The present disclosure is directed to methods and systems of purifying solvents. The purified solvents can be used for cleaning a semiconductor substrate in a multistep semiconductor manufacturing process.

Provided is a cell culture apparatus including a culture vessel that stores a cell suspension containing cells; a first filter part that has a first filter membrane that performs membrane separation treatment on the cell suspension extracted from the culture vessel; a first circulation flow path that allows components blocked by the first filter membrane to return to the culture vessel; a second filter part that has a second filter membrane that performs membrane separation treatment on components of the cell suspension permeated through the first filter membrane; a second circulation flow path that allows components permeated through the second filter membrane to return to the culture vessel; and a recovery flow path that recovers components blocked by the second filter membrane. In the cell culture apparatus, an average hole diameter of the first filter membrane is 20 ?m or smaller, and 0<B/A?0.5 is satisfied in a case where an average hole diameter of the first filter membrane is A and an average hole diameter of the second filter membrane is B; or an average hole diameter of the first filter membrane is 20 ?m or smaller, and the second filter membrane is an ultrafiltration membrane.

An aqueous solution flows through a desalination system that separates the aqueous solution into purified water and concentrated brine. The concentrated brine is directed into an electrodialysis system that includes an anode and a cathode and at least two monovalent selective ion exchange membranes between the anode and the cathode. At least one of the monovalent selective ion exchange membranes separates at least one diluate channel from at least one concentrate channel in the electrodialysis system, and this membrane selectively allows at least one monovalent ion to pass through the membrane while blocking or inhibiting the transport therethrough of multi-valent ions. The concentrated brine flows through at least the concentrate channel while a voltage is applied to the anode and cathode; and additional aqueous solution flows through the diluate channel.

Methods of recovering lithium from a lithium source or a lithium-containing material using low pH solutions and membrane technologies to purify and concentrate the recovered lithium. The lithium sources may include a spent lithium-ion battery/cell, a lithium-containing mineral deposit, or other lithium containing materials. The processes described herein recovery the lithium after digestion of the lithium-containing material with a low pH solution through one or more acid-stable, semipermeable membranes.

A feed of at least one of (a) a source liquid including a solvent with a dissolved impurity and (b) a retentate of the source liquid is pumped in a substantially closed loop through a liquid-separation module. The liquid-separation module includes a membrane that passes at least partially purified solvent to a permeate side of the membrane while diverting the impurity in a retentate on the retentate side of the membrane. The purified solvent is extracted from the permeate side of the membrane; and the retentate from the liquid-separation module is pumped to or through a pressurized reservoir with a variable volume for the feed component and recirculated as a component of the feed. Over time, the volume for the feed is reduced and the pressure applied to the feed in the reservoir is increased to balance against an increasing difference in osmotic pressure across the membrane.

A method is provided for sanitizing a reverse osmosis system to supply high-purity permeate. Included in the method is supplying raw water to a feed tank and to a filter module using a raw-water inlet line having an inlet valve. A primary circuit is provided, and has a first pump connected to the filter module. A secondary circuit is provided, and has a second pump and a heater, both of which are connected to the filter module. The primary circuit is separated from the secondary circuit using a semipermeable membrane disposed in the filter module. The secondary circuit of the reverse osmosis system is cleaned or disinfected while the raw-water inlet line is in a disconnected state and the inlet valve is in a closed state using the second pump and the heater.

Described are improved electrodialysis (ED) desalination systems and methods comprising voltage regulation and/or improved stack geometries. The systems and methods provide product water concentrations suitable for drinking (having a total dissolved solids concentration of less than 500 mg/L or 500 ppm) and have a high product recovery ratio.

An apparatus for separating a gas mixture is provided in the form of a first membrane separation stage, a second membrane separation stage, a first and a second measuring device, and a controller. The first membrane separation stage is imparted with a first membrane area and separates the gas mixture into a first permeate stream and a first retentate stream. The second membrane separation stage is imparted with a second membrane area and is configured to separate the first permeate stream into a second permeate stream and a second retentate stream. The first and the second measuring devices are configured to measure process parameters and generate process control signals. Based on the process control signals, the controller modifies a membrane ratio defined with reference to the first membrane area and the second membrane area.

A multistage membrane distillation device includes a plurality of membrane distillation cells each having at least one membrane. Each membrane defines a feed space at one surface thereof and a vapor space at an opposite surface thereof, and is configured to allow a part of a feed flowing in the feed space to evaporate and pass through the membrane as a vapor phase into the vapor space where the vapor phase is condensed to a distillate including a volatile and condensable substance, and the non-evaporated feed to exit the feed space as a concentrated fluid. The device further includes a fluid connection for allowing the distillate from an i.sup.th cell to flow as a feed into the feed space of an (i+1).sup.th cell to produce a further distillate with a higher concentration of the volatile and condensable substance. The concentrated fluid from each cell is prevented from entering the feed space of other cells.

The invention relates to a system for treating contaminated wastewater, comprising a feed line (3) that leads into a separator (5) and a discharge line (10) that leaves the separator, which discharge line leads directly or indirectly into an access line (16) into an ultrafiltration system (18), wherein the ultrafiltration system (18) has a permeate outlet line (19) and a concentrate outlet line (17). According to the invention, a system and a method for treating contaminated wastewater that operate effectively and reliably with low component complexity are provided or specified. This is achieved in that the permeate outlet line (19) can be connected to the feed line (3) in a controllable manner. According to the corresponding method, water separated from the wastewater in the separator (5) exits into a discharge line (10), and the water is then fed to an ultrafiltration system (18), in which the water is separated into a concentrate discharged into a concentrate outlet line (17) and a permeate discharged into a permeate outlet line (19), wherein the permeate can be fed back into the feed line (3) of the separator (5) for reaction with a supplied precipitant, and heavy metal, for example, is separated from the permeate in the separator (5).