RESUMO
The high ion leaching, low photogenerated charge separation efficiency, and slow metal valence cycling of Fe-based metal organic frameworks (MOFs) have limited their application in the deep treatment of organic pollutants. Herein, FeCu bimetallic MOFs (FeCuBDC) were synthesized using a modified solvothermal method, and a coupled photo-Fenton degradation system was successfully constructed. Degradation performance tests showed that FeCuBDC could efficiently degrade 99.3% ± 0.1% of 50 mg/L phenol within 40 min. The reaction rate constants of the photo-Fenton system were 11.0 and 64.7 times higher than those of the single Fenton reaction and photocatalysis, respectively. FeCuBDC also exhibits good cycling stability, degradation generalization, and excellent photoelectric catalytic properties. Such a considerable enhancement in the overall performance pertains to the following. First, the introduction of Cu into Fe-MOFs not only improves the crystallinity and stability, but also reduces the band gap value, increases the absorption capacity of visible light, and promotes the generation of photogenerated carriers. Second, the FeCu in MOFs are all mixed valence. Initially, the high-valence FeCu captures photogenerated electrons and promotes photogenerated charge separation and transfer. Then, the low-valence FeCu adsorbs and decomposes H2O2, accelerating the valence cycling of the bimetallic sites. The core of the reaction mechanism is that FeCuBDC effectively promotes the photo-Fenton synergy.
RESUMO
This work provides a simple and rapid method for synthesis uniform simetryn imprinted nanoparticles, which can be used to pretreat the tested samples before detecting. A series of computational approach were employed for design simetryn-imprinted polymer. Based on the conclusion of theoretical calculation, the simetryn imprinted nanoparticles were synthesized using simetryn as template, methacrylic acid as monomer with different solvent volume and synthesis conditions. The obtained nanoparticles have small size, uniform distribution and high imprinted factor. Scatchard analysis and quantum chemical calculations were applied for evaluating the interaction of simetryn with methacrylic acid in the imprinting process. The selectivity and recognition ability of the simetryn imprinted nanoparticles for six triazine herbicides and two other type herbicides were investigated. The results show that the simetryn imprinted nanoparticles had high selectivity and binding capacity and could be used for the separation and enrichment of four triazine pesticide residues from actual samples. A method of molecularly imprinted matrix solid phase extraction ultra-performance liquid chromatography tandem mass spectrometry was established for detecting four kinds of triazine herbicide residues in tobacco. The recovery rate of terbuthylazine, simetryn, atrazine, and prometryn in tobacco was 84.03-119.05%, and the relative standard deviation was 0.35-10.12%.
