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1.
J Appl Psychol ; 2024 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-39023995

RESUMEN

Owing to consecutive global crises (e.g., the COVID-19 pandemic, multiple regional wars), interest has grown in understanding and promoting organizational resilience. There is scant knowledge about how a human resource management (HRM) system can foster organizational resilience. This study examines the role of a high-performance work system in the organizational resilience process during the COVID-19 pandemic. We focus on two properties of the resilience process: stability during the jolt phase and flexibility during the turnaround phase. We test our hypotheses using quarterly sales data from 268 Korean firms during the COVID-19 pandemic. Our findings show that an high-performance work system reduces the severity of loss during the jolt phase (i.e., it maintains stability) through an increased climate of trust and enhances the scale of recovery during the turnaround phase (i.e., it improves flexibility) through an increased climate of innovation. We advance research on HRM, organizational resilience, and crisis management, showing how an HRM system can foster two essential properties for the resilience process to unfold effectively over time after the onset of a crisis. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

2.
Angew Chem Int Ed Engl ; 63(31): e202404271, 2024 Jul 29.
Artículo en Inglés | MEDLINE | ID: mdl-38700507

RESUMEN

Integrating controllable spin states into single-molecule magnets (SMMs) enables precise manipulation of magnetic interactions at a molecular level, but remains a synthetic challenge. Herein, we developed a 3d-4f metallacrown (MC) magnet [DyNi5(quinha)5(Clsal)2(py)8](ClO4) ⋅ 4H2O (H2quinha=quinaldichydroxamic acid, HClsal=5-chlorosalicylaldehyde) wherein a square planar NiII is stabilized by chemical stacking. Thioacetal modification was employed via post-synthetic ligand substitutions and yielded [DyNi5(quinha)5(Clsaldt)2(py)8](ClO4) ⋅ 3H2O (HClsaldt=4-chloro-2-(1,3-dithiolan-2-yl)phenol). Thanks to the additional ligations of thioacetal onto the NiII site, coordination-induced spin state switching (CISSS) took place with spin state altering from low-spin S=0 to high-spin S=1. The synergy of CISSS effect and magnetic interactions results in distinct energy splitting and magnetic dynamics. Magnetic studies indicate prominent enhancement of reversal barrier from 57 cm-1 to 423 cm-1, along with hysteresis opening and an over 200-fold increment in coercive field at 2 K. Ab initio calculations provide deeper insights into the exchange models and rationalize the relaxation/tunnelling pathways. These results demonstrate here provide a fire-new perspective in modulating the magnetization relaxation via the incorporation of controllable spin states and magnetic interactions facilitated by the CISSS approach.

3.
Chem Sci ; 15(10): 3661-3669, 2024 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-38455005

RESUMEN

Ferroelastic materials have gained widespread attention as promising candidates for mechanical switches, shape memory, and information processing. Their phase-transition mechanisms usually originate from conventional order-disorder and/or displacive types, while those involving dynamic coordination bonds are still scarce. Herein, based on a strategic molecular design of organic cations, we report three new polar hybrid crystals with a generic formula of AA'RbBiCl6 (A = A' = Me3SO+ for 1; A = Me3SO+ and A' = Me4N+ for 2; A = A' = Me3NNH2+ for 3). Their A-site cations link to the [RbBiCl6]n2n- inorganic framework with lon topology through Rb-O/N coordination bonds, while their significantly different interactions between A'-site cations and inorganic frameworks provide distinct phase-transition behaviour. In detail, the strongly coordinative A'-site Me3SO+ cations prevent 1 from a structural phase transition, while coordinatively free A'-site Me4N+ cations trigger a conventional order-disorder ferroelastic transition at 247 K in 2, accompanied by a latent heat of 0.63 J g-1 and a usual "high → low" second-harmonic-generation (SHG) switch. Interestingly, the A'-site Me3NNH2+ cations in 3 reveal unusual dynamic coordination bonds, driving a high-temperature ferroelastic transition at 369 K with a large latent heat of 18.34 J g-1 and an unusual "low → high" SHG-switching behaviour. This work provides an effective molecular assembly strategy to establish dynamic coordination bonds in a new type of host-guest model and opens an avenue for designing advanced ferroelastic multifunctional materials.

