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1.
Langmuir ; 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39024504

RESUMO

Thousands of chemicals have been released into the environment in recent decades. The presence of emerging contaminants (ECs) in water has emerged as a pressing concern. Adsorption is a viable solution for the removal of ECs. Metal-organic frameworks (MOFs) have shown great potential as efficient adsorbents, but their dispersed powder form limits their practical applications. Recently, researchers have developed various separable MOF-based adsorbents to improve their recyclability. The purpose of this review is to summarize the latest developments in the construction of separable MOF-based adsorbents and their applications in adsorbing ECs. The construction strategies for separable MOFs are classified into four categories: magnetic MOFs, MOF-fiber composites, MOF gels, and binder-assisted shaping. Typical emerging contaminants include pesticides, pharmaceuticals and personal care products, and endocrine-disrupting compounds. The adsorption performance of different materials is evaluated based on the results of static and dynamic adsorption experiments. Additionally, the regeneration methods of MOF-based adsorbents are discussed in detail to facilitate effective recycling and reuse. Finally, challenges and potential future research opportunities are proposed, including reducing performance losses during the shaping process, developing assessment systems based on dynamic purification and real polluted water, optimizing regeneration methods, designing multifunctional MOFs, and low-cost, large-scale synthesis of MOFs.

2.
Small ; 19(7): e2206407, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36464629

RESUMO

Seeking highly-efficient, non-pollutant, and chemically robust photocatalysts for visible-light-driven ammonia production still remained challenging, especially in pure water. The key bottle-necks closely correlate to the nitrogen activation, water oxidization, and hydrogen evolution reaction (HER) processes. In this study, a novel Bi decorated imine-linked COF-TaTp (Bi/COF-TaTp) through N-Bi-O coordination is reasonably designed to achieve a boosting solar-to-ammonia conversion of 61 µmol-1  g-1  h-1 in the sacrificial-free system. On basis of serial characterizations and DFT calculations, the incorporated Bi is conducive to the acceleration of charge carriers transfer and N2 activation through the donation and back-donation mode. The N2 adsorption energy of 5% Bi/COF-TaTp is calculated to be -0.19 eV in comparison with -0.09 eV of the pure COF-TaTp and the electron exchange between N2 and the modified catalyst is much more intensive. Moreover, the accompanied hydrogen production process is effectively inhibited by Bi modification, demonstrated by the higher energy barrier for HER over Bi/COF-TaTp (2.62 eV) than the pure COF-TaTp (2.31 eV) when using H binding free energy (ΔGH* ) as a descriptor. This work supplies novel insights for the design of photocatalysts for N2 reduction and intensifies the understanding of N2 adsorption and activation over covalent organic frameworks-based materials.

3.
Environ Res ; 216(Pt 1): 114541, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36228690

RESUMO

Semiconductor-based solar-driven CO2 to fuels has been widely reckoned as an ingenious approach to tackle energy crisis and climate change simultaneously. However, the high carrier recombination rate of the photocatalyst severely dampens their photocatalytic uses. Herein, an inorganic-organic heterojunction was constructed by in-situ growing a dioxin-linked covalent organic framework (COF) on the surface of rod-shaped ß-Ga2O3 for solar-driven CO2 to fuel. This novel heterojunction is featured with an ultra-narrow bandgap COF-318 (absorption edge = 760 nm), which is beneficial for fully utilizing the visible light spectrum, and a wide bandgap ß-Ga2O3 (absorption edge = 280 nm) to directional conduct electrons from COF to reduce CO2 without electron-hole recombination occurred. Results showed that the solar to fuels performance over ß-Ga2O3/COF was much superb than that of COF. The optimized Ga2O3/COF achieved an outstanding CO evolution rate of 85.8 µmol h-1·g-1 without the need of any sacrificial agent or cocatalyst, which was 15.6 times more efficient than COF. Moreover, the analyses of photoluminescence electrochemical characterizations and density functional theory (DFT) calculations revealed that the fascinate construction of ß-Ga2O3/COF heterojunction significantly favored charge separation and the directional transfer of photogenerated electrons from COF to ß-Ga2O3 followed by CO2. This study paves the way for developing effective COF-based semiconductor photocatalysts for solar-to-fuel conversion.


