Electronic structure tuning is an effective strategy to activate transition metals. In this study, silica-promoted γ-Al 2 O 3 -supported Fe-based hydrodesulfurization catalysts of Fe species with electron loss were successfully prepared by transferring electrons from Fe to Si. The characterization results showed that the Fe-based hydrodesulfurization catalyst with the addition of silica modulated the structure and properties of the active metal, which not only improved the degree of sulfidation of the active metal but also promoted the generation of Fe(III)-S. The hydrodesulfurization rate of dibenzothiophene showed a remarkable rise from 38.4 to 83.2% at 673 K. Importantly, the formation of Fe(III)-S greatly stretched the bond length of Fe-S bonds, exhibiting an increase of approximately 21%, this facilitating the generation of coordinatively unsaturated active site. Finally, the HDS reaction performance of the Fe-based hydrodesulfurization catalysts was mainly influenced by the Fe(III)-S/Fe(II)-S ratio, with the most significant enhancement in the direct desulfurization reaction path. The results of this study provide a promising approach for the design and development of environmentally friendly and economical Fe-based catalysts in the field of clean fuels.
Sitao Wang,Zhijie Liu,Bolun Pang,Yuting Gao,Santu Luo,Qiaosong Li,Hailan Chen,Michael G Kong
Antibiotics are widely used to treat or prevent infectious diseases in human and veterinary medicine. Excessive residues in the aquatic environment lead to increasingly prominent antibiotic pollution; therefore, it is urgent to develop sustainable strategies for rapidly degrading antibiotics. In this study, a highly synergetic effect for norfloxacin (NOR) remediation is achieved by coupling underwater bubble plasma formation with a Fe (III)–S (IV) system due to the efficient utilization of reactive species in chain reactions. The degradation rate using synergetic approach can reach 76.4% within 50 min discharge, and further increases significantly to 94.4% after 5 h post-discharge. The effects of pulsed peak voltage and Fe (III)/S (IV) dosage on NOR removal are characterized. The existence of hydroxyl radicals ( • OH) and sulfate radicals (SO 4 •− ) are proved by electron spin resonance spectrometer (ESR) during degradation. Furthermore, radical scavenger experiments demonstrate that • OH and SO 4 •− play a crucial role in degradation. Underwater bubble plasma provides the oxic and acidic liquid environment for the Fe (III)–S (IV) system to accelerate the self-perpetuating chain reactions. These reactions not only introduce SO 4 •− and generate more • OH during plasma-on, but also induce their regeneration and further prolong the degradation process during plasma-off through plasma-generated effects. Finally, the degradation intermediates of NOR are identified, and a possible degradation pathway is proposed. The possible contribution weight of each approach on the degradation rate is speculated. These new findings offer promising applications for developing a technology with real potential for the treatment of organic compounds in industrial wastewater treatment.
危险品化学品经营许可证（带存储）