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Borgmeyer T, Zhou L, Breider F, Rossi MJ, Ludwig C. Natural and simulated weathering of polystyrene: A molecular view of the polymeric interface. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 947:174609. [PMID: 38997043 DOI: 10.1016/j.scitotenv.2024.174609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 06/23/2024] [Accepted: 07/06/2024] [Indexed: 07/14/2024]
Abstract
This work presents the changing abundance of surface functional groups (SFGs) on polystyrene (PS) upon weathering within one or a few molecular monolayers from a molecular point of view. PS particles were aged by exposing it to a gas flow of typically (5 %) O3 in O2 (PSO3), UV radiation using a solar simulator under controlled conditions in the laboratory (PSSS) and to the water/air interface immerged in a freshwater lake for 2 months (PSL). The chemical composition of the interface of weathered, compared to pristine (virgin or PSV) material was established using a titration technique that probed the chemical composition of the molecular interface of the polymer. The main conclusions of this exploratory study are: (a) The interface of PS changes significantly compared to ATR-FTIR spectra that do not show additional absorptions in the mid-IR spectrum over a penetration depth of more than hundred monolayers at 10 μm; (b) The average surface functionalization of the gas-solid interface, corresponding to the sum of all examined types of SFG, increases from 20 % of a monolayer for PSV to 40, 50 and 84 % for PSL, PSO3 and PSSS, respectively; (c) in all cases the most important SFG was surface -OH ranging from 11.2 to 64 % for PSV and PSSS, respectively; (d) each PS sample shows a characteristic SFG pattern or fingerprint using several probe gases; (e) O3 interaction led to interface acidification; (f) UV treatment leads to the highest degree of surface -OH functionalization compared to PSO3 and PSL. The accumulation of SFG's renders the interface more reactive towards adsorption of probe gases.
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Affiliation(s)
- T Borgmeyer
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIE GR-LUD, Station 2, CH-1015 Lausanne, Switzerland.
| | - L Zhou
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIE GR-CEL, Station 2, CH-1015 Lausanne, Switzerland; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China
| | - F Breider
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIE GR-CEL, Station 2, CH-1015 Lausanne, Switzerland.
| | - M J Rossi
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIE GR-LUD, Station 2, CH-1015 Lausanne, Switzerland.
| | - C Ludwig
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIE GR-LUD, Station 2, CH-1015 Lausanne, Switzerland; Paul Scherrer Institute, PSI Center for Energy and Environmental Sciences, 5232 Villigen PSI, Switzerland.
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Liu Y, He G, Chu B, Ma Q, He H. Atmospheric heterogeneous reactions on soot: A review. FUNDAMENTAL RESEARCH 2023; 3:579-591. [PMID: 38933550 PMCID: PMC11197571 DOI: 10.1016/j.fmre.2022.02.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 01/26/2022] [Accepted: 02/17/2022] [Indexed: 10/18/2022] Open
Abstract
Soot particles, composed of elemental carbon and organic compounds, have attracted widespread attention in recent years due to their significant impacts on climate, the environment and human health. Soot has been found to be chemically and physically active in atmospheric aging processes, which leads to alterations in its composition, morphology, hygroscopicity and optical properties and thus changes its environmental and health effects. The heterogeneous reactions on soot also have a significant impact on the transformation of gaseous pollutants into secondary aerosols. Therefore, the interactions between soot and atmospheric substances have been widely investigated to better understand the environmental behaviors of soot. In this review, we systematically summarize the progress and developments in the heterogeneous chemistry on soot over the past 30 years. Atmospheric trace constituents such as NO2, O3, SO2, N2O5, HNO3, H2SO4, OH radical, HO2 radical, peroxyacetyl nitrate etc., are presented in detail from the aspect of their heterogeneous reactions on soot. The possible mechanisms and the effects of environmental conditions on these heterogeneous reactions are also addressed. Further, the impacts of the heterogeneous reactions of soot on the atmospheric environment are discussed, and some aspects of soot-related research which require further investigation are proposed as well.
