A method of obtaining a compound may include adding a substrate to a medium in a reactor, and reacting the substrate in the reactor to form the compound. A first stream is separated from the reaction liquid through a first membrane. A second stream is separated from the reaction liquid through a second membrane. The first membrane is a filtration membrane and the second membrane is configured for liquid-gas or liquid-liquid extraction The first membrane and the second membrane are at least partially immersed in the medium and are moved relative to the reactor during the separation steps.

A process for recovery of lithium ions from a lithium-bearing brine includes contacting the lithium-bearing brine with a lithium ion sieve (where that LIS includes an oxide of titanium or niobium) in a first stirred reactor to form a lithium ion complex with the lithium ion sieve, and decomplexing the lithium ion from the lithium ion sieve in a second stirred reactor to form the lithium ion sieve and an acidic lithium salt eluate.

An electrochlorination system includes an electrolyzer fluidically connectable between a source of feed fluid and a product fluid outlet, and a sub-system configured to one of increase a pH of the feed fluid, or increase a ratio of monovalent to divalent ions in the feed fluid, upstream of the electrolyzer.

A method of obtaining a compound may include adding a substrate to a medium in a reactor, and reacting the substrate in the reactor to form the compound. A first stream is separated from the reaction liquid through a first membrane. A second stream is separated from the reaction liquid through a second membrane. The first membrane is a filtration membrane and the second membrane is configured for liquid-gas or liquid-liquid extraction The first membrane and the second membrane are at least partially immersed in the medium and are moved relative to the reactor during the separation steps.

A method of predicting membrane fouling in a reverse osmosis process includes collecting information relative to the reverse osmosis process being performed over a predetermined period of time, the collected information including a process factor and a water quality factor, the process factor including a produced water flow rate; calculating a salt removal rate and a pressure drop based on the collected information; normalizing the produced water flow rate, the salt removal rate, and the pressure drop; generating a prediction equation using normalized values of the produced water flow rate, the salt removal rate, and the pressure drop values; and predicting membrane fouling through the generated prediction equation to determine a chemical cleaning time. Process and water quality factors are normalized to temperature and/or flow rate, and the prediction equation uses the normalized factors. Both short-term and long-term predictions are made for chemical cleaning time and membrane module replacement time.

The present invention relates to a formate production method including: a first step of producing a formate by causing a reaction between carbon dioxide and hydrogen in a solution containing a solvent, a catalyst dissolved in the solvent, and a metal salt or an organic salt; and a second step of separating, by a separation membrane, the catalyst from a reaction solution obtained in the first step, in which the catalyst contains at least one metal element selected from the group consisting of metal elements belonging to Group 8, Group 9, and Group 10 of a periodic table.

An electrochemical system includes a first reservoir comprising a first fluid and a catalyst, wherein the first fluid comprises a reaction mixture that reacts to form first and second products, and a second reservoir comprises a second fluid. A first electrode contacts a redox-active electrolyte material solution and has a reversible redox reaction with the electrolyte material to accept at least one ion. A second electrode contacts a redox-active electrolyte material solution and has a reversible redox reaction with the electrolyte material to drive at least one ion into the second fluid as an electrical potential is supplied. A diluted effluent comprising the second product and the catalyst exits the second reservoir, wherein the second product is removed from the first reservoir via electroosmosis, and optionally concurrently via osmosis, and a product stream comprising the first product exits the first reservoir.

The present invention provides a method of preparing oxalic acid (H.sub.2C.sub.2O.sub.4), the method at least comprising the steps of: (a) providing a metal formate (HCO.sub.2M) containing stream, wherein the metal (M) of the metal formate (HCO.sub.2M) is a monovalent metal selected from the group consisting of Li, Na, K, Cs, Rb and a mixture thereof; (b) heating the metal formate (HCO.sub.2M) containing stream thereby obtaining a metal oxalate (M.sub.2C.sub.2O.sub.4) containing stream; (c) subjecting the metal oxalate (M.sub.2C.sub.2O.sub.4) containing stream to electrodialysis, thereby obtaining at least oxalic acid (M.sub.2C.sub.2O.sub.4) and a metal hydroxide (MOH).

A membrane module includes a housing. The housing includes a housing, comprising: a first plurality of porous hollow fiber membranes, and a second plurality of porous hollow fiber membranes different from the first plurality of porous hollow fiber membranes. The first plurality of porous hollow fiber membranes has a first length, and the second plurality of porous hollow fiber membranes has a second length that is at least 1.1 times greater than the first length. The membrane module can be used in separation methods, such as membrane distillation methods.

Provided is a method for treating a hexavalent chromium-containing aqueous solution by water treatment employing a titanium dioxide photocatalyst that is excellent in both photocatalytic activity and solid-liquid separation performance. The method according to the present disclosure includes the steps of: adding catalyst particles to the aqueous solution; reducing hexavalent chromium by irradiating the aqueous solution with light having a wavelength of 200 nanometers or more and 400 nanometers or less while stirring the catalyst particles in the aqueous solution; and stopping the stirring and separating the catalyst particles from the aqueous solution by sedimentation. Each catalyst particle is composed only of a titanium dioxide particle and a zeolite particle, the titanium dioxide particle is adsorbed on the outer surface of the zeolite particle, the zeolite particle has a silica/alumina molar ratio of 10 or more, and the catalyst particles are contained in the aqueous solution at a concentration of 0.4 grams/liter or more and 16 grams/liter or less.