Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
1.
J Colloid Interface Sci ; 678(Pt C): 948-958, 2024 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-39326166

RESUMEN

Co-based bimetallic zeolite imidazolate frameworks (ZIFs) have been shown as promising electrocatalysts for the oxygen evolution reaction, but their electronic structure's influence on the catalytic performance for overall water splitting still needs further investigation. In this study, Co15V-ZIF, structured as two-dimensional (2D) nanosheet arrays, are grown on nickel foam using one-step co-precipitation strategy. Owing to the synergistic effects of vanadium (V) and cobalt (Co) reasonably regulating the electronic structure, the synthesized bimetallic ZIFs demonstrate superior catalytic performance, which required the overpotentials of only 227 and 68 mV to achieve a current density of 10 mA cm-2 in 1 M KOH for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. Furthermore, the water electrolyzer assembled with bimetallic ZIF as cathode and anode exhibits the capability to achieve 10 mA cm-2 at a low cell voltage of 1.57 V. In situ Raman spectroscopy reveals that the introduction of V facilitates the formation of V-CoOOH, the real active site for OER, at lower applied potentials. Besides, it induces a local acidic environment on V-Co(OH)2, the real active sites, thereby enhancing the HER performance of the sample. Density Functional Theory (DFT) calculations further show that the synergistic effects of V and Co induce electron redistribution, thereby improving electrical conductivity, reducing the energy barrier for water dissociation and hydrogen adsorption, which promotes the formation of H3O+ and triggering H3O+-induced water reduction in alkaline media. This work provides new insight into tailoring electronic structures to rationally design highly efficient ZIF electrocatalysts.

2.
Angew Chem Int Ed Engl ; : e202412566, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39198218

RESUMEN

The advanced oxygen reduction reaction (ORR) catalysts, integrating with well-dispersed single atom (SA) and atomic cluster (AC) sites, showcase potential in bolstering catalytic activity. However, the precise structural modulation and in-depth investigation of their catalytic mechanisms pose ongoing challenges. Herein, a proactive cluster lockdown strategy is introduced, relying on the confinement of trinuclear clusters with metal atom exchange in the covalent organic polymers, enabling the targeted synthesis of a series of multicomponent ensembles featuring FeCo (Fe or Co) dual-single-atom (DSA) and atomic cluster (AC) configurations (FeCo-DSA/AC) via thermal pyrolysis. The designed FeCo-DSA/AC surpasses Fe- and Co-derived counterparts by 18 mV and 49 mV in ORR half-wave potential, whilst exhibiting exemplary performance in Zn-air batteries. Comprehensive analysis and theoretical simulation elucidate the enhanced activity stems from adeptly orchestrating dz2-dxz and O 2p orbital hybridization proximate to the Fermi level, fine-tuning the antibonding states to expedite OH* desorption and OOH* formation, thereby augmenting catalytic activity. This work elucidates the synergistic potentiation of active sites in hybrid electrocatalysts, pioneering innovative targeted design strategies for single-atom-cluster electrocatalysts.

