2021 Fiscal Year Annual Research Report
Complete elimination with a combined system of aerobic granular sludge and photocatalytic technology for the treatment of petroleum refinery wastewater
| Project/Area Number |
21J10826
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| Research Institution | University of Tsukuba |
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Principal Investigator |
MING Jie 筑波大学, 生命環境科学研究科, 特別研究員(DC2)
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| Project Period (FY) |
2021-04-28 – 2023-03-31
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| Keywords | Water disinfection / Photocatalysis / Safety and stability / Public health |
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| Outline of Annual Research Achievements |
In this fiscal year, to investigate the photocatalytic performance and mechanism of Ag/Ag2O/BiPO4/Bi2WO6, the study was conducted according to following four key points. (1) Investigate the disinfection performance of Ag/Ag2O/BiPO4/Bi2WO6 toward E. coli under simulated solar light irradiation; (2) Clarify the disinfection mechanism of Ag/Ag2O/BiPO4/Bi2WO6 from the bactericidal process and major active species; (3) Evaluate the practicability of Ag/Ag2O/BiPO4/Bi2WO6 for environmental water disinfection from the effects of various environmental factors; (4) Explore the safety and stability of Ag/Ag2O/BiPO4/Bi2WO6 for water disinfection. The results showed the photocatalyst showed remarkable bactericidal efficiency toward E. coli under simulated solar light irradiation. For the disinfection mechanism, the results demonstrated the deteriorated antioxidant system was responsible for the damaged cell membrane, which further led to the leakage of intracellular components and final collapse of bacteria. The photogenerated active species including superoxide radicals and holes played major roles in bactericidal process. In addition, the composite exhibited high adaptability for water disinfection at a wide range of environmental factors including light intensity, temperature, pH and humic acid. The slight release of Ag+ and high stability of photocatalysts further implied its great potential for application. The current research could contribute to further improve the public health level around the world.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In this fiscal year, the photocatalytic performance and mechanism of Ag/Ag2O/BiPO4/Bi2WO6 was investigated using the Escherichia coli (E. coli) as the model bacteria, simulated solar light as the light source. The study was conducted following the four keys: (1) The disinfection performance of Ag/Ag2O/BiPO4/Bi2WO6 toward E. coli under simulated solar light irradiation was studied; (2) The disinfection mechanism of E. coli inactivated by Ag/Ag2O/BiPO4/Bi2WO6 was clarified from the bactericidal process and major active species; (3) The practicability of Ag/Ag2O/BiPO4/Bi2WO6 for environmental water disinfection was evaluated from the effects of various environmental factors (light intensity, pH, temperature and humic acid); (4) The safety and stability of Ag/Ag2O/BiPO4/Bi2WO6 for water disinfection was explored. And the results indicated the great potential of Ag/Ag2O/BiPO4/Bi2WO6 composite for environmental water disinfection, which could contribute to further improve the public health level around the world.
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| Strategy for Future Research Activity |
After investigating the photocatalytic performance and mechanism, the solar-light-driven photocatalytic film continuous system will be developed for water treatment. And the research will go through the following two steps.
(1) Development of solar-light-driven photocatalytic film system for water purification.
(2) Construction and evaluation of the combined system with aerobic granular sludge and photocatalytic technology for water treatment.
In this fiscal year, following the research plan, a solar-light-driven photocatalytic film system for water purification will be developed. And then the performance of combined system will be evaluated for water treatment. According to most researches, the practical application of photocatalytic technology is limited by the difficulty of photocatalyst recovery. So, it is essential to develop an immobilized photocatalytic system for water purification. According to the previous studies, our lab developed the polyethylene glycol modified photocatalytic thin film, which exhibited higher photocatalytic activity and stability. Therefore, based on these, a solar-light-driven photocatalytic thin film system using polyethylene glycol as binder agent for water purification will be developed. And the combined system will be constructed and evaluated for water treatment.
Based on the above experiments, the results will be summarized and presented on conferences. In addition, the research paper will be summarized and submitted to the international journal.
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