A reverse osmosis unit for processing a feed solution is provided. The unit includes a pressure vessel includes an inlet end, an outlet end, and a vessel body extending between the inlet end and the outlet end. The reverse osmosis unit further includes a plurality of first membrane modules positioned within the pressure vessel. Each first membrane module of the plurality of first membrane modules has a first salt permeance value. At least one second membrane module is positioned within the pressure vessel and coupled in flow communication to the plurality of first membrane modules. The at least one second membrane module has a second salt permeance value that is different from the first salt permeance value.

A method for producing an ethanol solution includes obtaining, from a starting liquid, a liquid feed having less than by weight of constituents and having 3% to 25% by weight of ethanol, supplying the liquid feed to a feed stream inlet of a reverse osmosis separation system having a first pass, wherein (i) each pass has an reverse osmosis membrane filtration unit, each membrane filtration unit having an ethanol rejection percentage of between 50% to 99%, and (ii) each pass has the feed stream inlet for a feed stream, a permeate stream outlet for a permeate stream, and a retentate stream outlet for a retentate stream, operating the system to maintain pressure in one of the membrane filtration units in a range of 1,200 to 4,000 psi, and obtaining retentate that is enriched with ethanol, the retentate differs from the starting liquid by absence of the removed constituents.

A method for efficient separation and enrichment of lithium includes the following steps: pretreatment: diluting and filtering salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate, wherein the operation pressure of the nanofiltration separation system is 1.0 MPa5.0 MPa; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; and second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, wherein the electrodialysis concentrate is a solution enriching lithium ions. The present application couples several different membrane separation technologies and adopts the monovalent ion selective nanofiltration membrane having good separation performance in the process of nanofiltration.

A method for separation and enrichment of lithium includes the following steps: pretreatment: diluting and filtering salina aged brine to obtain pretreated brine; separation: separating the pretreated brine via a nanofiltration separation system to obtain nanofiltration permeate and nanofiltration concentrate; first concentration: carrying out first concentration on the nanofiltration permeate via a reverse osmosis system to obtain reverse osmosis concentrate and reverse osmosis permeate; second concentration: carrying out second concentration on the reverse osmosis concentrate via an electrodialysis system to obtain electrodialysis concentrate and electrodialysis permeate, and the electrodialysis concentrate is solution enriching lithium ions. The present application couples several different membrane separation technologies by utilizing the advantages of different membrane separation technologies, thereby achieving the purposes of improving the separation efficiency of magnesium and lithium and improving the enrichment efficiency of lithium.

The present invention relates to processes and systems for basic gas, e.g., ammonia, recovery and/or acid-gas separation. In some embodiments, a system for acid gas separation may be integrated with an ammonia abatement cycle employing a high temperature absorber. In some embodiments, a system for acid gas separation may employ a higher temperature absorber due to the lower energy consumption and cost of the integrated ammonia abatement cycle. Advantageously, heat may be recovered from the absorber to power at least a portion of any acid gas desorption in the process. Reverse osmosis or other membranes may be employed.

An integrated system includes a desalination plant including a reverse osmosis (RO) array to produce an RO permeate blending stream and a nanofiltration (NF) array to produce an NF permeate blending stream. The integrated system also includes a blending system, a control unit, and an injection system for an injection well that penetrates an oil-bearing layer of a reservoir. The blending system is to blend the RO permeate blending stream and the NF permeate blending stream to produce a blended injection water stream. The control unit is to dynamically alter operation of the blending system to adjust amounts of at least one of the RO permeate blending stream and the NF permeate blending stream to alter the composition of the blended injection water stream from an initial composition to a target composition.

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 process for the coupled production of sweet whey and lactic acid from acid whey is suggested, comprising the following steps: (a) providing acid whey having a lactic acid content of about 0.1 to about 1% by weight; (b) nanofiltration of the acid whey, obtaining a first permeate P1 and a first retentate R1; (c) optionally, redilution of the first retentate R1 with water to reconstitute the initial dry matter content, and preparation of the second nanofiltration step; (d) nanofiltration or nano-diafiltration of the retentate R1, obtaining a second permeate P2 and sweet whey as a second retentate R2; (e) combining the two permeates P1 and P2 and subjecting the mixture to reverse osmosis, obtaining a third permeate P3 which, substantially, only contains water, and a concentrate of lactic acid as a third retentate R3.

The present invention relates to processes and systems for basic gas, e.g., ammonia, recovery and/or acid-gas separation. In some embodiments, a system for acid gas separation may be integrated with an ammonia abatement cycle employing a high temperature absorber. In some embodiments, a system for acid gas separation may employ a higher temperature absorber due to the lower energy consumption and cost of the integrated ammonia abatement cycle. Advantageously, heat may be recovered from the absorber to power at least a portion of any acid gas desorption in the process. Reverse osmosis or other membranes may be employed.