3.
Diabetes Obes Metab ; 26(4): 1395-1406, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38287130

RESUMEN

AIM: Novel long-acting drugs for type 2 diabetes mellitus may optimize patient compliance and glycaemic control. Exendin-4-IgG4-Fc (E4F4) is a long-acting glucagon-like peptide-1 receptor agonist. This first-in-human study investigated the safety, tolerability, pharmacokinetic, pharmacodynamic and immunogenicity profiles of a single subcutaneous injection of E4F4 in healthy subjects. METHODS: This single-centre, randomized, double-blind, placebo-controlled phase 1 clinical trial included 96 subjects in 10 sequential cohorts that were provided successively higher doses of E4F4 (0.45, 0.9, 1.8, 3.15, 4.5, 6.3, 8.1, 10.35, 12.6 and 14.85 mg) or placebo (ChinaDrugTrials.org.cn: ChiCTR2100049732). The primary endpoint was safety and tolerability of E4F4. Secondary endpoints were pharmacokinetic, pharmacodynamic and immunogenicity profiles of E4F4. Safety data to day 15 after the final subject in a cohort had been dosed were reviewed before commencing the next dose level. RESULTS: E4F4 was safe and well tolerated among healthy Chinese participants in this study. There was no obvious dose-dependent relationship between frequency, severity or causality of treatment-emergent adverse events. Cmax and area under the curve of E4F4 were dose proportional over the 0.45-14.85 mg dose range. Median Tmax and t1/2 ranged from 146 to 210 h and 199 to 252 h, respectively, across E4F4 doses, with no dose-dependent trends. For the intravenous glucose tolerance test, area under the curve of glucose in plasma from time 0 to 180 min showed a dose-response relationship in the 1.8-10.35 mg dose range, with an increased response at the higher doses. CONCLUSION: E4F4 exhibited an acceptable safety profile and linear pharmacokinetics in healthy subjects. The recommended phase 2 dose is 4.5-10.35 mg once every 2 weeks.


Asunto(s)
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Exenatida/efectos adversos , Voluntarios Sanos , Área Bajo la Curva , Prueba de Tolerancia a la Glucosa , Método Doble Ciego , Relación Dosis-Respuesta a Droga
4.
Ecotoxicol Environ Saf ; 266: 115547, 2023 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-37806130

RESUMEN

China is conducting ecological restoration work in urban water bodies. Under anoxic and anaerobic conditions, pollutants transform and produce odorous and black substances, deteriorating the water quality, which is a significant problem in urban water bodies. Vallisneria natans has received widespread attention for its applications in water treatment and restoration. However, the efficiency by which V. natans reduces water pollution and allows sediment remediation requires further improvement. Therefore, in this study, we investigated the effect of V. natans coupled with carbon fiber on the restoration of water bodies and sediment compared with the control group that grew V. natans without carbon fiber. The oxidation-reduction potential (ORP) was selected as the main evaluation index for the water and sediment. Dissolved oxygen in the water and total organic carbon and total nitrogen (TN) in the sediment were also evaluated. V. natans coupled with carbon fiber significantly increased the ORP; that of surface sediment increased by 50 % and that of the water body increased by 60 % compared with the sediment without any bioremediation. Chemical oxygen demand, total phosphorous, and TN in water decreased by 61.2 %, 22.9 %, and 48.3 %, respectively. These results indicate that planting V. natans with carbon fiber can reduce pollutants in water (including humus) and sediments, effectively improving ORP in water and sediment.


Asunto(s)
Contaminantes Ambientales , Hydrocharitaceae , Contaminantes Químicos del Agua , Fibra de Carbono , Biodegradación Ambiental , Contaminación del Agua , Fósforo , Nitrógeno/análisis , Contaminantes Químicos del Agua/análisis
5.
Comput Math Methods Med ; 2022: 3329360, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36277023

RESUMEN

Background: Narrative medicine has been applied as a model for humane medical practice in many countries. However, it was not introduced in China until 2011 and there has been no standardized assessment of Chinese medical personnel regarding their perception and application of narrative medicine-related theories. This study is aimed at investigating Chinese medical personnel's knowledge, attitude, and practice regarding narrative medicine and the factors that influence it. Methods: An online questionnaire based on the knowledge, attitude, and practice model was distributed among Chinese medical personnel from December 2021 to March 2022. All in-service medical personnel across China who had access to the Internet were eligible. Two independent samples t-tests, one-way analysis of variance, Pearson's correlation analysis, and multivariate linear regression were conducted for data analyses. Results: The participants' scoring rates for knowledge, attitude, and practice were 49.62%, 47.18%, and 41.43%, respectively. Significant influencing factors for knowledge were education level, religious belief, professional role, title, working years, and institution categories; those for attitude were education level, religious belief, professional role, and working years; and those for practice were professional title, religious belief, working years, and institution categories. Conclusions: Chinese medical personnel have generally good knowledge of, attitudes towards, and practice of narrative medicine; however, there remain deficiencies in their understanding of certain important concepts, their attitude towards narrative medicine, and the application of narrative skills in their daily work. Thus, to improve narrative medicine practice in China, the application of strategies based on theoretical, educational, and institutional aspects is warranted.


