Abstract
Most of previous studies proved bicarbonate (HCO<sub>3</sub><sup>-</sup>) was free radical scavenger in advanced oxidation processes, however, in this study, the positive influence of HCO<sub>3</sub><sup>-</sup> was confirmed in heterogeneous Fenton. The results showed that the degradation efficiency of Rhodamine B increased from 13.7% to 95.3% by adding appropriate concentration of HCO<sub>3</sub><sup>-</sup>, and the zeolite supported Co and Cu oxides (Co/Cu/zeolite) could catalyze the HCO<sub>3</sub><sup>-</sup> enhanced Fenton process. The response surface method was employed to optimize the concentration of HCO<sub>3</sub><sup>-</sup> needed in the heterogeneous Fenton system. Radicals quenching results showed that <sup>1</sup>O<sub>2</sub> and O<sub>2</sub><sup>·-</sup> rather than ·OH played important roles in the degradation of Rhodamine B. Mechanism studies indicated that carbonate radical (CO<sub>3</sub><sup>·-</sup>) was the key intermediate in the formation of <sup>1</sup>O<sub>2</sub> and O<sub>2</sub><sup>·-</sup>, and CO<sub>3</sub><sup>·-</sup> could be generated through the reaction between HCO<sub>3</sub><sup>-</sup> and ·OH. In addition, peroxymonocarbonate (HCO<sub>4</sub><sup>-</sup>), which further produced CO<sub>3</sub><sup>·-</sup>, was also generated in the bicarbonate enhancement system. The electron transfer between Cu and Co promoted the heterogeneous Fenton process in generating ·OH that reacted with HCO<sub>3</sub><sup>-</sup>, or catalyzed HCO<sub>4</sub><sup>-</sup> to generate CO<sub>3</sub><sup>·-</sup>.
Funder
National Natural Science Foundation of China
Publisher
Korean Society of Environmental Engineering
Subject
Environmental Engineering