Hybrid sorbent on the base of anion-exchange polymeric matrix with HFO for selective sorption of arsenic characterized in that, HFO exists in matrix as particles, which at most are amorphous ferrihydrite, fraction of which is not less than 80%, preferably more than 90% from total mass of HFO. The object of the invention and the technical result achieved with the use of the invention is to develop new hybrid sorbent with HFO with increased sorption kinetics of two arsenic forms As(III) and As(V) simultaneously.

Hybrid sorbent on the base of anion-exchange polymeric matrix with HFO for selective sorption of arsenic characterized in that, HFO exists in matrix as particles, which at most are amorphous ferrihydrite, fraction of which is not less than 80%, preferably more than 90% from total mass of HFO. The object of the invention and the technical result achieved with the use of the invention is to develop new hybrid sorbent with HFO with increased sorption kinetics of two arsenic forms As(III) and As(V) simultaneously.

A method of removing boron from water to be treated includes subjecting the water to be treated to reverse osmosis membrane treatment, subjecting at least part of permeated water after the reverse osmosis membrane treatment to cation-removing treatment, and measuring a concentration of boron in the resulting permeated water after the cation-removing treatment, in which a measured value for the concentration of boron is used to regulate at least one of: (a) the recovery rate of water to be treated in the above reverse osmosis membrane treatment, (b) the temperature of the water to be treated, (c) the pH of the water to be treated, (d) the supply pressure of the water to be treated, which pressure is applied to the reverse osmosis membrane during the reverse osmosis membrane treatment, and (e) when the reverse osmosis membrane used for the reverse osmosis membrane treatment should be changed.

The present invention relates to a method for producing purified water comprising a step (a) of passing water through a mixed bed ion exchanger comprising beads having a diameter between 0.2 and 0.7 mm and a step (b) of passing water through a fibrous ion-exchange material. The invention further relates to a module comprising the mixed bed ion exchange resin and the fibrous material and to a water treatment system for producing ultrapure water comprising the mixed bed ion exchange resin and the fibrous material.

The present invention relates to a method for producing purified water comprising a step (a) of passing water through a mixed bed ion exchanger comprising beads having a diameter between 0.2 and 0.7 mm and a step (b) of passing water through a fibrous ion-exchange material. The invention further relates to a module comprising the mixed bed ion exchange resin and the fibrous material and to a water treatment system for producing ultrapure water comprising the mixed bed ion exchange resin and the fibrous material.

An ion exchange membrane containing: a layer S containing a fluorine-containing polymer having a sulfonic acid group; a layer C containing a fluorine-containing polymer having a carboxylic acid group; and—a plurality of reinforcing materials functioning as at least one of reinforcement yarn and sacrifice yarn; wherein, when the ion exchange membrane is viewed from a top surface, an average cross-sectional thickness A of the ion exchange membrane measured in pure water for a region, is μm or more and 75 μm or less, and wherein a strength change ratio calculated from strength S2 of the ion exchange membrane measured after the ion exchange membrane is subjected to a predetermined electrolysis test and strength S1 of the ion exchange membrane measured before the ion exchange membrane is subjected to the electrolysis test, in terms of 100×S2/S1, is 85% or more and 120% or less.

An ion exchange membrane containing: a layer S containing a fluorine-containing polymer having a sulfonic acid group; a layer C containing a fluorine-containing polymer having a carboxylic acid group; and—a plurality of reinforcing materials functioning as at least one of reinforcement yarn and sacrifice yarn; wherein, when the ion exchange membrane is viewed from a top surface, an average cross-sectional thickness A of the ion exchange membrane measured in pure water for a region, is μm or more and 75 μm or less, and wherein a strength change ratio calculated from strength S2 of the ion exchange membrane measured after the ion exchange membrane is subjected to a predetermined electrolysis test and strength S1 of the ion exchange membrane measured before the ion exchange membrane is subjected to the electrolysis test, in terms of 100×S2/S1, is 85% or more and 120% or less.

A cation exchange chromatographic matrix comprising a base material, and a copolymer with one monomer unit having at least a sulfonic acid group, the copolymer being immobilized on the base material, wherein: the copolymer forms substantially no cross-linked structure, and the copolymer comprises neither acrylamide nor an acrylamide derivative as a monomer unit, or comprises acrylamide or an acrylamide derivative as a monomer unit in a range which has no substantial influence; the ratio of the mass of the copolymer to the mass of the base material is 5% or more and 200% or less; and the density of the sulfonic acid group is higher than 30 mmol/L and 200 mmol/L or lower.

A cation exchange chromatographic matrix comprising a base material, and a copolymer with one monomer unit having at least a sulfonic acid group, the copolymer being immobilized on the base material, wherein: the copolymer forms substantially no cross-linked structure, and the copolymer comprises neither acrylamide nor an acrylamide derivative as a monomer unit, or comprises acrylamide or an acrylamide derivative as a monomer unit in a range which has no substantial influence; the ratio of the mass of the copolymer to the mass of the base material is 5% or more and 200% or less; and the density of the sulfonic acid group is higher than 30 mmol/L and 200 mmol/L or lower.

An ion-exchange apparatus includes a raw-water tank 1, a treatment section, an ion exchanger and a hydrophilic layer. The raw-water section contains a liquid to be treated with impurity ions. The treatment tank 2 contains a treatment material with exchange ions exchangeable with the impurity ions. The ion exchanger 3 enables the passage of the impurity ions from the raw-water tank 1 to the treatment tank 2 and the passage of the exchange ions from the treatment tank 2 to the raw-water tank 1. The hydrophilic layer M, with a water contact angle of 30° or less, is disposed on at least a surface of the ion exchanger adjacent to the treatment tank 2.