Asunto(s)
Medicina Narrativa , Humanos , Estudios Transversales , Conocimientos, Actitudes y Práctica en Salud , Actitud del Personal de Salud , Encuestas y Cuestionarios , China
6.
ACS Appl Mater Interfaces ; 14(40): 45880-45892, 2022 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-36165501

RESUMEN

The integration of membranes with additives such as functionalized nanomaterials can be recognized as an effective method to enhance membrane performance. However, to obtain an efficient nanoparticle-decorated membrane, the compatibility of nanomaterials remains a challenge. Hydrophilic carboxylated covalent organic frameworks (COF-COOH) might be expected to avoid the drawbacks of aggregation and easy shedding of inorganic materials caused by the poor interfacial compatibility. Herein, a highly compatible dip-coating strategy was proposed for the superhydrophilic modification of polyvinylidene fluoride membrane via COF-COOH integrated with dopamine. COF-COOH together with polydopamine nanoparticles were uniformly and stably attached to the membrane due to the high interfacial compatibility, constructing a coating with rough hierarchical nanostructures and abundant carboxyl groups. The synergistic effects of multiscale structures and chemical groups endow the membrane with superhydrophilicity and underwater superoleophobicity, the water contact angle decreased from 123 to 15°, and the underwater oil contact angle increased from 132 to 162°. Accordingly, the modified membrane exhibits an ultrahigh oil rejection ratio (>98%), a high flux (the maximum reaches 1843.48 L m-2 h-1 bar-1), attractive antifouling ability, and impregnable stability. This work would provide a momentous reference for the application of COF-COOH in practical oily wastewater treatment.

7.
J Hazard Mater ; 438: 129438, 2022 09 15.
Artículo en Inglés | MEDLINE | ID: mdl-35820333

RESUMEN

Semiconductor materials dominated photocatalytic technology is one of the most efficient approaches to degrade organic pollutants. However, the limited light absorption range and rapid recombination of photogenerated carriers greatly restrict the application of photocatalysts. Rational design of photocatalysts to achieve high catalytic activity and stability is of great importance. Herein, ZnIn2S4/Bi4Ti3O12 S-scheme heterojunction is synthesized by growing the ZnIn2S4 nanosheets on the sheet-like Bi4Ti3O12 surface via a low-temperature solvothermal method. The TC removal efficiency of optimized heterojunction reaches 82.1% within 60 min under visible light, and the rate constant is nearly 6.8 times than that of pristine ZnIn2S4. The favorable photocatalytic performance of heterojunction is attributed to the tight contact interface and efficient separation of photogenerated carriers. Besides, the difference in work function between ZnIn2S4 and Bi4Ti3O12 leads to band bending and the establishment of built-in electric field on the contact interface of heterojunction, which facilitates the migration and separation of photogenerated carriers. Furthermore, the cycling test demonstrates the attractive stability of heterojunction. The possible TC photodegradation pathways and toxicity assessment of the intermediates are also analyzed. In conclusion, this work provides an effective strategy to prepare S-scheme heterojunction photocatalysts with favorable photocatalytic activity, which can enhance wastewater purification efficiency.


Asunto(s)
Bismuto , Titanio , Antibacterianos , Procesos Fotoquímicos , Tetraciclina
8.
Biotechnol Lett ; 44(5-6): 729-740, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35570244

RESUMEN

Six 60-L benthic microbial electrochemical systems (BMESs) were built for the bioremediation of river sediment. Carbon mesh anodes with honeycomb-structure supports were compared with horizontal anodes, and the system was tested using different cover depths and anode densities. The pollutant removal, electricity generation, and electrochemistry of the six BMES with different anodes was examined using the Ashi River (Harbin, China) as a case study. Total organic carbon and total nitrogen removal from sediments in BMES with Honeycomb-structure anodes were 20-30% and 20-33% higher for the other reactors. The maximum power densities of 43.2 mW m-2 was obtained in BMES. The maximum power densities in BMES with honeycomb-structure anodes were 10-40% higher than that of BMESs with horizontal anode reactors.


