Abstract: The present invention provides a novel and practical method for treating a perchlorate ion-containing liquid. The perchlorate ion-containing liquid is brought into contact with a weak base anion exchange resin, so that perchlorate ions are adsorbed to the weak base anion exchange resin, and then an acid is brought into contact with the resin, so as to remove the perchlorate ions from the weak base anion exchange resin to which the perchlorate ions are adsorbed. This makes it possible to repeatedly use the weak base anion exchange resin.

Abstract: An aqueous emulsion comprising an olefin-based copolymer comprising structural units derived from an ?-olefin and/or ethylene and structural units derived from a vinyl compound having a substituent, an emulsifier and a compound having 1 to 13 carbon atoms, wherein the compound having 1 to 13 carbon atoms has a hydroxyl group, an amino group, or both a hydroxyl group and an amino group, and the compound having 1 to 13 carbon atoms has, in the molecule thereof, at least two hydrogen atoms derived from a hydroxyl group or an amino group.

Abstract: An emulsion comprising a dispersoid dispersed in water together with an emulsifier, wherein the dispersoid is an olefin copolymer containing a structural unit derived from ethylene, linear ?-olefin, or ethylene and linear ?-olefin, and a structural unit derived from the following vinyl compound (I), or an olefin copolymer modified material obtained by further graft-polymerizing unsaturated carboxylic acids to the olefin copolymer, and the volume-based median diameter of the dispersoid contained in the emulsion is 0.01 to 1 ?m. CH2?CH—R??(I) (wherein, R in the vinyl compound (I) represents a secondary alkyl group, tertiary alkyl group or alicyclic hydrocarbon group.).