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1.
Environ Sci Pollut Res Int ; 31(32): 44983-44994, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38955967

RESUMO

Elemental doping is a promising way for enhancing the electrocatalytic activity of metal oxides. Herein, we fabricate Ti/ Ti4O7-CB-Ce anode materials by the modification means of carbon black and cerium co-doped Ti4O7, and this shift effectively improves the interfacial charge transfer rate of Ti4O7 and •OH yield in the electrocatalytic process. Remarkably, the Ti4O7-CB-Ce anode exhibits excellent efficiency of minocycline (MNC) wastewater treatment (100% removal within 20 min), and the removal rate reduces from 100 to 98.5% after five cycles, which is comparable to BDD electrode. •OH and 1O2 are identified as the active species in the reaction. Meanwhile, it is discovered that Ti/ Ti4O7-CB-Ce anodes can effectively improve the biochemical properties of the non-biodegradable pharmaceutical wastewater (B/C values from 0.25 to 0.44) and significantly reduce the toxicity of the wastewater (luminescent bacteria inhibition rate from 100 to 26.6%). This work paves an effective strategy for designing superior metal oxides electrocatalysts.


Assuntos
Antibacterianos , Cério , Oxirredução , Fuligem , Águas Residuárias , Cério/química , Antibacterianos/química , Águas Residuárias/química , Catálise , Fuligem/química , Eletrodos , Titânio/química , Tetraciclina/química , Poluentes Químicos da Água/química
2.
Environ Sci Pollut Res Int ; 31(32): 45105-45116, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38958858

RESUMO

Diesel soot is a significant contributor to air pollution. Soot particles present in diesel engine exhaust have a negative impact on the environment and human health. Diesel oxidation catalysts (DOCs) and diesel particulate filters (DPFs) currently use noble metal-based catalysts for soot oxidation. Due to the use of noble metals in the catalyst, the cost of diesel after-treatment systems is steadily rising. As a result, diesel vehicles have become commercially less viable than gasoline vehicles and electronic vehicles. The study focuses on an alternative diesel oxidation catalyst with efficiency similar to that of a noble metal catalyst but with a much lower cost. CeO2-Al2O3 catalysts are known for their oxygen storage capacity and high redox activity, making them suitable for soot oxidation. Adding Zr to these catalysts has been shown to influence their structural and chemical properties, significantly affecting their catalytic behavior. Therefore, the current study is focused on using Zr/CeO2-Al2O3 as a substitute for noble metal-based catalysts to enhance its performance for diesel soot oxidation in automotive exhaust. Evaporation-induced self-assembly (EISA) was used to prepare 1, 3, and 5 weight (wt) % Zr supported mesoporous CeO2-Al2O3 catalysts. Morphological, structural, and physicochemical properties of the synthesized catalysts were examined using Brunauer-Emmett-Teller (BET) absolute isotherm, Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Temperature programmed reduction (TPR), and Temperature-programmed desorption of ammonia (NH3-TPD). XRD, BET, and SEM data confirmed that the catalysts were mesoporous and low-crystalline with a high surface area. The soot oxidation activity of the catalysts was evaluated using a thermogravimetric analysis (TGA) technique. The loose contacts soot oxidation activity test suggested that 50% oxidation of soot occurred at 390 °C in the absence of a catalyst. T50 of CeO2-Al2O3 catalyzed soot oxidation was 296 °C. Adding Zr to the catalyst significantly improved catalytic activity for diesel soot oxidation. We observed a further drastic change in T50 of soot over 1, 3, and 5% Zr/CeO2-Al2O3, which were 220 °C, 210 °C, and 193 °C, respectively. According to these results, incorporating Zr into the CeO2-Al2O3 catalyst significantly improved the oxidation process of soot.


