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1.
J Am Chem Soc ; 146(3): 1904-1913, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38133928

RESUMO

Partitioning the pores of covalent organic frameworks (COFs) is an attractive strategy for introducing microporosity and achieving new functionality, but it is technically challenging to achieve. Herein, we report a simple strategy for partitioning the micropores/mesopores of multivariate COFs. Our approach relies on the predesign and synthesis of multicomponent COFs through imine condensation reactions with aldehyde groups anchored in the COF pores, followed by inserting additional symmetric building blocks (with C2 or C3 symmetries) as pore partition agents. This approach allowed tetragonal or hexagonal pores to be partitioned into two or three smaller micropores, respectively. The synthesized library of pore-partitioned COFs was then applied for the capture of iodine pollutants (i.e., I2 and CH3I). This rich inventory allowed deep exploration of the relationships between the COF adsorbent composition, pore architecture, and adsorption capacity for I2 and CH3I capture under wide-ranging conditions. Notably, one of our developed pore-partitioned COFs (COF 3-2P) exhibited greatly enhanced dynamic I2 and CH3I adsorption performances compared to its parent COF (COF 3) in breakthrough tests, setting a new benchmark for COF-based adsorbents. Results present an effective design strategy toward functional COFs with tunable pore environments, functions, and properties.

2.
J Environ Sci (China) ; 141: 63-89, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38408835

RESUMO

Covalent organic frameworks (COFs) are a new kind of crystalline porous materials composed of organic molecules connected by covalent bonds, processes the characteristics of low density, large specific surface area, adjustable pore size and structure, and easy to functionalize, which have been widely used in the field of membrane separation technology. Recently, there are more and more researches focusing on the preparation methods, separation application, and mechanism of COF membranes, which need to be further summarized and compared. In this review, we primarily summarized several conventional preparation methods, such as two-phase interfacial polymerization, in-situ growth on substrate, unidirectional diffusion method, layer-by-layer assembly method, mixed matrix membranes, and so on. The advantages and disadvantages of each method are briefly summarized. The application potential of COF membrane in liquid separation are introduced from four aspects: dyeing wastewater treatment, heavy metal removal, seawater desalination and oil-water separation. Then, the mechanisms including pore structure, hydrophilic/hydrophobic, electrostatic repulsion/attraction and Donnan effect are introduced. For the efficient removal of different kind of pollutions, researchers can select different ligands to construct membranes with specific pore size, hydrophily, salt or organic rejection ability and functional group. The ideas for the design and preparation of COF membranes are introduced. Finally, the future direction and challenges of the next generation of COF membranes in the field of separation are prospected.


Assuntos
Estruturas Metalorgânicas , Separação de Fases , Cloreto de Sódio , Difusão , Poluição Ambiental
3.
Langmuir ; 39(51): 18696-18712, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38079289

RESUMO

With the rapid development of nuclear technology and peaceful utilization of nuclear energy, plentiful U(VI) not only is required to be extracted from solutions for a sustainable nuclear fuel supply but also is inevitably released into the surrounding environment to result in pollution and threaten human health. Thereby, realizing selective extraction of U(VI) from aqueous solutions is crucial for U(VI) pollution control and a sustainable nuclear industry. Metal organic frameworks (MOFs) have gained multidisciplinary attention due to their excellent properties including large specific surface areas, tunable pore structures, easy functionalization, etc. This Review comprehensively summarizes the research progress of MOFs and MOF-based materials on U(VI) removal from aqueous solutions by sorption, photocatalysis, electrocatalysis, membrane separation, etc. The efficient high extraction ability is dependent on the intrinsic properties of MOFs and the techniques used. The removal properties of MOF-based materials as adsorbents, photocatalysts, and electrocatalysts for U(VI) are discussed. Information about the interaction mechanisms between U(VI) and MOF-based materials are analyzed in-depth, including experiments, theoretical calculations, and advanced spectroscopy analysis. The removal properties for U(VI) of various MOF-based materials are assessed through different techniques. Finally, a summary and perspective on the direction and challenges of MOF-based materials and various pollutant removal technologies are proposed to provide some significant information on designing and fabricating MOF-based materials for environmental pollution management.