Asunto(s)
Fuentes de Energía Bioeléctrica , Electricidad , Electrodos , Nitrógeno , Ríos
9.
Environ Sci Pollut Res Int ; 28(40): 56727-56740, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-34060018

RESUMEN

It is of great significance to establish a carbon emission management system and carbon emission reduction target to put forward emission reduction measures for each subunit of a sewage treatment plant. In this paper, a mathematical model was constructed for calculating carbon emission in the whole sewage treatment system process. Meanwhile, the model calculated the carbon emission changes after upgrading three sewage treatment plants and identified the critical controlling unit. The results showed that the CO2 produced from electric energy consumption and chemical application was the primary source of carbon emission of wastewater treatment. Raising sewage discharge standards appropriately could effectively reduce the carbon emission generated by each link of the wastewater treatment plant. Further improvement of effluent standards could adversely affect sewage treatment plants in terms of energy, resources, and greenhouse gas emissions. In addition, raising the standard of total phosphorus concentration in the effluent may lead to a corresponding increase in the amount of phosphorus removal agents, as well as an increase in indirect carbon emission, material consumption, and chemical sludge. Therefore, it is necessary to develop sewage treatment technologies that are economical, applicable, energy-saving, and environmental friendly to realize the environmental benefits of carbon emission reduction in sewage treatment and sustainable utilization of energy and resource from wastewater.


Asunto(s)
Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Carbono , Fósforo , Aguas Residuales
10.
J Colloid Interface Sci ; 596: 455-467, 2021 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-33848748

RESUMEN

Cobalt-based perovskite material, an effective activator of PMS, is widely employed for wastewater remediation, but still affected by the leakage of the cobalt ions. In this study, a porous core-shell structured perovskite LaFe0.1Co0.9O3-λ/SiO2 core @ZrO2 shell (LFCS@ZrO2) was fabricated and partially etched to enlarge channels to further enhance mass transfer ability. The well-designed core-shell structure can not only restrain metal ion leaching by changing the surface microenvironment but also provide an additional driving force attributed to the enriched concentration gradient, thus enhancing the catalytic oxidation performance. Results showed that the partially etched LFCS@ZrO2 (eLFCS@ZrO2) particles exhibited an increased pore size and showed an attractive catalytic performance as well as a suppressed cobalt ion leaching (3.61 to 0.67 mg/L). Over 99% of tetracycline hydrochloride (20 mg/L) could be degraded in 15 min, and the reaction rate increased 2 folds compared with pristine LaFe0.1Co0.9O3-λ. Besides, quenching test and electron paramagnetic resonance analysis proved that sulfate radicals and singlet oxygen were the two predominant reactive oxygen species during the catalytic oxidation. This work provides a novel perspective for the fabrication of an environmentally friendly perovskite catalyst, which has a great potential application in organic pollutant degradation.

