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1.
J Colloid Interface Sci ; 675: 549-559, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38986328

RESUMEN

The efficiency of photocatalytic Nitric Oxide(NO) oxidation is limited by the lack of oxygen(O2) active sites and poor charge carrier separation. To address this challenge, we developed a molecular Cobalt Phthalocyanine modified MIL-68(In)-NH2 photocatalyst with a robust Built-in electric field(BIEF). In the 2 % CoPc-MIN sample, the BIEF strength is increased by 3.54 times and 5.83 times compared to pristine CoPc and MIL-68(In)-NH2, respectively. This BIEF facilitates the efficient S-scheme charge transfer, thereby enhancing photogenerated carrier separation. Additionally, the Co-N4(II) sites in CoPc can effectively trap the separated photoexcited electrons in the S-scheme system. In addition, the Co-N4(II) sites can also serve as active sites for O2 adsorption and activation, promoting the generation of superoxide radical (O2-), thereby driving the direct conversion of NO to nitrate(NO3-). Consequently, the 2 % CoPc-MIN sample exhibits a remarkable photocatalytic NO removal efficiency of 79.37 % while effectively suppressing the formation of harmful by-product nitrogen dioxide(NO2) to below 3.5 ppb. This study provides a feasible strategy for designing high-efficiency O2 activation photocatalysts for NO oxidation.

2.
J Colloid Interface Sci ; 675: 721-730, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38996702

RESUMEN

The lack of compactness in heterojunction interfaces and poor charge separation is a great challenge in developing high-efficiency heterojunction photocatalysts. Herein, a novel Bi4Ti3O12-BiPO4 heterojunction was successfully prepared for the first time by epitaxial growth of BiPO4 on the surface of Bi4Ti3O12 nanosheets. The optimized Bi4Ti3O12-BiPO4-0.5 increased the NO oxidation efficiency to 73.05%, surpassing pure Bi4Ti3O12 (63.45%) and BiPO4 (8.35%). Experiments and theoretical calculations indicated that the closely contacted heterointerface between BTO and BPO promoted the generation of the built-in electric field, which led to the formation of the Z- scheme transfer pathway for the photogenerated carriers. Therefore, the separation of photogenerated carriers was facilitated while retaining high redox potential, generating more ·O2- and ·OH to participate in NO oxidation. Furthermore, the adsorption of NO and O2 was enhanced by introducing BiPO4, further improving the photocatalytic NO oxidation performance. This work emphasizes the critical role of heterointerface in accelerating charge transfer, providing a basis for the design and construction of tightly contacted heterojunction photocatalysts.

3.
Front Chem ; 12: 1413489, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39045334

RESUMEN

Catalytic oxidation is used to control carbon monoxide (CO) emissions from industrial exhaust. In this work, The prepared Pta-Fe(OH) x catalysts (x represents the mass fraction of Pt loading (%), a = 0.5, 1 and 2) by the one-pot reduction method exhibited excellent CO catalytic activity, with the Pt2-Fe(OH) x catalyst, 70% and ∼100% CO conversion was achieved at 30°C and 60°C, respectively. In addition, the Pt2-Fe(OH) x catalyst also showed excellent H2O resistance and hydrothermal stability in comparison to the Pt2/Fe(OH) x catalyst prepared by impregnation method. Characterization results showed that the excellent catalytic performance of the catalysts was mainly attributed to the abundant surface oxygen species and Pt0 the presence of H2O, which promoted the catalytic reaction of CO, and Density functional theory (DFT) calculation showed that this was mainly attributed to the catalytic activity of the hydroxyl (-OH) species on Pt2-Fe(OH) x surface, which could easily oxidize CO to -COOH, which could be further decomposed into CO2 and H atoms. This study provides valuable insights into the design of high-efficiency non-precious metal catalysts for CO catalytic oxidation catalysts with high efficiency.