4.
Environ Sci Technol ; 57(29): 10870-10881, 2023 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-37431600

RESUMO

Efficient and sustainable methods for 99TcO4- removal from acidic nuclear waste streams, contaminated water, and highly alkaline tank wastes are highly sought after. Herein, we demonstrate that ionic covalent organic polymers (iCOPs) possessing imidazolium-N+ nanotraps allow the selective adsorption of 99TcO4- under wide-ranging pH conditions. In particular, we show that the binding affinity of the cationic nanotraps toward 99TcO4- can be modulated by tuning the local environment around the nanotraps through a halogenation strategy, thereby enabling universal pH 99TcO4- removal. A parent iCOP-1 possessing imidazolium-N+ nanotraps showed fast kinetics (reaching adsorption equilibrium in 1 min), a high adsorption capacity (up to 1434.1 ± 24.6 mg/g), and exceptional selectivity for 99TcO4- and ReO4- (nonradioactive analogue of 99TcO4-) removal in contaminated water. By introducing F groups near the imidazolium-N+ nanotrap sites (iCOP-2), a ReO4- removal efficiency over 58% was achieved in 60 min in 3 M HNO3 solution. Further, introduction of larger Br groups near the imidazolium-N+ binding sites (iCOP-3) imparted a pronounced steric effect, resulting in exceptional adsorption performance for 99TcO4- under super alkaline conditions and from low-activity waste streams at US legacy Hanford nuclear sites. The halogenation strategy reported herein guides the task-specific design of functional adsorbents for 99TcO4- removal and other applications.


Assuntos
Halogenação , Polímeros , Ânions , Água , Concentração de Íons de Hidrogênio
5.
Angew Chem Int Ed Engl ; 62(30): e202303129, 2023 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-37117155

RESUMO

Optimizing the electronic structure of covalent organic framework (COF) photocatalysts is essential for maximizing photocatalytic activity. Herein, we report an isoreticular family of multivariate COFs containing chromenoquinoline rings in the COF structure and electron-donating or withdrawing groups in the pores. Intramolecular donor-acceptor (D-A) interactions in the COFs allowed tuning of local charge distributions and charge carrier separation under visible light irradiation, resulting in enhanced photocatalytic performance. By optimizing the optoelectronic properties of the COFs, a photocatalytic uranium extraction efficiency of 8.02 mg/g/day was achieved using a nitro-functionalized multicomponent COF in natural seawater, exceeding the performance of all COFs reported to date. Results demonstrate an effective design strategy towards high-activity COF photocatalysts with intramolecular D-A structures not easily accessible using traditional synthetic approaches.

6.
Rheumatology (Oxford) ; 62(1): 439-449, 2022 12 23.
Artigo em Inglês | MEDLINE | ID: mdl-35385111

RESUMO

OBJECTIVE: To explore the longitudinal association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with OA-related biomarkers. METHODS: Eighteen OA-related biochemical biomarkers of 600 knee OA participants in the Foundation for the National Institutes of Health OA Biomarkers Consortium (FNIH) study were extracted. The quantitative IPFP signal intensity measures were acquired based on magnetic resonance imaging, including mean value [Mean (IPFP)] and standard deviation [sDev (IPFP)] of the whole IPFP signal intensity, median value [Median (H)] and upper quartile value [UQ (H)] of high signal intensity, the ratio of volume of high signal intensity to volume of whole IPFP signal intensity [Percentage (H)] and Clustering factor (H). The linear mixed-effect model was applied to determine the longitudinal associations between IPFP signal intensity alteration and biochemical biomarkers over 2 years. RESULTS: All IPFP measures except for Clustering factor (H) were positively associated with urine collagenase-cleaved type II collagen neoepitope (uC2C), urine C-terminal cross-linked telopeptide of type II collagen (uCTX-II), urine C-terminal cross-linked telopeptide of type I collagen-α (uCTX-Iα) and urine N-terminal cross-linked telopeptide of type I collagen (uNTX-I). Mean (IPFP), Median (H) and Percentage (H) were positively associated with the nitrated form of an epitope located in the triple helix of type II collagen (Coll2-1 NO2). Mean (IPFP), Median (H) and UQ (H) were positively associated with sCTX-I and uCTX-Iß. Positive associations between sDev (IPFP), Percentage (H) and serum hyaluronic acid (sHA) were found. CONCLUSION: Our results suggest a role of IPFP signal intensity alteration in joint tissue remodelling on a molecular level.


