摘要：Humic substances are ubiquitous redox-active organic compounds of environment. In this study, experiments were conducted to determine the reduction capacity of humic acid in the matrix of bromate and Fe(Ⅲ) solutions and the role of Fe(Ⅲ) in this redox process. The results showed that the humic acid regenerated Fe(Ⅱ) and reduced bromate abiotically. The addition of Fe(Ⅲ) could accelerate the bromate reduction rate by forming humic acid-Fe(Ⅲ) complexes. Iron species acts as electron mediator and catalyst for the bromate reduction by humic acid, in which humic acid transfers electrons to the complexed Fe(Ⅲ) to form Fe(Ⅱ), and the regenerated Fe(Ⅱ) donate the electrons to bromate. The kinetics study on bromate reduction further indicated that bromate reduction by humic acid-Fe(Ⅲ.....