Provided are an apparatus for removing boron and a method for removing boron for reducing the boron concentration in water to be treated, and an apparatus and a method for producing pure water wherein the boron concentration is reduced. An apparatus for removing boron includes: a first electrodeionization device to which water to be treated is supplied; an ultraviolet oxidation device to which the water treated by the first electrodeionization device is supplied; an oxide removal device to which the water treated by the ultraviolet oxidation device is supplied; and a second electrodeionization device to which the water treated by the oxide removal device is supplied. A method for removing boron using the apparatus is provided. The oxide removal device is equipped with a platinum group metal catalyst, and the water that has been treated by the oxide removal device has a hydrogen peroxide concentration of less than 1 ppb.

The methods and systems disclosed here relate to treating water. In certain embodiments, a treatment system comprises an electrochemical water treatment device, a recirculating concentrate stream in fluid communication with the electrochemical water treatment device, a flow control device in fluid communication with a first flow path comprising acidic water and configured to be in fluid communication with the recirculating concentrate stream, and a second flow path comprising feed water and configured to be in fluid communication with the recirculating concentrate stream, and a control system in communication with the flow control device. The treatment system may further comprise a recirculating dilution stream in fluid communication with a second inlet and a second outlet of the electrochemical water treatment device.

The methods and systems disclosed here relate to treating water. In certain embodiments, a treatment system comprises an electrochemical water treatment device, a recirculating concentrate stream in fluid communication with the electrochemical water treatment device, a flow control device in fluid communication with a first flow path comprising acidic water and configured to be in fluid communication with the recirculating concentrate stream, and a second flow path comprising feed water and configured to be in fluid communication with the recirculating concentrate stream, and a control system in communication with the flow control device. The treatment system may further comprise a recirculating dilution stream in fluid communication with a second inlet and a second outlet of the electrochemical water treatment device.

An electrochemical separation device includes a first electrode, a second electrode, and a cell stack including a plurality of sub-blocks each having alternating depleting compartments and concentrating compartments and each including frame and channel portions disposed between the first electrode and the second electrode. An internal seal formed of a first material is disposed between and in contact with the channel portions between adjacent sub-blocks in the cell stack and configured to prevent leakage between depleting compartments and concentrating compartments in the adjacent sub-blocks. An external seal formed of a second material having at least one material parameter different from the first material is disposed between and in contact with the frames of the adjacent sub-blocks in the cell stack and configured to prevent leakage from an internal volume of the electrochemical separation device to outside of the electrochemical separation device.

Provided are a curable composition including a compound expressed by General Formula (1) below; a polymerization initiator; and a chain transfer agent, and a cured polymer product. ##STR00001##
In General Formula (1), m represents an integer of 1 to 4, and n represents an integer of 1 to 4. Here, a sum of m and n is not greater than 5. M.sup.A represents a hydrogen ion, an inorganic ion, or an organic ion. Here, an inorganic ion and an organic ion may be bivalent or higher ions. Each of R.sup.1 and R.sup.2 independently represents a hydrogen atom or an alkyl group.

An ion exchange membrane obtained by using an ionic monomer having at least two or more polymerizable functional groups, in which a hydrophobicity index H obtained by an expression below from a monomer for forming an ion exchange resin and a material fixed to the resin in the ion exchange membrane is 1.6 or greater, and a manufacturing method therefor. Hydrophobicity index H=Σ{(log P of each component)×(molar ratio of each material in resin)}.

Methods and circuits for a device for interrupting concentration-related polarisation phenomenon and for self-cleaning of electromembrane processes by application of asymmetric inverse-polarity pulses with high intensity and variable frequency are described. The device, a bipolar switch, is based on the use of solid-state electronics to carry out polarity inversion in a range of frequencies, intensities and pulse widths to prevent or reduce formation of precipitates on the surfaces of the membranes. The inversion protocol, with a frequency that varies as a function of the appearance of dirt on the membranes, as measured by the decrease in voltage or electrical resistance of the membrane cell during electromembrane processes, is also provided. This device and configuration provides application of modulated and stable high-intensity pulses using a second power source. Electromembrane processes can be updated by replacing electrodes, suitable for polarity inversion, and adding a second power source and the bipolar switch described.

Electrochemical purification apparatuses for treating water and methods of assembling the devices are provided. The apparatuses may be cross-flow electrochemical devices. The devices may be assembled and sealed through masking and application of a potting material. The devices may comprise various structures configured to improve the current efficiency of the device, reduce leakage, and improve the distribution of potting material to the assembly.

Electrochemical purification apparatuses for treating water and methods of assembling the devices are provided. The apparatuses may be cross-flow electrochemical devices. The devices may be assembled and sealed through masking and application of a potting material. The devices may comprise various structures configured to improve the current efficiency of the device, reduce leakage, and improve the distribution of potting material to the assembly.

Ion exchange membranes may comprise a polymeric microporous substrate and a cross-linked ion transferring polymeric layer on the substrate. The cross-linked ion transferring polymeric layer may comprise a polymerization product of at least a functional monomer and a low value r.sub.2/r.sub.s monomer. The ion exchange membranes may have an apparent permselectivity of at least about 95% and a resistivity of less than about 1.5 Ohm-cm.sup.2.