A solar-thermal vapor-permeation membrane is provided. The solar-thermal vapor-permeation membrane includes a thermally conductive, microporous support layer having a feed surface, and an active separation layer adjacent the feed surface of the support layer. The support layer is capable of absorbing solar-thermal radiation. Utilization of solar energy for a membrane separation process replaces fossil-fuel derived energy with renewable energy as the driving force and does not involve the generation of undesirable greenhouse gas emissions. Therefore, the solar-thermal vapor-permeation process using the provided membrane is cost effective, energy efficient, and environmentally friendly.

The present invention provides a membrane separation system suitable for suppressing a decrease in a content of an organic compound in a permeated fluid. A membrane separation system of the present invention includes a membrane separation device that has a separation membrane, a feed space and a permeation space. When an aqueous solution containing a volatile organic compound is supplied to the feed space and the permeation space is decompressed, the separation membrane separates the aqueous solution into a permeated fluid having a content of the organic compound higher than that in the aqueous solution and a non-permeated fluid having a content of the organic compound lower than that in the aqueous solution. The membrane separation system performs a pressurizing procedure that increases a pressure in the permeation space when at least one condition selected from the group consisting of conditions (A1) to (A3) is satisfied.

A high salinity water purification system and process, including a forward osmosis system and a reverse osmosis or nanofiltration system. A solids membrane separation system removes solids from the influent water being processed. A pervaporation (PV) system eliminates liquid impurities from the influent water being processed.

A method of determining composition of an aqueous solution is disclosed. The method includes obtaining the aqueous solution, removing oxygen from the aqueous solution, determining concentration of dissolved oxygen, removing hydrogen peroxide from the aqueous solution, and determining concentration of dissolved oxygen. The method includes calculating the difference between the concentrations of dissolved oxygen to determine concentration of hydrogen peroxide. A system for determining composition of an aqueous solution is also disclosed. The system includes a feed line connectable to a source of the aqueous solution, an oxygen removal unit, a hydrogen peroxide removal unit, and dissolved oxygen analyzers.

Methods and systems for removing or reducing water and producing epoxide. The methods may include providing a first mixture that includes t-butyl hydroperoxide, t-butyl alcohol, and a first amount of water; and contacting at least a portion of the first mixture with a membrane to reduce the amount of water in the first mixture.

Disclosed are a solar seawater desalination membrane, a preparation method and a seawater desalination treatment method thereof. The preparation method includes: carrying out hydrophilic treatment on a first carbon cloth to obtain a second carbon cloth with hydrophilicity greater than that of the first carbon cloth; an average pore size of the second carbon cloth is of micron-scale; carrying out a coating treatment on the second carbon cloth based on a preset copper mesh to obtain a first cloth membrane; processing the first cloth membrane to obtain a second cloth membrane; the second cloth membrane includes a graphdiyne structure and the average pore size of the second cloth membrane is of nanometer-scale; processing the second cloth membrane to obtain the solar seawater desalination membrane. The solar seawater desalination membrane contains poly-dopamine particles, and the average pore size of the membrane is smaller than that of the second cloth membrane.

Systems and techniques for removing fluoride from waste water may involve acidifying a waste water that includes fluoride ions to form hydrofluoric acid. After acidifying the waste water, the acidified waste water can contact a first side of a membrane to cause at least a portion of the hydrofluoric acid to pass through the membrane to a second side of the membrane. The second side of the membrane can be contacted with a collection fluid to collect the hydrofluoric acid passing through the membrane. A treated wastewater having a reduced concentration of fluoride ions can be discharged from a housing containing the membrane. The collection fluid having collected the hydrofluoric acid passing through the membrane can also be discharged from the housing containing the membrane. In some applications, the collection fluid having collected the hydrofluoric acid can be processed to separate and recover the hydrofluoric acid for subsequent use.

A method of determining composition of an aqueous solution is disclosed. The method includes obtaining the aqueous solution, removing oxygen from the aqueous solution, determining concentration of dissolved oxygen, removing hydrogen peroxide from the aqueous solution, and determining concentration of dissolved oxygen. The method includes calculating the difference between the concentrations of dissolved oxygen to determine concentration of hydrogen peroxide. A system for determining composition of an aqueous solution is also disclosed. The system includes a feed line connectable to a source of the aqueous solution, an oxygen removal unit, a hydrogen peroxide removal unit, and dissolved oxygen analyzers.

A membrane separation system includes a membrane separation unit, a condensation unit, and a decompression unit. The condensation unit is disposed between the membrane separation unit and the decompression unit. The membrane separation unit has a pervaporation membrane. The pervaporation membrane separates a feed liquid containing a volatile organic compound and a gas into a permeated fluid and a non-permeated fluid. The condensation unit condenses the organic compound contained in the permeated fluid. The decompression unit decompresses an inside of a permeation space of the membrane separation unit. An operating condition of the decompression unit is controlled in such a manner that a pressure in the permeation space of the membrane separation unit has, during operation, a value larger than a minimum value of a pressure that the inside of the permeation space of the membrane separation unit can reach during rated operation of the decompression unit.

The present invention provides a pervaporation membrane suitable for a long-term process for separating a volatile organic compound from an aqueous solution containing the organic compound. A pervaporation membrane includes a separation functional layer including a silicone resin. A ratio R of a value to a Young's modulus A1 (MPa) of the separation functional layer before a test below is 30% or more, the value being determined by subtracting the Young's modulus Al from a Young's modulus A2 (MPa) of the separation functional layer after the test. Test: The separation functional layer is immersed in a liquid mixture consisting of n-butanol and water for three weeks. The separation functional layer is taken out of the liquid mixture and dried. A content of n-butanol in the liquid mixture is 1.0 wt %, and the liquid mixture has a temperature of 80 C.