Assuntos
Óxido de Alumínio , Oxirredução , Fuligem , Emissões de Veículos , Zircônio , Catálise , Zircônio/química , Óxido de Alumínio/química , Fuligem/química , Cério/química , Gasolina
3.
Environ Sci Technol ; 58(26): 11578-11586, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38899536

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) are the primary organic carbons in soot. In addition to PAHs with even carbon numbers (PAHeven), substantial odd-carbon PAHs (PAHodd) have been widely observed in soot and ambient particles. Analyzing and understanding the photoaging of these compounds are essential for assessing their environmental effects. Here, using laser desorption ionization mass spectrometry (LDI-MS), we reveal the substantially different photoreactivity of PAHodd from PAHeven in the aging process and their MS detection through their distinct behaviors in the presence and absence of elemental carbon (EC) in soot. During direct photooxidation of organic carbon (OC) alone, the PAHeven are oxidized more rapidly than the PAHodd. However, the degradation of PAHodd becomes preponderant over PAHeven in the presence of EC during photoaging of the whole soot. All of these observations are proposed to originate from the more rapid hydrogen abstraction reaction from PAHodd in the EC-photosensitized reaction, owing to its unique structure of a single sp3-hybridized carbon site. Our findings reveal the photoreactivity and reaction mechanism of PAHodd for the first time, providing a comprehensive understanding of the oxidation of PAHs at a molecular level during soot aging and highlight the enhanced effect of EC on PAHodd ionization in LDI-MS analysis.


Assuntos
Carbono , Hidrocarbonetos Policíclicos Aromáticos , Fuligem , Hidrocarbonetos Policíclicos Aromáticos/química , Carbono/química , Fuligem/química , Processos Fotoquímicos , Oxirredução , Fotoquímica
4.
Water Res ; 258: 121811, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38833811

RESUMO

Urban stormwater runoff is considered a key component of future water supply portfolios for water-stressed cities. Beneficial use of runoff, such as capture for recharge of drinking water aquifers, relies on improved stormwater treatment. Many dissolved constituents, including metals and trace organic contaminants (TrOCs) such as hydrophilic pesticides and poly- and perfluoroalkyl substances (PFASs), are of concern due to their toxicity, persistence, prevalence in stormwater runoff, and poor removal in conventional stormwater control measures. This study explores the operational flow rate limitations of black carbon (BC)-amended engineered media filters for removal of a wide suite of dissolved metals and TrOCs and provides validation for a previously developed predictive TrOC transport model. Column experiments were conducted with face velocities of 40 and 60 cm h-1 to assess Douglas Fir-based biochar and regenerated activated carbon (RAC) filter performance in light of media-contaminant removal kinetic limitations. This study found that increasing the face velocity in BC-amended filters to 40 and 60 cm h-1, which are representative of field conditions, decreased the removal of total suspended solids, turbidity, dissolved hydrophilic TrOCs, and PFASs when expressed as volume treated relative to previous studies conducted at 20 cm h-1. Dissolved metals and hydrophobic TrOCs removal were not substantially affected by the increased flow rates. A predictive 1-d intraparticle pore diffusion-limited sorption model with sorption and effective tortuosity parameters determined previously from experiments conducted at 20 cm h-1 was validated for these higher flow rates. This work provides insights to the kinetic limitations of contaminant removal within biochar and RAC filters and implications for stormwater filter design and operation.


Assuntos
Filtração , Poluentes Químicos da Água , Purificação da Água , Poluentes Químicos da Água/química , Cinética , Purificação da Água/métodos , Carvão Vegetal/química , Chuva , Fuligem/química , Carbono/química
5.
ACS Appl Mater Interfaces ; 16(25): 32702-32712, 2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38870327

RESUMO

Herein, we report a dual-functional flexible sensor (DFFS) using a magnetic conductive polymer composed of nickel (Ni), carbon black (CB), and polydimethylsiloxane (PDMS). The material selection for the DFFS utilizes the excellent elasticity of the PDMS matrix and the synergistic interaction between Ni and CB. The DFFS has a wide strain range of 0-170%, a high sensitivity of 74.13 (140-170%), and a low detection limit of 0.3% strain. The DFFS based on superior performance can accurately detect microstrain/microvibration, oncoming/contacting objects, and bicycle riding speed. Additionally, the DFFS can be used for comprehensive monitoring of human movements. Therefore, the DFFS of this work shows significant value for implementation in intelligent wearable devices and noncontact intelligent control.


