Adsorption of water vapor and carbon dioxide at carboxylic functional groups on the surface of coal

Nishino, Junya

doi:10.1016/s0016-2361(00)00136-8

Cited by 158 publications

(89 citation statements)

References 25 publications

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“…Since freshly emitted discharge soot particles are known to be hydrophobic, physisorption of water vapor on soot was suggested as mechanism for adsorption, supported by the water vapor's small desorption lifetime . The H 2 O specific parameters α s,0,H 2 O and τ d,H 2 O are adapted from Rogaski et al (1997) and Pöschl et al (2001), and σ H 2 O is taken from Nishino (2001).…”

Section: Surface Reactionsmentioning

confidence: 99%

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O3, NO2, and H2O on soot coated with benzo[a]pyrene

2009

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Abstract. This study assesses in detail the effects of heterogeneous chemistry on the particle surface and gas-phase composition by modeling the reversible co-adsorption of O 3 , NO 2 , and H 2 O on soot coated with benzo[a]pyrene (BaP) for an urban plume scenario over a period of five days. By coupling the Pöschl-Rudich-Ammann (PRA) kinetic framework for aerosols ) to a box model version of the gas phase mechanism RADM2, we are able to track individual concentrations of gas-phase and surface species over the course of several days. The flux-based PRA formulation takes into account changes in the uptake kinetics due to changes in the chemical gas-phase and particle surface compositions. This dynamic uptake coefficient approach is employed for the first time in a broader atmospheric context of an urban plume scenario. Our model scenarios include one to three adsorbents and three to five coupled surface reactions. The results show a variation of the O 3 and NO 2 uptake coefficients of more than five orders of magnitude over the course of the simulation time and a decrease in the uptake coefficients in the various scenarios by more than three orders of magnitude within the first six hours. Thereafter, periodic peaks of the uptake coefficients follow the diurnal cycle of gas-phase O 3 -NO x reactions. Physisorption of water vapor reduces the half-life of the coating substance BaP by up to a factor of seven by permanently occupying ∼75% of the soot surface. Soot emissions modeled by replenishing reactive surface sites lead to maximum gas-phase O 3 depletions Correspondence to: D. A. Knopf (daniel.knopf@stonybrook.edu) of 41 ppbv and 7.8 ppbv for an hourly and six-hourly replenishment cycle, respectively. This conceptual study highlights the interdependence of co-adsorbing species and their nonlinear gas-phase feedback. It yields further insight into the atmospheric importance of the chemical oxidation of particles and emphasizes the necessity to implement detailed heterogeneous kinetics in future modeling studies.

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Section: Surface Reactionsmentioning

confidence: 99%

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O3, NO2, and H2O on soot coated with benzo[a]pyrene

2009

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“…Finalmente, la cantidad de agua adsorbida fue estimada calculando la diferencia entre el valor en peso final e inicial de la muestra. La cantidad adsorbida (N ads ) fue calculada como g de agua por g de carbón [15,20,[24][25][26][27][28][29][30]. La Fig.…”

Section: Isotermas De Adsorciónunclassified

“…La adsorción se incrementa a medida que aumenta la actividad de agua. Este comportamiento está de acuerdo con los estudios disponibles de la pareja sortiva carbón/agua [11,[15][16][17][31][32][33][34]. La cantidad de vapor de agua en los contenedores de adsorción se incrementa debido al aumento en la presión de vapor del sistema (actividad acuosa).…”

Section: Isotermas De Adsorciónunclassified

“…Los resultados obtenidos indicaron que el calor isostérico solo es afectado por la heterogeneidad energética de la superficie. Nishino [15] realizó una investigación sobre la adsorción de vapor de agua en veinte muestras de carbón mineral, provenientes de países como Australia, Japón, Rusia, entre otros. En la experimentación se analizó la relación que existe entre la cantidad de oxígeno en el adsorbente y los grupos hidroxílicos presentes en su superficie, para así obtener isobaras que relacionen la cantidad adsorbida entre el número de grupos en la superficie del carbón.…”

Section: Introductionunclassified

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Effect of the temperature in adsorption phenomena of water onto Sub-Bituminous coal