4.
Environ Sci Pollut Res Int ; 31(4): 5032-5042, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38148459

RESUMEN

Arsenic contamination of groundwater has affected human health and environmental safety worldwide. Hundreds of millions of people in more than 100 countries around the world are directly or indirectly troubled by arsenic-contaminated groundwater. In addition, arsenic contamination of groundwater caused by leakage of leachate from municipal solid waste landfills has occurred in some countries and regions, which has attracted widespread attention. Understanding how domestic waste landfill leachate affects the arsenic's migration and transformation in shallow groundwater is crucial for accurate assessment of the distribution and ecological hazards of arsenic in groundwater. Based on literature review, this study systematically summarized and discussed the basic characteristics of landfill leachate, the mechanism of arsenic pollution in groundwater, and the effect of landfill leachate on the migration and transformation of arsenic in groundwater. Combined with relevant research findings and practical experience, countermeasures and suggestions to limit the impact of landfill leachate on the migration and transformation of arsenic in groundwater are put forward.


Asunto(s)
Arsénico , Agua Subterránea , Eliminación de Residuos , Contaminantes Químicos del Agua , Humanos , Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis , Residuos Sólidos/análisis , Instalaciones de Eliminación de Residuos
5.
Sci Rep ; 13(1): 12127, 2023 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-37495616

RESUMEN

Air pollution is a serious problem that affects economic development and people's health, so an efficient and accurate air quality prediction model would help to manage the air pollution problem. In this paper, we build a combined model to accurately predict the AQI based on real AQI data from four cities. First, we use an ARIMA model to fit the linear part of the data and a CNN-LSTM model to fit the non-linear part of the data to avoid the problem of blinding in the CNN-LSTM hyperparameter setting. Then, to avoid the blinding dilemma in the CNN-LSTM hyperparameter setting, we use the Dung Beetle Optimizer algorithm to find the hyperparameters of the CNN-LSTM model, determine the optimal hyperparameters, and check the accuracy of the model. Finally, we compare the proposed model with nine other widely used models. The experimental results show that the model proposed in this paper outperforms the comparison models in terms of root mean square error (RMSE), mean absolute error (MAE) and coefficient of determination (R2). The RMSE values for the four cities were 7.594, 14.94, 7.841 and 5.496; the MAE values were 5.285, 10.839, 5.12 and 3.77; and the R2 values were 0.989, 0.962, 0.953 and 0.953 respectively.


Asunto(s)
Contaminación del Aire , Escarabajos , Animales , Algoritmos , Ciudades , Desarrollo Económico
6.
Chem Sci ; 14(22): 5965-5973, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37293638

RESUMEN

Hybrid ferroelastics have attracted increasing attention for their potential application as mechanical switches. The sporadically documented anomalous ferroelastic phase transitions, i.e., ferroelasticity that appears at a high-temperature phase rather than a low-temperature phase, are of particular interest but are not well understood at the molecular level. By judiciously choosing a polar and flexible organic cation (Me2NH(CH2)2Br+) with cis-/anti- conformations as an A-site component, we obtained two new polar hybrid ferroelastics, A2[MBr6] (M = Te for 1 and Sn for 2). These materials undergo distinct thermal-induced ferroelastic phase transitions. The larger [TeBr6]2- anions anchor the adjacent organic cations well and essentially endow 1 with a conventional ferroelastic transition (P21 → Pm21n) arising from a common order-disorder transition of organic cations without conformational changes. Moreover, the smaller [SnBr6]2- anions can interact with the adjacent organic cations in energetically similar sets of intermolecular interactions, enabling 2 to undergo an anomalous ferroelastic phase transition (P212121 → P21) arising from an unusual cis-/anti-conformational reversal of organic cations. These two instances demonstrate the importance of the delicate balance of intermolecular interactions for inducing anomalous ferroelastic phase transitions. The findings here provide important insights for seeking new multifunctional ferroelastic materials.