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Affiliation(s)
- Yuan Liu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guangzhi He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Biwu Chu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qingxin Ma
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong He
- State Key Joint Laboratory of Environment Simulation and Pollution Control, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Liu Y, Wu S, Fan C, Wang X, Liu F, Chen H. Variations in surface functional groups, carbon chemical state and graphitization degree during thermal deactivation of diesel soot particles. J Environ Sci (China) 2023; 124:678-687. [PMID: 36182173 DOI: 10.1016/j.jes.2022.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 12/28/2021] [Accepted: 01/08/2022] [Indexed: 06/16/2023]
Abstract
The thermal deactivation of diesel soot particles exerts a significant influence on the control strategy for the regeneration of diesel particulate filters (DPFs). This work focused on the changes in the surface functional groups, carbon chemical state, and graphitization degree during thermal treatment in an inert gas environment at intermediate temperatures of 600°C, 800°C, and 1000°C and explore the chemical species that were desorbed from the diesel soot surface during thermal treatment using a thermogravimetric analyser coupled with a gas-chromatograph mass spectrometer (TGA-GC/MS). The surface functional groups and carbon chemical state were characterized using Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The graphitization degree was evaluated by means of Raman spectroscopy (RS). The concentrations of aliphatic C-H, C-OH, C=O, and O-C=O groups are reduced for diesel soot and carbon black when increasing the thermal treatment temperature, while the sp2/sp3 hybridized ratio and graphitization degree enhance. These results provide comprehensive evidence of the decreased reactivity of soot samples. Among oxygenated functional groups, the percentage reduction during thermal treatment is the largest for the O-C=O groups owing to its worst thermodynamic stability. TGA-GC/MS results show that the aliphatic and aromatic chains and oxygenated species would be desorbed from the soot surface during 1000°C thermal treatment of diesel soot.
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Affiliation(s)
- Ye Liu
- Institute for Transport Studies, University of Leeds, Leeds LS2 9JT, UK
| | - Sijin Wu
- Institute for Transport Studies, University of Leeds, Leeds LS2 9JT, UK
| | - Chenyang Fan
- Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China.
| | - Xin Wang
- Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China
| | - Fangjie Liu
- Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang 471003, China
| | - Haibo Chen
- Institute for Transport Studies, University of Leeds, Leeds LS2 9JT, UK
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Liu Y, Fan C, Wang X, Liu F, Chen H. Thermally induced variations in the nanostructure and reactivity of soot particles emitted from a diesel engine. CHEMOSPHERE 2022; 286:131712. [PMID: 34333188 DOI: 10.1016/j.chemosphere.2021.131712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/18/2021] [Accepted: 07/27/2021] [Indexed: 06/13/2023]
Abstract
This work focuses on the thermally induced variation in the nanostructure, size of primary particles and oxidative reactivity of diesel soot and a commercial carbon black in an inert gas environment at temperatures ranging from 600 to 1000 °C. Soot nanostructure and size were characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD). The soot reactivity was evaluated with respect to activation energy (Ea) and characteristic oxidation temperature, including peak temperature (TP) and burnout temperature (Tb), using thermogravimetric analysis (TGA). The mass loss of diesel soot and carbon black rises when increasing the thermal treatment temperature, especially at 1000 °C, and a significant quantity of mass loss can be observed, which is primarily due to thermal fragmentation and the desorption of chemical species on soot surfaces. The HRTEM and XRD results all indicate that the thermally treated soot samples have more ordered nanostructure than the untreated samples. There is a reduction in the size of primary particles as thermal treatment temperature increases. The soot reactivity decreases after thermal treatment, as manifested by the elevation in Ea, TP, and Tb values. Moreover, the oxidation reactivity of soot samples is closely associated with the fringe length, tortuosity, and fringe tortuosity. Compared to carbon black, diesel soot with a more disorder structure has a higher oxidative reactivity.
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Affiliation(s)
- Ye Liu
- Institute for Transport Studies, University of Leeds, Leeds, LS2 9JT, UK.
| | - Chenyang Fan
- Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang, 471003, China.
