Abstract: Rare earth metals are adsorbed on an ion exchange fiber comprising an ion exchanger having a strong cation exchange group and a weak cation exchange group, and the adsorbed metals are fractionally eluted with an aqueous solution of a chelating agent, whereby the respective rare earth metals can be separated at high efficiency in a short time. According to this method, elution can be accomplished at an elution rate of 5.0 or above in terms of space velocity.

Abstract: A novel enzyme-active fibrous material is proposed comprising fibers of a rtially aminoacetalized polyvinyl alcohol as the support and an enzyme adsorbed and bonded thereto such as glucose isomerase, invertase, urease and the like. The enzyme-active fibrous material of the invention is readily prepared by dipping fibers of the partially aminoacetalized polyvinyl alcohol in an aqueous solution of the desired enzyme. The enzymatic activity and the physical properties of the fibers are remarkably improved by the use of extra-fine fibers prepared with composite fibers of a partially aminoacetalized polyvinyl alcohol and a polyethyleneoxide subjected to selective leaching away of the latter component or by the use of so-called sheath-and-core type or side-by-side type composite fibers of which one of the components is a partially aminoacetalized polyvinyl alcohol.

Abstract: Superfine fibers of polyvinyl alcohol type having a single fiber diameter of 0.1-1.0.mu. and a fineness of 0.8-80.times.10.sup.-4 d/f are baked in the presence of a dehydration catalyst so that the weight loss ratio of fibers falls under the range of about 5 to 40%.When ion-exchange radicals are introduced into the partially dehydrated fiber, superfine fibers with a high ion-exchange rate are obtained.

Abstract: A partially polyenized polyvinyl alcohol fiber is obtained by heating and dehydration polyvinyl alcohol type fibers at temperatures of about 80.degree. to 350.degree. C so that the dehydration weight loss falls within the range of about 5% to 40%. An ion-exchange radical is introduced into the partially polyenized polyvinyl alcohol fiber to obtain fibers with an ion-exchange capacity. The ion-exchange fiber thus obtained exhibits an exchange capacity comparable to ion-exchange resins and has practical properties as fibers, such as good chemical resistance and flexibility.