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1.
Chemistry ; 28(54): e202201437, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-35735906

RESUMO

Metal-organic frameworks (MOFs) with abundant active sites, a class of materials composed of metal nodes and organic ligands, is widely used for photocatalytic degradation of pollutants. However, the rapid recombination of photoinduced carriers of MOFs limits its photocatalytic degradation performance. Herein, Ti3 C2 Tx nanosheets-based NH2 -MIL-101(Fe) hybrids with Schottky-heterojunctions were fabricated by in situ hydrothermal assembly for improved photocatalytic activity. The photodegradation efficiencies of the NH2 -MIL-101(Fe)/Ti3 C2 Tx (N-M/T) hybrids for phenol and chlorophenol were 96.36 % and 99.83 % within 60 minutes, respectively. The N-M/T Schottky-heterojunction duly transferred electrons to the Ti3 C2 Tx nanosheets surface via built-in electric fields, effectively suppressing the recombination of photogenerated carriers, thereby improving the photocatalytic performance of NH2 -MIL-101(Fe). Moreover, the Fe-mixed-valence in the N-M/T led to improvement in the efficiency of the in situ generated photo-Fenton reactions, further enhancing the photocatalytic activity with more generated reactive oxygen species (ROS). The study proposes a highly effective removal of phenolic pollutants in wastewater.


Assuntos
Clorofenóis , Poluentes Ambientais , Estruturas Metalorgânicas , Ligantes , Estruturas Metalorgânicas/química , Fenóis , Espécies Reativas de Oxigênio , Titânio , Águas Residuárias
2.
J Colloid Interface Sci ; 622: 690-699, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35533483

RESUMO

The slow conversion of Fe(Ⅱ)/Fe(III) cycle was largely limited the degradation efficiency of many photo-Fenton systems. Herein, four Fe-MOFs nanorods (namely Fe-TCPP-1, Fe-TCPP-2, Fe-TCPP-3, Fe-TCPP-4) with decreasing length-diameter ratios were synthesized in a household microwave oven, using photosensitizer porphyrin and iron ions with Fenton activity as building blocks. Among them, the Fe-TCPP-3 exhibited high photogenerated electron-hole (e--h+) separation efficiency and largest pore structure, endowing Fe-TCPP-3 with superior photo-Fenton property. In addition, Fe-TCPP-3 based photo-Fenton system was applied to efficiently degrade antibiotic ciprofloxacin (CIP) under neutral condition, due to the continuously generated reactive species (h+, e-, OH·, O2·-, 1O2) in Fe-TCPP-3 under visible-light irradiation. With irradiation for 30 min, the degradation efficiency of the system could reach about 73 %, which was about 26-fold towards the system without light irradiation. This study paved a way to modulating the photo-Fenton activity of MOF-based catalysts.


Assuntos
Ciprofloxacina , Porfirinas , Compostos Férricos , Peróxido de Hidrogênio/química , Ferro/química
3.
Mikrochim Acta ; 189(5): 181, 2022 04 08.
Artigo em Inglês | MEDLINE | ID: mdl-35394213

RESUMO

A catalyst-free co-reaction luminol-H2O2-K2S2O8 chemiluminescence (CL) system was developed, with long-life and high-intensity emission, and CL emission lasting for 6 h. A possible mechanism of persistent and intense emission in this CL system was discussed in the context of CL spectra, cyclic voltammetry, electron spin resonance (ESR), and the effects of radical scavengers on luminol-H2O2-K2S2O8 system. H2O2 and K2S2O8 co-reactants can promote each other to continuously generate corresponding radicals (OH•, 1O2, O2•-, SO4•-) that trigger the CL emission of luminol. H2O2 can also be constantly produced by the reaction of K2S2O8 and H2O to further extend the persistence of this CL system. CL emission can be quenched via ascorbic acid (AA), which can be generated through hydrolysis reaction of L-ascorbic acid 2-phosphate trisodium salt (AAP) and alkaline phosphatase (ALP). Next, a CL-based method was established for the detection of ALP with good linearity from 0.08 to 5 U·L-1 and a limit of detection of 0.049 U·L-1. The proposed method was used to detect ALP in human serum samples.


Assuntos
Fosfatase Alcalina/análise , Luminescência , Luminol , Humanos , Peróxido de Hidrogênio , Limite de Detecção , Medições Luminescentes/métodos
4.
Mikrochim Acta ; 188(8): 272, 2021 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-34302224

RESUMO

Based on the laccase-mimicking activity of Cu2+-modified University of Oslo (UiO) metal-organic framework (UiO-67-Cu2+), we developed a colorimetric sensor array for distinguishing a series of phenols with different number and position of substituted hydroxyl group (-OH) and different substituent group on the benzene ring, including phenol, catechol, quinol, resorcinol, pyrogallol, phloroglucinol, o-chlorophenol, o-aminophenol, and o-nitrophenol. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of phenolic compounds were obtained by theoretical calculation. The results show that the lower the LUMO energy level, the easier the chromogenic reaction occurs. The UiO-67-Cu2+-catalyzed phenol chromogenic reaction showed a good linearity in the range from 0.1 to 200 µM with limit of detection approximately 61 nM. Through the detection of phenol in tap water and river water, the recovery rate and RSD (n = 3) were calculated as 94.1~103% and 1.0~3.3, respectively, showing good recovery, reliable results, and outstanding stability. Therefore, the proposed colorimetric sensor array will have a great potential for the detection of phenols in the environment. Schematic presentation of a simple and sensitive colorimetric strategy based on the laccase-mimicking activity of Cu2+-modified UiO-type metal-organic framework (MOFs, Uio-67-Cu2+) to distinguish phenols with analogous structures.

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