Assuntos
Dimetilpolisiloxanos , Microesferas , Níquel , Fuligem , Dispositivos Eletrônicos Vestíveis , Dimetilpolisiloxanos/química , Humanos , Níquel/química , Fuligem/química , Movimento , Condutividade Elétrica
6.
Int J Biol Macromol ; 273(Pt 1): 133056, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38862058

RESUMO

Solar steam generation (SSG) offers a sustainable approach to fresh water production. Herein, a novel dual-functional natural rubber/carbon black composite foam evaporator is presented for a cost-efficient SSG system that both produces fresh water and eliminates heavy metals present in the water. The composite foam is produced using the Dunlop process, and in its optimized form, it absorbed >96 % of sunlight. The foam evaporator exhibited a thermal conductivity of 0.052 W/m⋅K, a water evaporation rate of 1.40 kg/m2/h, converted 83.38 % of light to heat under 1 sun irradiation, and showed outstanding stability. The technology required to produce this composite foam is already available to make large-scale production feasible, while the natural raw materials are abundant. On the basis of its performance qualities, the rubber foam composite appears to be an excellent candidate for application as a viable solar absorber for SSG to produce fresh, clean water for commercial purposes.


Assuntos
Metais Pesados , Borracha , Luz Solar , Borracha/química , Metais Pesados/química , Látex/química , Purificação da Água/métodos , Água/química , Descontaminação/métodos , Vapor , Poluentes Químicos da Água/química , Fuligem/química
7.
Environ Pollut ; 354: 124181, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38768677

RESUMO

Through a comprehensive investigation into the historical profiles of black carbon derived from ice cores, the spatial distributions of light-absorbing impurities in snowpit samples, and carbon isotopic compositions of black carbon in snowpit samples of the Third Pole, we have identified that due to barriers of the Himalayas and remove of wet deposition, local sources rather than those from seriously the polluted South Asia are main contributors of light-absorbing impurities in the inner part of the Third Pole. Therefore, reducing emissions from residents of the Third Pole themselves is a more effective way of protecting the glaciers of the inner Third Pole in terms of reducing concentrations of light-absorbing particles in the atmosphere and on glaciers.


Assuntos
Poluentes Atmosféricos , Monitoramento Ambiental , Monitoramento Ambiental/métodos , Poluentes Atmosféricos/análise , Camada de Gelo/química , Ásia , Fuligem/química , Atmosfera/química , Neve/química , Ásia Meridional , Himalaia
8.
Talanta ; 275: 126154, 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-38703477

RESUMO

Additive manufacturing is a technique that allows the construction of prototypes and has evolved a lot in the last 20 years, innovating industrial fabrication processes in several areas. In chemistry, additive manufacturing has been used in several functionalities, such as microfluidic analytical devices, energy storage devices, and electrochemical sensors. Theophylline and paracetamol are important pharmaceutical drugs where overdosing can cause adverse effects, such as tachycardia, seizures, and even renal failure. Therefore, this paper aims at the development of miniaturized electrochemical sensors using 3D printing and polylactic acid-based conductive carbon black commercial filament for theophylline and paracetamol detection. Electrochemical characterizations of the proposed sensor were performed to prove the functionality of the device. Morphological characterizations were carried out, in which chemical treatment could change the surface structure, causing the improvement of the analytical signal. Thus, the detection of theophylline at a linear range of 5.00-150 µmol L-1 with a limit of detection of 1.2 µmol L-1 was attained, and the detection of paracetamol at a linear range of 1.00-200 µmol L-1 with a limit of detection of 0.370 µmol L-1 was obtained, demonstrating the proposed sensor effectively detected pharmaceutical drugs.