Assuntos
Estruturas Metalorgânicas , Catálise , Dióxido de Carbono , Fotossíntese , Semicondutores
4.
Small ; 18(52): e2205388, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36344463

RESUMO

Exploiting cost-effective, high-efficiency, and contamination-free semiconductors for photocatalytic nitrogen reduction reaction (N2 RR) is still a great challenge, especially in sacrificial-free system. On basis of the electron "acceptance-donation" concept, a boron-doped and carbon-deficient g-C3 N4 (Bx CvN) is herein developed through precise dopant and defect engineering. The optimized B15 CvN exhibisted an NH3 production rate of 135.3 µmol h-1  g-1 in pure water with nine-fold enhancement to the pristine graphitic carbon nitride (g-C3 N4 ), on account of the markedly elevated visible-light harvesting, N2 activation, and multi-directional photoinduced carriers transfer. The decorated B atoms with coexistent occupied and empty sp3 hybridized orbitals are theoretically proved to be in charge of the increase of N2 adsorption energy from -0.08 to -0.26 eV and the change in N2 adsorption model from one-way to two-way end-on pattern. Noticeably, the elaborate coordination of doped B atoms and carbon vacancies greatly facilitated the interlayer interaction and vertical charge migration of Bx CvN, which is distinctly revealed through the charge density difference calculations. The current study provides an alternative groundbreaking perspective for advancing photocatalytic N2 RR through the targeted configuration of the defect and dopant sites.

5.
Chemistry ; 26(8): 1864-1870, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31774593

RESUMO

Facile fabrication of nanocatalysts consisting of metal nanoparticles (NPs) anchored on a functional support is highly desirable, yet remains challenging. Covalent organic frameworks (COFs) provide an emerging materials platform for structural control and functional design. Here, a facile one-pot in situ reduction approach is demonstrated for the encapsulation of small Pd NPs into the shell of COF-derived hollow polyamine spheres (Pd@H-PPA). In the one-pot synthetic process, the nucleation and growth of Pd NPs in the cavities of the porous shell take place simultaneously with the reduction of imine linkages to secondary amine groups. Pd@H-PPA shows a significantly enhanced catalytic activity and recyclability in the tandem dehydrogenation of ammonia borane and selective hydrogenation of nitroarenes through an adsorption-activation-reaction mechanism. The strong interactions of the secondary amine linkage with borane and nitroarene molecules afford a positive synergy to promote the catalytic reaction. Moreover, the hierarchical structure of Pd@H-PPA allows the accessibility of active Pd NPs to reactants.

6.
Environ Res ; 190: 110018, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32810495

RESUMO

Photocatalytic bacterial inactivation under visible light emerges as a new alternative to control microbial contamination by utilizing free and renewable sunlight. However, the exploration of highly effective and safe visible-light-driven (VLD) photocatalysts remains an important step toward accessing this new technology. Herein, an eco-friendly photocatalyst, namely Indium Sulfide (In2S3), was fabricated through a facile hydrothermal method for VLD photocatalytic inactivation of bacteria. The energy band gap of the as-prepared In2S3 was measured as 2.25 eV. As expected, the obtained In2S3 photocatalyst showed remarkable inactivation efficiency toward E. coli under fluorescent tubes irradiation. The photocatalytic inactivation kinetic was perfectly fitted by a mathematical model for bacteria inactivation. In addition, In2S3 exhibited high stability and could be reused. The leakage of In3+ was not significant and showed no toxic effect to the bacteria. Based on the results of scavenger study and ESR technology, the dominant reactive species causing In2S3 VLD photocatalytic bacterial inactivation were proposed as O2-, h+, H2O2 and e-, rather than OH. The SEM study suggested that the damages to the intracellular components occurred prior to the destruction of cell wall. This study provides novel application of In2S3 for VLD photocatalytic inactivation of bacteria as well as comprehensive insight into the inactivation mechanism.


