A hydrothermal-assisted strategy to transform Fe-doped MOF into 3D interwoven network structure of CNTs boosting the degradation of antibiotics via peroxymonosulfate activation

Abstract

Carbon-based catalysts with low toxicity and facile functional modification have received increasing attention in activating peroxymonosulfate (PMS). However, the poor reusability and catalytic activity inhibit their widespread application. Herein, a hydrothermal-assisted Fe doping strategy is proposed, where Fe-doped metal-organic framework (MOF) is transformed into three-dimensional (3D) interwoven network structure of carbon nanotubes (CNTs) and named FxZHC. The catalysts present good catalytic performance when tetracycline (TTCH) is chosen as the target pollutant, which can be attributed to two aspects: (i) More Fe-doped CNTs were generated based on the above strategy, which enhanced the conductivity, accelerated the electron transfer, and enhanced the reaction kinetics (structural optimization); (ii) Fe and N-doped create abundant reaction active sites and increase the generation rate of reactive oxygen species (composition optimization). For comparison, Fe-doped ZIF-8 without hydrothermal denoted as F0.2ZNHC was also prepared for testing and the results show that F0.2ZHC exhibit enhanced TTCH degradation rate of 0.13 min−1, which is 30 % higher than that of F0.2ZNHC. F0.2ZHC/PMS system was investigated as a 1O2 based non-radical degradation pathway by quenching experiment and electron paramagnetic resonance (EPR). The hydrothermal assisted Fe doping strategy is expected to be extended to the application of MOF-derived heteroatom doping.