Assuntos
Acetaminofen , Técnicas Eletroquímicas , Poliésteres , Fuligem , Teofilina , Acetaminofen/análise , Fuligem/química , Técnicas Eletroquímicas/métodos , Teofilina/análise , Poliésteres/química , Limite de Detecção , Impressão Tridimensional , Miniaturização
9.
Anal Chim Acta ; 1307: 342645, 2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719410

RESUMO

Electrochemical biosensors with high sensitivity can detect low concentrations of biomarkers, but their practical detection applications in complex biological environments such as human serum and sweat are severely limited by the biofouling. Herein, a conductive hydrogel based on bovine serum albumin (BSA) and conductive carbon black (CCB) was prepared for the construction of an antifouling biosensor. The BSA hydrogel (BSAG) was doped with CCB, and the prepared composite hydrogel exhibited good conductivity originated from the CCB and antifouling capability owing to the BSA hydrogel. An antifouling biosensor for the sensitive detection of cortisol was fabricated by drop-coating the conductive hydrogel onto a poly(3,4-ethylenedioxythiophene) (PEDOT) modified electrode and further immobilizing the cortisol aptamer. The constructed biosensor showed a linear range of 100 pg mL-1 - 10 µg mL-1 and a limit of detection of 26.0 pg mL-1 for the detection of cortisol, and it was capable of assaying cortisol accurately in complex human serum. This strategy of preparing antifouling and conductive hydrogels provides an effective way to develop robust electrochemical biosensors for biomarker detection in complex biological media.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Hidrocortisona , Hidrogéis , Soroalbumina Bovina , Fuligem , Humanos , Técnicas Biossensoriais/métodos , Soroalbumina Bovina/química , Hidrocortisona/sangue , Hidrocortisona/análise , Fuligem/química , Técnicas Eletroquímicas/métodos , Hidrogéis/química , Bovinos , Incrustação Biológica/prevenção & controle , Limite de Detecção , Animais , Eletrodos , Aptâmeros de Nucleotídeos/química , Polímeros , Compostos Bicíclicos Heterocíclicos com Pontes
10.
Chemosphere ; 359: 142247, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38705410

RESUMO

Mn or Co supported CeO2 fiber catalysts were synthesized following a biotemplating route and evaluated in soot combustion and benzene total oxidation. The catalysts were characterized by SEM, EDX, N2 physisorption, FTIR-ATR, XRD, RAMAN and XPS. SEM results confirmed that the "twisted ribbon" morphology of the biotemplate was mostly maintained. XRD and Raman showed that Mn and Co cations partially insert into ceria lattice and also segregate at the surface of the fibers. XPS allowed to determine that both set of catalysts exhibit Ce3+ and Ce4+ species, in addition to adsorbed and lattice oxygen. Also, the average oxidation state (AOS) of surface Mn could be calculated. Compared to bare Fib Ce, the performances for both reactions were improved for the supported catalysts, except from the catalyst with lowest Mn content for soot combustion. The catalytic activity was discussed in terms of the physicochemical features of the supported catalysts.


Assuntos
Benzeno , Cério , Cobalto , Manganês , Oxirredução , Fuligem , Cério/química , Benzeno/química , Catálise , Manganês/química , Cobalto/química , Fuligem/química
11.
Environ Sci Technol ; 58(18): 8096-8108, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38627223

RESUMO

Particulate matter, represented by soot particles, poses a significant global environmental threat, necessitating efficient control technology. Here, we innovatively designed and elaborately fabricated ordered hierarchical macroporous catalysts of Ce0.8Zr0.2O2 (OM CZO) integrated on a catalyzed diesel particulate filter (CDPF) using the self-assembly method. An oxygen-vacancy-enriched ordered macroporous Ce0.8Zr0.2O2 catalyst (VO-OM CZO) integrated CDPF was synthesized by subsequent NaBH4 reduction. The VO-OM CZO integrated CDPF exhibited a markedly enhanced soot oxidation activity compared to OM CZO and powder CZO coated CDPFs (T50: 430 vs 490 and 545 °C, respectively). The well-defined OM structure of the VO-OM CZO catalysts effectively improves the contact efficiency between soot and the catalysts. Meanwhile, oxygen vacancies trigger the formation of a large amount of highly reactive peroxide species (O22-) from molecular oxygen (O2) through electron abstraction from the three adjacent Ce3+ (3Ce3+ + Vö + O2 → 3Ce4+ + O22-), contributing to the efficient soot oxidation. This work demonstrates the fabrication of the ordered macroporous CZO integrated CDPF and reveals the importance of structure and surface engineering in soot oxidation, which sheds light on the design of highly efficient PM capture and removal devices.