4.
Environ Sci Technol ; 58(23): 10388-10397, 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38828512

RESUMEN

Selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3-SCR) is an efficient NOx reduction strategy, while the denitrification (deNOx) catalysts suffer from serious deactivation due to the coexistence of multiple poisoning substances, such as alkali metal (e.g., K), SO2, etc., in industrial flue gases. It is essential to understand the interaction among various poisons and their effects on the deNOx process. Herein, the ZSM-5 zeolite-confined MnSmOx mixed (MnSmOx@ZSM-5) catalyst exhibited better deNOx performance after the poisoning of K, SO2, and/or K&SO2 than the MnSmOx and MnSmOx/ZSM-5 catalysts, the deNOx activity of which at high temperature (H-T) increased significantly (>90% NOx conversion in the range of 220-480 °C). It has been demonstrated that K would occupy both redox and acidic sites, which severely reduced the reactivity of MnSmOx/ZSM-5 catalysts. The most important, K element is preferentially deposited at -OH on the surface of ZSM-5 carrier due to the electrostatic attraction (-O-K). As for the K&SO2 poisoning catalyst, SO2 preferred to be combined with the surface-deposited K (-O-K-SO2ads) according to XPS and density functional theory (DFT) results, the poisoned active sites by K would be released. The K migration behavior was induced by SO2 over K-poisoned MnSmOx@ZSM-5 catalysts, and the balance of surface redox and acidic site was regulated, like a synergistic promoter, which led to K-poisoning buffering and activity recovery. This work contributes to the understanding of the self-detoxification interaction between alkali metals (e.g., K) and SO2 on deNOx catalysts and provides a novel strategy for the adaptive use of one poisoning substance to counter another for practical NOx reduction.


Asunto(s)
Zeolitas , Zeolitas/química , Catálisis , Oxidación-Reducción , Óxidos de Nitrógeno/química , Óxidos/química , Amoníaco/química , Desnitrificación , Metales/química
5.
Environ Sci Pollut Res Int ; 31(22): 32200-32211, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38644427

RESUMEN

F-doped V2O5-WO3/TiO2 catalyst has been confirmed to have excellent denitration activity at low temperatures. Since the V2O5-WO3/TiO2 catalyst is a structure-sensitive catalyst, the loading order of V2O5 and WO3 may affect its denitration performance. In this paper, a series of F-doped V2O5-WO3/TiO2 catalysts with different V2O5 and WO3 loading orders were synthesized to investigate the effect of denitration performance at low temperatures. It was found that the loading orders led to significant gaps in denitration performance in the range of 120-240 °C. The results indicated loading WO3 first better utilized the oxygen vacancies on the TiF carrier promoting the generation of reduced vanadium species. In addition, loading WO3 first facilitated the dispersion of V2O5 thus enhanced the NH3 adsorption capacity of VWTiF. In situ DRIFT verified the rapid reaction between NO2, nitrate, and nitrite species and adsorbed NH3 over the VWTiF, confirming that the NH3 selective catalytic reduction (NH3-SCR) reaction over VWTiF at 240 °C proceeded by the Langmuir-Hinshelwood (L-H) mechanism. This research established the constitutive relationship between the loading order of V2O5 and WO3 and the denitration performance of the F-doped VWTi catalyst providing insights into the catalyst design process.


Asunto(s)
Titanio , Tungsteno , Vanadio , Tungsteno/química , Catálisis , Titanio/química , Vanadio/química , Óxidos/química , Compuestos de Vanadio/química , Adsorción
6.
Regen Ther ; 25: 320-330, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38327716

