東京工業大学 · Environmental Science
Manabu Fujii 교수의 연구실은 자연유기물(NOM)의 화학적 반응성과 금속 이온(특히 철)과의 상호작용을 중심으로 한 환경화학 및 광화학 반응 메커니즘을 연구합니다. 특히, 철 이온의 생물가용성, 광화학적 전환, 그리고 자연물질 내에서의 반응성 변화를 고해상도 질량분석 및 동위원소 표지 기법을 통해 규명하고 있습니다. 연구는 환경 내 금속 순환, 수질 정화, 그리고 유해 조류의 생장 조절 등 실제 환경 문제 해결에 기여하고자 합니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Thermodynamic and kinetic parameters for ferric iron (Fe[III]) complexation by well-characterized humic substances (HS) from various origins were determined by a competitive ligand method with 5-sulfosalicylic acid at circumneutral pH (6.0-8.0) and an ionic strength of ∼0.06 M. The measured Fe binding properties including conditional stability constants and complexation capacities ranged over more than 2 orders of magnitude, depending on the origin and the particular operationally defined fracti
Brominated and/or chlorinated organic compounds (referred to as organohalogens) are frequently detected in natural and engineered environments. However, ultrahigh-resolution mass spectrometry (UHR-MS)-based nontargeted identification of organohalogens remains challenging because of the coexistence of a vast number of halogenated and nonhalogenated organic molecules. In this study, a new algorithm, namely, the NOMDBP code, was developed to simultaneously identify organohalogens and non-organohalo
Increasing the evaporation zone inside the solar distiller (SD) is a pivotal method for augmenting its freshwater production. Hence, in this work, a newly designed prismatic absorber basin covered by linen wicks was utilized instead of the conventional flat absorber basin to increase the surface area of the vaporization zone in a double-slope solar distiller (DSSD). Meanwhile, for further enhancement of modified DSSD performance, dual parallel spraying nozzles are incorporated underneath the gla
Visible light was observed to induce reductive dissociation of organically complexed Fe and dramatically increase the short-term uptake rate of radiolabeled Fe by Microcystis aeruginosa PCC7806 in Fraquil* medium buffered by a single metal chelator, ethylenediaminetetraacetic acid (EDTA). Only wavelengths <500 nm activated Fe uptake indicating that Fe photochemistry rather than biological factors is responsible for the facilitated uptake. The measured rate of photochemical Fe(II) production comb
Isotopically labeled FT-ICR-MS combined with multiple post-analyses, including interpretable machine learning (IML) and a paired mass distance (PMD) network, was employed to unravel the reactivity and transformation of natural organic matter (NOM) during ultraviolet (UV) irradiation. FT-ICR-MS analysis was used to assign formulas, which were classified on the basis of their molecular compositions and structural categories. Isotope (deuterium, D) labeling was utilized to unequivocally determine t
We have investigated the mechanism of Fe uptake by a toxic strain of the freshwater cyanobacterium Microcystis aeruginosa (PCC7806) with particular attention given to the effect of Fe(II) and Fe(III) transformation kinetics on Fe uptake. Chemiluminescence analysis revealed that M. aeruginosa produces extracellular superoxide (a moderate Fe reducing agent) at rates of 0.4-1.2 amol cell(-1) h(-1) depending on initial Fe concentration in the culture medium. Short-term assimilation assays using (55)
We have investigated the kinetics of superoxide-mediated dissolution of amorphous ferric oxyhydroxide (AFO) in seawater by spectrophotometrically examining the rate of formation of a ferrous-ferrozine complex (Fe(II)(FZ)3) with particular attention given to the effect of aging and iron concentration on the rate of superoxide-mediated dissolution of AFO. The production rates of Fe(II)(FZ)3 decreased with aging of AFO for iron concentrations from 50 to 500 nM, indicating that changes to the chemic