Assuntos
Oxirredução , Catálise , Peróxidos/química , Fuligem/química , Filtração , Material Particulado/química , Emissões de Veículos
12.
ACS Appl Bio Mater ; 7(5): 2734-2740, 2024 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-38651321

RESUMO

3D printing of a living bioanode holds the potential for the rapid and efficient production of bioelectrochemistry systems. However, the ink (such as sodium alginate, SA) that formed the matrix of the 3D-printed bioanode may hinder extracellular electron transfer (EET) between the microorganism and conductive materials. Here, we proposed a biomimetic design of a 3D-printed Shewanella bioanode, wherein riboflavin (RF) was modified on carbon black (CB) to serve as a redox substance for microbial EET. By introducing the medicated EET pathways, the 3D-printed bioanode obtained a maximum power density of 252 ± 12 mW/m2, which was 1.7 and 60.5 times higher than those of SA-CB (92 ± 10 mW/m2) and a bare carbon cloth anode (3.8 ± 0.4 mW/m2). Adding RF reduced the charge-transfer resistance of a 3D-printed bioanode by 75% (189.5 ± 18.7 vs 47.3 ± 7.8 Ω), indicating a significant acceleration in the EET efficiency within the bioanode. This work provided a fundamental and instrumental concept for constructing a 3D-printed bioanode.


Assuntos
Materiais Biocompatíveis , Teste de Materiais , Impressão Tridimensional , Riboflavina , Shewanella , Riboflavina/química , Riboflavina/metabolismo , Shewanella/metabolismo , Transporte de Elétrons , Materiais Biocompatíveis/química , Fontes de Energia Bioelétrica , Eletrodos , Fuligem/química , Tamanho da Partícula , Tinta
13.
ACS Sens ; 9(4): 2156-2165, 2024 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-38629405

RESUMO

Anisotropic strain sensors capable of multidirectional sensing are crucial for advanced sensor applications in human motion detection. However, current anisotropic sensors encounter challenges in achieving a balance among high sensitivity, substantial stretchability, and a wide linear detection range. To address these challenges, a facile freeze-casting strategy was employed to construct oriented filler networks composed of carbon nanotubes and conductive carbon black within a brominated butyl rubber ionomer (iBIIR) matrix. The resulting anisotropic sensor based on the iBIIR composites exhibited distinct gauge factors (GF) in the parallel and vertical directions (GF∥ = 4.91, while GF⊥ = 2.24) and a broad linear detection range over a strain range of 190%. This feature enables the sensor to detect various human activities, including uniaxial pulse, finder bending, elbow bending, and cervical spine movements. Moreover, the ion-cross-linking network within the iBIIR, coupled with strong π-cation interactions between the fillers and iBIIR macromolecules, imparted high strength (12.3 MPa, nearly twice that of pure iBIIR) and an ultrahigh elongation at break (>1800%) to the composites. Furthermore, the sensor exhibited exceptional antibacterial effectiveness, surpassing 99% against both Escherichia coli and Staphylococcus aureus. Notably, the sensor was capable of wireless sensing. It is anticipated that anisotropic sensors will have extensive application prospects in flexible wearable devices.