Assuntos
Escherichia coli , Peróxido de Hidrogênio , Catálise , Cinética , Luz
7.
J Am Chem Soc ; 141(18): 7615-7621, 2019 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-30998334

RESUMO

Photocatalytic reduction of CO2 into energy-rich carbon compounds has attracted increasing attention. However, it is still a challenge to selectively and effectively convert CO2 to a desirable reaction product. Herein, we report a design of a synergistic photocatalyst for selective reduction of CO2 to CO by using a covalent organic framework bearing single Ni sites (Ni-TpBpy), in which electrons transfer from photosensitizer to Ni sites for CO production by the activated CO2 reduction under visible-light irradiation. Ni-TpBpy exhibits an excellent activity, giving a 4057 µmol g-1 of CO in a 5 h reaction with a 96% selectivity over H2 evolution. More importantly, when the CO2 partial pressure was reduced to 0.1 atm, 76% selectivity for CO production is still obtained. Theoretical calculations and experimental results suggest that the promising catalytic activity and selectivity are ascribed to synergistic effects of single Ni catalytic sites and TpBpy, in which the TpBpy not only serves as a host for CO2 molecules and Ni catalytic sites but also facilitates the activation of CO2 and inhibits the competitive H2 evolution.

8.
Small ; 15(3): e1804419, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30548927

RESUMO

Yolk-shell nanoreactors have received considerable interest for use in catalysis. However, the controlled synthesis of continuous crystalline shells without imperfections or cracks remains challenging. Here, a strategy for the synthesis of yolk-shell metal nanoparticles@covalent organic framework (MNPs@COF) nanoreactors by using MNPs@ZIF-8 core-shell nanostructures as a self-template is designed and developed. The COF shell is formed through an amorphous-to-crystalline transformation process of a polyimine shell in a mildly acidic solution, while the ZIF-8 is etched in situ, generating a void space between the MNPs core and the COF shell. With the protection of the COF shell, multiple ligand-free MNPs are confined inside of the hollow nanocages. Importantly, the synthetic strategy can be generalized to engineer the functions and properties of the designed yolk-shell nanocages by varying the structure of the COF shell and/or the composition of the core MNPs. Representative Pd@H-TpPa yolk-shell nanocages with active Pd NP cores and permeable TpPa shells exhibit high catalytic activity and stability in the reduction of 4-nitrophenol by NaBH4 at room temperature.

9.
Molecules ; 21(2)2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26891284

RESUMO

MoS2 quantum dots (QDs)/CdS core/shell nanospheres with a hierarchical heterostructure have been prepared by a simple microwave hydrothermal method. The as-prepared samples are characterized by XRD, TEM, SEM, UV-VIS diffuse reflectance spectra (DRS) and N2-sorption in detail. The photocatalytic activities of the samples are evaluated by water splitting into hydrogen. Results show that the as-prepared MoS2 QDs/CdS core/shell nanospheres with a diameter of about 300 nm are composed of the shell of CdS nanorods and the core of MoS2 QDs. For the photocatalytic reaction, the samples exhibit a high stability of the photocatalytic activity and a much higher hydrogen evolution rate than the pure CdS, the composite prepared by a physical mixture, and the Pt-loaded CdS sample. In addition, the stability of CdS has also been greatly enhanced. The effect of the reaction time on the formations of nanospheres, the photoelectric properties and the photocatalytic activities of the samples has been investigated. Finally, a possible photocatalytic reaction process has also been proposed.