7.
J Appl Psychol ; 108(10): 1699-1716, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37289527

RESUMEN

Domain-specific roles of service climate and safety climate are well-established, but little is known about their cross-domain roles. In this study, we examined the cross-domain main roles of service climate (on safety performance) and safety climate (on service performance) and their joint roles in predicting service and safety performance. Drawing on the exploration-exploitation framework, we further introduced team exploration and team exploitation as explanatory mechanisms for the cross-domain relationships. We conducted two multiwave, multisource field studies using nursing teams in hospitals. Results from Study 1 showed that service climate had a positive relationship with service performance but a nonsignificant relationship with safety performance. Safety climate, though, had a positive relationship with safety performance but a negative relationship with service performance. Study 2 found support for all main relationships and also revealed that safety climate moderated the indirect relationships that service climate had with safety and service performance through team exploration. Moreover, service climate moderated the indirect relationships that safety climate had with service and safety performance through team exploitation. We extend the climate literature by uncovering the missing cross-domain relationships between service and safety climates. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Asunto(s)
Cultura Organizacional , Seguridad , Humanos
8.
Angew Chem Int Ed Engl ; 61(43): e202208875, 2022 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-36043492

RESUMEN

Ge-based hybrid perovskite materials have demonstrated great potential for second harmonic generation (SHG) due to the geometry and lone-pair induced non-centrosymmetric structures. Here, we report a new family of hybrid 3D Ge-based bromide perovskites AGeBr3 , A=CH3 NH3 (MA), CH(NH2 )2 (FA), Cs and FAGe0.5 Sn0.5 Br3 , crystallizing in polar space groups. These compounds exhibit tunable SHG responses, where MAGeBr3 shows the strongest SHG intensity (5×potassium dihydrogen phosphate, KDP). Structural and theoretical analysis indicate the high SHG efficiency is attributed to the displacement of Ge2+ along [111] direction and the relatively strong interactions between lone pair electrons of Ge2+ and polar MA cations along the c-axis. This work provides new structural insights for designing and fine-tuning the SHG properties in hybrid metal halide materials.

9.
J Appl Psychol ; 107(12): 2285-2305, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-35324221

RESUMEN

As the diversity field evolves, scholars are shifting the attention from mitigating "problems" associated with diversity to searching for ways to leverage the potential value in diversity. We advance this field by studying how an inclusive climate benefits organizational innovation, an important foundation for sustained competitive advantage. Adopting a synergy perspective, we examine the internal (i.e., workplace demographic diversity in terms of age, gender, and region) and external contingencies (i.e., environmental scanning and environmental uncertainty) for an inclusive climate to foster incremental and radical innovation through the mechanism of knowledge management capacity. We tested our research model with a three-wave data collection from multiple sources (i.e., employees, human resource managers, and executives) in 102 organizations. We found that workplace age and regional diversity (but not gender diversity) strengthened the positive effect of inclusive climate on knowledge management capacity, and subsequently incremental and radical innovation. The facilitating effect of environmental scanning was only significant for organizations that experienced higher environmental uncertainty. Our research highlights the importance of considering the synergistic potential of internal human resources and external environments for organizations to capitalize on their inclusive climate for knowledge management and innovation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Asunto(s)
Gestión del Conocimiento , Lugar de Trabajo , Humanos , Innovación Organizacional , Organizaciones , Creatividad , Cultura Organizacional
10.
Inorg Chem ; 61(4): 2219-2226, 2022 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-35048692