Assuntos
Elastômeros , Nanotubos de Carbono , Tecnologia sem Fio , Humanos , Elastômeros/química , Nanotubos de Carbono/química , Anisotropia , Dispositivos Eletrônicos Vestíveis , Fuligem/química , Movimento , Staphylococcus aureus/isolamento & purificação
14.
Chemosphere ; 356: 141940, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38588894

RESUMO

Dissolved black carbon (DBC) is the ubiquitous component of dissolved organic matter pools with the high reactivity for disinfection byproducts formation. However, it is unknown that the influence of molecular weight (MW) of natural organic matter (NOM) on the DBC removal from potable water sources. Therefore, it was studied that the DBC removal by coagulation in the presence of the NOM with various molecular weights. The DBC removal was promoted due to the presence of NOM and the promotion degree decreased with decreasing MW of NOM. Furthermore, the removal ratio of humic-like component increased as the MW of NOM decreased, suggesting that the competition between DBC and NOM increased with decreasing MW. The functional groups after coagulation were the same with that before coagulation as the MW of NOM varied, suggesting that the molecular structure was not the key factor of influencing the DBC removal. This study will give the deep insight into the prediction of the DBC removal ratio by coagulation based on the MW of NOM in water sources.


Assuntos
Substâncias Húmicas , Peso Molecular , Purificação da Água , Purificação da Água/métodos , Substâncias Húmicas/análise , Carbono/química , Poluentes Químicos da Água/química , Fuligem/química , Água Potável/química , Desinfecção , Compostos Orgânicos/química , Compostos Orgânicos/isolamento & purificação
15.
Waste Manag ; 182: 21-31, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38631177

RESUMO

This research investigates the formation mechanism of soot and particulate matter during the pyrolysis and gasification of waste derived from Municipal Solid Waste (MSW) in a laboratory scale drop tube furnace. Compared with CO2 gasification atmosphere, more ultrafine particles (PM0.2, aerodynamic diameter less than 0.2 µm) were generated in N2 atmosphere at 1200℃, which were mainly composed of polycyclic aromatic hydrocarbons (PAHs), graphitic carbonaceous soot and volatile alkali salts. High reaction temperatures promote the formation of hydrocarbon gaseous products and their conversion to PAHs, which ultimately leads to the formation of soot particles. The soot particles generated by waste derived from MSW pyrolysis and gasification both have high specific surface area and well-developed pore structure. Compared with pyrolysis, the soot generated by gasification of waste derived from MSW had smaller size and higher proportion of inorganic components. The higher pyrolysis temperature led to the collapse of the mesoporous structure of submicron particles, resulting in a decrease in total pore volume and an increase in specific surface area. Innovatively, this research provides an explanation for the effect of reaction temperature/ CO2 on the formation pathways and physicochemical properties of soot and fine particulate matter.


Assuntos
Temperatura Alta , Material Particulado , Pirólise , Resíduos Sólidos , Fuligem , Material Particulado/análise , Material Particulado/química , Resíduos Sólidos/análise , Fuligem/análise , Fuligem/química , Eliminação de Resíduos/métodos , Incineração/métodos , Dióxido de Carbono/análise , Dióxido de Carbono/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Tamanho da Partícula
16.
Environ Sci Process Impacts ; 26(3): 499-509, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38318974

RESUMO

Black carbon (BC) exhibits promising potential as a sediment amendment owing to its commendable adsorption capacity for hydrophobic organic contaminants (HOCs), thereby resulting in HOC-laden sediments. Desorption kinetic studies play a crucial role in comprehending the release potential of HOCs from BC-sediment systems. Although the adsorption capacity of BC for HOCs has been found to decrease with aging, there is limited research on its impact on HOC desorption kinetics. In this study, BCs derived from agricultural waste (rice straw carbon, RC) and industrial waste (fly ash carbon, FC), respectively, were used to investigate the desorption kinetics of nonylphenol (NP). Additionally, a predictive model was established using the fitting parameters obtained from the modified two-domain model. The results showed that desorption of NP was divided into three fractions: rapid fraction (Frap), slow fraction (Fslow) and resistant fraction (Fr). BCs significantly decreased, while ageing increased the desorption amount and rate of NP. The performance of RC in controlling NP release was superior to that of FC. The predicted values calculated by the established model exhibit significant positive correlations with the measured values (p < 0.01). Additionally, the correlation analysis between sorption sites and desorption fractions revealed that the concentration of NP in the desorbing fraction was nearly equivalent to that of NP in partition sites within aged sediment/FC-sediment systems. However, the aged RC-sediment systems do not conform well to this rule. In other words, the estimation of NP release risk from sediments with a strong adsorbent would be overestimated, if Frap + Fsolw is considered equivalent to the desorbing fraction.


