2D/2D FeNi-layered double hydroxide/bimetal-MOFs nanosheets for enhanced photo-Fenton degradation of antibiotics: Performance and synergetic degradation mechanism

The photo-Fenton system exhibits great potential in environmental remediation. However, photo-Fenton process suffers from slow reaction kinetics, which is caused by the low yield of available charge carriers and active radicals. In this work, the 2D/2D FeNi-layered double hydroxide/bimetal-organic frameworks nanosheets (FeNi-LDH/BMNSs) photocatalyst was fabricated via an in-situ semi-sacrificial template strategy. The optimized FeNi-LDH/BMNSs + H2O2+Vis system showed excellent tetracycline hydrochloride (TC-HCl) removal rate of 95.76% in 60 min. Besides, the high TC-HCl degradation rates (above 80%) are obtained in a wide pH range and the total organic carbon (TOC) removal rate of 48.98% was remained after four cycles. Experiments and characterizations identified the fast catalysis process were ascribed to the synergetic effect between 2D/2D heterojunctions and Lewis acid sites with mixed-valence (Fe (III)/Ni (II)) in FeNi-LDH/BMNSs. As a result, the catalysis of H2O2 and the reduction of O-2 was accelerated by the continuous generation of Fe (II) and available photogenerated electrons, respectively, producing abundant active radicals including center dot OH and center dot O-2(-). Finally, this photo-Fenton system exhibited high removal rate to oxycycline, levofloxacin, norfloxacin and doxycycline and showed excellent performance for TC-HCl removal in different composed wastewater. The findings provide a new strategy towards creating 2D/2D active heterogeneous catalysts for photo-Fenton catalytic application.