Effective Removal of Bromate in Water by Iron-Modified Spent Bleaching Earth Carbon: Reaction Behavior and Mechanism

In this study, the spent bleaching earth carbon (SBE@C) was modified with iron to obtain the iron-modified spent bleaching earth carbon (defined as Fe x O y -SBE@C) to remove bromate. The pseudo-second-order kinetic model and Langmuir model could well fit the bromate removal process. When the temperature was increased from 25 to 45 °C, bromate removal efficiency increased, and Fe x O y -SBE@C exhibited the highest bromate removal capacity of 521.82 mg/g at 45 °C. The effect of coexisting anions was investigated, and their adverse effects decreased in the order of PO 4 3- >NO 3 - >SO 4 2- . The higher the concentration of coexisting ions, the greater their inhibitory effect on bromate removal. By studying the effect of pH, it was found that the bromate removal was the highest at pH = 3. Characterization analysis confirmed that the iron was successfully loaded on the surface of SBE@C. The main mechanism for bromate removal by Fe x O y -SBE@C was the reduction of zero-valent iron and divalent iron with bromate to form the bromide ion. Overall, Fe x O y -SBE@C is a high-performance material for bromate removal. Graphical Abstract