ABSTRACT
In a d d i t i o n to the n o n - p o l a r m a c r o r e t i c u l a r R o h m a n d H a s s a n d A m b e r l i t e X A D resins ( X A D - 2 a n d X A D - 4 ) a w i d e range of p o l a r resins exist w h i c h are v e r y useful for the p reconcen t ra t ion of an ion ic a n d cat ionic species a n d have some app l i ca t ions i n the p reconcen t ra t ion of i on i c o rgan ic substances. In termedia te a n d h i g h l y p o l a r types of resins are c o m m o n l y refer red to as i o n exchange res ins . These m a y be s u b d i v i d e d in to cat ionic types (cat ion exchange resins) that are d i s cus sed i n this chapter a n d an ion ic types (an ion exchange resins) that h a v e b e e n d i scussed i n C h a p t e r 24. C a t i o n i c exchange resins ca r ry a nega t ive charge a n d this reacts w i t h p o s i t i v e l y cha rged meta l l i c ions (cations) o r ca t ionic organic species. A n i o n i c i o n exchange resins ca r ry a p o s i t i v e charge a n d this reacts w i t h nega t ive ly cha rged an ions or an ion ic o rgan ic species.
