The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
George A Sorial - One of the best experts on this subject based on the ideXlab platform.
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transport and deposition of ceo2 nanoparticles in water saturated porous media
Water Research, 2011Co-Authors: Zhen Li, Endalkachew Sahledemessie, Ashraf Aly Hassan, George A SorialAbstract:Abstract Ceria nanoparticles are used for fuel cell, Metal Polishing and automobile exhaust catalyst; however, little is known about the impact of their release to the environment. The stability, transport and deposition of engineered CeO2 nanoparticles through water-saturated column packed with sand were studied by monitoring effluent CeO2 concentration. The influence of solution chemistry such as ionic strength (1–10 mM) and pH (3–9) on the mobility and deposition of CeO2 nanoparticles was investigated by using a three-phase (deposition-rinse-reentrainment) procedure in packed bed columns. The results show that water chemistry governs the transport and deposition of CeO2 nanoparticles. Transport is significantly hindered at acidic conditions (pH 3) and high ionic strengths (10 mM and above), and the deposited CeO2 particles may not be re-entrained by increasing the pH or lowering the ionic strength of water. At neutral and alkaline conditions (pH6 and 9), and lower ionic strengths (below 10 mM), partial breakthrough of CeO2 nanoparticles was observed and particles can be partially detached and re-entrained from porous media by changing the solution chemistry. A mathematical model was developed based on advection-dispersion-adsorption equations and it successfully predicts the transport, deposition and re-entrainment of CeO2 nanoparticles through a packed bed. There is strong agreement between the deposition rate coefficients calculated from experimental data and predicted by the model. The successful prediction for attachment and detachment of nanoparticles during the deposition and re-entrainment phases is unique addition in this study. This work can be applied to access the risk of CeO2 nanoparticles transport in contaminated ground water.
Chun Wan Chen - One of the best experts on this subject based on the ideXlab platform.
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Field application of a newly developed personal nanoparticle sampler to selected Metalworking operations
Aerosol and Air Quality Research, 2013Co-Authors: Li-hao Young, Yun Hua Lin, Tzu Hsien Lin, Perng-jy Tsai, Ying Fang Wang, Shao Ming Hung, Chuen-jinn Tsai, Chun Wan ChenAbstract:A personal nanoparticle sampler (PENS) that simultaneously collects respirable particles (＜ 4 μm) and nanoparticles (＜ 0.1 μm) has recently been developed and calibrated in the laboratory. This study aims to evaluate the performance of the PENS in the workplace, and to determine the exposure characteristics during selected Metalworking operations. Metal Polishing/buffing, spot welding, and milling operations were selected to represent sources of solid Metal particles, fume aggregates and Metalworking fluid mists, respectively. In each operation, personal samples of a side-by-side PENS and SKC respirable dust aluminum cyclone were taken concurrently with ambient particle number size distribution measurements. The PENS-measured respirable particle mass concentrations (PM4) showed remarkable accuracy with respect to the reference SKC cyclone, regardless of particle type. The PENS-derived nanoparticle effective densities agreed reasonably well with the bulk densities expected for the substrate and materials in use. During the Metalworking operations, the nanoparticle mass concentrations (PM0.1) were poorly associated with the PM4 but strongly correlated with the ambient nanoparticle number concentrations (PN0.1), due to the persistent, elevated levels of nanoparticles formed during the operations. Overall, these results suggest that the PENS is applicable for use in the workplace to assess respirable and nanoparticle personal exposure, and that Metal Polishing/buffing, welding and milling generate a considerable amount of nanoparticles.
Qingsheng Wang - One of the best experts on this subject based on the ideXlab platform.