11.
Membranes (Basel) ; 11(4)2021 Apr 08.
Artículo en Inglés | MEDLINE | ID: mdl-33917725

RESUMEN

Nanofiltration membrane technology is an effective method for secondary treated sewage purification. However, membrane fouling, which is inevitable in the membrane-separation process, can reduce membrane performance and shorten membrane life. Installing a turbulence promoter is a promising means of improving the hydraulic conditions inside the membrane chamber. In this study, the effect of turbulence promoter on prolonging membrane life was studied for the first time. Flat-sheet polyethersulfone nanofiltration membrane was used to filter humic acid solution, used for simulating secondary treated sewage. By comparing photographs and SEM images of the membrane before and after the simulated secondary treated sewage filtration, it was found that humic acid tended to be deposited on the low-velocity region, which was reflected by COMSOL simulation. After incorporating a turbulence promoter, the reduction of the humic acid deposition area and membrane fouling resistance indicated that the turbulence promoter could reduce membrane fouling due to the improved hydraulic conditions. Additionally, the turbulence promoter also increased the flux and reduced the flux decay rate. The turbulence promoter was then place in the crossflow flat-sheet membrane filtration module, and the variation of flux with time was tested in simulated secondary treated sewage with different concentrations. The results showed that the membrane life for the filtration of simulated secondary treated sewage comprising 50, 250, and 500 ppm humic acid increased by 23.1%, 80.4%, and 85.7%, respectively. The results of this article can serve as a reference for the prediction of membrane life and the performance enhancement mechanism of membranes containing a turbulence promoter.

12.
Water Sci Technol ; 83(4): 894-905, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33617496

RESUMEN

Enough biomass of anaerobic ammonium oxidation (anammox) bacteria is essential for maintaining a stable partial nitrification/anammox (PN/A) wastewater treatment system. Present enrichment procedures are mainly labor-intensive and inconvenient for up-scaling. A simplified procedure was developed for enrichment of anammox biofilm by using secondary effluent as source water with no supplement of mineral medium and unstrict control of influent dissolved oxygen (DO). Anammox biofilm was successfully enriched in two pilot-scale reactors (XQ-cul and BT-cul) within 250 and 120 days, respectively. The specific anammox activity increased rapidly during the last 2 months in both reactors and achieved 2.54 g N2-N/(m2·d) in XQ-cul and 1.61 g N2-N/(m2·d) in BT-cul. Similar microbial diversity and community structure were obtained in the two reactors despite different secondary effluent being applied from two wastewater treatment plants. Anaerobic ammonium oxidizing bacteria genera abundance reached up to 37.4% and 43.1% in XQ-cul and BT-cul biofilm, respectively. Candidatus Brocadia and Ca. Kuenenia dominated the enriched biofilm. A negligible adverse effect of residual organics and influent DO was observed by using secondary effluent as source water. This anammox biofilm enrichment procedure could facilitate the inoculation and/or bio-augmentation of large-scale mainstream PN/A reactors.


Asunto(s)
Compuestos de Amonio , Reactores Biológicos , Biopelículas , Nitrificación , Nitritos , Nitrógeno , Oxidación-Reducción , Aguas Residuales , Agua
14.
Angew Chem Int Ed Engl ; 58(39): 13969-13975, 2019 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-31361387

RESUMEN

A BN membrane with a distinct nanoconfinement effect toward efficient ethylene/ethane separation is presented. The horizontal and inclined self-assembly of 2D BN nanosheets endow the BN membrane with abundant percolating nanochannels, and these nanochannels are further decorated by reactive ionic liquids (RILs) to tailor their sizes as well as to achieve nanoconfinement effect. The noncovalent interactions between RIL and BN nanosheets favor the ordered alignment of the cations and anions of RIL within BN nanochannels, which contributes to a fast and selective ethylene transport. The resultant membranes exhibit an unprecedented separation performance with superhigh C2 H4 permeance of 138 GPU and C2 H4 /C2 H6 selectivity of 128 as well as remarkably improved long-term stability for 180 h, outperforming reported state-of-the-art membranes.