Assuntos
Osteoartrite do Joelho , Humanos , Osteoartrite do Joelho/patologia , Colágeno Tipo I , Colágeno Tipo II , Articulação do Joelho/patologia , Imageamento por Ressonância Magnética/métodos , Tecido Adiposo/diagnóstico por imagem , Tecido Adiposo/patologia , Biomarcadores
7.
J Craniofac Surg ; 33(4): e355-e358, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35225590

RESUMO

PURPOSE: To evaluate the ciliary body mechanical load during low speed impact using finite element method to explain the mechanism of the cause of angle recession and cyclodialysis cleft. METHODS: Optical coherence tomography images were obtained to assess the patient's ciliary body angle recession. A finite element eye model was established based on Virginia Tech eye model with the consideration of dynamic impact of a projectile striking an eye. The mechanical properties of the ocular tissues were obtained from literatures. The stress and strain were evaluated. RESULTS: The stress distribution of the eye was calculated. The stress concentration at zonules was observed after 0.75 ms of the impact. The maximum stress at the cornea reached 3.8 MPa. The maximum stress at ciliary body was 57 KPa, which has high probability to cause ciliary body injury. The maximum stress at zonules was 0.98 MPa. The lateral expansion also reduces the forces transmitted along the sclera to the rear part of the eye. CONCLUSIONS: The eye under frontal impact will result in lateral expansion, which increase the stretch force of the lens, zonules and ciliary body. This mechanism can be seen as the protection for retina. The boundary of ciliary body is the most vulnerable position, where angle recession and cyclodialyses cleft will occur before retina damage occurrence. TRANSLATIONAL RELEVANCE: The finite element model explains the blunt low speed impact induced ciliary body related injuries, which enables us to assess the ocular injury for low energy impact and better diagnosis and treatment in clinics.


Assuntos
Corpo Ciliar , Traumatismos Oculares , Corpo Ciliar/diagnóstico por imagem , Corpo Ciliar/lesões , Simulação por Computador , Traumatismos Oculares/diagnóstico por imagem , Traumatismos Oculares/etiologia , Análise de Elementos Finitos , Humanos , Esclera
8.
J Environ Sci (China) ; 122: 1-13, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35717075

RESUMO

For the continuous utilization of nuclear energy and efficient control of radioactive pollution, low-cost materials with high efficient U(VI) removal are of great importance. In this study, low temperature plasma method was applied for the successful modification of O-phosphorylethanolamine (O-PEA) on the porous carbon materials. The produced materials (Cafe/O-PEA) could adsorb U(VI) efficiently with the maximum sorption capacity of 648.54 mg/g at 1 hr, T=298 K, and pH=6.0, much higher than those of most carbon-based composites. U(VI) sorption was mainly controlled by strong surface complexation. From FTIR, SEM-EDS and XPS analyses, the sorption of U(VI) was related to the complexation with -NH2, phosphate and -OH groups on Cafe/O-PEA. The low temperature plasma method was an efficient, environmentally friendly and low-cost method for surface modification of materials for the effective enrichment of U(VI) from aqueous solutions.


Assuntos
Carbono , Urânio , Adsorção , Café , Fosfatos , Porosidade , Temperatura
9.
Langmuir ; 35(1): 276-283, 2019 01 08.
Artigo em Inglês | MEDLINE | ID: mdl-30550286

RESUMO

To enhance the electron-hole separation and boost the practical performance of commercial titania (Degussa P25) under natural solar light, in this work, P25 was modified with Co(II) species (CoP25) through post-treatment with decomposition of Co-ethylenediaminetetraacetic acid precursors in a wet chemical anchoring process. With appropriate Co(II) loading amount as molecular cocatalyst, the resulted CoP25-4 showed significantly improved photocatalytic performance for Cr(VI) reduction and bisphenol A (BPA) oxidation under UV-light irradiation. The coexistence of Cr(VI) and BPA promoted mutually the degradation of both pollutants. Under simulated solar light (AM 1.5G) illumination, the Cr(VI) reduction rate over CoP25-4 was 8.5 times enhanced compared with that over P25, whereas the simultaneous degradation rate of BPA over CoP25-4 was 8 times higher than that over P25. Further investigations indicated that the covalent atomic Co(II) anchoring on P25 significantly promoted the photogenerated electron-hole separation and facilitated Cr(VI) reduction via the formation of a Co(I) intermediate and simultaneously boosted BPA oxidation. Our results demonstrated a facile strategy to modify P25 with remarkably improved performance for the practical application in environmental pollution management under natural light excitation.

