You searched for subject:(Catalysts Recycling).
Showing records 1 – 5 of
5 total matches.
No search limiters apply to these results.
Cape Peninsula University of Technology
1.
Folifac, Leo.
Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons
.
Degree: 2018, Cape Peninsula University of Technology
URL: http://etd.cput.ac.za/handle/20.500.11838/2751 
► Zeolites have found applications as heterogeneous or solid catalyst in the petrochemical and refining industries. Zeolite ZSM-5 in particular is a highly siliceous solid catalyst…
(more)
▼ Zeolites have found applications as heterogeneous or solid catalyst in the petrochemical and refining industries. Zeolite ZSM-5 in particular is a highly siliceous solid catalyst with a porous network that consists of medium pore structure (pore openings 5-5.5 A). The solid catalyst (ZSM-5) is well known for its high temperature stability and strong acidity, which makes it an established catalyst used for different petrochemical processes such as Methanol-To-Gasoline (MTG), isomerisation, disproportionation, and cracking. Unlike in the past, the synthesis of zeolite ZSM-5 from other sources that contains silica (Si) and alumina (Al) with the addition of a template (TPBr) as a structure-directing agent is eminent. Its synthesis can be achievable from coal fly ash that is a waste material and a cheap source of Si and Al. Coal fly ash is a waste material that is produced during the combustion of coal to generate electricity. The elemental composition of coal fly ash consists of mostly SiO2 and Al2O3 together with other significant and trace elements. Zeolite ZSM-5 catalyst synthesised from coal fly ash by previous authors required an excessive amount of additional source of silica even though the XRD spectra still show the presence of quartz and mullite phase in the final products. These phases prevented the use of fly ash (solid) as a precursor to synthesise zeolite ZSM-5 products. However, the synthesis of high purity zeolite ZSM-5 products by extracting silica and alumina from South African fly ash and then using it with small amounts of fumed silica was investigated This aim was achieved by fusing fly ash (FA) with sodium hydroxide (NaOH) under hydrothermal condition set at 550 °C for 1 hour 30 minutes. The quartz and mullite phase observed by previous authors was digested by the fusion process. Thereafter, the treatment of fused fly ash filtrate (FFAF) with concentrated H2SO4 (98-99%), precipitated silica and removed Al that therefore increased the Si/Al ratio from 1.97 in fly ash (FA) to 9.5 in the silica extract (named fused fly ash extract). This route was designed to improve the quality of the final products and reduced the amount of fumed silica added to the synthesis mixture prior to hydrothermal synthesis. In this line of investigation, the process of adding fumed silica to the hydrothermal gel was optimised. H-FF1 with a Si/Al ratio of 9.5 was synthesised using the silica extract without the addition of fumed silica. Its XRD, SEM and relative crystallinity results proved that H-FF1 was inactive and hence was not further characterised and utilised in the conversion of methanol to hydrocarbons (MTH). Purer phase zeolite ZSM-5 products (H-FF2 and H-FF3) that were synthesised from silica extract with the addition of small amounts of fumed silica were characterised and successfully used in the methanol to hydrocarbons (MTH) reaction. The synthesised ZSM-5 products had different Si/Al ratio, different morphology, crystal size, BET surface area, and relative crystallinity as well as different trends in the MTH…
Subjects/Keywords: Zeolite catalysts;
Zeolites – Synthesis;
Fly ash;
Fly ash – Recycling;
Zeolites – Industrial applications
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Folifac, L. (2018). Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons
. (Thesis). Cape Peninsula University of Technology. Retrieved from http://etd.cput.ac.za/handle/20.500.11838/2751
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Folifac, Leo. “Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons
.” 2018. Thesis, Cape Peninsula University of Technology. Accessed March 07, 2021.
http://etd.cput.ac.za/handle/20.500.11838/2751.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Folifac, Leo. “Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons
.” 2018. Web. 07 Mar 2021.
Vancouver:
Folifac L. Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons
. [Internet] [Thesis]. Cape Peninsula University of Technology; 2018. [cited 2021 Mar 07].
Available from: http://etd.cput.ac.za/handle/20.500.11838/2751.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Folifac L. Performance of zeolite ZSM-5 synthesised from South African fly ash in the conversion of methanol to hydrocarbons
. [Thesis]. Cape Peninsula University of Technology; 2018. Available from: http://etd.cput.ac.za/handle/20.500.11838/2751
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Canterbury
2.
Shang J.
Tailoring Acidity and Porosity of Alumina Catalysts via Transition Metal Doping for Glucose Conversion in Biorefinery.