15.
J Environ Sci (China) ; 69: 41-51, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29941267

RESUMEN

Sulfur dioxide (SO2) and benzene homologs are frequently present in the off-gas during the process of sewage sludge drying. A laboratory scale biofilter was set up to co-treat SO2 and o-xylene in the present study. SO2 and o-xylene could be removed simultaneously in a single biofilter. Their concentration ratio in the inlet stream influenced the removal efficiencies. It is worth noting that the removal of SO2 could be enhanced when low concentrations of o-xylene were introduced into the biofilter. Pseudomonas sp., Paenibacillus sp., and Bacillus sp. were the main functional bacteria groups in the biofilter. Sulfur-oxidizing bacteria (SOB) and o-xylene-degrading bacteria (XB) thrived in the biofilter and their counts as well as their growth rate increased with the increase in amount of SO2 and o-xylene supplied. The microbial populations differed in counts and species due to the properties and components of the compounds being treated in the biofilter. The presence of mixed substrates enhanced the diversity of the microbial population. During the treatment process, bioaerosols including potentially pathogenic bacteria, e.g., Acinetobacter lwoffii and Aeromonas sp., were emitted from the biofilter. Further investigation is needed to focus on the potential hazards caused by the bioaerosols emitted from waste gas treatment bioreactors.


Asunto(s)
Aerosoles/análisis , Contaminantes Atmosféricos/metabolismo , Reactores Biológicos/microbiología , Dióxido de Azufre/metabolismo , Eliminación de Residuos Líquidos/métodos , Xilenos/metabolismo , Contaminantes Atmosféricos/química , Contaminación del Aire/prevención & control , Bacterias/metabolismo , Filtración/métodos , Dióxido de Azufre/química , Xilenos/química
16.
ACS Appl Mater Interfaces ; 10(16): 13963-13974, 2018 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-29613760

RESUMEN

Protic ionic liquids (PILs) were utilized for the fabrication of composite membranes containing silver salt as the C2H4 transport carrier to perform C2H4/C2H6 separation for the first time. The intrinsic nanostructures of PILs were adopted to construct fast and selective C2H4 transport nanochannels. The investigation of structure-performance relationships of composite membranes suggested that transport nanochannels (polar domains of PILs) could be tuned by the sizes of cations, which greatly manipulated activity of the carrier and determined the separation performances of membranes. The role of different carriers in the facilitated transport was studied, which revealed that the PILs were good solvents for dissolution and activation of the carrier due to their hydrogen bond networks and waterlike properties. The operating conditions of separation process were investigated systemically and optimized, confirming C2H4/C2H6 selectivity was enhanced with the increase of silver salt concentration, the flow rate of sweep gas, and the feed ratio of C2H4 to C2H6, as well as the decrease of the transmembrane pressure and operating temperature. Furthermore, the composite membranes exhibited long-term stability and obtained very competitive separation performances compared with other results. In summary, PIL composite membranes, which possess good long-term stability, high C2H4/C2H6 selectivity, and excellent C2H4 permeability, may have a good perspective in industrial C2H4/C2H6 separation.

17.
J Biotechnol ; 251: 99-105, 2017 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-28450258

RESUMEN

The effects of two wastewater treatment processes (sequencing batch reactor, SBR; and anaerobic-anoxic-oxic, A2O) on sludge reduction with metabolic uncoupler 2,4-dichlorophenol (DCP) were studied in laboratory. The experimental results showed that the reduction of cumulative excess sludge in SBR and A2O was 43.7% and 44.2%, respectively, during the stable stage of the test. The two processes had similar average sludge yield and sludge yield reduction, i.e., 0.306 and 0.305mg of SS/mg chemical oxygen demand (COD), and 16.9% and 17.8%, respectively. The effect of DCP on the wastewater treatment efficiencies (namely, removal of COD, total nitrogen, NH4+-N, and total phosphorus) of the two processes were also similar. SBR was more likely to slightly retard the increase of activated sludge SVI with lesser increase in extracellular polymeric substances and protein/polysaccharide ratio. Although DCP did not dramatically affect the microbial communities of sludge, SBR was more favorable for increasing the activated sludge SOUR and maintaining the primary microorganisms of sludge than A2O.


