CO adsorbents comprising various alkaline sorption active phases supported on mesoporous AlO were prepared. The materials were tested regarding their CO adsorption behavior in the mid-temperature range, i.e.
View Article and Find Full Text PDFThe present work studies the adsorption of CO using a zeolitic industrial molecular sieve (IMS) with a high surface area. The effect of the CO feed concentration and the adsorption temperature in conjunction with multiple adsorption-desorption cycles was experimentally investigated. To assess the validity of the experimental results, theoretical calculations based on well-established equations were employed and the values of equilibrium, kinetic, and thermodynamic parameters are presented.
View Article and Find Full Text PDFGreenhouse gas emissions are a massive concern for scientists to minimize the effect of global warming in the environment. In this study, packed bed, coated wall, and membrane reactors were investigated using three novel nickel catalysts for the methanation of CO. CFD modelling methodologies were implemented to develop 2D models.
View Article and Find Full Text PDFThe catalytic oxidation of CO is probably the most investigated reaction in the literature, for decades, because of its extended environmental and fundamental importance. In this paper, the oxidation of CO on LaSrMnO perovskites (LSMx), either unloaded or loaded with dispersed Ir nanoparticles (Ir/LSMx), was studied in the temperature range 100-450 °C under excess O conditions (1% CO + 5% O). The perovskites, of the type LaSrMnO (x = 0.
View Article and Find Full Text PDFIn this study, we examine the effect of integrating different carbon nanostructures (carbon nanotubes, CNTs, graphene nanoplatelets, GNPs) into Ni- and Ni-W-based bi-functional catalysts for hydrocracking of heptane performed at 400 °C. The effect of varying the SiO2/Al2O3 ratio of the zeolite Y support (between 5 and 30) on the heptane conversion is also studied. The results show that the activity, in terms of heptane conversion, followed the order CNT/Ni-ZY5 (92%) > GNP/Ni-ZY5 (89%) > CNT/Ni-W-ZY30 (86%) > GNP/Ni-W-ZY30 (85%) > CNT/Ni-ZY30 (84%) > GNP/Ni-ZY30 (83%).
View Article and Find Full Text PDFIn this paper, we show how the composition of bimetallic Fe-Ni exsolution can be controlled by the nature and concentration of oxygen vacancies in the parental matrix and how this is used to modify the performance of CO-assisted ethane conversion. Mesoporous A-site-deficient LaSrTiFeNiO (0 ≤ α ≤ 0.2) perovskites with substantial specific surface area (>40 m/g) enabled fast exsolution kinetics ( < 500 °C, < 1 h) of bimetallic Fe-Ni nanoparticles of increasing size (3-10 nm).
View Article and Find Full Text PDFThis work presents information regarding PM10, PM2.5, Polycyclic Aromatic Hydrocarbons (PAHs), and trace elements that were obtained from two sampling stations, located in the region of Western Macedonia (North-Western Greece), over the course of a 12-month period. Τhe first sampling station was located near the village of Pontokomi (Station 1) and the second (Station 2) in the rural area of Petrana (Fig 1).
View Article and Find Full Text PDFSelective catalytic reduction (SCR) is probably the most widespread process for limiting NO emissions under lean conditions (O excess) and, in addition to the currently used NH or urea as a reducing agent, many other alternative reductants could be more promising, such as CH/CHO, H and CO. Different catalysts have been used thus far for NO abatement from mobile (automotive) and stationary (fossil fuel combustion plants) sources, however, perovskites demand considerable attention, partly due to their versatility to combine and incorporate various chemical elements in their lattice that favor deNO catalysis. In this work, the CH/CHO, H, and CO-SCR of NO on perovskite-based catalysts is reviewed, with particular emphasis on the role of the reducing agent nature and perovskite composition.
View Article and Find Full Text PDFThis manuscript presents the concentrations of inhalable suspended particles with diameter less than 10 µm (PM10) in the region of west Macedonia, Greece, from a total of nine locations, from 2010 to 2020. This region, the only landlocked region in the country, has acted as the pillar of electricity production in Greece since 1960, utilizing lignite in thermal power stations, which was open mined in the locality. However, following Greece's international commitments for climate action, the region has entered a transition, post-lignite process.
View Article and Find Full Text PDFIn the work presented herein, a joint experimental and theoretical approach has been carried out to obtain an insight into the desulfurization performance of an industrial molecular sieve (IMS), resembling a zeolitic structure with a morphology of cubic crystallites and a high surface area of 590 m g, with a view to removing HS from biogas. The impact of temperature, HS inlet concentration, gas matrix, and regeneration cycles on the desulfurization performance of the IMS was thoroughly probed. The adsorption equilibrium, sorption kinetics, and thermodynamics were also examined.
View Article and Find Full Text PDFThe present study provides, for the first time in the literature, a comparative assessment of the catalytic performance of Ni catalysts supported on γ-AlO and γ-AlO modified with LaO, in a continuous flow trickle bed reactor, for the selective deoxygenation of palm oil. The catalysts were prepared the wet impregnation method and were characterized, after calcination and/or reduction, by N adsorption/desorption, XRD, NH-TPD, CO-TPD, H-TPR, H-TPD, XPS and TEM, and after the time-on-stream tests, by TGA, TPO, Raman and TEM. Catalytic experiments were performed between 300-400 °C, at a constant pressure (30 bar) and different LHSV (1.
View Article and Find Full Text PDFCO methanation has recently emerged as a process that targets the reduction in anthropogenic CO emissions, via the conversion of CO captured from point and mobile sources, as well as H produced from renewables into CH. Ni, among the early transition metals, as well as Ru and Rh, among the noble metals, have been known to be among the most active methanation catalysts, with Ni being favoured due to its low cost and high natural abundance. However, insufficient low-temperature activity, low dispersion and reducibility, as well as nanoparticle sintering are some of the main drawbacks when using Ni-based catalysts.
View Article and Find Full Text PDFThe removal of the environmentally toxic and corrosive hydrogen sulfide (HS) from gas streams with varying overall pressure and HS concentration is a long-standing challenge faced by the oil and gas industries. The present work focuses on HS capture using a relatively new type of material, namely metal-organic frameworks (MOFs), in an effort to shed light on their potential as adsorbents in the field of gas storage and separation. MOFs hold great promise as they make possible the design of structures from organic and inorganic units, but also as they have provided an answer to a long-term challenging objective, i.
View Article and Find Full Text PDFIn the present study, Ni/Ce-Sm-xCu (x = 5, 7, 10 at.%) catalysts were prepared using microwave radiation coupled with sol-gel and followed by wetness impregnation method for the Ni incorporation. Highly dispersed nanocrystallites of CuO and NiO on the Ce-Sm-Cu support were found.
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