| | - Xin Wang
- Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang, 471003, China
| | - Fangjie Liu
- Vehicle & Transportation Engineering Institute, Henan University of Science and Technology, Luoyang, 471003, China
| | - Haibo Chen
- Institute for Transport Studies, University of Leeds, Leeds, LS2 9JT, UK
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Tapia A, Salgado MS, Martín MP, Rodríguez-Fernández J, Rossi MJ, Cabañas B. Chemical characterization of diesel and hydrotreated vegetable oil (HVO) soot after reactive gas probing using diffuse reflectance FTIR spectroscopy (DRIFTS). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2017; 24:7534-7543. [PMID: 28116624 DOI: 10.1007/s11356-017-8436-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/09/2017] [Indexed: 06/06/2023]
Abstract
A chemical characterization of diesel and hydrotreated vegetable oil (HVO) soot has been developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) before and after the reaction with different probe gases. Samples were generated under combustion conditions corresponding to an urban operation mode of a diesel engine and were reacted with probe gas-phase molecules in a Knudsen flow reactor. Specifically, NH2OH, O3 and NO2 were used as reactants (probes) and selected according to their reactivities towards specific functional groups on the sample surface. Samples of previously ground soot were diluted with KBr and were introduced in a DRIFTS accessory. A comparison between unreacted and reacted soot samples was made in order to establish chemical changes on the soot surface upon reaction. It was concluded that the interface of diesel and HVO soot before reaction mainly consists polycyclic aromatic hydrocarbons, nitro and carbonyl compounds, as well as ether functionalities. The main difference between both soot samples was observed in the band of the C=O groups that in diesel soot was observed at 1719 cm-1 but not in HVO soot. After reaction with probe gases, it was found that nitro compounds remain on the soot surface, that the degree of unsaturation decreases for reacted samples, and that new spectral bands such as hydroxyl groups are observed.
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Affiliation(s)
- A Tapia
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha, Avda. Camilo José Cela s/n, 13071, Ciudad Real, Spain
| | - M S Salgado
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha, Avda. Camilo José Cela s/n, 13071, Ciudad Real, Spain.
| | - M P Martín
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha, Avda. Camilo José Cela s/n, 13071, Ciudad Real, Spain
| | - J Rodríguez-Fernández
- Grupo de Combustibles y Motores, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla La Mancha, Avda. Camilo José Cela 10, 13071, Ciudad Real, Spain
| | - M J Rossi
- Labor für Atmosphärenchemie (LAC), Paul Scherrer Institute (PSI), OBBA006, 5232, Villigen PSI, Switzerland
| | - B Cabañas
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha, Avda. Camilo José Cela s/n, 13071, Ciudad Real, Spain
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Tapia A, Salgado MS, Martín MP, Lapuerta M, Rodríguez-Fernández J, Rossi MJ, Cabañas B. Molecular Characterization of the Gas-Particle Interface of Soot Sampled from a Diesel Engine Using a Titration Method. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:2946-2955. [PMID: 26886850 DOI: 10.1021/acs.est.5b05531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Surface functional groups of two different types of combustion aerosols, a conventional diesel (EN 590) and a hydrotreated vegetable oil (HVO) soot, have been investigated using heterogeneous chemistry (i.e., gas-particle surface reactions). A commercial sample of amorphous carbon (Printex XE2-B) was analyzed as a reference substrate. A Knudsen flow reactor was used to carry out the experiments under molecular flow conditions. The selected gases for the titration experiments were: N(CH3)3 for the identification of acidic sites, NH2OH for the presence of carbonyl groups, CF3COOH and HCl for basic sites of different strength, and O3 and NO2 for reducing groups. Reactivity with N(CH3)3 indicates a lower density of acidic functionalities for Printex XE2-B in relation to diesel and HVO soot. Results for NH2OH experiments indicates that commercial amorphous carbon exhibits a lower abundance of available carbonyl groups at the interface compared to the results from diesel and HVO soot, the latter being the one with the largest abundance of carbonyl functions. Reactions with acids indicate the presence of weak basic oxides on the particle surface that preferentially interact with the strong acid CF3COOH. Finally, reactions with O3 and NO2 reveal that diesel and especially HVO have a significantly higher reactivity with both oxidizers compared to that of Printex XE2-B because they have more reducing sites by roughly a factor of 10 and 30, respectively. The kinetics of titration reactions have also been investigated.
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Affiliation(s)
- A Tapia
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha , Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain
| | - M S Salgado
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha , Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain
| | - María Pilar Martín
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha , Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain
| | - M Lapuerta
- Grupo de Combustibles y Motores, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla la Mancha , Avda. Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - J Rodríguez-Fernández
- Grupo de Combustibles y Motores, Escuela Técnica Superior de Ingenieros Industriales, Universidad de Castilla la Mancha , Avda. Camilo José Cela 10, 13071 Ciudad Real, Spain
| | - M J Rossi
- Labor für Atmosphärenchemie (LAC), Paul Scherrer Institute (PSI) , OBBA006, CH-5232 Villigen PSI, Switzerland
| | - B Cabañas
- Departamento de Química Física, Facultad de Ciencias y Tecnologías Químicas, Universidad de Castilla La Mancha , Avda. Camilo José Cela s/n, 13071 Ciudad Real, Spain
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