Efficient oxidative degradation of chlorophenols by using magnetic surface carboxylated Cu0/Fe3O4 nanocomposites in a wide pH range

Enhanced Ultrasonic-Assisted Heterogeneous Fenton Degradation of Organic Pollutants over a New Copper Magnetite (Cu-Fe3O4/Cu/C) Nanohybrid Catalyst

“…The crystallographic structures of the as-prepared MOFs are revealed by the powder XRD patterns in Figure a. The diffraction peaks of Fe-MOF in good agreement with those in the simulated XRD pattern of pure MIL-101­(Fe) demonstrate the successful preparation of MIL-101-structured Fe-MOF . In the pattern of Cu/Fe-MOF, except for some peaks at 9.0, 16.5, 17.9, and 18.8° similar to those of Fe-MOF, two more peaks at 12.7 and 14.0° are assigned to the characteristic peaks of Cu-MOF.…”

“…Moreover, Schottky interfaces between Cu and Fe 3 O 4 spontaneously accumulate electrons, facilitating the generation of ·OH and ·O 2 – by activating H 2 O 2 ; meanwhile, the good electron conductivity of defect Fe 3 O 4 accelerates charge transfer, further boosting the Fe­(III)/Fe­(II) transformation. In addition, the redox potential of Cu­(I)/Cu(0) (0.52 V) and Cu­(II)/Cu­(I) (0.17 V) is lower than that of Fe­(III)/Fe­(II) (0.77 V), which could mean the stronger reducibility of Cu(0) and Cu­(I) than Fe­(II) . As indicated by eqs and , Cu­(II, sc)/Cu­(I, sc) species play a similar important role to Fe­(III, sc)/Fe­(II, sc) species in the heterogeneous Fenton reaction.…”

“…EPR spectroscopy was applied to verify the generation of the two main radical species, namely, ·OH and ·O 2 – . , As displayed in Figure a, the signal intensity of ·OH in the Cu-Fe 3 O 4 /Cu/C system is obviously higher than those of the Cu/C and Fe 3 O 4 /C systems. The signal intensity of ·O 2 – obeys the following order: Cu-Fe 3 O 4 /Cu/C > Cu/C > Fe 3 O 4 /C (Figure b).…”

“…The involved radicals were detected by an electron paramagnetic resonance (EPR) system (Bruker A300). 5,5-Dimethyl-1-pyrroline N -oxide (DMPO) mainly combining with ·OH in water system and ·O 2 – in methanol system was used as a radical scavenger . The possible intermediates in RhB degradation were analyzed using liquid chromatography–mass spectrometry (LC-MS, Finigan Voyager).…”

Degradation of 4‐chlorophenol by BM Fe/Cu‐O2 system: The symbiosis of and ·OH radicals

“…H 2 O 2 can be generated by two electron transfer reactions between Fe 0 and O 2 (Equation ). Further, H 2 O 2 can also be produced by combined with protons in acid condition, which seems to be the main pathway for H 2 O 2 production, as can be seen from the inhibition test (Equations and ; Ding, Ruan, Zhu, & Tang, ; Fan, Qin, & Jiang, ; Keenan & Sedlak, ; Qi et al., ). Therefore, the inhibition effect of excessive POD to H 2 O 2 was also detected in Figure c.…”