A novel process for decolorizing dyes with sulfate radicals (SO4 center dot-) using an Fe(II)/sulfite system is reported in this manuscript. The objective of this study was to investigate the conditions under which Fe(II) activates Na2SO3 to produce SO4 center dot- and decolorize organic dyes. Orange II, Rhodamine B, Indigo Carmine, and Reactive Brilliant Blue X-BR could be efficiently decolorized using this novel system, which was compared with the Fe(II)/persulfate and Fenton (Fe(II)/H2O2) systems. The Fe(II)/sulfite system surpassed the other two in the decolorization of these dyes, and detailed mechanisms of the Fe(II)/sulfite system were researched. Primary radical identification through quenching experiments using tert-butyl alcohol and ethanol confirmed the existence of SO4 center dot-, HO center dot, and SO5 center dot-. A kinetic model was established for the halide ion effect, and (k(1)(-),SO4 center dot- (3.2 X 10(11) mol(-1) L s(-1)) and RSO4 center dot-f (10(-4)-10(-3) mol L-1 s(-1)) were indirectly derived. In conclusion, the Fe(II)/sulfite system is a good candidate for use in detoxifying water contaminants.