scholarly journals Comparative Studies of Fischer-Tropsch Synthesis on Iron Catalysts Supported on Al2O3-Cr2O3 (2:1), Multi-Walled Carbon Nanotubes or BEA Zeolite Systems

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 605 ◽  
Author(s):  
Mierczynski ◽  
Dawid ◽  
Chalupka ◽  
Maniukiewicz ◽  
Witoska ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Physicochemical Properties ◽  
Temperature Programmed Desorption ◽  
Fixed Bed Reactor ◽  
Iron Catalysts ◽  
Fischer Tropsch ◽  
Zeolite Β ◽  
Multi Walled Carbon Nanotubes ◽  
Temperature Programmed ◽  
Walled Carbon Nanotubes

The main goal of the presented paper is to study the influence of a range of support materials, i.e., multi-walled carbon nanotubes (MWCNTs), Al2O3-Cr2O3 (2:1), zeolite β-H and zeolite β-Na on the physicochemical and catalytic properties in Fischer-Tropsch (F-T) synthesis. All tested Fe catalysts were synthesized using the impregnation method. Their physicochemical properties were extensively investigated using various characterization techniques such as the Temperature-Programmed Reduction of hydrogen (TPR-H2), X-ray diffraction, Temperature-Programmed Desorption of ammonia (TPD-NH3), Temperature-Programmed Desorption of carbon dioxide (TPD-CO2), Fourier transform infrared spectrometry (FTIR), Brunauer Emmett Teller method (BET) and Thermogravimetric Differential Analysis coupled with Mass Spectrometer (TG-DTA-MS). Activity tests were performed in F-T synthesis using a high-pressure fixed bed reactor and a gas mixture of H2 and CO (50% CO and 50% H2). The correlation between the physicochemical properties and reactivity in F-T synthesis was determined. The highest activity was from a 40%Fe/Al2O3-Cr2O3 (2:1) system which exhibited 89.9% of CO conversion and 66.6% selectivity toward liquid products. This catalyst also exhibited the lowest acidity, but the highest quantity of iron carbides on its surface. In addition, in the case of iron catalysts supported on MWCNTs or a binary oxide system, the smallest amount of carbon deposit formed on the surface of the catalyst during the F-T process was confirmed.

scholarly journals Assessing the colloidal properties of engineered nanoparticles in water: case studies from fullerene C60 nanoparticles and carbon nanotubes

2010 ◽  
Vol 7 (1) ◽  
pp. 10 ◽  
Author(s):  
Kai Loon Chen ◽  
Billy A. Smith ◽  
William P. Ball ◽  
D. Howard Fairbrother
Keyword(s):  
Carbon Nanotubes ◽  
Physicochemical Properties ◽  
Case Studies ◽  
Fullerene C60 ◽  
Engineered Nanoparticles ◽  
Aquatic Systems ◽  
Colloidal Properties ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Carbon Based

Environmental context. The fate and bioavailability of engineered nanoparticles in natural aquatic systems are strongly influenced by their ability to remain dispersed in water. Consequently, understanding the colloidal properties of engineered nanoparticles through rigorous characterisation of physicochemical properties and measurements of particle stability will allow for a more accurate prediction of their environmental, health, and safety effects in aquatic systems. This review highlights some important techniques suitable for the assessment of the colloidal properties of engineered nanoparticles and discusses some recent findings obtained by using these techniques on two popular carbon-based nanoparticles, fullerene C60 and multi-walled carbon nanotubes. Abstract. The colloidal properties of engineered nanoparticles directly affect their use in a wide variety of applications and also control their environmental fate and mobility. The colloidal stability of engineered nanoparticles depends on their physicochemical properties within the given aqueous medium and is ultimately reflected in the particles’ aggregation and deposition behaviour. This review presents some of the key experimental methods that are currently used to probe colloidal properties and quantify engineered nanoparticle stability in water. Case studies from fullerene C60 nanoparticles and multi-walled carbon nanotubes illustrate how the characterisation and measurement methods are used to understand and predict nanoparticle fate in aquatic systems. Consideration of the comparisons between these two classes of carbon-based nanoparticles provides useful insights into some major current knowledge gaps while also revealing clues about needed future developments. Key issues to be resolved relate to the nature of near-range surface forces and the origins of surface charge, particularly for the reportedly unmodified or ‘pure’ carbon-based nanoparticles.