RESUMEN

ABX3-type molecular perovskites provide an important platform to tune phase transitions, via judiciously choosing A-, B-, and X-site components, to approach advanced functional materials for applications. Although tetrafluoroborate can act as X-site component to assemble ten instances of ABX3 molecular perovskites, only two of them possess hexagonal perovskite structures. Herein, we report two tetrafluoroborate-based hexagonal molecular perovskites, A[Na(BF4)3], by judiciously choosing two different A-site cations: 1-methyl-1,4-diazabicyclo[2.2.2]octane-1,4-diium (Hmdabco2+) for 1 and 1-methylpiperazine-1,4-diium (H2mpz2+) for 2. They have high-temperature phases in the same space group (P63/mmc) revealing highly disordered A-site cations. Upon cooling, 1 undergoes two-step P63/mmc ↔ P3̅c1 ↔ P21/n transitions at 344 and 338 K, respectively, including a ferroelastic one (3̅mF2/m) accompanied by a spontaneous strain of 0.013. In contrast, the smaller H2mpz2+ cation with more adoptable conformations induces a one-step sharp P63/mmc ↔ P21/c ferroelastic transition (6/mmmF2/m(s)) at 418 K in 2, leading to more significant symmetry breaking and a considerable spontaneous strain of 0.129. This study provides important clues to modulate structural phase transitions by tuning diverse components for the multicomponent dense hybrid crystals.

11.
Chem Commun (Camb) ; 57(57): 7039-7042, 2021 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-34169945

RESUMEN

Our exploration of novel inorganic solids with large birefringence in the d10 Metal-Te4+-SO42- system afforded four new sulfate tellurites, Ga2(TeO3)(SO4)(OH)2, In2(TeO3)2(SO4)(H2O), Zn4(Te3O7)2(SO4)2(H2O) and Hg3(Te3O8)(SO4). Notably, Hg3(Te3O8)(SO4) exhibits the largest birefringence at 532 nm (0.184) and 1064 nm (0.166) among the reported metal sulfate tellurites.

12.
RSC Adv ; 11(25): 15030-15035, 2021 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35424063

RESUMEN

DNA small molecular probe study was considered as a promising approach to achieve DNA related disease diagnosis. Most related reports were performed under specific salinity. Herein, 4-imino-3-(pyridin-2-yl)-4H-quinolizine-1-carbonitrile (IPQC) was generated via a facile procedure with high yield (85%). It is found that IPQC could act as a universal probe for most tested ssDNA, dsDNA and G4 DNA in low [K+] concentration (less than 20 mM). However, IPQC showed highly selective G4 DNA binding via UV-vis and fluorescence response in increasing [K+] (e.g., 150 mM) conditions. The ion atmosphere effects are instructive for DNA probe exploration. This provides guidance for the design, selection and optimization of the probes for target DNA sensing.

13.
J Appl Psychol ; 106(1): 71-91, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-32202816

RESUMEN

The global trend of increasing workplace age diversity has led to growing research attention to the organizational consequences of age-diverse workforces. Prior research has primarily focused on the statistical relationship between age diversity and organizational performance without empirically probing potential mechanisms underlying this relationship. Adopting an intellectual capital perspective, we posit that age diversity affects organizational performance via human and social capital. Furthermore, we examine workplace functional diversity and age-inclusive management as two contingent factors shaping the effects of age diversity on human and social capital. Our hypotheses were tested with a large manager-report workplace survey data from the Society for Human Resource Management (N = 3,888). Results indicate that age diversity was positively associated with organizational performance through the mediation of increased human and social capital. In addition, functional diversity and age-inclusive management amplified the positive effects of age diversity on human and social capital. Our research sheds light on how age-diverse workforces may create value through cultivating knowledge-based organizational resources (i.e., human and social capital). (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Asunto(s)
Capital Social , Lugar de Trabajo , Humanos , Organizaciones , Encuestas y Cuestionarios
14.
Inorg Chem ; 59(11): 7852-7859, 2020 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-32388981

