Abstract: An ultrapure water production system that can stably produce ultrapure water having a boron concentration of 1 ng/L or less or a metal concentration of 0.1 ng/L or less, a method for producing ultrapure water using the ultrapure water production system, and a method and a system for washing electronic component members. In an ultrapure water production system that includes a mixed-bed deionization apparatus 16, which includes an anion-exchange resin and a cation-exchange resin, as a final deionization apparatus, the anion-exchange resin is an anion-exchange resin that has been verified to have a boron content of 50 ?g/L-anion-exchange resin (wet condition) or less or an anion-exchange resin in which the amount of leached cation is 100 ?g/L-anion-exchange resin (wet condition) or less.

Abstract: An electrodelonization apparatus comprising multiple anion exchange membranes 13 and cation exchange membranes 14 that are alternately arranged between a cathode 12 and an anode 11 to alternately form concentrating compartments 15 and desalting compartments 16 is described. The concentrating compartments 15 and the desalting compartments 16 are filled with ion exchangers, and the filling ratio of anion exchanger to cation exchanger of the ion exchanger in the concentrating compartments 15 is higher than that of the ion exchanger in the desalting compartments 16.

Abstract: An electrodeionization apparatus is provided, in which enough electric current flows even when voltage applied between the electrodes is low, thereby sufficiently performing deionization. A single first cation exchange membrane, a single anion exchange membrane, a single second cation exchange membrane are arranged between a cathode and an anode so that a concentration-cathode compartment, a desalting compartment, a concentrating compartment, and an anode compartment are formed, in this order, between the cathode and the anode. The concentration-cathode compartment and the anode compartment are filled with a cation exchange resin, respectively. The desalting compartment is filled with a mixture of the cation exchange resin and an anion exchange resin. Fed into the anode compartment is raw water or deionized water. Water from the anode compartment is sent to the concentrating compartment and the concentration-cathode compartment sequentially.

Abstract: An electrodelonization apparatus comprising multiple anion exchange membranes 13 and cation exchange membranes 14 that are alternately arranged between a cathode 12 and an anode 11 to alternately form concentrating compartments 15 and desalting compartments 16 is described. The concentrating compartments 15 and the desalting compartments 16 are filled with ion exchangers, and the filling ratio of anion exchanger to cation exchanger of the ion exchanger in the concentrating compartments 15 is higher than that of the ion exchanger in the desalting compartments 16.

Abstract: An electrodeionization apparatus in which enough electric current flows even when the voltage applied between the electrodes is low, thereby sufficiently performing deionization is provided. A single first cation exchange membrane 3, a single anion exchange membrane 4, a single second cation exchange membrane 3? are arranged between a cathode 1 and an anode 2 so that a concentration-cathode compartment 5, a desalting compartment 7, a concentrating compartment 10, and an anode compartment 6 are formed, in this order, between the cathode 1 and the anode 2. The concentration-cathode compartment 5 and the anode compartment 6 are filled with a cation exchange resin 8, respectively. The desalting compartment 7 is filled with a mixture of the cation exchange resin 8 and an anion exchange resin 9. Fed into the anode compartment 6 is raw water or deionized water. Water from the anode compartment is sent to the concentrating compartment 10 and the concentration-cathode compartment 5 sequentially.

Abstract: An electrodeionization apparatus has an anolyte compartment 17 having an anode 11, a catholyte compartment 18 having a cathode 12, concentrating compartments 15, and desalting compartments 16. The concentrating compartments 15 and the desalting compartments 16 are alternately formed between the anolyte compartment 17 and the catholyte compartment 18 by alternately arranging a plurality of anion-exchange membranes 13 and a plurality of cation-exchange membranes 14. The desalting compartments 16 are filled with ion-exchanger and the concentrating compartments 15 are filled with ion-exchanger, activated carbon, or electric conductor. Electrode water flows into the anolyte compartment 17 and the catholyte compartment 18. Concentrated water is introduced into the concentrating compartments 15. Raw water is fed into the desalting compartment 16 to produce the deionized water from the desalting compartment 16.

Abstract: An electrodeionization apparatus has an anolyte compartment 17 having an anode 11, a catholyte compartment 18 having a cathode 12, concentrating compartments 15, and desalting compartments 16. The concentrating compartments 15 and the desalting compartments 16 are alternately formed between the anolyte compartment 17 and the catholyte compartment 18 by alternately arranging a plurality of anion-exchange membranes 13 and a plurality of cation-exchange membranes 14. The desalting compartments 16 are filled with ion-exchanger and the concentrating compartments 15 are filled with ion-exchanger, activated carbon, or electric conductor. Electrode water flows into the anolyte compartment 17 and the catholyte compartment 18. Concentrated water is introduced into the concentrating compartments 15. Raw water is fed into the desalting compartment 16 to produce the deionized water from the desalting compartment 16.

Abstract: An electric deionizing apparatus comprising a first and a second electric deionizing apparatus arranged in series, in which water is deionized by the first electric deionizing apparatus and then deionized by the second electric deionizing apparatus, and a means for adding an aqueous electrolyte solution into water released from the first electric deionizing apparatus and which is supplied into the second electric deionizing apparatus. A process for electric deionization comprising supplying water to a first electric deionizing apparatus, deionizing the water in the first electric deionizing apparatus, adding an aqueous electrolyte solution to the deionized water, supplying the deionized water to a second electric deionizing apparatus and deionizing the supplied deionized water in the second electric deionizing apparatus. Silica and boron components in the water are effectively removed to obtain deionized water having a high resistivity.

Abstract: The electrodeionization apparatus is improved in concentration polarization of the ingredients including ions in the concentrating compartment so as to obtain the produced water with high purity. The electrodeionization apparatus has a spacer composed of a mesh and a frame-shaped gaskets superposed on the periphery of the mesh. The mesh has a thickness of 0.2 to 0.5 mm and the gaskets have thicknesses of equal to or less than 0.1 mm.