This work focuses on photodegradation of multi-herbicides simultaneously with series oxidized carbon nitrides (OCN), which were synthesized via a rapid acid-assisted method. Carbon nitrides, after treating with nitric acid solution at several concentrations, revealed variant oxygen content, surface morphology and structure characteristic. The photocatalytic activity was verified by degradation of ten typical herbicides in water. The influence of microplastics on the photocatalytic performance of OCN sample was investigated for the first time. Experimental results showed that microplastics contained in environmental matrix significantly influenced the photodegradation ratio. Moreover, holes (h(+)) and OH center dot radicals were found to be the main reactive species during this process. The OCN-10 sample demonstrated favourable reusability in recycling tests and exhibited satisfactory degradative capability for ten investigated herbicides both in soil and aqueous phase under simulated diurnal cycle. (C) 2017 Published by Elsevier B.V.