10.
Environ Sci Technol ; 53(11): 6454-6461, 2019 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-31081617

RESUMO

The effect of Cr(VI) and bisphenol A (BPA) on U(VI) photoreduction by C3N4 photocatalyst was demonstrated by the batch experiments, electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) techniques. The batch experiments manifested that Cr(VI) and BPA enhanced the photocatalytic activity of C3N4 for U(VI) photoreduction, whereas U(VI) photoreduction was significantly diminished with increased pH from 4.0 to 8.0. According to radical scavengers and ESR analysis, U(VI) was photoreduced to U(IV) by photogenerated electrons of conduction band edge, whereas Cr(VI) was reduced to Cr(III) by H2O2. BPA and its products such as organic acid and alcohols can capture photoinduced holes, which resulted in the enhancement of U(VI) photoreduction to U(IV). XPS and XANES analyses demonstrated that U(VI) was gradually photoreduced to U(IV) by C3N4 within irradiation 60 min, whereas U(IV) was reoxidized to U(VI) with increasing irradiation time. EXAFS analysis determined that the dominant interaction mechanisms of U(VI) on C3N4 after irradiation for 240 min were reductive precipitation and inner-sphere surface complexation. This work highlights the synergistic removal of radionuclides, heavy metals, and persistent organic pollutants by C3N4, which is crucial for the design and application of a high-performance photocatalyst in actual environmental cleanup.


Assuntos
Peróxido de Hidrogênio , Compostos Benzidrílicos , Cromo , Espectroscopia de Ressonância de Spin Eletrônica , Fenóis , Espectroscopia Fotoeletrônica
11.
Retina ; 39(5): 889-895, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-29360683

RESUMO

PURPOSE: To compare the 6-month efficacy of the intravitreal injection of conbercept or ranibizumab for patients with polypoidal choroidal vasculopathy (PCV). METHODS: This is a retrospective case-control study involved 79 PCV eyes of 77 patients. The PCV eyes were treated with an intravitreal injection of either ranibizumab (n = 44) or conbercept (n = 35). Three monthly loading doses were injected and followed by retreatment as needed. The best-corrected visual acuity and angiographic characteristics were evaluated after 6 months. RESULTS: The mean logarithm of the minimum angle of resolution best-corrected visual acuity had improved from 0.86 (Snellen equivalent, 20/145) at baseline to 0.70 (Snellen equivalent, 20/100) at 6 months in the conbercept group (P < 0.001), and from 0.74 (Snellen equivalent, 20/110) at baseline to 0.63 (Snellen equivalent, 20/85) at 6 months in the ranibizumab group (P = 0.032), respectively. The central foveal thickness was decreased from 407 ± 146 µm to 230 ± 71 µm in the conbercept group (P < 0.001), and from 394 ± 93 µm to 208 ± 56 µm in the ranibizumab group (P < 0.001). Polyps were completely regressed and in 21 (47.7%) eyes in the conbercept group at 6 months, significant higher than in 10 (28.6%) eyes in the ranibizumab group (P = 0.029). CONCLUSION: Both conbercept and ranibizumab effectively increased the visual acuity and regressed the polyps of PCV eyes. No significant difference was found in the visual acuity improvement of the patients with PCV between the conbercept group and ranibizumab group at 6 months. However, conbercept was superior to ranibizumab monotherapy in the regression of polyps.


Assuntos
Doenças da Coroide/tratamento farmacológico , Corioide/irrigação sanguínea , Pólipos/tratamento farmacológico , Ranibizumab/administração & dosagem , Proteínas Recombinantes de Fusão/administração & dosagem , Acuidade Visual , Inibidores da Angiogênese/administração & dosagem , Corioide/diagnóstico por imagem , Doenças da Coroide/diagnóstico , Feminino , Seguimentos , Fóvea Central/patologia , Humanos , Injeções Intravítreas , Masculino , Pessoa de Meia-Idade , Pólipos/diagnóstico , Estudos Retrospectivos , Fatores de Tempo , Tomografia de Coerência Óptica , Resultado do Tratamento , Fator A de Crescimento do Endotélio Vascular/antagonistas & inibidores
12.
Chem Rec ; 16(1): 295-318, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26915704

