X.sup.− is the same as Y.sup.− in the second ionic compound. X.sup.− in the first ionic compound is different from X.sup.− in the second ionic compound. X.sup.− differs from Y.sup.− in the third ionic compound. X.sup.− in the third ionic compound is the same as X.sup.− in the first ionic compound or X.sup.− in the second ionic compound. Y.sup.− in the third ionic compound is the same as Y.sup.− in the first ionic compound or Y.sup.− in the second ionic compound. A method for preparing an extracted material and a forward-osmosis water desalination system using the same are also provided.

A draw solute for forward osmosis comprising a semi-interpenetrating (semi-IPN) hydrogel which comprises a thermally responsive polymer and a hydrophilic polymer, such that the semi-IPN hydrogel is capable of switching between a hydrophilic and hydrophobic state in response to changes in temperature is provided. Also provided is a draw solute comprising a hydrogel of a polyionic thermally responsive polymer, wherein the hydrogel switches between a hydrophilic state to allow absorption of water osmosed from a feed solution and a hydrophobic state to allow release of the absorbed water in response to changes in temperature. There is also provided a forward osmosis method comprising: contacting a feed solution and the draw solute via a semi-permeable membrane, such that feed water in the feed solution passes through the membrane by osmotic pressure and moves into the draw solute; and separating the water from the draw solute to form a purified water product.

The present invention relates to a thermo-responsive solution and in particular, a solution for use in an osmosis process that is suitable for separating or purifying solutes and or water from an aqueous solution on a large scale and under energy efficient conditions.