RESUMEN

Introduction: It is essential to acknowledge that the cardiovascular toxicity associated with anthracycline drugs can be partially attributed to the damage inflicted on blood vessels and endothelial cells. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have the potential to repair cellular processes and promote tissue regeneration through the transfer of signaling molecules such as miRNAs. In the present study, we investigated the effects of MSC-EVs on daunorubicin (DNR)-damaged human cardiac microvascular endothelial cells (HCMEC) and developing blood vessels of Chicken Chorioallantoic Membrane (CAM) in vivo. Materials and methods: We constructed in vitro and in vivo models of DNR-damaged endothelial cells and developing blood vessel. Scratch wound assays, EdU assays, tube formation assays, and SA-ß-Gal staining were used to evaluate the effects of MSC-EVs on cell migration, proliferation, angiogenesis capacity and cell senescence. Blood vessel area was used to assess the effects of MSC-EVs on CAM vasculature. RT-qPCR was used to detect the mRNA expression levels of inflammatory molecules. RNA sequencing was employed to compare differential gene expression and downstream regulatory mechanisms. RNA interference experiments and miRNA mimic overexpression experiments were used to validate the regulatory effects of target genes and downstream signaling pathways. Results: We found that MSC-EVs improved the migration, proliferation, and angiogenesis of HCMEC, while also alleviating cellular senescence. The angiogenic effect on the developing blood vessels was confirmed in vivo. We identified that MSC-EVs downregulated the expression of PARP9, thereby inhibiting the STAT1/pSTAT1 signaling pathway. This downregulation effect is likely mediated by the transfer of miR-186-5p from MSC-EVs to HCMEC. Overexpression of miR-186-5p in DNR-damaged HCMEC also exhibited the aforementioned downregulation effect. In vivo, the introduction of miR-186-5p mimics enhanced angiogenesis in the CAM model. Conclusions: To summarize, our study reveals that MSC-EVs can restore the cellular function of DNR-damaged HCMEC and alleviate cellular senescence through the miR-185-5p-PARP9-STAT1/pSTAT1 pathway. This finding highlights the potential of MSC-EVs as a therapeutic strategy for mitigating the detrimental effects of anthracycline-induced endothelial damage.

7.
J Hazard Mater ; 465: 133481, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38219590

RESUMEN

Catalytic ozone (O3) decomposition at ambient temperature is an efficient method to mitigate O3 pollution. However, practical application is hindered by the poor water resistance of catalysts. Herein, Ag-Hollandite (Ag-HMO) with varying Ag+ content was synthesized. Catalysts with more Ag+ exhibited improved efficiency and water-resistance, with the optimal one maintaining 98% O3 conversion at 70% relative humidity (RH) within 8 h. Physicochemical characterizations revealed that Ag+ had entered the tunnel of OMS-2, facilitating oxygen species removal. Notably, enhanced H2O desorption and the complete inhibition of chemisorbed water formation on Ag-HMO were the primary reasons for its high-efficiency O3 conversion across a wide humidity range. The underlying mechanism arises from the charge redistribution induced by the Ag-O interaction within the tunnel, which reduces acidity and modulates hydrophilicity. This study aims to contribute insights for designing catalysts with higher water-resistance.

8.
ACS Nano ; 17(23): 24363-24373, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-37991830

RESUMEN

Enhancing the CO2 mass transfer and proton supply in the photocatalytic reduction of CO2 with H2O into CH3OH (PRC-M), while avoiding the hydrogen evolution reaction (HER), remains a challenge. Herein, we propose an approach to control the surface coverage of CO2 and H2O by modifying interfacial wettability, which is achieved by modulating the core-shell structure to expose either hydrophobic melamine-resorcinol-formaldehyde (MRF) or hydrophilic NiAl-layered double hydroxides (NAL). Characterizations reveal that an insufficient proton supply leads to the production of competing CO, while excessive coverage of H2O results in undesired HER. The NAL-MRF integrates hydrophobic and hydrophilic interfaces, contributing to the CO2 mass transfer and H2O adsorption, respectively. This combination forms a microreactor that facilitates the triphase photocatalysis of CO2, H2O, and catalyst, allowing for high local concentrations of both *CO and *H without competing binding sites. Importantly, the formation of covalent bonds and a Z-type heterojunction between hydrophilic NAL and hydrophobic MRF layers accelerates the charge separation. Furthermore, the density functional theory results indicate that the NAL linking promotes the continuous hydrogenation of *CO. As a result, an enhanced CH3OH yield of 31.41 µmol g-1 h-1, with selectivity of 93.62%, is achieved without hole scavengers or precious metals.

