ABSTRACT
Ion exchangers are water-insoluble, mostly solid substances which, when contacted with aqueous electrolyte solutions, take up positively or negatively charged ions from the latter and simultaneously release an equivalent amount of other, identically charged ions into the solution. According to the sign of the ions exchanged, cationic and anionic ion exchangers can be distinguished. The natural-base (cellulose, dextrane) and plastic resin-base (mostly divinyl-benzene and styrene copolymers) ion exchangers are the most widely used. These contain various functional groups. Strongly acidic cation exchanger resins are apt to exchange ions in a wide pH range and are capable to bind metal ions.
