Three modified polyacrylonitrile fibers were used as carriers of Fe(III)-[CH2N(CH2COOH)(2)](2) complex catalysts for oxidn. of air-contained H2S to S. The highest degree of H2S removal (near to 100%) was achieved when the fibers were modified by aminolysis with Me2N(CH2)(3)NH2 and following quaternization with epichlorohydrin or by introduction of COOH and CO(NHCH2CH2)(2)NH2 groups and the air humidity was higher than 80%.