Abstract: A graft-modified organic porous material comprising an organic porous material of 1-50 ml/g total pore volume having such an open cell structure that mesopores of 0.01-1000 ?m radius are present within walls between macropores communicating with each other and, provided on the surface of the organic porous material, grafted polymer chains, characterized in that the density of polymer chains is at least 0.1 polymer chain per nm2 of surface of organic porous material. Thus, there are provided a graft-modified organic porous material wherein polymer chains have been introduced at high density in surface portion of organic porous material and a process for producing the same.

Abstract: A performance-lowered ion exchanger hard to recover in performance by the conventional regeneration (ion exchange resin, ion exchange membrane, or the like) is endowed with the same electric charge as the electric charge of the ion exchanger. A performance-lowered ion exchanger hard to recover in performance by the conventional regeneration owing to adsorption thereon of a charged substance is endowed with an electric charge opposite to that of the charged substance. According to the foregoing operations, the ion exchangers are recovered in performance. At least one compound selected from among organic amine compounds and organic ammonium compounds, which are capable of being endowed with an electric charge through dissociation thereof in solution, is preferably used as a rejuvenation agent for an anion exchanger.

Abstract: A high-purity water producing apparatus has an excellent effect of environmental protection and is also capable of effectively removing boron. It comprises a pretreatment unit, and a double pass RO unit an EDI unit or a distillation unit or any combination thereof as principal deionization unit(s) but does not comprise any chemical-regeneration type ion exchanger. It further comprises a boron removing unit and the water treated by the principal deionization unit(s) is brought into contact with a boron-selective ion exchange resin.