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 O2 was accelerated by the continuous generation of Fe (II) and available photogenerated electrons, respectively, producing abundant active radicals including OH and O2−. 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.