The heterogeneous catalytic activation of peroxymonosulfate (PMS) for wastewater treatment is attracting increased research interest. Therefore, it is essential to find a sustainable, economical, and effective activated material for wastewater treatment. In this study, metal–organic framework (MOF)-5 was used as the precursor, and a stable and recyclable material ZnO@Ni 3 ZnC 0.7 that exhibited good adsorption and catalytic properties, was obtained by the addition of nickel and subsequent calcination. To investigate and optimize the practical application conditions, the elimination of rhodamine B (RhB) in water was selected as the model process. This study demonstrated that the degradation of organic matter in the system involved a coupling of the adsorption and degradation processes. Based on this, the mechanism of the entire process was proposed. The results of scanning electron microscopy, infrared spectrum analysis, and theoretical analysis confirmed that the van der Waals forces, electrostatic attraction, and hydrogen bonding influenced the adsorption process. Electron paramagnetic resonance analysis, masking experiments, and electrochemical tests conducted during the oxidative degradation process confirmed that the degradation mechanism of RhB included both radical and non-free radical pathways, and that the surface hydroxyl group was the key active site. The degradation of the adsorbed substrates enabled the regeneration of the active sites. The material regenerated using a simple method exhibited good efficiency for the removal of organic compounds in four-cycle tests. Moreover, this material can effectively remove a variety of organic pollutants, and can be easily recovered owing to its magnetic properties. The results demonstrated that the use of heterogeneous catalytic materials with good adsorption capacity could be an economical and beneficial strategy.
Shanshan Qiao,Yuqing Chen,Jiachao Shen,Pei Tao,Yanhong Tang,Haokun Shi,Hao Zhang,Jili Yuan,Chengbin Liu
Developing carbon dioxide (CO 2 ) photocatalysts from transition metal carbides (TMCs) with abundant active sites, modulable electron cloud density, as well as low cost and high stability is of great significance for artificial photosynthesis. Building an efficient electron transfer channel between the photo-excitation site and the reaction-active site to extract and steer photo-induced electron flow is necessary but challenging for the highly selective conversion of CO 2 . In this study, we achieved an oxygen-bridged Schottky junction between ZnO and Ni 3 ZnC 0.7 (denoted as Zn oxide –O–Zn TMC ) through a ligand-vacancy strategy of MOF. The ZnO–Ni 3 ZnC 0.7 heterostructure integrates the photo-exciter (ZnO), high-speed electron transport channel (Zn oxide –O–Zn TMC ), and reaction-active species (Ni 3 ZnC 0.7 ), where Zn oxide –O–Zn TMC facilitates the transfer of excited electrons in ZnO to Ni 3 ZnC 0.7 . The Zn atoms in Ni 3 ZnC 0.7 serve as electron-rich active sites, regulating the CO 2 adsorption energy, promoting the transformation of *COOH to CO, and inhibiting H 2 production. The ZnO–Ni 3 ZnC 0.7 shows a high CO yield of 2674.80 μmol g –1 h –1 with a selectivity of 93.40 % and an apparent quantum yield of 18.30 % (λ = 420 nm) with triethanolamine as a sacrificial agent. The CO production rate remains at 96.40 % after 18 h. Notably, ZnO–Ni 3 ZnC 0.7 exhibits a high CO yield of 873.60 μmol g –1 h –1 with a selectivity of 90.20 % in seawater.
ZnO/Ni3ZnC0.7/x% CNT (x = 0, 2, 5, 10) urchin-like structures have been synthesized using a facile method based on metal-organic frameworks (MOFs) and applied as the electromagnetic absorber. The results of the experiments demonstrate that the content of multi-wall carbon nanotubes (MWCNT) has a great influence on the absorbing performance of the hybrid material. Conduction loss, interfacial polarization and ferromagnetic resonance all contribute to the electromagnetic absorption. The urchin-like ZnO/Ni3ZnC0.7/5% CNT composite presents excellent absorbing properties. When the filler loading of ZnO/Ni3ZnC0.7/5% CNT composite in paraffin matrix is only 10 wt.%, a minimum reflection loss of −33.2 dB is achieved at a layer thickness of 4.9 mm.Keywords:MOF;electromagnetic absorbing properties;CNT;ZnO
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