Assuntos
Compostos de Cádmio/síntese química , Dissulfetos/química , Molibdênio/química , Nanosferas/química , Pontos Quânticos/química , Compostos de Cádmio/química , Catálise , Hidrogênio/química , Tamanho da Partícula , Processos Fotoquímicos
10.
Macromol Rapid Commun ; 36(20): 1799-805, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26292975

RESUMO

Covalent triazine-based frameworks (CTFs) with a graphene-like layered morphology have been controllably synthesized by the trifluoromethanesulfonic acid-catalyzed nitrile trimerization reactions at room temperature via selecting different monomers. Platinum nanoparticles are well dispersed in CTF-T1, which is ascribed to the synergistic effects of the coordination of triazine moieties and the nanoscale confinement effect of CTFs. CTF-T1 exhibits excellent photocatalytic activity and stability for H2 evolution in the presence of platinum under visible light irradiation (λ ≥ 420 nm). The activity and stability of CTF-T1 are comparable to those of g-C3 N4 . Importantly, as a result of the tailorable electronic and spatial structures of CTFs that can be achieved through the judicial selection of monomers, CTFs not only show great potential as organic semiconductor for photocatalysis but also may provide a molecular-level understanding of the inherent heterogeneous photocatalysis.


Assuntos
Triazinas/química , Água/química , Catálise , Técnicas Eletroquímicas , Grafite/química , Hidrogênio/química , Oxirredução , Oxigênio/química , Processos Fotoquímicos , Raios Ultravioleta
11.
Angew Chem Int Ed Engl ; 53(11): 2951-5, 2014 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-24520001

RESUMO

Monolayer HNb3O8 2D nanosheets have been used as highly chemoselective and active photocatalysts for the selective oxidation of alcohols. The nanosheets exhibit improved photocatalytic activity over their layered counterparts. Results of in situ FTIR, DRS, ESR, and DFT calculations show the formation of surface complexes between the Lewis acid sites on HNb3O8 2D nanosheets and alcohols. These complexes play a key role in the photocatalytic activity of the material. Furthermore, the unique structural features of the nanosheets contributed to their high photocatalytic activity. An electron transition from the coordinated alcohol species to surface Nb atoms takes place and initiates the aerobic oxidation of alcohols with high product selectivity under visible light irradiation. This reaction process is distinct from that of classic semiconductor photocatalysis.

12.
Spectrochim Acta A Mol Biomol Spectrosc ; 323: 124915, 2024 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-39096672

RESUMO

The development of innovative multi-emission sensors for the rapid and accurate detection of contaminants is both vital and challenging. In this study, utilizing two rigid ligands (H3ICA and H4BTEC), a series of water-stable bimetallic organic frameworks (EuTb-MOFs) were synthesized. Luminescent investigations have revealed that EuTb-MOF-1 exhibits prominent multiple emission peaks, attributed to the distinctive fluorescence characteristics of Eu(III) and Tb(III) ions. Therefore, EuTb-MOF-1 efficiently recognized various metal ions and pharmaceutical compounds through 2D decoded maps. Fe3+ and Pb2+ exhibited significant quenching effects on the luminescence of EuTb-MOF-1, which were attributed to the internal filtering effect and the interaction between Lewis basic sites within EuTb-MOF-1 and Pb2+ ions, respectively. Furthermore, EuTb-MOF-1 demonstrated high sensitivity to sulfonamide antibiotics, with detection limits of 0.037 µM for SMZ and 0.041 µM for SDZ, respectively. In addition, EuTb-MOF-1 was immobilized to prepare MOF-based test strips, enabling direct visual detection of sulfonamides as a portable sensor. With excellent water stability, multi-responsive recognition capabilities, and high sensitivity to specific analytes, EuTb-MOF-1 is a promising candidate for environmental contaminant detection in aquatic systems.