9.
Mol Immunol ; 158: 91-102, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37178520

RESUMEN

B-lineage acute lymphoblastic leukemia (B-ALL) is one of the most common malignancies in children. Despite advances in treatment, the role of the tumor microenvironment in B-ALL remains poorly understood. Among the key components of the immune microenvironment, macrophages play a critical role in the progression of the disease. However, recent research has suggested that abnormal metabolites may influence the function of macrophages, altering the immune microenvironment and promoting tumor growth. Our previous non-targeted metabolomic detection revealed that the metabolite 1,5-anhydroglucitol (1,5-AG) level in the peripheral blood of children newly diagnosed with B-ALL was significantly elevated. Except for its direct influence on leukemia cells, the effect of 1,5-AG on macrophages is still unclear. Herein, we demonstrated new potential therapeutic targets by focusing on the effect of 1,5-AG on macrophages. We used polarization-induced macrophages to determine how 1,5-AG acted on M1-like polarization and screened out the target gene CXCL14 via transcriptome sequencing. Furthermore, we constructed CXCL14 knocked-down macrophages and a macrophage-leukemia cell coculture model to validate the interaction between macrophages and leukemia cells. We discovered that 1,5-AG upregulated the CXCL14 expression, thereby inhibiting M1-like polarization. CXCL14 knockdown restored the M1-like polarization of macrophages and induced leukemia cells apoptosis in the coculture model. Our findings offer new possibilities for the genetic engineering of human macrophages to rehabilitate their immune activity against B-ALL in cancer immunotherapy.


Asunto(s)
Macrófagos , Leucemia-Linfoma Linfoblástico de Células Precursoras , Niño , Humanos , Quimiocinas CXC/metabolismo , Quimiocinas CXC/farmacología , Inmunoterapia , Macrófagos/metabolismo , Microambiente Tumoral
10.
Chemosphere ; 329: 138613, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37030352

RESUMEN

The synergistic degradation of VOCs and NOx that were emitted from the incineration of municipal and medical wastes by a single catalyst is challenging, due to the poor activity at low temperatures, and the SO2 poisoning on the active sites. Herein, N-doped TiO2 (N-TiO2) was used as the support for designing a highly efficient and stable catalyst system for CB/NOx synergistic degradation even in the presence of SO2. The prepared SbPdV/N-TiO2 catalyst, which presented excellent activity and tolerance to SO2 in the CBCO + SCR process, was investigated by a series of characterizations (such as XRD, TPD, XPS, H2-TPR and so on) as well as DFT calculations. The electronic structure of the catalyst was effectively modulated after N doping, resulting in effective charge flow between the catalyst surface and gas molecules. More importantly, the adsorption and deposition of sulfur species and reaction transient intermediates on active centers were restrained, while a new N adsorption center for NOx was provided. Abundant adsorption centers and superior redox properties ensured smooth CB/NOx synergistic degradation. The removal of CB mainly follows the L-H mechanism, while NOx elimination follows both E-R and L-H mechanisms. As a result, N doping provides a new approach to develop more advanced anti-SO2 poisoning CB/NOx synergistic catalytic removal systems for extensive applications.


Asunto(s)
Amoníaco , Óxidos , Óxidos/química , Amoníaco/química , Titanio/química , Oxidación-Reducción
11.
Eur J Pharmacol ; 945: 175618, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36841284