Degree: 2019, University of Canterbury
URL: http://hdl.handle.net/10092/17841
► Efficient conversion of food waste to value-added products necessitates the development of high-performance heterogeneous catalysts. This study evaluated the use of Al2O3 as a low-cost…
(more)
▼ Efficient conversion of food waste to value-added products necessitates the development of high-performance heterogeneous catalysts. This study evaluated the use of Al2O3 as a low-cost and abundant support material for fabricating Lewis acid catalysts, i.e., through the in-situ doping of Cu, Ni, Co, and Zr into Al2O3 followed by calcination. The characterisation results show that all catalysts were mainly amorphous. In particular, adding the transition metals to the Al2O3 matrix resulted in the increase of acidity and meso-/micro-pores. The catalysts were evaluated in the conversion of glucose, which can be easily derived from starch-rich food waste (e.g., bread waste) via hydrolysis, to fructose in biorefinery. The results indicate that the Ni-doped Al2O3 (Al-Ni-C) achieved the highest fructose yield (19 mol%) and selectivity (59 mol%) under heating at 170 °C for 20 min, of which the performance falls into the range reported in literature. In contrast, the Zr-doped Al2O3 (Al-Zr-C) presented the lowest fructose selectivity despite the highest glucose conversion, meaning that the catalyst was relatively active towards the side reactions of glucose and intermediates. The porosity and acidity, modified via metal impregnation, were deduced as the determinants of the catalytic performance. It is noteworthy that the importance of these parameters may vary in a relative sense and the limiting factor could shift from one parameter to another. Therefore, evaluating physicochemical properties as a whole, instead of the unilateral improvement of a single parameter, is encouraged to leverage each functionality for cost-effectiveness. This study provides insights into the structure-performance relationships to promote advance in catalyst design serving a sustainable food waste biorefinery.
Subjects/Keywords: biomass valorisation; waste management/recycling; sustainable biorefinery; platform chemicals; green catalysts; glucose isomerisation; Field of Research::09 - Engineering::0904 - Chemical Engineering::090402 - Catalytic Process Engineering
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
J, S. (2019). Tailoring Acidity and Porosity of Alumina Catalysts via Transition Metal Doping for Glucose Conversion in Biorefinery. (Thesis). University of Canterbury. Retrieved from http://hdl.handle.net/10092/17841
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
J, Shang. “Tailoring Acidity and Porosity of Alumina Catalysts via Transition Metal Doping for Glucose Conversion in Biorefinery.” 2019. Thesis, University of Canterbury. Accessed March 07, 2021.
http://hdl.handle.net/10092/17841.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
J, Shang. “Tailoring Acidity and Porosity of Alumina Catalysts via Transition Metal Doping for Glucose Conversion in Biorefinery.” 2019. Web. 07 Mar 2021.
Vancouver:
J S. Tailoring Acidity and Porosity of Alumina Catalysts via Transition Metal Doping for Glucose Conversion in Biorefinery. [Internet] [Thesis]. University of Canterbury; 2019. [cited 2021 Mar 07].
Available from: http://hdl.handle.net/10092/17841.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
J S. Tailoring Acidity and Porosity of Alumina Catalysts via Transition Metal Doping for Glucose Conversion in Biorefinery. [Thesis]. University of Canterbury; 2019. Available from: http://hdl.handle.net/10092/17841
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Georgia Tech
3.
Nguyen, Joseph Vu.
Design, synthesis, and optimization of recoverable and recyclable silica-immobilized atom transfer radical polymerization catalysts.
Degree: PhD, Chemical Engineering, 2005, Georgia Tech
URL: http://hdl.handle.net/1853/6860
► Despite the growing interest in heterogeneous polymerization catalysis, the majority of the polymerization catalysts used industrially are single-use entities that are left in the polymer…
(more)
▼ Despite the growing interest in heterogeneous polymerization catalysis, the majority of the polymerization
catalysts used industrially are single-use entities that are left in the polymer product. Recoverable and recyclable polymerization
catalysts have not reached the industrial utility of single-use
catalysts because the catalyst and product separation have not become economical. The successful development of recyclable transition metal polymerization
catalysts must take a rational design approach, hence academic and industrial researchers need to further expand the fundamental science and engineering of recyclable polymerization catalysis to gain an understanding of critical parameters that allow for the design of economically viable, recoverable solid polymerization
catalysts.
Unfortunately, the rapid development of Atom Transfer Radical Polymerization over the past 10 years has not resulted in its wide spread industrial practice. Numerous reports regarding the immobilization of transition metal ATRP
catalysts, in attempts to increase its applicability, have extended the fundamentals of recyclable polymerization catalysis. However, for industrial viability, more research is required in the area of how the catalyst complex immobilization methodology and support structure affect the catalyst polymerization performance, regeneration, and recyclability. A comprehensive rational catalyst design approach of silica-immobilized ATRP catalyst was undertaken to answer these questions and are discussed here.