Asunto(s)
Reactores Biológicos , Clorofenoles , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Compuestos de Amonio/metabolismo , Anaerobiosis , Análisis de la Demanda Biológica de Oxígeno , Reactores Biológicos/microbiología , Nitrógeno/metabolismo , Oxígeno/metabolismo , Fósforo/metabolismo , Aguas del Alcantarillado/microbiología , Contaminantes Químicos del Agua/metabolismo
18.
J Hazard Mater ; 333: 63-72, 2017 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-28342356

RESUMEN

In this work, the simple preparation of novel polymer supported polyoxometallates (POMs) catalysts has been reported. Soluble task-specific cross-linked poly (ionic liquid) (PIL) was prepared with N,​N-​dimethyl-​dodecyl-​(4-​vinylbenzyl) ammonium chloride and divinylbenzene as co-monomers. The as-prepared cationic PILs were assembled with different commercial POMs to form the interlinked mesoporous catalysts, and the formation mechanism was provided. The catalytic oxidation activities of the catalysts were closely related to the formation pathway of their corresponding peroxide active species. The catalyst with H2W12O4210- as counterion, which exhibited the best activity in the oxidation of benzothiophene (BT) and dibenzothiophene (DBT) to sulfones in model oil with hydrogen peroxide (H2O2, 30wt%) as oxidant, was characterized by different techniques and systematically studied for its sulfur removal performance. As for the oxidative desulfurization of a real diesel, it was observed that almost all of the original sulfur compounds could be completely converted, and the catalyst could be reused for at least eight cycles without noticeable changes in both catalytic activity and chemical structure. In the end, a catalytic mechanism was put forward with the assistant of Raman analysis.

19.
J Mol Model ; 21(2): 32, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25636268

RESUMEN

Melting point T m and kinetic coefficient µ (a proportional constant between the interfacial velocity ν and undercooling ΔT), along with the structural roughness of the solid-liquid interface for body centered cubic (BCC) Fe were calculated by molecular dynamics (MD) simulation. All simulations applied the Sutton-Chen potential, and adopted average bond orientational order (ABOO) parameters together with Voronoi polyhedron method to characterize atomic structure and calculate atomic volume. Anisotropy of T m was found through about 20~40 K decreasing from [100] to [110] and continuously to [111]. Anisotropy of µ with three low index orientations was found as: µ s,[100] > > µ s,[110] > µ s,[111] for solidifying process and µ m,[100] > > µ m,[111] > µ m,[110] for melting process. Slight asymmetry between melting and solidifying was discovered from that the ratios of µ m/µ s are all slightly larger than 1. To explain these, interfacial roughness R int and area ratio S/S 0 (ratio of realistic interfacial area S and the ideal flat cross-sectional area S 0) were defined to verify the anisotropy of interfacial roughness under different supercoolings/superheatings. The results indicated interfacial roughness anisotropies were approximately [100] > [111] > [110]; the interface in melting process is rougher than that in solidifying process; asymmetry of interfacial roughness was larger when temperature deviation ΔT was larger. Anisotropy and asymmetry of interfacial roughness fitted the case of kinetic coefficient µ very well, which could give some explanations to the anisotropies of T m and µ.

20.
J Environ Sci (China) ; 24(5): 891-6, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22893967

RESUMEN

A wire-mesh catalyst coated by La0.8Sr0.2MnO3 was combined with a dielectric barrier discharge (DBD) reactor for toluene removal at atmospheric pressure. It was found that toluene removal efficiency and carbon dioxide selectivity were enhanced in the catalytic packed-bed reactor. In addition, ozone and nitrogen monoxide from the gas effluent byproducts decreased. This is the first time that ultrasound combined with plasma has been used for toluene removal. A synergistic effect on toluene removal was observed in the plasma-assisted ultrasound system. At the same time, the system increased toluene conversion and reduced ozone emission.


Asunto(s)
Gases em Plasma/química , Tolueno/aislamiento & purificación , Ultrasonido/métodos , Dióxido de Carbono/análisis , Monóxido de Carbono/análisis , Catálisis , Electricidad , Compuestos de Manganeso/química , Óxido Nítrico/química , Óxidos/química , Ozono/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA