Fe-Cu bimetal metal-organic framework for efficient decontamination via Fenton-like process: Synthesis, performance and mechanism.

Constructing Fe-Cu bimetal catalysts is an efficient strategy to promote Fe(III)/Fe(II) cycle, whereas there is still a long way to go before fully understanding the role of the Cu in the catalysts. Herein, a new Fe-MOF namely BUC-96(Fe) was fabricated from FeSO4·7H2O, 4,4'-bipyridine (bpy) and 2,5-dihydroxyterephthalic acid (H4dhtp) by both hydrothermal reaction and microwave-assisted method. Also, bimetal BUC-96(FeCu-x) were obtained when the CuSO4 was added into the system identical to the synthesis process of BUC-96(Fe). Series BUC-96 MOFs showed good organics elimination performance via Fenton-like process, where 88.1% (k = 0.0672 min-1) of chloroquine phosphate (CQ, 20 mg/L) was decomposed over pristine BUC-96(Fe) within 30 min. Interestingly, nearly 100% CQ was degraded over BUC-96(FeCu-5) as catalyst under the identical conditions within 5 min, whose reaction rate (1.3527 min-1) was 20.1-fold higher than that of BUC-96. Additionally, BUC-96(FeCu-5) exhibited excellent Fenton-like oxidation degradation performance for 10 selected emerging organic pollutants. The reaction mechanism was studied in detail by experiments, and density functional theory (DFT) calculation. The results revealed that the introduced Cu not only accelerated Fe(III)/Fe(II) cycles, hydroxyl radical (·OH) generation, electron transfer, but also lowered H2O2 dissociated energy barrier. This work advanced the bimetal MOFs construction and application in wastewater treatment via Fenton-like process.