RESUMO

Graphene oxides (GOs) have come under intense multidisciplinary study because of their unique physicochemical properties and possible applications. The large amount of oxygen-containing functional groups on GOs leads to a high sorption capacity for the removal of various kinds of organic and inorganic pollutants from aqueous solutions in environmental pollution cleanup. However, the lack of selectivity results in difficulty in the selective removal of target pollutants from aqueous solutions in the presence of other coexisting pollutants. Herein, the surface grafting of GOs with special oxygen-containing functional groups using low-temperature plasma techniques and the application of the surface-modified GOs for the efficient removal of organic and inorganic pollutants in environmental pollution are reviewed. This paper gives an account of our research on the application of GO-based nanomaterials in environmental pollution cleanup, including: (1) the synthesis and surface grafting of functional groups on GOs, summarizing various types of low-temperature plasma techniques for the synthesis of graphene/GOs; and (2) the application of graphene/GOs and their composites for the efficient removal of organic and inorganic pollutants from aqueous solutions, including the interaction mechanism according to recently published results.


Assuntos
Poluentes Ambientais/química , Poluentes Ambientais/isolamento & purificação , Grafite/química , Nanoestruturas/química , Óxidos/química , Propriedades de Superfície
13.
Magn Reson Imaging ; 107: 130-137, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38278311

RESUMO

PURPOSE: To investigate the diagnostic efficacy of T1ρ dispersion and Gd-EOB-DTPAenhanced T1mapping in the identification of early liver fibrosis (LF) and non-alcoholic steatohepatitis (NASH) in a non-alcoholic fatty liver disease (NAFLD) rabbit model induced by a high-fat diet using histopathological findings as the standard reference. METHODS: A total of sixty rabbits were randomly allocated into the standard control group (n = 12) and the NAFLD model groups (8 rabbits per group) corresponding to different high-fat high cholesterol diet feeding weeks. All rabbits underwent noncontrast transverse T1ρ mapping with varying spin-locking frequencies (FSL = 0 Hz and 500 Hz), native T1 mapping, and Gd-EOB-DTPA-enhanced T1 mapping during the hepatobiliary phase. The histopathological findings were assessed based on the NASH CRN Scoring System. Statistical analyses were conducted using the intraclass correlation coefficient, analysis of variance, multiple linear regression, and receiver operating characteristics. RESULTS: Except for native T1, T1ρ, T1ρ dispersion, HBP T1, and △T1 values significantly differed among different liver fibrosis groups (F = 14.414, 18.736, 10.15, and 9.799, respectively; all P < 0.05). T1ρ, T1ρ dispersion, HBP T1, and △T1 values also exhibited significant differences among different NASH groups (F = 4.138, 4.594, 21.868, and 22.678, respectively; all P < 0.05). In the multiple regression analysis, liver fibrosis was the only factor that independently influenced T1ρ dispersion (R2 = 0.746, P = 0.000). Among all metrics, T1ρ dispersion demonstrated the best area under curve (AUC) for identifying early LF (≥ F1 stage) and significant LF (≥ F2 stage) (AUC, 0.849 and 0.916, respectively). The performance of △T1 and HBP T1 (AUC, 0.948 and 0.936, respectively) were better than that of T1ρ and T1ρ dispersion (AUC, 0.762 and 0.769, respectively) for diagnosing NASH. CONCLUSION: T1⍴ dispersion may be suitable for detecting liver fibrosis in the complex background of NAFLD, while Gd-EOB-DTPA enhanced T1 mapping is superior to nonenhanced T1⍴ mapping (T1⍴ and T1⍴ dispersion) for identifying NASH.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Coelhos , Hepatopatia Gordurosa não Alcoólica/patologia , Fígado/diagnóstico por imagem , Fígado/patologia , Meios de Contraste , Imageamento por Ressonância Magnética , Gadolínio DTPA , Cirrose Hepática/patologia , Medição de Risco
14.
Nat Commun ; 15(1): 2671, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38531870