RESUMEN

The search of novel second-harmonic generation crystals in gallium selenite systems results in three new compounds of MGa2(SeO3)4 (M = Sr, Pb) and BiGa(SeO3)3. The isostructural MGa2(SeO3)4 (M = Sr, Pb) are centrosymmetric (P1̅, no. 2). The structures represent a complicated three-dimensional skeleton containing two different types of Ga4Se4 8-member polyhedral ring tunnels with the counter cations located at the broad ones. When the divalent counter cations were substituted by a trivalent lone pair cation of Bi(III), a novel noncentrosymmetric compound of BiGa(SeO3)3 was achieved. BiGa(SeO3)3 displays a 3D gallium selenite framework with 1D bismuth oxide chains filling in the 12-member polyhedral ring tunnels. Frequency doubling measurements showed that BiGa(SeO3)3 presented an apparent SHG signal comparable to the commercial KDP and can realize phase matching. The lone pair anionic groups of SeO32- made the major contribution according to the SHG density analyses. BiGa(SeO3)3 exhibits a wide transparent range and large optical bandgap (3.90 eV). The laser-induced damage threshold of BiGa(SeO3)3 was estimated to be 98.68 MW/cm2, about 44 × AGS.

15.
Sci Total Environ ; 734: 139266, 2020 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-32464380

RESUMEN

The core for simultaneous removal of SO2, NO and Hg0 is the oxidation of NO and Hg0. Radical induced oxidation of NO and Hg0 is considered to be the most efficient method. We develop a novel gas phase advanced oxidation process (AOP) of UV-Heat/H2O2-NaClO2 to simultaneously remove SO2, NO and Hg0 due to a great synergism between H2O2 and NaClO2 under thermal and ultraviolet (UV) co-catalysis. The results indicated that the SO2 removal was always good, while the removal of NO and Hg0 was affected by NaClO2 and UV. Higher catalytic temperature and longer flue gas residence time favored the removal of NO and Hg0. The presence of SO2 and NO facilitated Hg0 removal. Kinetics analyses were conducted to provide the reaction rate of removal of NO and Hg0 under different conditions. X-ray photoelectron spectroscopy (XPS) revealed the product composition as Cl-, Hg2+, NO3- and SO42-. Electron spin resonance (ESR) tests confirmed the generation of HO. Cost analyses demonstrated the better cost performance of the proposed method compared to SCR-ACI combined method. HO and ClO2 were proved to be the main oxidant. The reaction mechanism for removal of NO and Hg0 by using UV-Heat/H2O2-NaClO2 were proposed finally.

16.
J Hazard Mater ; 383: 121135, 2020 02 05.
Artículo en Inglés | MEDLINE | ID: mdl-31542692

RESUMEN

We developed a novel method, microwave (MW) induced ultraviolet (UV) irradiating H2O/O2, to cooperatively remove NO and Hg0, with the efficiencies of 89.3% and 99.5%. It also can remove 97% SO2. O2 at a content of 2-8% was sufficient to conduct a good removal of NO and Hg0. Ozone (O3) and hydroxyl radical (HO•) were proved to be the major oxidants for the removal of Hg0 and NO, respectively. High temperature facilitated NO removal but impaired Hg0 removal. SO2 greatly promoted the removal of NO and Hg0 due to the formation of SO4•-. The presence of Cl- and Br-suppressed NO removal but promoted Hg0 removal, because Cl- and Br-quenched HO• to produce Cl- and Br-radicals. The produced NO2 could be totally absorbed by the Na2SO3 solution that followed the main reactor. The O3 yield and the formation of HO• under different conditions were determined using iodine quantity method and electron spin resonance (ESR). The distributions of anion concentration and mercury proportion were obtained using ion chromatography (IC) and cold atom fluorescence spectrometry (AFS), and the main products were identified to be SO42-, NO3- and HgO. The mechanisms of removal of SO2, NO and Hg0 were speculated.