Advisors/Committee Members: Jones, Christopher (Committee Chair), Eckert, Charles (Committee Member), Schork, Joseph (Committee Member), Weck, Marcus (Committee Member), Zhang, John (Committee Member).
Subjects/Keywords: Heterogeneous polymerization catalysis; ATRP; Catalyst design; Recyclable; Recoverable; Silica-immobilized catalyst; Transition metal catalysts; Recycling (Waste, etc.); Polymerization; Catalysts
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Nguyen, J. V. (2005). Design, synthesis, and optimization of recoverable and recyclable silica-immobilized atom transfer radical polymerization catalysts. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/6860
Chicago Manual of Style (16th Edition):
Nguyen, Joseph Vu. “Design, synthesis, and optimization of recoverable and recyclable silica-immobilized atom transfer radical polymerization catalysts.” 2005. Doctoral Dissertation, Georgia Tech. Accessed March 07, 2021.
http://hdl.handle.net/1853/6860.
MLA Handbook (7th Edition):
Nguyen, Joseph Vu. “Design, synthesis, and optimization of recoverable and recyclable silica-immobilized atom transfer radical polymerization catalysts.” 2005. Web. 07 Mar 2021.
Vancouver:
Nguyen JV. Design, synthesis, and optimization of recoverable and recyclable silica-immobilized atom transfer radical polymerization catalysts. [Internet] [Doctoral dissertation]. Georgia Tech; 2005. [cited 2021 Mar 07].
Available from: http://hdl.handle.net/1853/6860.
Council of Science Editors:
Nguyen JV. Design, synthesis, and optimization of recoverable and recyclable silica-immobilized atom transfer radical polymerization catalysts. [Doctoral Dissertation]. Georgia Tech; 2005. Available from: http://hdl.handle.net/1853/6860
Georgia Tech
4.
Sommer, William J.
Supported catalysts, from polymers to gold nanoparticles supports.
Degree: PhD, Chemistry and Biochemistry, 2007, Georgia Tech
URL: http://hdl.handle.net/1853/16140
► In today s world, the need to limit the use of nonrenewable resources and the importance of recycling has been recognized. One important contribution of…
(more)
▼ In today s world, the need to limit the use of nonrenewable resources and the importance of
recycling has been recognized. One important contribution of chemists toward the general goal of limiting their use is to find
catalysts that can be reused and recycled thereby limiting the need for expensive metal precursors and metal waste. Strategies to recycle
catalysts are multifold and range from the employment of soluble polymers as catalyst supports to the use of membrane-encapsulated catalyst. The use of soluble polymers as a support not only offers the advantage of being soluble under the catalytic reaction conditions but also, to be removable by changing the conditions of the surrounding media. Despite the great potential of these soluble supported
catalysts, their use is very limited in today s synthesis. In addition, no set of rules have been established to guide the synthesis of efficient supported
catalysts. In order to establish a tool box for the synthesis of supported
catalysts, the study of several parameters such as the choice of the support and the choice and the stability of the catalyst are necessary. To establish this set of rules, a limited number of catalytic transformations, were studied. These catalytic reactions are the Heck-Mizoroki, Suzuki-Miyaura and Sonogashira coupling reactions. These transformations became fundamental for the synthesis of drugs and materials. The first and second chapters provide background information by describing and evaluating the main supports that were previously used for
catalysts and the two main
catalysts that are used in this thesis, the palladium pincer complex and the palladium N-heterocyclic complex. In chapter 3, the synthesis of a soluble polymer supported catalyst is described. The polymer chosen for the study is poly(norbornene), and the catalyst is a 1,3-disubstituted benzene ligand with sulfurs in the side-chains able to chelate to the metal center, better known as pincer ligand. These ligands are abbreviated by the three atoms that coordinate to the metal center, in this study, SCS. The metal used for the investigation of the activity of this supported pincer is palladium. The importance of the nature of the linkage on the stability of the Pd-SCS pincer complex has been reported in the literature, leading to the synthesis of Pd-SCS pincer complex tethered to the polymer via an ether and an amide linkage. The synthesized poly(norbornene) supported Pd-SCS pincer complexes were evaluated using the Heck transformation of iodobenzene with n-butyl acrylate. Kinetic studies and leaching tests using poly(vinyl pyridine) and mercury were carried out resulting in the conclusion that the active species during the catalysis is not the palladium pincer complex but a leached palladium (0) species. In chapter 4, Pd-PCP pincer complexes with the ether and amide tether were synthesized. Kinetic and poisoning studies were carried out resulting in a similar conclusion. Furthermore, 31P NMR experiments were conducted to investigate the unstability of the complex.…
Advisors/Committee Members: Marcus Weck (Committee Chair), Christoph J. Fahrni (Committee Member), Christopher W. Jones (Committee Member), E. Kent Barefield (Committee Member), Mostapha A. El-Sayed (Committee Member).