RESUMO

Radioiodine capture from nuclear fuel waste and contaminated water sources is of enormous environmental importance, but remains technically challenging. Herein, we demonstrate robust covalent organic frameworks (COFs) with antiparallel stacked structures, excellent radiation resistance, and high binding affinities toward I2, CH3I, and I3- under various conditions. A neutral framework (ACOF-1) achieves a high affinity through the cooperative functions of pyridine-N and hydrazine groups from antiparallel stacking layers, resulting in a high capacity of ~2.16 g/g for I2 and ~0.74 g/g for CH3I at 25 °C under dynamic adsorption conditions. Subsequently, post-synthetic methylation of ACOF-1 converted pyridine-N sites to cationic pyridinium moieties, yielding a cationic framework (namely ACOF-1R) with enhanced capacity for triiodide ion capture from contaminated water. ACOF-1R can rapidly decontaminate iodine polluted groundwater to drinking levels with a high uptake capacity of ~4.46 g/g established through column breakthrough tests. The cooperative functions of specific binding moieties make ACOF-1 and ACOF-1R promising adsorbents for radioiodine pollutants treatment under practical conditions.

15.
Eco Environ Health ; 2(4): 252-256, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38435361

RESUMO

Japan recently announced the plan to discharge over 1.2 million tons of radioactive water into the Pacific Ocean, which contained hazardous radionuclides such as 60Co, 90Sr, 125Sb, 129I, 3H, 137Cs, and 99TcO4-, etc. The contaminated water will pose an enormous threat to global ecosystems and human health. Developing materials and technologies for efficient radionuclide removal is highly desirable and arduous because of the extreme conditions, including super acidity or alkalinity, high ionic strength, and strong ionizing radiation. Recently, advanced porous material, such as porous POPs, MOFs, COFs, PAFs, etc., has shown promise of improved separation of radionuclides due to their intrinsic structural advantages. Furthermore, emerging technologies applied to radionuclide removal have also been summarized. In order to better deal with radionuclide contamination, higher requirements for the design of nanomaterials and technologies applied to practical radionuclide removal are proposed. Finally, we call for comprehensive implementation of strategies and strengthened cooperation to mitigate the harm caused by radioactive contamination to oceans, atmosphere, soil, and human health.

16.
Eco Environ Health ; 2(3): 117-130, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38074995

RESUMO

To date, significant efforts have been devoted to eliminating hazardous components to purify wastewater through the development of various nanomaterials. Covalent organic frameworks (COFs), an important branch of the porous crystalline family, possess the peculiarity of ultrahigh surface area, adjustable pore size, and facile functionality. Exciting studies from design fabrication to potential applications in water treatment by COF-based membranes (COMs) have emerged. This review summarizes various preparation strategies and synthesis mechanisms for COMs, including layer-by-layer stacking, in situ growth, interfacial polymerization, and electrochemical synthesis, and briefly describes the advanced characterization techniques for COMs. Moreover, the application of COMs in heavy metal removal, dye separation, purification of radionuclides, pollutant detection, sea water desalination, and so on, is described and discussed. Finally, the perspectives on future opportunities for designing COMs in water purification have been proposed.

17.
Nat Commun ; 14(1): 1106, 2023 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-36849444

RESUMO

Covalent organic frameworks (COFs) represent an emerging class of organic photocatalysts. However, their complicated structures lead to indeterminacy about photocatalytic active sites and reaction mechanisms. Herein, we use reticular chemistry to construct a family of isoreticular crystalline hydrazide-based COF photocatalysts, with the optoelectronic properties and local pore characteristics of the COFs modulated using different linkers. The excited state electronic distribution and transport pathways in the COFs are probed using a host of experimental methods and theoretical calculations at a molecular level. One of our developed COFs (denoted as COF-4) exhibits a remarkable excited state electron utilization efficiency and charge transfer properties, achieving a record-high photocatalytic uranium extraction performance of ~6.84 mg/g/day in natural seawater among all techniques reported so far. This study brings a new understanding about the operation of COF-based photocatalysts, guiding the design of improved COF photocatalysts for many applications.