Assuntos
Elementos da Série dos Lantanídeos , Medições Luminescentes , Estruturas Metalorgânicas , Elementos da Série dos Lantanídeos/química , Água/química , Estruturas Metalorgânicas/química , Medições Luminescentes/métodos , Cátions/química , Ferro/análise , Ferro/química , Chumbo/análise , Chumbo/química , Limite de Detecção
13.
J Colloid Interface Sci ; 661: 761-771, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38325174

RESUMO

Tetracycline (TC) antibiotics, extensively utilized in livestock farming and aquaculture, pose significant environmental challenges. Photocatalysis, leveraging renewable sunlight and reusable photocatalysts, offers a promising avenue for mitigating TC pollution. However, identifying robust photocatalysts remains a formidable challenge. This study introduces a novel hollow-flower-ball-like nanoheterojunction composed of a nitrogen-rich covalent organic framework (N-COF) coupled with BiOBr (BOB), a semiconductor with a higher Fermi level. The synthesized N-COF/BOB S-scheme nanoheterojunction features an expanded contact interface, strengthened chemical bonding, and unique band topologies. The N-COF/BOB composites showcased exceptional TC degradation performance, achieving an 81.2% removal of 60 mg/L TC within 2 h, markedly surpassing the individual efficiencies of N-COF and BOB by factors of 3.80 and 5.96, respectively. Furthermore, the total organic carbon (TOC) removal efficiency highlights a superior mineralization capacity in the N-COF/BOB composite compared to the individual components, N-COF and BOB. The toxicity assessment revealed that the degradation intermediates possess diminished environmental toxicity. This enhanced performance is ascribed to the robust S-scheme nanoheterojunction structure, which promotes efficient photoinduced electron transfer from BOB to N-COF. This process also augments the separation of photogenerated charge carriers, resulting in an increased yield of superoxide radicals (∙O2-) and hydroxyl radicals (∙OH). These reactive species significantly contribute to the degradation and mineralization of TC. Consequently, this study introduces a sustainable approach for addressing emerging antibiotic contaminants, employing COF-based photocatalysts.


Assuntos
Antibacterianos , Bismuto , Radical Hidroxila , Transporte de Elétrons , Tetraciclinas , Tetraciclina
14.
Chemosphere ; 352: 141446, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38354866

RESUMO

Heterogeneous photocatalytic degradation of antibiotic involves the activation of antibiotic molecules and the photocatalytic oxidation process. However, the simultaneous improvement of these processes is still a challenge. Herein, S-scheme heterojunctions consisted of Cu2O nanocluster with defective WO3 nanosheets were constructed for efficient photocatalytic degradation of levofloxacin (LVX). The typical CNS-5 composite (5 wt% Cu2O/WO3) achieves an optimal LVX degradation efficiency of 97.9% within 80 min. The spatial charge separation and enhancement of redox capacity were realized by the formation of S-scheme heterojunction between Cu2O and WO3. Moreover, their interfacial interaction would lead to the loss of lattice oxygen and the generation of W5+ sites. It is witnessed that the C-N of piperazine ring and CO of carboxylic acid in LVX are coordinated with W5+ sites to build the electronic bridge to activate LVX, greatly promoting the further degradation. This work highlights the important role of selective coordination activation cooperated with S-type heterojunctions for the photocatalytic degradation and offers a new view to understand the degradation of antibiotics at molecular level.


Assuntos
Antibacterianos , Levofloxacino , Ácidos Carboxílicos , Eletrônica , Oxigênio
15.
J Colloid Interface Sci ; 643: 102-114, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37054545