Subjects/Keywords: Kinetic study; Heck reaction; Coupling chemistry; Poisoning; Suzuki reaction; Catalysts; Supported catalysts; Polymers; Gold nanoparticles; Polymers Synthesis; Water-soluble polymers; Catalysts Recycling
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Sommer, W. J. (2007). Supported catalysts, from polymers to gold nanoparticles supports. (Doctoral Dissertation). Georgia Tech. Retrieved from http://hdl.handle.net/1853/16140
Chicago Manual of Style (16th Edition):
Sommer, William J. “Supported catalysts, from polymers to gold nanoparticles supports.” 2007. Doctoral Dissertation, Georgia Tech. Accessed March 07, 2021.
http://hdl.handle.net/1853/16140.
MLA Handbook (7th Edition):
Sommer, William J. “Supported catalysts, from polymers to gold nanoparticles supports.” 2007. Web. 07 Mar 2021.
Vancouver:
Sommer WJ. Supported catalysts, from polymers to gold nanoparticles supports. [Internet] [Doctoral dissertation]. Georgia Tech; 2007. [cited 2021 Mar 07].
Available from: http://hdl.handle.net/1853/16140.
Council of Science Editors:
Sommer WJ. Supported catalysts, from polymers to gold nanoparticles supports. [Doctoral Dissertation]. Georgia Tech; 2007. Available from: http://hdl.handle.net/1853/16140
5.
McPartland, Jack S.
The extraction of metals from metal containing catalysts by supercritical fluids.
Degree: 1989, University of Nevada – Reno
URL: http://hdl.handle.net/11714/1512
► Experiments were conducted to determine the feasibility of leaching cobalt from a hydrotreating catalyst material using supercritical aqueous ammonia solvents. Supercritical phase leaching conditions were…
(more)
▼ Experiments were conducted to determine the feasibility of leaching cobalt from a hydrotreating catalyst material using supercritical aqueous ammonia solvents. Supercritical phase leaching conditions were attained using a modified Autoclave Engineers Supercritical Screening System. The effects on cobalt extraction caused by variations in solvent composition, pressure and temperature, including subcritical conditions, were investigated. Four series of experiments, each using various solvent compositions ranging from O to 30 percent ammonia at one temperature - pressure condition, were conducted. Cobalt in the catalyst material was leachable at supercritical and subcritical solvent phase conditions. Cobalt extraction at supercritical phase conditions was generally higher than extraction obtained at any of the other pressure – temperature conditions tested. Leaching enhancement at supercritical conditions was determined not to be solely the result of simple pressure or temperature effects. Rather, leaching enhancement is probably caused by the improved transport properties exhibited by supercritical fluid solvents. Cobalt extraction at supercritical conditions was enhanced by an average of 14.2 percent over extraction at supercritical pressure - elevated temperature conditions, 6.8 percent over extraction at low pressure - low temperature conditions, and 4.0 percent over extraction at supercritical pressure - low temperature conditions. Cobalt extraction generally increased with increasing ammonia concentration at all four temperature – pressure conditions tested.
Advisors/Committee Members: Bautista, Renato G. (advisor).
Subjects/Keywords: leaching cobalt; leaching; hydrotreating catalyst material; supercritical aqueous ammonia solvents; Autoclave Engineers Supercritical Screening System; cobalt extraction; solvent composition; subcritical conditions; Mackay Science Project; supercritical fluid extraction; cobalt catalysts; platinum catalysts; metals – recycling – research
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
McPartland, J. S. (1989). The extraction of metals from metal containing catalysts by supercritical fluids. (Thesis). University of Nevada – Reno. Retrieved from http://hdl.handle.net/11714/1512
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
McPartland, Jack S. “The extraction of metals from metal containing catalysts by supercritical fluids.” 1989. Thesis, University of Nevada – Reno. Accessed March 07, 2021.
http://hdl.handle.net/11714/1512.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
McPartland, Jack S. “The extraction of metals from metal containing catalysts by supercritical fluids.” 1989. Web. 07 Mar 2021.
Vancouver:
McPartland JS. The extraction of metals from metal containing catalysts by supercritical fluids. [Internet] [Thesis]. University of Nevada – Reno; 1989. [cited 2021 Mar 07].
Available from: http://hdl.handle.net/11714/1512.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
McPartland JS. The extraction of metals from metal containing catalysts by supercritical fluids. [Thesis]. University of Nevada – Reno; 1989. Available from: http://hdl.handle.net/11714/1512
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
. 
Open Access Theses and Dissertations