2019 Fiscal Year Annual Research Report
太陽光を利用した水中細菌の新規光触媒処理システムの開発
| Project/Area Number |
18J20620
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| Research Institution | University of Tsukuba |
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Principal Investigator |
LIU NA 筑波大学, 生命環境科学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2018-04-25 – 2021-03-31
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| Keywords | Photocatalyst / Visible-light-driven / Water disinfection / Various bacteria / Glue immobilization |
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| Outline of Annual Research Achievements |
During the second fiscal year of my research, in order to develop a continuous-cycle sterilization system with efficient photocatalytic disinfection ability, the study was carried out through the following three key points. (1) Evaluate the photocatalytic inactivation ability on four kinds pathogenic microorganisms in slurry reactor. (2) Construct a glue-immobilized photocatalyst reactor based on P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst. (3) Investigate the stability and reusability of the developed glue-immobilized photocatalyst reactor for the continuous-cycle water disinfection.
The results showed the novel P/Ag/Ag2O/Ag3PO4/TiO2 composite could effectively inactivate various bacteria under visible light irradiation. Even under dark condition, the new composite also have sterilization ability on Gram-negative bacteria. More importantly, the developed glue-immobilized photocatalyst reactor based on the novel composite has shown excellent stability and reusability, suggesting it being readily applicable for continuous water treatment system.
The present results have been presented at 5 conferences and also been published in three international Journals as the co-author.
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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 FY 2019, with the aim of " developing a continuous-cycle sterilization system with efficient photocatalytic disinfection ability", a glue-immobilized photocatalyst reactor based on our novel visible-light-driven P/Ag/Ag2O/Ag3PO4/TiO2 composite was successfully developed with excellent stability and reusability. According to the previous studies, the novel visible-light-driven P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst, firstly synthesized by our lab, has demonstrated remarkable disinfection ability on two different types of microorganisms (E. coli and Enterococcus sp.) both in single and mixed bacteria system. Therefore, in this fiscal year, in order to further test its practical application ability on various microorganisms, another two kinds pathogenic bacteria (Salmonella and Staphylococcus aureus) which were separated from real wastewater plant were used to further evaluate the disinfection ability of P/Ag/Ag2O/Ag3PO4/TiO2 composite. Moreover, in order to solve the tedious post-separation problem by using the photocatalyst powder for disinfection and further scale up the present disinfection system, a glue-immobilized photocatalytic reactor was successfully developed based on P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst for the continuous-cycle water disinfection.
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| Strategy for Future Research Activity |
During the previous two fiscal years research, the novel P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst has shown remarkable disinfection ability for different kinds water pathogen bacteria under visible light irradiation. And the possible disinfection mechanism by this new photocatalyst under light condition was also systemically studied. According to recently experiment results, an interesting finding was that even under dark condition, our new composite also have sterilization ability on gram-negative bacteria. Therefore, during this fiscal year, a series experiments will be conducted to clarify the possible photocatalytic disinfection mechanism of P/Ag/Ag2O/Ag3PO4/TiO2 composite under dark condition. On the other hand, during my last fiscal year research, a glue-immobilized photocatalyst reactor has been successfully developed with excellent stability and reusability. Hence, in this fiscal year, following the research plan, the optimum conditions of the developed glue-immobilized photocatalyst reactor for the continuous-cycle water disinfection will be established. With the advantages of simple preparation, easy operation and high efficiency, this developed glue-immobilized photocatalytic reactor based on the novel visible-light-driven P/Ag/Ag2O/Ag3PO4/TiO2 photocatalyst will have great potential for the practical large-scale water sterilization.
Based on the above experiments, the results will be summarized and presented on conferences. Also, the research paper will be summarized and submitted to the international journal.
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