RESUMEN

Non-alcoholic steatohepatitis (NASH) is the hepatic manifestation of metabolic syndrome. Non-resolving inflammation, triggered by sustained accumulation of lipids, is an important driving force of NASH. Thus, unveiling metabolic immune regulation could help better understand the pathology and intervention of NASH. In this study, we found the recruitment of neutrophils is an early inflammatory event in NASH mice, following the formation of neutrophil extracellular traps (NETs). NET is an initiating factor which exacerbates inflammatory responses in macrophages. Inhibition of NETs using DNase I significantly alleviated inflammation in NASH mice. We further carried out a metabolomic study to identify possible metabolic triggers of NETs, and linoleic acid (LA) metabolic pathway was the most altered pathway. We re-analyzed published clinical data and validated that LA metabolism was highly correlated with NASH. Consistently, both LA and γ-linolenic acid (GLA) were active in triggering NETs formation by oxidative burst. Furthermore, we identified silybin, a hepatoprotective agent, as a potent NETosis inhibitor, which effectively blocked NETs formation both in vitro and in vivo. Together, this study not only provide new insights into metabolism-immune causal link in NASH progression, but also demonstrate silybin as an important inhibitor of NETs and its therapeutical potential in treating NETosis-related diseases.


Asunto(s)
Trampas Extracelulares , Enfermedad del Hígado Graso no Alcohólico , Animales , Ratones , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Trampas Extracelulares/metabolismo , Silibina/farmacología , Modelos Animales de Enfermedad , Neutrófilos , Ácidos Grasos Insaturados/farmacología , Inflamación/metabolismo
12.
J Environ Sci (China) ; 125: 319-331, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36375917

RESUMEN

Oxidation-absorption technology is a key step for NOx removal from low-temperature gas. Under the condition of low O3 concentration (O3/NO molar ratio = 0.6), F-TiO2 (F-TiO2), which is cheap and environmentally friendly, has been prepared as ozonation catalysts for NO oxidation. Catalytic activity tests performed at 120°C showed that the NO oxidation efficiency of F-TiO2 samples was higher than that of TiO2 (about 43.7%), and the NO oxidation efficiency of F-TiO2-0.15 was the highest, which was 65.3%. Combined with physicochemical characteristics of catalysts and the analysis of active species, it was found that there was a synergistic effect between F sites and oxygen vacancies on F-TiO2, which could accelerate the transformation of monomolecular O3 into multi-molecule singlet oxygen (1O2), thus promoting the selective oxidation of NO to NO2. The oxidation reaction of NO on F-TiO2-0.15 follows the Eley-Rideal mechanism, that is, gaseous NO reacts with adsorbed O3 and finally form NO2.


Asunto(s)
Dióxido de Nitrógeno , Oxígeno , Catálisis , Oxidación-Reducción , Oxígeno/química , Titanio/química , Ozono/química , Óxido Nítrico/química
13.
FASEB J ; 36(9): e22468, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35913801

RESUMEN

Cholestasis is a common complication of hepatitis B virus (HBV) infection, characterized by increased intrahepatic and plasma bile acid levels. Cholestasis was found negatively associated with hepatitis outcome, however, the exact mechanism by which cholestasis impacts anti-viral immunity and impedes HBV clearance remains elusive. Here, we found that cholestatic mice are featured with dysfunctional T cells response, as indicated by decreased sub-population of CD25+ /CD69+ CD4+ and CD8+ cells, while CTLA-4+ CD4+ and CD8+ subsets were increased. Mechanistically, bile acids disrupt intracellular calcium homeostasis via inhibiting mitochondria calcium uptake and elevating cytoplasmic Ca2+ concentration, leading to STIM1 and ORAI1 decoupling and impaired store-operated Ca2+ entry which is essential for NFAT signaling and T cells activation. Moreover, in a transgenic mouse model of HBV infection, we confirmed that cholestasis compromised both CD4+ and CD8+ T cells activation resulting in poor viral clearance. Collectively, our results suggest that bile acids play pivotal roles in anti-HBV infection via controlling T cells activation and metabolism and that targeting the regulation of bile acids may be a therapeutic strategy for host-virus defense.