Multi-walled carbon nanotubes production by ethane decomposition over silica-supported iron-catalysts

2008 ◽  
Vol 205 (10) ◽  
pp. 2422-2427 ◽  
Author(s):  
Giacomo Messina ◽  
Saveria Santangelo ◽  
Maria G. Donato ◽  
Maurizio Lanza ◽  
Candida Milone ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Iron Catalysts ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Supported Iron

Effect of Operating Conditions for Higher Alcohols Synthesis from Synthesis Gas over Alkali-Modified Co-Rh-Mo Trimetallic Catalyst Supported on Multi-Walled Carbon Nanotubes

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Venkateswara Rao Surisetty ◽  
Janusz Kozinski ◽  
Ajay K. Dalai
Keyword(s):  
Carbon Nanotubes ◽  
Synthesis Gas ◽  
Fixed Bed ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Optimum Operating ◽  
Higher Alcohols ◽  
Higher Alcohols Synthesis ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The effects of operating conditions on the higher alcohols synthesis reaction from synthesis gas were studied in a single-pass tubular downflow fixed-bed reactor, using sulfided K-promoted trimetallic Co-Rh-Mo catalyst supported on multi-walled carbon nanotubes (MWCNTs). The p CO conversion increased monotonically with increasing reaction temperature (from 275 to 350°C) and pressure (from 800 to 1400 psi), while decreasing monotonically with increasing GHSV (from 2.4 to 4.2 m3 (STP)/(kg of cat./h)). To maximize the ethanol STY and selectivity, the optimum operating conditions were determined as 330°C, 1320 psi, and 3.8 m3 (STP)/kg of cat./h). Maximum ethanol STY and selectivity were obtained using gas with H2 to CO molar ratio around 1.25.

The Role of Metal Catalyst in Near Ambient Hydrogen Adsorption on Multi-walled Carbon Nanotubes

2004 ◽  
Vol 837 ◽  
Author(s):  
Yong-Won Lee ◽  
Rohit Deshpande ◽  
Anne C. Dillon ◽  
Michael J. Hebe ◽  
Hongjie Dai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Hydrogen Adsorption ◽  
Chemical Vapor ◽  
Metal Catalyst ◽  
Ambient Conditions ◽  
Multiwalled Carbon ◽  
Multi Walled Carbon Nanotubes ◽  
Methane Source ◽  
Temperature Programmed ◽  
Walled Carbon Nanotubes

ABSTRACTMultiwalled carbon nanotubes (MWNTs) were continuously synthesized by hot wire chemical vapor deposition (HWCVD) using a methane source catalyzed by metal-organic ferrocene. The microstructure of the MWNTs and the catalyst particles were subsequently characterized with transmission electron microscopy which identified three different phases, i.e., bcc α-Fe, fcc γ-Fe and orthorhombic Fe3C. The hydrogen storage capacity of MWNTs was determined with temperature-programmed desorption (TPD) technique. Hydrogen adsorption at near ambient conditions was observed only in as-synthesized MWNTs containing iron particles and was dramatically increased after hydrogen reducing treatment. Possible adsorption mechanism was also discussed.

scholarly journals Naproxen removal by CWPO with Fe3O4/multi-walled carbon nanotubes in a fixed-bed reactor

2021 ◽  
Vol 9 (2) ◽  
pp. 105110
Author(s):  
Y. Huaccallo-Aguilar ◽  
S. Álvarez-Torrellas ◽  
M. Larriba ◽  
V.I. Águeda ◽  
J.A. Delgado ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes
Sign in / Sign up

Export Citation Format

Share Document