AbstractThe effect of the number of crosslinks in polymers on the ion exchange process has been investigated, assuming the exchanger to be a polyelectrolyte. An increase in the number of crosslinks (divinylbenzene content from 2 to 16%) has been found to cause no change in the character of the adsorption both in homovalent as well as heterovalent exchange. The processes obey the law of mass action regardless of whether contact is made between a polymer with varying divinylbenzene (DVB) content and solution of constant concentration or between one with constant DVB content and variously diluted solutions. With change in the crosslinking agent content of the polymer, the selectivity of ionic adsorption, which is determined by the property and size of the exchanging ions, varies. Changes in the number and arrangement of active groups in the polymer network have different effects on the ion exchange processes. An increase in the amount of active groups without marked changes in the swelling properties of the resin has no noticeable effect on the ion exchange processes, but as the concentration of active groups is increased with simultaneous increase in the specific volume of the resin considerable change in the selectivity of the ions being adsorbed takes place during the ion exchange process. With varying arrangement of the same active groups in the network of the ion exchanger, if different crosslinking agents are used in its synthesis its properties change, depending upon the medium in which the exchange is taking place. For example, the exchanger EDE‐10P synthesized on the basis of polyethylenepolyamine and epichlorohydrin may be considered to have practically only secondary and tertiary amine groups if one neglects a small amount of active groups of the quaternary ammonium bases. This exchanger adsorbs the anions of acids (H2SO4 and HCl) in acid medium and possesses a total exchange capacity of 10.5 meq./g. From a neutral medium (0.1N solution NaCl) it adsorbs about 0.95 meq./g. Cl−. On contact of the OH form of the resin with 0.1N CuSO4 and 0.02N H2SO4 it adsorbs 6.08 meq./g. SO42− and 5.75 meq./g. Cu2+ and on contact with 0.1N ZnCl2, 6.2 meq./g. Cl− and 5.92 meq./g. Zn2+. Under the same conditions the exchanger AN‐2F synthesized from phenol, polyethylenepolyamines, and formaldehyde and containing active N and NH groups practically adsorbs no copper. The capacity for CuSO4 adsorption by the anion exchanger EDE‐10P is not simple molecular sorption taking place with various exchangers on contact with acid and salt solutions. In this case, as has been demonstrated, complex compounds such as [(R2NH)2Me(H2O)2]X2 and [(R3N)2Me(H2O)2]X2 are formed. Such complexes are not formed by other anion exchangers containing secondary and tertiary amino groups.