Asunto(s)
Colestasis , Hepatitis B , Animales , Ácidos y Sales Biliares , Linfocitos T CD8-positivos/metabolismo , Calcio/metabolismo , Colestasis/complicaciones , Hepatitis B/complicaciones , Virus de la Hepatitis B/metabolismo , Ratones
14.
Chem Commun (Camb) ; 58(56): 7801-7804, 2022 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-35735213

RESUMEN

Low-viscous homologue-paired liquids (HPLs) are designed and employed as special non-ionic deep eutectic solvents for selective separation of SO2 from CO2 and N2. The HPLs are found to have excellent inherent properties (e.g., low cost, volatility and viscosity), high absorption capacity, fast absorption rate, and moderate Lewis acid-base interaction with SO2. Regeneration experiments are done to show their excellent recyclability, and industrial desulfurization is exemplified in a small column with suitable parameters to show their potential as SO2 absorbents.

15.
Environ Sci Technol ; 56(12): 7696-7706, 2022 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-35613430

RESUMEN

An innovative strategy to control nitrogen oxide emission from flue gas was developed using the wet flue gas denitrification technology. The use of cyclodextrin (CD) as an additive facilitated NO2 absorption by the sulfite absorbent. Compared with absorption by a sulfite solution (59.12%), the instantaneous absorption efficiencies employing CD improved to 94.57%. Moreover, 48 h of continuous absorption indicated cyclic utilization of CD. The favorable role of CD was ascribed to facilitating the limiting step for the entire NO2 absorption-dissolution process which included both water solubility and gas-liquid mass transfer. Furthermore, we propose a potential mechanism of CD/sulfite mixed solution absorbing NO2, among which the favorable role of the additive is related to its amphiphilic behavior toward gas and liquid phases. Additionally, a kinetic model describing the rates of gas-liquid transfer and macro absorption was established based on various operating conditions. This model explains the absorption improvement in the kinetic aspect and provides theoretical guidance for practical applications.


Asunto(s)
Ciclodextrinas , Dióxido de Nitrógeno , Óxido Nítrico , Óxidos de Nitrógeno , Sulfitos
16.
J Hazard Mater ; 430: 128451, 2022 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-35158243

RESUMEN

Electrochemical reduction of NO to NH3 (NORR) is an attractive approach to mildly realize NO removal and valuable NH3 production. The electrolyte, as function as the NO absorbent, is crucial to apply electrochemical technology in practical de-NO engineering. In this paper, the ferrous chelate acted as the electrolyte for effective NO absorption in NORR based on the Brown-ring reaction. The rGO and Au/rGO catalysts served as cathodes to realize ferrous regeneration for continuous NO reduction. The results revealed that ferric chelate could be fully reduced at lower onset potential on rGO electrode. The Au/rGO catalyst exhibited excellent average yield and selectivity for NH3 at - 0.1 V and pH = 6.32, (14.6 µmol* h-1 * cm-2 and 65.2%, respectively). The Faradaic Efficiency of NH3 could reach 98.3% at pH = 1.0. This work provides a valuable reference for effective NO adsorption and sustainable NO-to-NH3 conversion.


Asunto(s)
Técnicas Electroquímicas , Grafito , Técnicas Electroquímicas/métodos , Electrodos , Electrólitos
17.
J Colloid Interface Sci ; 609: 901-909, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34865741

RESUMEN

The rapid recombination of photoinduced charge carriers and low selectivity are still challenges for the CO2 photoreduction. Herein, we proposed that ZIF-67-derived Co3O4 hollow polyhedrons (CoHP) were embedded into NaCl-template-assisted synthesized 3D graphitic carbon nitride (NCN), subsequently, loading Ag by photo-deposition as efficient composites (CoHP@NCN@Ag) for CO2 photoreduction. This integration simultaneously constructs two heterojunctions: p-n junction between Co3O4 and g-C3N4 and metal-semiconductor junction between Ag and g-C3N4, in which Co3O4 and Ag serve as hole (h+) trapping sites and electron (e-) sinks, respectively, achieving spatial separation of charge carriers. The donor-acceptor structure design of NCN realize a good photogenerated e--h+ separation efficiency. The mesoporous structure of hollow Co3O4 facilitate gas-diffusion efficiency, light scattering and harvesting. And the introduction of plasmonic Ag further strengthens the light-harvesting and charge migration. Benefiting from the rational design, the optimized ternary heterostructures exhibit a high CO2-CO yield (562 µmol g-1), which is about 4-fold as high as that of the NCN (151 µmol g-1). Moreover, the conjectural mechanism was systematically summarized. We hope this study provides a promising strategy for designing efficient g-C3N4 systems for the CO2 photoreduction.

