A novel hydrogen accelerated oxygen reduction Fenton reaction system: Effectively promoted the cycle of Fe(II)/Fe(III) and self-generation of H2O2

Both the iron sludge and usage of H2O2 restrict the promotion of the Fenton reaction. Herein, we proposed a hydrogen-accelerated oxygen reduction Fenton reaction system named MHORF-UiO-66(Zr) to try to solve the two problems under normal temperature and pressure. The active hydrogen, which is derived from H2 catalyzed by the composite of Pd/UiO-66(Zr), could accelerate the reduction of Fe(III) and promote the electron transfer of two-electron oxygen reduction reaction to realize the self-generation of H2O2. And 45.9 mM of H2O2 could be detected. As expected, 91 % of trimethoprim (TMP) could be degraded within 30 min in this system in the condition of 25 μM Fe(II), H2 30 mL·min−1, and Pd/UiO-66(Zr) 2g·L−1, which was 2.94 times that of the control Fenton system. Based on these results, the feasibility of fundamentally achieving zero emission of iron sludge was successfully verified. It was confirmed that both the hydroxyl radical and singlet oxygen played the dominant roles during the reaction process through the analysis of electron spin resonance spectroscopy. After six reaction cycles, the removal efficiency of TMP could be maintained at least 94 %. It found that both the properties and morphology of this composite could remain based on the systematic characterization.