Hydrogen Peroxide Generation in Divided-Cell Trickle Bed Electrochemical Reactor

2017 ◽  
Vol 56 (39) ◽  
pp. 11058-11064 ◽  
Author(s):  
Ghassan H. Abdullah ◽  
Yangchuan Xing
2017 ◽  
Author(s):  
◽  
Ghassan Hamad Abdulla

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Crude oil contains natural organic components such as organosulfur compounds, and these compounds largely remain in refined petroleum products such as gasoline, diesel and jet fuel products. During fuel combustion, sulfur was emitted as sulfur dioxide or sulfate, which is one of the main causes of air pollution and acid rain. The oil price is inversely proportional to the sulfur content because upgrade of heavy, high-sulfur-containing oil is much more difficult than the light feeds. Many regulations have been established by different countries to control sulfur level in fuels; in the U.S. the maximum required concentration is 15 ppm (parts per million) sulfur in diesel. The most commonly used technology to remove sulfur from diesel fuel is hydrodesulfurization (HDS). The major drawback of HDS is the harsh operating conditions that require high temperatures and pressures with consumption of a large amount of hydrogen. The HDS process is only able to reduce sulfur content to about 500 ppm in diesel. Further reduction requires more intense processing with a significant increase in hydrogen usage, particularly in removing the refractory sulfur compounds, such as benzothiophene (BT), dibenzothiophene (DBT), and their alkyl derivatives. In this dissertation, an efficient and cost-effective process for oxidation of organosulfur compounds (OSCs) in diesel has been developed and investigated. A divided-cell trickle bed electrochemical reactor (TBER) was first developed to produce hydrogen peroxide. The divided-cell trickle bed electrochemical reactor (TBER) has a porous cathode composed of carbon black and polytetrafluoroethylene. It was designed and fabricated to have hydrophobic and hydrophilic components for liquid and gas flows. Hydrogen peroxide generation was successfully demonstrated from reducing oxygen in concentrated alkaline electrolyte solutions. An important feature of the reactor was a cathode made with stainless steel meshes that divide it into four packed-bed cells. This division into sectional cathode resulted in a concentration of hydrogen peroxide that more than doubles that produced in an undivided cathode. The much-improved performance was attributed to the even distribution of the electrolyte and oxygen in the cathode bed, as well as an effective mass transport of oxygen from the gas phase to the electrolyte-cathode interface. After the successful production of hydrogen peroxide, the TBER was employed for in situ oxidation desulfurization of diesel fuel. The possibility of diesel desulfurization with in situ generated hydrogen peroxide in the presence of DBT was systematically investigated. The maximum concentration of hydrogen peroxide after two-hour electrolysis was 31.79 mM without diesel, whereas in the presence of 10% diesel (by volume) in the electrolyte was 18.0 mM. DBT was successfully oxidized in situ in the TBER, with conversion efficiency of 97.75% in six hours. To further improve the efficiency of the hydrogen peroxide production, cathode was modified with MnO2, a potentially more active catalyst for hydrogen peroxide production in alkaline electrolytes. It was found that incorporation of MnO2 indeed promoted in situ oxidation of DBT which was attributed to more hydrogen peroxide produced. The results showed the in situ oxidation process in the divided-cell TBER is a promising and environmentally friendly approach for desulfurization of diesel.


Author(s):  
Yangming Lei ◽  
Hong Liu ◽  
Chengchun Jiang ◽  
Zhemin Shen ◽  
Wenhua Wang

AbstractA trickle bed electrochemical reactor was used to generate hydrogen peroxide in dilute electrolyte and then degrade an azo dye, i.e. reactive brilliant red X-3B in water by electro-Fenton process. The trickle bed reactor was composed of carbon black-polytetrafluoroethylene coated graphite chips. During the preparation of coated graphite chips, coating times and surfactant dosage were optimized to improve electro-generation of H


ACS Catalysis ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 2454-2459
Author(s):  
Zhe Wang ◽  
Qin-Kun Li ◽  
Chenhao Zhang ◽  
Zhihua Cheng ◽  
Weiyin Chen ◽  
...  

Redox Biology ◽  
2021 ◽  
Vol 43 ◽  
pp. 101980
Author(s):  
Andree G. Pearson ◽  
Juliet M. Pullar ◽  
John Cook ◽  
Emma S. Spencer ◽  
Margreet CM. Vissers ◽  
...  

2003 ◽  
Vol 279 (3) ◽  
pp. 1665-1675 ◽  
Author(s):  
Juan A. Rosado ◽  
Pedro C. Redondo ◽  
Ginés M. Salido ◽  
Emilio Gómez-Arteta ◽  
Stewart O. Sage ◽  
...  

1991 ◽  
Vol 18 (2) ◽  
pp. 133-143 ◽  
Author(s):  
Hiroshi Ogasawara ◽  
Shiro Yoshimura ◽  
Takeo Kumoi

2019 ◽  
Vol 74 (3-4) ◽  
pp. 101-104 ◽  
Author(s):  
Milja Pesic ◽  
Sébastien Jean-Paul Willot ◽  
Elena Fernández-Fueyo ◽  
Florian Tieves ◽  
Miguel Alcalde ◽  
...  

Abstract There is an increasing interest in the application of peroxygenases in biocatalysis, because of their ability to catalyse the oxyfunctionalisation reaction in a stereoselective fashion and with high catalytic efficiencies, while using hydrogen peroxide or organic peroxides as oxidant. However, enzymes belonging to this class exhibit a very low stability in the presence of peroxides. With the aim of bypassing this fast and irreversible inactivation, we study the use of a gradual supply of hydrogen peroxide to maintain its concentration at stoichiometric levels. In this contribution, we report a multienzymatic cascade for in situ generation of hydrogen peroxide. In the first step, in the presence of NAD+ cofactor, formate dehydrogenase from Candida boidinii (FDH) catalysed the oxidation of formate yielding CO2. Reduced NADH was reoxidised by the reduction of the flavin mononucleotide cofactor bound to an old yellow enzyme homologue from Bacillus subtilis (YqjM), which subsequently reacts with molecular oxygen yielding hydrogen peroxide. Finally, this system was coupled to the hydroxylation of ethylbenzene reaction catalysed by an evolved peroxygenase from Agrocybe aegerita (rAaeUPO). Additionally, we studied the influence of different reaction parameters on the performance of the cascade with the aim of improving the turnover of the hydroxylation reaction.


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