Open Access. Powered by Scholars. Published by Universities.®
Articles 91 - 98 of 98
Full-Text Articles in Entire DC Network
Dehydration Of Ethanol To Diethyl Ether Over Beta Zeolite Catalysts, Montri Thapplee
Dehydration Of Ethanol To Diethyl Ether Over Beta Zeolite Catalysts, Montri Thapplee
Chulalongkorn University Theses and Dissertations (Chula ETD)
The catalytic ethanol dehydration to diethyl ether was investigated using synthesized beta zeolite catalysts having different Na and mixed Na-H form. The Na form in catalyst was synthesized by the hydrothermal process including non-calcined (Na-BEA_N) and calcined (Na-BEA_C) catalysts. The catalysts having different mixed Na-H forms were synthesized under ion-exchange method. In this study, two different cycles were chosen including one cycle (M-BEA_1) and four cycles (M-BEA_4). These catalysts were characterized by various techniques. The catalysts were tested to measure the catalytic activity at atmospheric pressure and the reaction temperature ranged from 150 to 400 °C. The results presented that …
Electrode Improvement Using Diamond-Like Carbon For Electrochemical Advanced Oxidation In Diuron Degradation, Nimit Kantiyawong
Electrode Improvement Using Diamond-Like Carbon For Electrochemical Advanced Oxidation In Diuron Degradation, Nimit Kantiyawong
Chulalongkorn University Theses and Dissertations (Chula ETD)
Diuron is one of the pesticides. Its residual can contaminate natural water resource resulting in environmental and human health problems. Several processes have been used to remove diuron contamination. Nowadays, an electrochemical advanced oxidation process (EAOP) in a microchannel reactor is used to degrade diuron owing to its high efficiency. In this research, the diamond-like carbon (DLC) thin film was used as an electrochemical electrode because it has superior hardness and electrical conductivity. In this research, we have successfully synthesized the DLC thin films using graphite as target material on the surface of 304 stainless steel substrate by the direct …
The Development Of Pt/Wox/Al2o3 For 1,3-Propanediol Production From Glycerol, Parama Uttraporn
The Development Of Pt/Wox/Al2o3 For 1,3-Propanediol Production From Glycerol, Parama Uttraporn
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this work, the researcher studied the hydrogenolysis of glycerol to 1,3-propanediol, by compared the catalytic activity between AlOOH (boehmite) and g-Al2O3. The catalysts were prepared by wet impregnation method. To investigate the properties, catalysts were characterized by XRD, XPS, BET, H2-TPR, H2-TPD, H2-TPR, SEM-EDX, Py-IR, NH3-IR, and XAS. The type of support showed to be of significance in deciding the activity and the selectivity to 1,3-propanediol. It was found that 2%Pt/WOx/g-Al2O3 gave higher activity and selectivity of 1,3-propanediol, which due to a large amount of active site and Brønsted acid site in the catalyst. The effects of H2 pressure, …
Dual-Electrolyte System For Suppressing Corrosion Of Aluminum Electrode In Aluminum-Air Flow Battery, Pemika Teabnamang
Dual-Electrolyte System For Suppressing Corrosion Of Aluminum Electrode In Aluminum-Air Flow Battery, Pemika Teabnamang
Chulalongkorn University Theses and Dissertations (Chula ETD)
Aluminum-air batteries have received considerable attention as an electrical power source due to their theoretical specific capacity reaching 2.98 Ah/g. Further, Al-air batteries are abundant and low cost. On the other hand, the aluminum in the batteries has a problem, such that it is subject to self-corrosion in alkaline. Herein, this work concentrates on the aluminum's corrosive behavior and self-corrosion in methanol-3M KOH mixed solution containing different percentages of deionized water i.e. (0, 5, 10 and 20)%wt, using electrochemical (half-cell testing). The aluminum-air battery consists of: aluminum anode | anolyte | anion exchange membrane | catholyte | air cathode. The …
