CQDs modulating Z-scheme g-C3N4/BiOBr heterostructure for photocatalytic removing RhB, BPA and TC and E. coli by LED light

•A novel Z-scheme CQDs/g-C3N4/BiOBr was prepared.•CQDs/g-C3N4/BiOBr can effectively remove RhB, BPA, TC and E. coli under LED light.•h+, •O2- and •OH are all active substances in photocatalytic reactions.•Z-scheme in CQDs/g-C3N4/BiOBr produces a strong redox ability.•CQDs are favorable for transfer of charge carriers and light absorption ability.