2016

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The presence of water in coal presents a technological challenge for its industrial use in energetic processes. Therefore, this study aims to study the temperature effect on the water adsorption onto coals at 21, 30, 40 and 50°C. A Colombian bituminous coal was used as sample. The coal was characterized by nitrogen adsorption at 77 K (SBET), Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, elemental analysis (C-H-N elemental). The results showed that the water uptake increased as the vapor pressure increased. The Talu and Meunier model [1] was used to fit the adsorption isotherms, and the mean square root error (MSRE%) was lower than 10%. Additionally, the Gibbs free energy was found to have negative values, which corroborates the spontaneous adsorption process.Keywords: Adsorption; Coal; Isotherm; Water Efecto de la temperatura en el proceso de adsorción de agua en Carbón sub-bituminoso colombiano Resumen La presencia de agua en carbones presenta un reto tecnológico para su uso industrial en procesos energéticos. Por tal motivo, este estudio pretende analizar el efecto de temperatura en la adsorción de agua en carbones a 21, 30, 40 y 50°C. Un carbón sub-bituminoso Colombiano fue usado como muestra. El carbón fue caracterizado por adsorción de nitrógeno a 77K (SBET), Microscopía electrónica de barrido (SEM), Espectroscopia infrarroja por transformada de Fourier (FT-IR), análisis elemental (C-H-N). Los resultados muestran que la captura de agua se incrementa a medida que la presión de vapor aumenta. El modelo Talu & Meunier [1] fue utilizado para ajustar las isotermas de adsorción, presentando un buen ajuste. MSRE% menor al 10%. Adicionalmente, se calculó la energía libre de Gibbs obteniendo valores negativos, lo cual corrobora el proceso espontáneo de adsorción.

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“…These studies showed that there are many factors (e.g., oxygen-containing functional groups, RWC, pore volume, and RH) that affect EWC of dewatered lignite [6][7][8][9][10][11][12][13] . Early work was based on the measurement of adsorption-desorption isotherms of water, and water in lignite can be categorized into free, capillary, multilayer, and monolayer water, which is the basis for the scienti c studies today 7,8) .…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

et al. 2016

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Measurements of equilibrium water contents (EWCs) in samples obtained from hydrothermal treatment (HT) and HT coupled with mechanical compression (HT-MC) were undertaken across a range of relative humidities (RHs) to investigate the performance of EWC and its mechanism. The changes in the concentrations of carboxyl groups and mesopore volume were measured by an improved barium ion exchange and N 2 adsorption-desorption isotherms methods, respectively. The results showed that EWCs decreased with progressively severe HT and HT-MC conditions and EWCs of HT-MC samples were lower than those of HT samples, indicating that HT and HT-MC can upgrade lignite by reducing water loading capacity and HT-MC was better than HT. At low RHs (RH ≤ 10%), the factor that controls EWC is water moleculesactive sites interactions and one to two water molecules are associated with each carboxyl group, while at medium RHs (10 < RH ≤ 92%) the amount of monolayer water and mesopore volume gain in signi cance and ca. two multilayer water molecules are bound to each monolayer water molecule. At high RHs (RH > 92%), EWC is determined by comprehensive factors such as macropores and cracks. Furthermore, EWC can be either higher or lower than residual water content (RWC) based on the RH within a threshold residual water level (ca. 5 to 16%). EWC was generally higher than RWC below a RWC of ca. 5% and the opposite relationship was observed for samples with RWC above ca. 16%. These provide information for the operation of lignite dewatering technique, the control of its water re-adsorption, and storage.

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Adsorption of water vapor and carbon dioxide at carboxylic functional groups on the surface of coal

Cited by 158 publications

References 25 publications

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O<sub>3</sub>, NO<sub>2</sub>, and H<sub>2</sub>O on soot coated with benzo[a]pyrene

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O<sub>3</sub>, NO<sub>2</sub>, and H<sub>2</sub>O on soot coated with benzo[a]pyrene

Effect of the temperature in adsorption phenomena of water onto Sub-Bituminous coal

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

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Adsorption of water vapor and carbon dioxide at carboxylic functional groups on the surface of coal

Cited by 158 publications

References 25 publications

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O&lt;sub&gt;3&lt;/sub&gt;, NO&lt;sub&gt;2&lt;/sub&gt;, and H&lt;sub&gt;2&lt;/sub&gt;O on soot coated with benzo[a]pyrene

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O&lt;sub&gt;3&lt;/sub&gt;, NO&lt;sub&gt;2&lt;/sub&gt;, and H&lt;sub&gt;2&lt;/sub&gt;O on soot coated with benzo[a]pyrene

Effect of the temperature in adsorption phenomena of water onto Sub-Bituminous coal

Effect of Hydrothermal Treatment Coupled with Mechanical Compression on Equilibrium Water Content of Loy Yang Lignite and Mechanism

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Product

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Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O<sub>3</sub>, NO<sub>2</sub>, and H<sub>2</sub>O on soot coated with benzo[a]pyrene

Detailed heterogeneous chemistry in an urban plume box model: reversible co-adsorption of O<sub>3</sub>, NO<sub>2</sub>, and H<sub>2</sub>O on soot coated with benzo[a]pyrene