RESUMO

Covalent organic frameworks (COFs) are crystalline porous materials with enormous potential for realizing solar-driven CO2-to-fuel conversion, yet the sluggish transfer/separation of photoinduced electrons and holes remains a compelling challenge. Herein, a step (S)-scheme heterojunction photocatalyst (CuWO4-COF) was rationally fabricated by a thermal annealing method for boosting CO2 conversion to CO. The optimal CuWO4/COF composite sample, integrating 10 wt% CuWO4 with an olefin (C═C) linked COF (TTCOF), achieved a remarkable gas-solid phase CO yield as high as 7.17 ± 0.35 µmol g-1h-1 under visible light irradiation, which was significantly higher than the pure COF (1.6 ± 0.29 µmol g-1h-1). The enhanced CO2 conversion rate could be attributable to the interface engineering effect and the formation of internal electric field (IEF) directing from TTCOF to CuWO4 according to the theoretical calculation and experimental results, which also proves the electrons transfer from TTCOF to CuWO4 upon hybridization. In addition, driven by the IEF, the photoinduced electrons can be steered from CuWO4 to TTCOF under visible light irradiation as well-elucidated by in-situ irradiated X-ray photoelectron spectroscopy, verifying the S-scheme charge transfer pathway over CuWO4/COF composite heterojunctions, which greatly foster the photoreduction activity of CO2. The preparation technique of the S-scheme heterojunction photocatalyst in this study provides a paradigmatic protocol for photocatalytic solar fuel generation.

16.
J Colloid Interface Sci ; 652(Pt B): 1568-1577, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37660613

RESUMO

A series of dehydrated MoS2/UiO-66(SH)2 (MS/UiS) composites has been prepared as photocatalysts for N2 fixation. Typically, 10% MS/UiS exhibits the best performance with an NH4+ yield rate of 54.08 µmol∙g-1∙h-1. 15N isotope test confirmed that the sample 10% MS/UiS was most effective for reducing N2 to ammonia. Such enhanced activity was due to the presence of abundant unsaturated Zr and Mo sites which would synergistically promote the adsorption and activation of N2. The photogenerated electrons would transfer to the unsaturated Zr-O clusters while part of photogenerated electrons at the interface migrate to MS via MoVI-O interactions between MS and UiS. These two electron transfer pathways effectively promote the separation of photogenerated carriers. The activated N2 is reduced to ammonia by the synergistic effect of protonated hydrogen and photogenerated electrons. Finally, a possible N2 fixation mechanism is proposed which emphasizes the significant roles of nitrogen activation and interface interaction in composites photocatalyst for improving photocatalytic performance.

17.
J Colloid Interface Sci ; 631(Pt B): 154-163, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36401923

RESUMO

Designing efficient metal organic frameworks (MOF)-based photocatalysts has recently attracted wide attention. In this work, Au nanoparticles(NPs)-decorated defective DUT-67(Zr) (Au@DUT-67(Zr)) with enlarged channels was successfully fabricated and achieved 7.5 times higher conversion than Au NPs-decorated UiO-66(Zr) (Au@UiO-66(Zr)) for photocatalytic selective oxidation of amines to imines driven by visible light. Au NPs are more effectively fixed on DUT-67(Zr) due to its partially hollow structure. Au@DUT-67(Zr) possesses more active sites including unsaturated Zr atoms and oxygen vacancies (VO) than Au@UiO-66(Zr). In situ Fourier transform infrared (FTIR) spectrum reveals that benzylamine is activated on unsaturated Zr sites via HN…Zr species, facilitating deprotonation of -CH2 in benzylamine. VO can not only adsorb and activate oxygen (O2) but also capture plasmonic hot electrons, enhancing the forming of superoxide radical (O2-). Plasmonic hot holes assisted with O2- effectively achieve the selective oxidation of benzylamine. Finally, a possible synergetic mechanism combining the plasmon with the molecular activation is presented to illustrate the photocatalytic pathway at the molecular level.

