| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a cation exchange membrane, a hydrogen ion permselective membrane and a method of recovering an acid which enable recovering a high-concentration acid more efficiently than conventional methods. <P>SOLUTION: The cation exchange membrane used has a ratio (S<SB>min</SB>/S<SB>max</SB>) of 0.2-0.8 of a minimum value (S<SB>min</SB>) appearing close to the central part of the cation exchange membrane in the thickness direction to the average value (S<SB>max</SB>) of the first maximum value (S<SB>max1</SB>) appearing close to one surface of the cation exchange membrane and the second maximum value (S<SB>max2</SB>) appearing close to the other surface of the cation exchange membrane, in the X-ray intensity distribution of a sulfer element in the thickness direction of the cation exchange membrane, measured using a X-ray element analyzer. <P>COPYRIGHT: (C)2011,JPO&INPIT |