17.
Molecules ; 24(23)2019 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-31775363

RESUMEN

In previous work, we applied the rotation-limiting strategy and introduced a substituent at the 3-position of the pyrazolo [3,4-d]pyrimidin-4-amine as the affinity element to interact with the deeper hydrophobic pocket, discovered a series of novel quinazolinones as potent PI3Kδ inhibitors. Among them, the indole derivative 3 is one of the most selective PI3Kδ inhibitors and the 3,4-dimethoxyphenyl derivative 4 is a potent and selective dual PI3Kδ/γ inhibitor. In this study, we replaced the carbonyl group in the quinazolinone core with a sulfonyl group, designed a series of novel 2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide derivatives as PI3Kδ inhibitors. After the reduction of nitro group in N-(2,6-dimethylphenyl)-2-nitrobenzenesulfonamide 5 and N-(2,6-dimethylphenyl)-2-nitro-5-fluorobenzenesulfonamide 6, the resulting 2-aminobenzenesulfonamides were reacted with trimethyl orthoacetate to give the 3-methyl-2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide derivatives. After bromination of the 3-methyl group, the nucleophilic substitution with the 3-iodo-1H-pyrazolo[3,4-d]pyrimidin-4-amine provided the respective iodide derivatives, which were further reacted with a series of arylboronic acids via Suzuki coupling to furnish the 2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide derivatives 15a-J and 16a-d. In agreement with the quinazolinone derivatives, the introduction of a 5-indolyl or 3,4-dimethoxyphenyl at the affinity pocket generated the most potent analogues 15a and 15b with the IC50 values of 217 to 266 nM, respectively. In comparison with the quinazolinone lead compounds 3 and 4, these 2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide derivatives exhibited much decreased PI3Kδ inhibitory potency, but maintained the high selectivity over other PI3K isoforms. Unlike the quinazolinone lead compound 4 that was a dual PI3Kδ/γ inhibitor, the benzthiadiazine 1,1-dioxide 15b with the same 3,4-dimethoxyphenyl moiety was more than 21-fold selective over PI3Kγ. Moreover, the introducing of a fluorine atom at the 7-position of the 2H-benzo[e][1,2,4]thiadiazine 1,1-dioxide core, in general, was not favored for the PI3Kδ inhibitory activity. In agreement with their high PI3Kδ selectivity, 15a and 15b significantly inhibited the SU-DHL-6 cell proliferation.


Asunto(s)
Fosfatidilinositol 3-Quinasa Clase I/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/síntesis química , Quinazolinonas/química , Tiadiazinas/síntesis química , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Fosfatidilinositol 3-Quinasa Clase I/química , Diseño de Fármacos , Humanos , Simulación del Acoplamiento Molecular , Neoplasias/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Quinazolinonas/síntesis química , Quinazolinonas/farmacología , Relación Estructura-Actividad , Tiadiazinas/química , Tiadiazinas/farmacología
18.
Inorg Chem ; 58(16): 11155-11163, 2019 Aug 19.
Artículo en Inglés | MEDLINE | ID: mdl-31365247

RESUMEN

Two new indium sulfate tellurites, namely, In2(SO4)(TeO3)(OH)2(H2O) and In3(SO4)(TeO3)2F3(H2O), were synthesized by hydrothermal method in a one-pot reaction. Their pure phase yields have been successfully optimized to 76% and 21%, respectively. In2(SO4)(TeO3)(OH)2(H2O) crystallized in centrosymmetric (CS) space group P21/n, while In3(SO4)(TeO3)2F3(H2O) formed a non-centrosymmetric (NCS) and chiral space group P212121. The CS compound features a 2D layered structure composed of 2D indium oxide layers decorated by sulfate tetrahedra and tellurite groups. The NCS compound displays a 3D network consisting of indium tellurite layers bridged by sulfate tetrahedra. Powder second harmonic generation measurements disclosed that In3(SO4)(TeO3)2F3(H2O) exhibits a weak frequency-doubling efficiency about 11% of the commercial KDP. Its powder laser damage threshold quantity was estimated to be 79.6 MW/cm2, which is about 36 times that of AGS. The two samples present wide optical band gaps of 4.86 and 4.10 eV, respectively, which were determined by Te, In, and O atoms based on density functional theory calculations.