18.
Chemosphere ; 311(Pt 1): 137053, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36332732

RESUMO

ZnIn2S4 ultrathin 2D nanosheets with a positive surface charge are synthesized by a hydrothermal method and different contents of surface S vacancies are induced via heat treatment of as-prepared ZnIn2S4 (ZIS). As the S vacancies contents increased, the photocatalytic degradation efficiency of ceftriaxone (CTRX) sodium is promoted. Especially, ZIS-300 shows the best degradation efficiency (88.8%) for an initial CTRX concentration of 10 mg L-1 in 2 h. It is found that S vacancies cause the electron density of surface metal atoms (Zn, In) to be decreased, which makes the effective adsorption and activation of ceftriaxone anions through electrostatic adsorption interactions. Meanwhile, S vacancies also serve as active centers to promote the absorption of O2 and gather electrons to form •O2- species. The photogenerated holes quickly transfer to the surface of the catalyst to directly degrade the adsorbed CTRX. Thus, the photocatalytic CTRX degradation efficiency is significantly improved. Finally, a possible mechanism for over defective ZIS is proposed. This work provides a feasible strategy for the efficient degradation of antibiotics from the perspective of electrostatic adsorption and molecule activation.


Assuntos
Antibacterianos , Ceftriaxona , Eletricidade Estática , Catálise , Adsorção
19.
J Colloid Interface Sci ; 615: 876-886, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35182857

RESUMO

The functionalization of metal-organic frameworks (MOFs) is imperative and challenging for the development of practical MOF-based materials. Herein, a magnetically functionalized Zr-MOF (Fe3O4@MOF-525) was synthesized via secondary-growth approach to obtain an easily-separated and recyclable adsorbent for the removal of pharmaceuticals (tetracycline (TC) and diclofenac sodium (DF)). After loading Fe3O4 nanoparticles (NPs), due to the increase of micropore volume and specific surface area caused by defects, the adsorption performance of Fe3O4@MOF-525 was improved. The kinetics could be described by the pseudo-second-order kinetic model. The different adsorption capacity and initial rate were attributed to the properties of the pharmaceuticals, including the molecular size and hydrophobicity/hydrophilicity. In isotherm experiments, the maximum adsorption capacities of DF and TC on Fe3O4@MOF-525 calculated by Sips model reached 745 and 277 mg·g-1, respectively. The thermodynamic studies indicated the adsorption was endothermic and spontaneous. The effect of pH suggested that electrostatic interaction, π-π interaction, anion-π interaction, and H-bonding were possibly involved in the adsorption process. The adsorbent was separated by magnetic and regenerated. Washed with ethanol, Fe3O4@MOF-525 remained about 80% adsorption capacity after four cycles. In-situ photo-regeneration under visible-light irradiation was another attractive method, where > 95% TC was degraded in 4 h. The reaction with scavengers revealed that 1O2 was the dominant reactive species in our system, indicating the occurrence of Type II photosensitization. The separability, excellent adsorption performance, and recyclability of Fe3O4@MOF-525 may lead to its beneficial applications in water treatment.


Assuntos
Estruturas Metalorgânicas , Poluentes Químicos da Água , Purificação da Água , Adsorção , Cinética , Estruturas Metalorgânicas/química , Preparações Farmacêuticas , Regeneração , Poluentes Químicos da Água/química , Purificação da Água/métodos
20.
Nanomaterials (Basel) ; 12(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36500734

RESUMO

Photocatalysis offers a sustainable approach for recalcitrant organic pollutants degradation, yet it is still challenging to seek robust photocatalysts for application purposes. Herein, a novel NiFe layered double hydroxide (LDH)/covalent triazine framework (CTF-1) Z-scheme heterojunction photocatalyst was rationally designed for antibiotics degradation under visible light irradiation. The NiFe-LDH/CTF-1 nanocomposites were readily obtained via in situ loading of NiFe-LDH on CTF-1 through covalent linking. The abundant coupling interfaces between two semiconductor counterparts lay the foundation for the formation of Z-scheme heterostructure, thereby effectively promoting the transfer of photogenerated electrons, inhibiting the recombination of carriers, as well as conferring the nanocomposites with stronger redox ability. Consequently, the optimal photocatalytic activity of the LDH/CTF heterojunction was significantly boosted for the degradation of a typical antibiotic, tetracycline (TC). Additionally, the photodegradation process and the mineralization of TC were further elucidated. These results envision that the LDH/CTF-1 can be a viable photocatalyst for long-term and sustainable wastewater treatment.

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