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study of hydrogen explosion control measures by using l phenylalanine for aluminum wet dust removal systems
RSC Advances, 2018Co-Authors: Xin Zheng, Kaili Xu, Yantong Wang, Qingsheng Wang, Ruiqing ShenAbstract:Wet dust removal systems are an effective design for preventing aluminum dust explosion in the process of Metal Polishing. However, wet dust removal systems pose hydrogen fire and explosion risks because aluminum dust can react with water to produce hydrogen gas. According to previous studies, L-phenylalanine can be used to solve the corrosion problem of Metal slabs. In this work, a hydrogen inhibition method was proposed to inhibit hydrogen production in wet dust removal systems by using L-phenylalanine. The hydrogen evolution curves of aluminum particles reacting with different concentrations of L-phenylalanine solutions obtained via hydrogen inhibition experiments revealed that when the concentration of L-phenylalanine solutions reached 20 g L−1, essentially no hydrogen gas was produced. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were used to characterize the aluminum particles before and after the reaction. This work shows that L-phenylalanine is a good inhibitor. The adsorption of L-phenylalanine on the aluminum particle surface obeys the Langmuir adsorption isotherm. Additionally, Fourier transform infrared (FTIR) analysis was conducted to explain the physicochemical mechanism of the L-phenylalanine inhibition of hydrogen production. L-Phenylalanine is an environmentally friendly inhibitor and hence can be used in wet dust removal systems for the treatment of aluminum dust, which can reduce the hydrogen fire and explosion risk.
Zhen Li - One of the best experts on this subject based on the ideXlab platform.
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transport and deposition of ceo2 nanoparticles in water saturated porous media
Water Research, 2011Co-Authors: Zhen Li, Endalkachew Sahledemessie, Ashraf Aly Hassan, George A SorialAbstract:Abstract Ceria nanoparticles are used for fuel cell, Metal Polishing and automobile exhaust catalyst; however, little is known about the impact of their release to the environment. The stability, transport and deposition of engineered CeO2 nanoparticles through water-saturated column packed with sand were studied by monitoring effluent CeO2 concentration. The influence of solution chemistry such as ionic strength (1–10 mM) and pH (3–9) on the mobility and deposition of CeO2 nanoparticles was investigated by using a three-phase (deposition-rinse-reentrainment) procedure in packed bed columns. The results show that water chemistry governs the transport and deposition of CeO2 nanoparticles. Transport is significantly hindered at acidic conditions (pH 3) and high ionic strengths (10 mM and above), and the deposited CeO2 particles may not be re-entrained by increasing the pH or lowering the ionic strength of water. At neutral and alkaline conditions (pH6 and 9), and lower ionic strengths (below 10 mM), partial breakthrough of CeO2 nanoparticles was observed and particles can be partially detached and re-entrained from porous media by changing the solution chemistry. A mathematical model was developed based on advection-dispersion-adsorption equations and it successfully predicts the transport, deposition and re-entrainment of CeO2 nanoparticles through a packed bed. There is strong agreement between the deposition rate coefficients calculated from experimental data and predicted by the model. The successful prediction for attachment and detachment of nanoparticles during the deposition and re-entrainment phases is unique addition in this study. This work can be applied to access the risk of CeO2 nanoparticles transport in contaminated ground water.
Li-hao Young - One of the best experts on this subject based on the ideXlab platform.
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Field application of a newly developed personal nanoparticle sampler to selected Metalworking operations
Aerosol and Air Quality Research, 2013Co-Authors: Li-hao Young, Yun Hua Lin, Tzu Hsien Lin, Perng-jy Tsai, Ying Fang Wang, Shao Ming Hung, Chuen-jinn Tsai, Chun Wan ChenAbstract:A personal nanoparticle sampler (PENS) that simultaneously collects respirable particles (＜ 4 μm) and nanoparticles (＜ 0.1 μm) has recently been developed and calibrated in the laboratory. This study aims to evaluate the performance of the PENS in the workplace, and to determine the exposure characteristics during selected Metalworking operations. Metal Polishing/buffing, spot welding, and milling operations were selected to represent sources of solid Metal particles, fume aggregates and Metalworking fluid mists, respectively. In each operation, personal samples of a side-by-side PENS and SKC respirable dust aluminum cyclone were taken concurrently with ambient particle number size distribution measurements. The PENS-measured respirable particle mass concentrations (PM4) showed remarkable accuracy with respect to the reference SKC cyclone, regardless of particle type. The PENS-derived nanoparticle effective densities agreed reasonably well with the bulk densities expected for the substrate and materials in use. During the Metalworking operations, the nanoparticle mass concentrations (PM0.1) were poorly associated with the PM4 but strongly correlated with the ambient nanoparticle number concentrations (PN0.1), due to the persistent, elevated levels of nanoparticles formed during the operations. Overall, these results suggest that the PENS is applicable for use in the workplace to assess respirable and nanoparticle personal exposure, and that Metal Polishing/buffing, welding and milling generate a considerable amount of nanoparticles.