Ion Exchange resins are insoluble granular substances which have in their molecular structure acidic or basic radicals that can be exchanged. The positive or negative ions fixed on these radicals are replaced by ions of the same sign in solution in the liquid in contact with them.
Now days, the ion exchange substances are used almost exclusively under the name of resins. There are two categories of resins: the resins of the gel type and those of the macroporous or loosely cross-linked type. Their basic structure is identical: the macromolecular structure is obtained in both cases by co-polymerization. The difference between them lies in their porosity.

Ion Exchange resins are insoluble granular substances which have in their molecular structure acidic or basic radicals that can be exchanged. The positive or negative ions fixed on these radicals are replaced by ions of the same sign in solution in the liquid in contact with them.
Now days, the ion exchange substances are used almost exclusively under the name of resins. There are two categories of resins: the resins of the gel type and those of the macroporous or loosely cross-linked type. Their basic structure is identical: the macromolecular structure is obtained in both cases by co-polymerization. The difference between them lies in their porosity.