18.
JACS Au ; 3(1): 239-251, 2023 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-36711090

RESUMO

Covalent organic frameworks (COFs) can be designed to allow uranium extraction from seawater by incorporating photocatalytic linkers. However, often sacrificial reagents are required for separating photogenerated charges which limits their practical applications. Herein, we present a COF-based adsorption-photocatalysis strategy for selective removal of uranyl from seawater in the absence of sacrificial reagents. A series of ternary and quaternary COFs were synthesized containing the electron-rich linker 2,4,6-triformylphloroglucinol as the electron donor, the electron-deficient linker 4,4'-(thiazolo[5,4-d]thiazole-2,5-diyl)dibenzaldehyde as the acceptor, and amidoxime nanotraps for selective uranyl capture (with the quaternary COFs incorporating [2,2'-bipyridine-5,5'-diamine-Ru(Bp)2]Cl2 as a secondary photosensitizer). The ordered porous structure of the quaternary COFs ensured efficient mass transfer during the adsorption-photocatalysis capture of uranium from seawater samples, with photocatalytically generated electrons resulting in the reduction of adsorbed U(VI) to U(IV) in the form of UO2. A quaternary COF, denoted as COF 2-Ru-AO, possessed a high uranium uptake capacity of 2.45 mg/g/day in natural seawater and good anti-biofouling abilities, surpassing most adsorbents thus far. This work shows that multivariate COF adsorption-photocatalysts can be rationally engineered to work efficiently and stably without sacrificial electron donors, thus opening the pathway for the economic and efficient extraction of uranium from the earth's oceans.

19.
RMD Open ; 9(1)2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36697038

RESUMO

OBJECTIVE: To determine the association of quantitative infrapatellar fat pad (IPFP) signal intensity alteration with knee osteoarthritis (OA) progression. METHOD: This study was performed based on the Foundation for the National Institutes of Health OA Biomarkers Consortium study, a nested case-control study consisting of 600 participants. The IPFP signal intensity alterations were quantitatively measured at baseline, 12 months and 24 months. The associations of baseline and time-integrated values over 12 and 24 months of IPFP signal intensity measures with knee OA progression over 48 months were evaluated with adjustment for baseline confounders. RESULTS: The baseline level of clustering effect of high signal intensity (Clustering factor (H)) was predictive of clinically relevant progression (both radiographic and pain progression) (OR 1.22). The time-integrated values of all IPFP signal intensity measures, except for mean value of IPFP signal intensity (Mean (IPFP)) over 24 months (ORs ranging from 1.23 to 1.39) as well was all except for Mean (IPFP) and mean value of IPFP high signal intensity (Mean (H)) over 12 months (ORs ranging from 1.20 to 1.31), were positively associated with clinically relevant progression. When the associations of quantitative IPFP signal intensity measures with radiographic and pain progression were examined separately, more IPFP signal intensity measures with stronger effect sizes were associated with radiographic progression compared with pain progression. CONCLUSION: The associations of short-term alteration in quantitative IPFP signal intensity measures with long-term knee OA progression suggest that these measures might serve as efficacy of intervention biomarkers of knee OA.


Assuntos
Osteoartrite do Joelho , Estados Unidos , Humanos , Osteoartrite do Joelho/diagnóstico por imagem , Estudos de Casos e Controles , Imageamento por Ressonância Magnética/métodos , Tecido Adiposo/diagnóstico por imagem , Dor , Biomarcadores
20.
Adv Sci (Weinh) ; 10(30): e2303536, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37691107

RESUMO

The selective removal of the ß-emitting pertechnetate ion (99 TcO4 - ) from nuclear waste streams is technically challenging. Herein, a practical approach is proposed for the selective removal of 99 TcO4 - (or its surrogate ReO4 - ) under extreme conditions of high acidity, alkalinity, ionic strength, and radiation field. Hollow porous N-doped carbon capsules loaded with ruthenium clusters (Ru@HNCC) are first prepared, then modified with a cationic polymeric network (R) containing imidazolium-N+ units (Ru@HNCC-R) for selective 99 TcO4 - and ReO4 - binding. The Ru@HNCC-R capsules offer high binding affinities for 99 TcO4 - /ReO4 - under wide-ranging conditions. An electrochemical redox process then transforms adsorbed ReO4 - to bulk ReO3 , delivering record-high removal capacities, fast kinetics, and excellent long-term durability for removing ReO4 - (as a proxy for 99 TcO4 - ) in a 3 m HNO3 , simulated nuclear waste-Hanford melter recycle stream and an alkaline high-level waste stream (HLW) at the U.S. Savannah River Site (SRS). In situ Raman and X-ray absorption spectroscopy (XAS) analyses showed that adsorbed Re(VII) is electrocatalytically reduced on Ru sites to a Re(IV)O2 intermediate, which can then be re-oxidized to insoluble Re(VI)O3 for facile collection. This approach overcomes many of the challenges associated with the selective separation and removal of 99 TcO4 - /ReO4 - under extreme conditions, offering new vistas for nuclear waste management and environmental remediation.

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