18.
J Hazard Mater ; 422: 126825, 2022 01 15.
Artículo en Danés, Holandés, Inglés, Esperanto, Estonio | MEDLINE | ID: mdl-34416686

RESUMEN

A new method was developed to scrub NOx compounds in flue gases during the integrated technology of WFGD associated with ozone oxidation, among which polyethylene glycol (PEG) was utilized initially as an additive to facilitate the absorption of NO2 by sulfite solution. Notably, absorption was significantly facilitated with adding PEG into absorbent. Compared to absorption by sulfite solution alone, NO2 removal efficiency with PEG addition increased from 58.75% to 89.17%. Furthermore, the favorable role of PEG was considered to be ascribed to the its improvement on the rate-determining step among absorption process ── mass transfer of NO2 into the liquid phase. A potential chemical transformation pathway between NO2, SO32- and PEG was proposed, and based on the hydrogen bonding between the various compounds. Additionally, a kinetic model was established based on various operating parameters that included adsorbent pH, ionic strength of S species, temperature, flow rate, and inlet SO2 concentration. This model provides theoretical support for practical engineering.


Asunto(s)
Dióxido de Nitrógeno , Dióxido de Azufre , Cinética , Polietilenglicoles , Sulfitos
19.
Environ Sci Pollut Res Int ; 29(9): 13534-13540, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34595700

RESUMEN

Activated coke-based catalysts have attracted extensive attention in denitration by selective catalytic reduction by NH3 (NH3-SCR), due to their excellent catalytic performance at low temperature. In the paper, the V2O5/AC catalyst was prepared by the impregnation method to investigate the effect of pre-oxidation process on its NH3-SCR activity. Activity test results show that the V2O5/AC catalyst with 4-h pre-oxidation exhibits the best NOx removal efficiency, which reaches the NOx conversion is over 75% in the range of 200-240 °C and exhibits an excellent resistance to SO2 and H2O. Characterization results demonstrate that the V4+ was oxidized by oxygen molecule during pre-oxidation process, which contributes to the formation of V5+ ions and surface-active oxygen species. The surface-active oxygen species are conducive to promoting the "fast SCR" reaction; thus, the pre-oxidized process can contribute to the superior NH3-SCR performance for V2O5/AC catalyst at low temperature.


Asunto(s)
Amoníaco , Frío , Catálisis , Oxidación-Reducción , Temperatura
20.
J Colloid Interface Sci ; 611: 71-81, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-34933192

RESUMEN

The flaky carbon nitride containing nitrogen defects (NDCN) could effectively perform the photocatalytic reduction of carbon dioxide (CO2) due to its abundant active sites. Reducing the recombination of electrons and holes was also a method of semiconductor photocatalyst design. A nanosphere ball-flower Indium sulfide (In2S3) was synthesized via a simple hydrothermal approach, and then calcined to obtain the ß-In2S3/NDCN heterojunction photocatalyst and applied for CO2 photocatalytic reduction. The best total yield (carbon monoxide, CO: 20.32 µmol·g-1·h-1; methane, CH4: 2.12 µmol·g-1·h-1) could be obtained at the optimized 20% ß-In2S3/NDCN under near room temperature and pressure and without using any sacrificial agents or promoters, almost 1.7 times higher compared with NDCN. The composite catalyst still exhibited excellent stability after four cycles. The improvement of excellent performance was due to not only the enhancement of fine CO2 adsorption/activation and the light absorption ability, but also attributed to the formation of heterojunction, which accelerated the effective separation of electrons and holes. This work might provide a novel approach to design carbon nitride heterojunction photocatalysts with nitrogen defects for CO2 utilization.

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