19.
Environ Sci Technol ; 53(14): 8324-8332, 2019 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-31241322

RESUMEN

A novel method of ultraviolet-heat synergistically catalyzing H2O2-X (X: NaCl, NaBr, HCl, and HBr) for removal of elemental mercury (Hg0) was developed. In terms of Hg0 removal efficiency and economy, HCl and HBr were the suitable additives. Hg0 removal efficiencies reached 93.6% for H2O2-HCl and 91.4% for H2O2-HBr, the concentrations of H2O2, HCl and HBr were 1 M, 4.2 mM and 0.5 mM. The doses of gaseous Cl and Br-oxidants were 6.27 and 0.75 ppm. The costs by using H2O2-HCl and H2O2-HBr were 1,180 USD/lb-Hg0 and 1,170 USD/lb-Hg0. The best temperature for heat catalysis was 413 K. Hg0 removal was enhanced by 500 mg/m3 SO2 and 300 mg/m3 NO due to the formation of sulfuric and NO2. Mercury distribution analyses indicated that 500 mg/m3 SO2, 300 mg/m3 NO, and 6% O2 favored KCl retaining Hg2+. When the H2O2 concentration was adjusted to 3 M, the simultaneous removal efficiencies of NO and Hg0 reached 83.7% and 99.2% for H2O2-HCl, and 82.8% and 98.8% for H2O2-HBr. Electron spin resonance demonstrated that ClOH•-/BrOH•- and Cl2•-/Br2•- played leading roles in Hg0 oxidation, besides Cl2/Br2. The mercury forms in spent KCl were HgCl2, HgBr2, and HgNO3, according to X-ray photoelectron spectroscopy.


Asunto(s)
Mercurio , Catálisis , Calor , Peróxido de Hidrógeno , Oxidación-Reducción
20.
J Hazard Mater ; 374: 120-128, 2019 07 15.
Artículo en Inglés | MEDLINE | ID: mdl-30986639

RESUMEN

A novel advanced oxidation process (AOP) of ultraviolet/chlorite-ammonia (UV/NaClO2-NH4OH) was developed to remove Hg0 from flue gas. The distribution of mercury concentration in three solutions of NaClO2-NH4OH, KCl, and H2SO4-KMnO4 was determined by cold atom fluorescence spectrometry (AFS). The role of NH4OH was to help NaClO2 preserving and/or stabilizing Hg2+ meanwhile inhibiting the photo-production of ClO2. In the absence of UV, decreasing pH promoted the release of Hg2+ from NaClO2-NH4OH; introducing NO, SO2, O2, Br-, Cl-, and HCO3- suppressed Hg0 oxidation. In the presence of UV, rising temperature accelerated the release of Hg2+ from NaClO2-NH4OH; while SO2, Br- and HCO3- facilitated Hg0 oxidation. In the absence and presence of UV, Hg0 oxidation was controlled by ClO2- and by ClO/Cl2O2/HO/ClO2, respectively. The formations of ClO/HO/ClO2 were confirmed by electron spin resonance (ESR). X-ray photoelectron spectroscopy (XPS) revealed that the products of Hg0 and ClO2- were HgCl2, and ClO2, Cl-, ClO3-, Cl2, and ClO4-, respectively. Analysis of kinetics showed that the Hatta numbers were 23-133 and 69-305 without and with UV, respectively, thus, the gas-film mass transfer was the rate-determining step. This paper gives a new insight in radical behavior in Hg0 oxidation.

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