Reducing agents enhanced prometon degradation by CuBi2O4/peroxymonosulfate: Development of interfacial electron transport and circulation of Cu+/Cu2+

•The interfacial electron transfer generated by reducing agents regenerates Cu(I).•The production rate of SO4•− increases by 1.8 and 2.9 times with adding AA or HA.•The byproducts of reducing agents are environmentally friendly.•The quenching of •OH by AA results in less radicals for pollutant degradation.•The addition of HA developed the COD removal efficiency in effluent wastewater.