Catalytic degradation of Acid Orange 7 by manganese oxide octahedral molecular sieves with peroxymonosulfate under visible light irradiation.

•OMS-2/PMS/Vis system could efficiently catalyze the degradation of organic dyes.•The system showed much higher activity than that of OMS-2/PMS and OMS-2/Vis.•The OMS-2 catalyst exhibited stable performance for multiple runs.•Sulfate radicals were suggested to be the major reactive species in the system.•The radicals production might involve the redox cycle of Mn(IV)/Mn(III) and Mn(III)/Mn(II).