The Effect Of Mcm-41 Addition To Pva/Pan/Pvp Polymer Electrolyte For Zinc-Air Batteries, Sirinuch Nanthapong
The Effect Of Mcm-41 Addition To Pva/Pan/Pvp Polymer Electrolyte For Zinc-Air Batteries, Sirinuch Nanthapong
Chulalongkorn University Theses and Dissertations (Chula ETD)
A membrane separator is one of the main components in zinc-air batteries playing an important role in controlling the mass transfer for the electrochemical reaction in the battery which determines the battery performance. This work aimed to develop a new membrane separator for the zinc-air battery. Polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), and their blends were used for the fabrication of separator in this work. In addition, an inorganic nanoparticle with high hydroxide content such as MCM-41 was also applied as the filler for the polymers. The results revealed that the addition of PAN in PVA enhanced the electrolyte …
Improving The Efficiency Of Dye-Sensitized Solar Cells With Ultrasonic Spray-Coated Tio2 Electrode That Was Modified By Mno2, Coo, Or Sno2, Supasun Thanadvanichkul
Improving The Efficiency Of Dye-Sensitized Solar Cells With Ultrasonic Spray-Coated Tio2 Electrode That Was Modified By Mno2, Coo, Or Sno2, Supasun Thanadvanichkul
Chulalongkorn University Theses and Dissertations (Chula ETD)
This research investigated the modification of TiO2 electrode by adding the second metal oxide, namely, manganese dioxide (MnO2), cobalt oxide (CoO), or tin dioxide (SnO2) use in for dye-sensitized solar cell (DSSCs). TiO2 and modified TiO2 sols were synthesized via sol-gel methods. The sols were sprayed 500 times onto the fluorine-doped tin oxide glass substrates as a thin film using an ultrasonic spray coater. Finally, the thin film electrode was calcined at 400ºC for two hours. The amount of MnO2, CoO, or SnO2 was varied at 0, 0.1, 0.5, 1.0, and 3.0%wt. The photovoltaic efficiency of DSSCs was measured using …
Effect Of Tio2 Polymorphs And Crystallite Size On The Catalytic Properties Of Pt/Tio2 In The Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Thunyaporn Kaewla-Ueat
Effect Of Tio2 Polymorphs And Crystallite Size On The Catalytic Properties Of Pt/Tio2 In The Selective Hydrogenation Of Furfural To Furfuryl Alcohol, Thunyaporn Kaewla-Ueat
Chulalongkorn University Theses and Dissertations (Chula ETD)
Furfuryl alcohol (FA) is an important intermediate for the manufacturing of many fine chemical products such as furan, resin, vitamin C, and lysine. In this research, the selective hydrogenation of furfural to FA was carried out in a batch reactor at 50ºC, 20 bar H2 and 2 h reaction time using Pt (0.5 wt. %) on TiO2 support. The Pt/TiO2 catalysts were prepared by the incipient wetness impregnation on different commercial TiO2 polymorphs and different temperatures calcined TiO2 sol-gel. Among the commercially available TiO2, it was found that Pt supported on P25 exhibited the highest furfural conversion and selectivity of …
Analysis And Design Of Vanadium Redox Flow Battery, Tossaporn Jirabovornwisut
Analysis And Design Of Vanadium Redox Flow Battery, Tossaporn Jirabovornwisut
Chulalongkorn University Theses and Dissertations (Chula ETD)
In this study, the dynamic model of a vanadium redox flow battery (VRFB) was developed to analyze the battery performance and capacity degradation caused by an electrolyte imbalance from hydrogen and oxygen evolution and self-discharge side reactions. The model-based analysis of the VRFB performance revealed that the rate of battery capacity loss resulting from the electrolyte imbalance considerably depended on electrode and membrane material as well as operating conditions. Self-discharge reactions were controlled by the operational time of the battery. In addition, the rate of capacity degradation increased with an increase in the total vanadium concentration and operating temperature, affecting …