Assuntos
Sedimentos Geológicos , Fenóis , Cinética , Sedimentos Geológicos/química , Fenóis/química , Carbono/química , Fuligem/química , Adsorção
17.
Water Res ; 251: 121138, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38244298

RESUMO

Dissolved black carbon (DBC) has high photoactivity, which plays an important role in contaminants photodegradation. However, it is unclear how pyrolysis temperatures would affect the composition and photo-reactivity of DBC at the molecular level. Herein, we combined complementary techniques to study the characteristics of DBC pyrolyzed at 200 - 500 ℃, as well as the photoproduction of reactive species and the photodegradation of tetracycline (TC). Bulk composition characterization found that condensed aromatic carbonyl compounds (ConAC) with narrow molecular weights in DBC experienced an increase from 200 to 500 °C, which enhanced the photoproduction of 3DBC*,1O2, and ·OH. Molecular-level data suggested that 3DBC* and 1O2 were both related to the same DBC compounds. Comparatively, the patterns for ·OH were less pronounced, implying its precursor was not 3DBC* and had more complexity. Plentiful CHOx species of ConAC in DBC400 and DBC500 (DBCT, where T = pyrolysis temperature) accelerated the generation of 3DBC* and 1O2, enhancing the photodegradation of TC, and mainly triplet states of quinones reacted with TC. In contrast, DBC200 and DBC300 exhibited inhibition since massive CHOx species in lignin-like reduced 3TC* to TC. Our data revealed the diverse photochemical behavior mechanisms of DBC pyrolyzed at 200 - 500 ℃ at the molecular level and the implications for aquatic contaminants photochemistry.


Assuntos
Pirólise , Fuligem , Temperatura , Fotólise , Análise Espectral , Fuligem/análise , Fuligem/química , Antibacterianos , Tetraciclina , Carbono
18.
Environ Sci Technol ; 57(51): 21593-21604, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-37955649

RESUMO

Decades of research have established the toxicity of soot particles resulting from incomplete combustion. However, the unique chemical compounds responsible for adverse health effects have remained uncertain. This study utilized mass spectrometry to analyze the chemical composition of extracted soot organics at three oxidation states, aiming to establish quantitative relationships between potentially toxic chemicals and their impact on human alveolar basal epithelial cells (A549) through metabolomics-based evaluations. Targeted analysis using MS/MS indicated that particles with a medium oxidation state contained the highest total abundance of compounds, particularly oxygen-containing polycyclic aromatic hydrocarbons (OPAHs) composed of fused benzene rings and unsaturated carbonyls, which may cause oxidative stress, characterized by the upregulation of three specific metabolites. Further investigation focused on three specific OPAH standards: 1,4-naphthoquinone, 9-fluorenone, and anthranone. Pathway analysis indicated that exposure to these compounds affected transcriptional functions, the tricarboxylic acid cycle, cell proliferation, and the oxidative stress response. Biodiesel combustion emissions had higher concentrations of PAHs, OPAHs, and nitrogen-containing PAHs (NPAHs) compared with other fuels. Quinones and 9,10-anthraquinone were identified as the dominant compounds within the OPAH category. This knowledge enhances our understanding of the compounds contributing to adverse health effects observed in epidemiological studies and highlights the role of aerosol composition in toxicity.


