A method for separation and enrichment of lithium includes the following steps: pretreatment: carrying out at least two dilutions and at least two filtrations on 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 and dilutes the salina aged brine for many times, thereby realizing the purposes of improving separation efficiency of magnesium and lithium and improving the enrichment efficiency of lithium.

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 MPa˜5.0 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.

Disclosed is a process for enriching silicate content in drinking water that includes separating raw water via reverse osmosis into a permeate comprising demineralised raw water and a retentate comprising mineral enriched raw water. The permeate is mixed with a water glass solution comprising sodium silicate and/or potassium silicate. An ion exchange process is used to reduce the concentration of sodium and/or potassium ions in at least part of the mixture. At least part of the retentate is supplied to the mixture after reducing the concentration of sodium and/or potassium ions to provide a silicate-enriched drinking water. Also disclosed is an apparatus for producing a drinking water enriched with silicate. The apparatus includes a reverse osmosis unit, a mixing unit, an ion exchanger, and a feed unit for feeding at least part of the retentate to the mixture after reducing the concentration of sodium and/or potassium ions.

A method for extracting and purifying Dendrobium officinale polysaccharides comprises following steps: (1) fully disperse Dendrobium officinale powder in pure water to obtain crude liquid; (2) removing insoluble impurities from the crude liquid through a microfiltration membrane to obtain permeate 1 and retentate 1; (3) performing macroporous ultrafiltration treatment of the permeate 1 and collect permeate 2 and retentate 2; (4) adding an aqueous solution of edible alkali metal inorganic salt to the retentate 2, fully stirring and dissolving to obtain polysaccharide crude liquid, performing macroporous ultrafiltration treatment and collecting permeate 3 and retentate 3; (5) combining the permeate 2 and permeate 3, adding the combined permeate into an electrodialysis device for desalination, and collecting dilute solution and concentrated solution; (6) performing microporous ultrafiltration treatment of the dilute solution and collect retentate 4 and permeate 4; (7) carrying out freeze-drying of the retentate 4 to obtain Dendrobium officinale polysaccharides.

Methods of producing an ion exchange membrane support are disclosed. The methods include saturating a polymeric microporous substrate with a charged monomer solution comprising at least one functional monomer, a cross-linking agent, and an effective amount of at least one photopolymerization initiator and polymerizing the at least one functional monomer by exposing the saturated polymeric microporous substrate to ultraviolet light under conditions effective to cross-link the at least one functional monomer and produce the ion exchange membrane support. Methods of producing a monovalent selective ion exchange membrane are also disclosed. The methods include functionalizing an exterior surface of the ion exchange membrane support with a charged compound layer, drying the ion exchange membrane support and soaking the ion exchange membrane support in a solution comprising an acid or a base for an amount of time effective to produce the monovalent selective ion exchange membrane.

A water treatment system for brackish water is disclosed. The water treatment system includes a first electrochemical separation stage fluidly connected to a second, downstream electrochemical separation stage, with the concentrate outlet of the second electrochemical separation stage fluidly connectable to the concentration compartment of the first electrochemical separation stage and a control system configured to regulate feed directed to the concentration compartments of the first and the second electrochemical separation stages. Methods of treating brackish water to produce potable water and methods of treating brackish water using systems of the invention are disclosed. The Donnan potential difference and osmotic water losses are lessened by controlling a source and a flowrate of a make-up feed water directed to concentration compartments of first and the second electrochemical separation stages of the systems.

The present disclosure relates to methods and systems for algae cultivation including the integration of electrochemical carbonate production for enhancing algae growth. More particularly, the present disclosure relates to methods and systems for producing a sodium hydroxide from brine using an electrochemical cell, contacting the sodium hydroxide stream with a CO.sub.2 gas sweep and producing a carbonate stream, and cultivating an algae slurry in a cultivation vessel comprising at least a portion of the carbonate stream.

A polymer film obtainable by curing a composition comprising a compound of Formula (I) wherein: R′ is vinyl, epoxy C.sub.1-3_alkylenethiol: n has a value of 1 or 2; m has a value of 1, 2 or 3; M′.sup.+ is a cation; wherein X is as defined in the claims; and wherein the molar fraction of the compound of Formula (I) in relation to all curable compounds in the composition is greater than 0.25. Also claimed are compositions, processes membranes and their uses.

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Non-gas emitting electrodes having a very high surface area, high electric capacitance, and low electric resistance are integrated with silver and/or silver chloride for use in electrodialysis/electrodeionization cells, or in any other system requiring the generation of electric fields through electrolyte solutions, and are capable of generating an electric field for extensive periods of time without generation of gases, and without the occurrence of water splitting electrode reactions. Each electrode is highly porous and highly conductive, such as a carbon aerogel electrode, and thus has a very large internal surface area, which is infused with silver and/or silver chloride. This combination supercapacitor and pseudocapacitor electrode can sustain electrode reactions for longer periods of time, and at much higher current densities, as compared to conventional (solid) silver/silver chloride electrodes.

A method for separating and recovering carbon dioxide from ambient air includes continuously bringing ambient air into contact with a basic aqueous solution; electrodialysis of the solution using bipolar and anion-selective ion exchange membranes as well as recycling the depleted solution; separating CO.sub.2 from the enriched solution and recycling the solution depleted of CO.sub.2. The absorption is performed in an absorber, open basin, or a combination thereof. Separation is achieved by thermal desorption of CO.sub.2 by steam stripping to obtain a carbon dioxide/steam mixture; and/or by chemical reaction of the (hydrogen-) carbonate ions, in which the CO.sub.2 contained is converted into a water-insoluble salt or a gas and simultaneously removed from the solution. The pH of either obtained solution is measured before the recycling or before the separation, and is adjusted to a predetermined value. pH is measured and adjusted based on how absorption and separation are performed.