Intimately coupled photocatalysis and functional bacterial system enhance degradation of 1,2,3-and 1,3,5-trichlorobenzene

Intimate coupling of photocatalysis and biodegradation (ICPB) is considered a promising approach for the degradation of recalcitrant organic compounds. In this work, using Trichoderma with benzene degradation ability coupled with activated sludge as a biological source and sugarcane bagasse cellulose composite as a carrier, the ICPB system showed excellent degradation and mineralization of trichlorobenzene under visible light induction. The biofilm inside the ICPB carrier can degrade and mineralize the photocatalytic products. ICPB increased the degradation efficiency of 1,2,3-TCB and 1,3,5-TCB by 12.43% and 4.67%, respectively, compared to photo-catalysis alone. The biofilms inside the ICPB carriers can mineralize photocatalytic products, which increases the mineralization efficiency by 18.74%. According to the analysis of intermediates, the degradation of 1,2,3-TCB in this coupled system involved stepwise dechlorination and ring opening. The biofilm in ICPB carrier evolved to be enriched in Cutaneotrichosporon, Trichoderma, Apiotrichum, Zoogloea, Dechloromonas, Flavihumibacter and Cupriavidus, which are known for biodegradable aromatic hydrocarbon and halogenate. Novel microbial seeds supplemented with Trichoderma-based ICPB seem to provide a new potential strategy for effective degradation and mineralization of TCB.

Automated summary

This study achieved effective degradation and mineralization of the recalcitrant organic compound trichlorobenzene through the coupling of specific microorganisms and photocatalytic materials. The coupled system showed improved degradation and mineralization efficiency, and the degradation mechanism was revealed through intermediate analysis. Moreover, the evolution of biofilms provided support for degradation and mineralization.