Development of new photochemical reaction model for predicting water quality transformation efficiency

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H01462
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Yoshimura Chihiro 東京工業大学, 環境・社会理工学院, 教授 (10402091)
• Co-Investigator(Kenkyū-buntansha): 佐野 大輔 東北大学, 工学研究科, 教授 (80550368)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 光化学反応 / ラジカル / 溶存有機物 / 光学特性 / 微量有機汚染物質

Outline of Final Research Achievements

Indirect photolysis via radicals is poorly understood for water quality control in aquatic environments. The objective of this study was to develop a photochemical reaction model to predict the quantum yield of radical photoproduction by focusing on the photochemical properties of dissolved organic matter. It allows us to describe and predict the conversion efficiency of persistent substances and pathogenic microorganisms in water. Chemical analyses and photochemical experiments were conducted for surface waters collected from dam reservoirs, lakes, and coastal areas throughout Japan to model the quantum yields of excited triplet dissolved organic matter and singlet oxygen. The results showed that they can be accurately estimated based on their optical properties, and novel photochemical reaction models were developed for accurate estimation of photodegradation in various water environments.

Free Research Field

環境光化学

Academic Significance and Societal Importance of the Research Achievements

水環境に蓄積する難分解性物質については光化学反応が水環境中の主な分解プロセスであると言われている。そこで、水中の難分解性物質や病原微生物に対する変換効率を予測するために、溶存有機物の光特性に着目して、ラジカルの光生成の量子収率を予測する光化学反応モデルを構築した。その結果、量子収率は光学特性に基づき精度良く推測できることが示され、多様な水環境における光分解を精度良く推定できる新規光化学反応モデルが構築された。これにより、水環境中の難分解性物質や病原微生物の定量的な管理、そして、水処理過程におけるそれらの分解効率の予測のための基盤となる知見を得た。