A cation exchanger with an exchange capacity of 4.85 meq/g and mechanical strength of 96% was obtained by sulfonation of a styrene copolymer grafted to petroleum asphaltite. It can be used for sorption of ions at temperatures up to 100 degrees C and radiation doses of up to 6.710(6) Gy. The adsorbents made from this type of raw material are characterized by a developed micropore structure.