Assuntos
Poluentes Atmosféricos , Hidrocarbonetos Policíclicos Aromáticos , Compostos Policíclicos , Humanos , Compostos Policíclicos/análise , Fuligem/análise , Fuligem/química , Fuligem/toxicidade , Espectrometria de Massas em Tandem , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Pulmão , Oxigênio/análise , Metaboloma , Poluentes Atmosféricos/análise , Emissões de Veículos/análise
19.
Chemosphere ; 334: 138995, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37211160

RESUMO

Increasing the contact efficiency and improving the intrinsic activity are two effective strategies to obtain efficient catalysts for soot combustion. Herein, the electrospinning method is used to synthesize fiber-like Ce-Mn oxide with a strong synergistic effect. The slow combustion of PVP in precursors and highly soluble manganese acetate in spinning solution facilitates the formation of fibrous Ce-Mn oxides. The fluid simulation clearly indicates that the slender and uniform fibers provide more interwoven macropores to capture soot particles than the cubes and spheres do. Accordingly, electrospun Ce-Mn oxide exhibits better catalytic activity than reference catalysts, including Ce-Mn oxides by co-precipitation and sol-gel methods. The characterizations suggest that Mn3+ substitution into fluorite-type CeO2 enhances the reducibility through the acceleration of Mn-Ce electron transfer, improves the lattice oxygen mobility by weakening the Ce-O bonds, and induces oxygen vacancies for the activation of O2. The theoretical calculation reveals that the release of lattice oxygen becomes easy because of a low formation energy of oxygen vacancy, while the high reduction potential is beneficial for the activation of O2 on Ce3+-Ov (oxygen vacancies). Due to above Ce-Mn synergy, the CeMnOx-ES shows more active oxygen species and higher oxygen storage capacity than CeO2-ES and MnOx-ES. The theoretical calculation and experimental results suggest that the adsorbed O2 is more active than lattice oxygen and the catalytic oxidation mainly follows the Langmuir-Hinshelwood mechanism. This study indicates that electrospinning is a novel method to obtain efficient Ce-Mn oxide.


Assuntos
Cério , Óxidos , Óxidos/química , Fuligem/química , Cério/química , Oxirredução , Catálise , Oxigênio
20.
Environ Sci Pollut Res Int ; 30(30): 76143-76156, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37231133

RESUMO

In order to avoid the high cost of existing precious metal catalyst like Pt, Ag/CeO2 was the most promising catalysts for mobile source soot emission control technologies, but there was a clear trade-off between hydrothermal aging resistance and catalytic oxidation performance hindered the application of this catalyst. In order to reveal the hydrothermal aging mechanism of Ag/CeO2 catalysts, the TGA (thermogravimetric analysis) experiments were investigated to reveal the mechanism of Ag modification on catalytic activity of CeO2 catalyst between fresh and hydrothermal aging and were also characterized with the related characterization experiments to in-depth research the lattice morphology and valence changes. The degradation mechanism of Ag/CeO2 catalysts in vapor with high-temperature was also explained and demonstrated based on density functional and molecular thermodynamics theories. The experimental and simulation data showed that the catalytic activity of soot combustion within Ag/CeO2 decreased more significantly after hydrothermal aging than CeO2 due to the less agglomerated, which caused by the decreased in OII/OI and Ce3+/Ce4+ compared with CeO2. As shown in density function theory (DFT) calculation, the decreased surface energy and the increased oxygen vacancy formation energy of the low Mille index surface after Ag modification led to the instability structure and the high catalytic activity. Ag modification also increased the adsorption energy and Gibbs free energy of H2O on the low Miller index surface compared to CeO2, indicating that the desorption temperature of H2O molecules in (1 1 0) and (1 0 0) was higher than (1 1 1) in CeO2 and Ag/CeO2, which led to the migration of (1 1 1) crystal surfaces to (1 1 0) and (1 0 0) in the vapor environment. These conclusions can provide a valuable addition to the regenerative application of Ce-based catalysts in diesel exhaust aftertreatment system the aerial pollution.


Assuntos
Cério , Fuligem , Fuligem/química , Teoria da Densidade Funcional , Cério/química , Oxirredução , Emissões de Veículos , Poeira
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