Systems and methods for treating water may involve a first electrochemical separation module that includes at least one ion exchange membrane having a first set of performance characteristics, and a second electrochemical separation module that includes at least one ion exchange membrane having a second set of performance characteristics that is different than the first set of performance characteristics. Performance characteristics may relate to at least one of water loss, electrical resistance, and permselectivity. Staged treatment systems and methods may provide improved efficiency.

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.

Disclosed herein is a system for removing carbon dioxide (CO.sub.2) from seawater including an electrodialysis flow cell comprising a bipolar membrane having an acidified seawater product stream with a pH less than or equal to 8.5 and a basified seawater product stream with a pH greater than or equal to 9.0; a photobioreactor; and a microbially induced carbonate precipitation component; wherein the electrodialysis flow cell is in fluid communication with the photobioreactor via the acidified seawater product stream and in fluid communication with the microbially induced carbonate precipitation component via the basified seawater product stream.

A device for the electrodeionization of a sample liquid. The device has an anode chamber having two openings and an anode, a cathode chamber having two openings and a cathode, and a treatment chamber, that is arranged between the anode chamber and the cathode chamber and has two openings and ion exchanger. The anode chamber and the cathode chamber are separated from the treatment chamber in each case by a permselective membrane and an energy source is operatively connected to the anode and the cathode. In addition, a method for the electrodeionization of a sample liquid is provided.

The invention relates to an electrodialysis device for the desalination of water for oil and gas applications comprising: a membrane stack comprising alternating cation- and anion-exchange membranes (2.1, 2.3) and; a plurality of spacers (2.2, 2.4), each spacer being arranged between two successive membranes; wherein at least one of the spacers (2.2, 2.4) comprises a recessed area (3.2) and a non-recessed area (3.3), the non-recessed area (3.3) surrounding the recessed area (3.2), and wherein: the spacer (2.2, 2.4) comprises a central opening (3.1) within the recessed area (3.2); the spacer (2.2, 2.4) is provided with at least four orifices (3.4, 3.5) within the non-recessed area (3.3); the spacer (2.2, 2.4) is provided with respective channels (3.6) which connect at least two of the orifices (3.4) with the central opening (3.1); and one cation-exchange or anion-exchange membrane (2.1, 2.3) is accommodated in the recessed area (3.2). The invention also relates to a water desalination process using the electrodialysis device mentioned above, a process for extracting hydrocarbons from a subterranean formation, as well as a process for the desalination of water performed at a temperature from 35 to 80 C.

An electrodialysis module includes at least one base unit. The base unit includes a working tank, a first ion-exchange membrane, a second ion-exchange membrane, at least one first electrode, and at least two second electrodes. The first ion-exchange membrane and the second ion-exchange membrane are located in the working tank. The first ion-exchange membrane and the second ion-exchange membrane together divide the working tank into two electrode compartments and a desalination compartment therebetween. The at least one first electrode is disposed in the desalination compartment. The at least two second electrodes are disposed in each of the electrode compartments, respectively, in which the at least two second electrodes and the at least one first electrode have different polarities.

An ion suppressor includes ion exchange membranes between a pair of electrodes. Regeneration liquid channels are provided in the spaces between the electrodes and the ion exchange membranes, and an eluent channel is provided between the ion exchange membranes. Ion re-exchange in the eluent on the downstream side of the eluent channel is suppressed, thereby making it possible to improve the detection sensitivity for the ion to be measured. For example, the eluent channel has a folded structure, thereby increasing the amount of current on the downstream side of the eluent channel, and thus, the accumulation of ions is suppressed, and accordingly, ion re-exchange in the eluent can be suppressed.

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.

Electrochemical cell array for the treatment of a sample via electro-(end-)osmotic flow, comprising (i) an electrode chamber, comprising a cathodic compartment (CC) and an anodic compartment (AC), (ii) a cathode (C), being arranged in the cathodic compartment (CC), (iii) an anode (A), being arranged in the anodic compartment (AC), (iv) an intermediate cathodic compartment (C1) (v) an intermediate anodic compartment (A1) (iv) a first selective membrane (M1) being arranged between said cathodic compartment (CC) and said first intermediate cathodic compartment (C1) (v) a second selective membrane (M2) being arranged between said anodic compartment (AC) and said first intermediate anodic compartment (A1) (vi) a treatment compartment (T) for the sample being arranged between said intermediate cathodic compartment (C1) and said intermediate anodic compartment (A1), further comprising a first separator membrane (S1) between said treatment compartment (T) and said intermediate cathodic compartment (C1) and a second separator membrane (S2) arranged between said treatment compartment (T) and said intermediate anodic compartment (A1).

A wastewater treatment system for treating regeneration wastewater generated by a regeneration process using an acidic aqueous solution for a desalination device for desalting water containing ammonia includes a bipolar membrane electrodialyzer for separating, from the regeneration wastewater containing an ammonia salt produced by reaction between ammonia captured by the desalination device and the acidic aqueous solution or from a solution derived from the regeneration wastewater, an aqueous solution containing an acidic solute that is the same as the acidic aqueous solution as a regeneration acidic aqueous solution. The wastewater treatment system is configured such that the regeneration acidic aqueous solution is used as at least part of the acidic aqueous solution for regeneration of the desalination device.