Sunlight may lead to changes in disinfection byproducts (DBPs) formation potentials of source water via transforming dissolved organic matter (DOM); however, the underlying mechanisms behind these changes remain unclear. This work systematically investigated the effect of photochemical transformation of DOM from reservoir water (DOM) and micropolluted river water (DOM) after 36 h of simulated sunlight irradiation (equivalent to one month under natural sunlight) on DBPs formation. Upon irradiation, high molecular weight (MW) and aromatic molecules tended to be mineralized or converted into low-MW and highly oxidized (O/C > 0.5) ones which might react with chlorine to generate high levels of DBPs, resulting in an elevation in the yields (μg DBP/mg C) of almost all the measured DBPs and the quantities of unknown DBPs in both DOM samples after chlorination. Additionally, DOM contained more aromatic molecules susceptible to photooxidation than DOM. Consequently, irradiated DOM exhibited a greater increase in the formation potentials of haloacetonitriles, halonitromethanes, and specific regulated DBPs, with nitrogenous DBPs being responsible for the overall rise in the calculated cytotoxicity following chlorination. This work emphasized the importance of a comprehensive removal of phototransformation products that may serve as DBPs precursors from source waters, especially from micropolluted source waters.
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http://dx.doi.org/10.1021/acs.est.3c08155 | DOI Listing |
Org Biomol Chem
January 2025
Henan Key Laboratory of Chemical Biology and Organic Chemistry, Key Laboratory of Applied Chemistry of Henan Universities, Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou 450052, China.
We present a visible-light-promoted radical cascade cyclization reaction sulfonylmethylation, cyano insertion, and radical cyclization of unactivated alkenes bearing cyano groups. This strategy enables the rapid synthesis of sulfonylmethylated phenanthridines under mild conditions with broad substrate compatibility, operational simplicity, and mild reaction conditions. The developed approach provides a novel pathway for assembling complex polycyclic nitrogen-containing frameworks, addressing a critical synthetic challenge and expanding the toolbox of photochemical transformations in organic synthesis.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, The University of Hong Kong, Hong Kong 999077, P. R. China.
Electron donor-acceptor complexes are commonly employed to facilitate photoinduced radical-mediated organic reactions. However, achieving these photochemical processes with catalytic amounts of donors or acceptors can be challenging, especially when aiming to reduce catalyst loadings. Herein, we have unveiled a framework-based heterogenization approach that significantly enhances the photoredox activity of perylene diimide species in radical addition reactions with alkyl silicates by promoting faster and more efficient electron donor-acceptor complex formation.
View Article and Find Full Text PDFAstrobiology
January 2025
Experimental Biophysics and Space Sciences, Department of Physics, Freie Universitaet Berlin, Berlin, Germany.
The (PSS) experiment was part of the European Space Agency's mission and was conducted on the International Space Station from 2014 to 2016. The PSS experiment investigated the properties of montmorillonite clay as a protective shield against degradation of organic compounds that were exposed to elevated levels of ultraviolet (UV) radiation in space. Additionally, we examined the potential for montmorillonite to catalyze UV-induced breakdown of the amino acid alanine and its potential to trap the resulting photochemical byproducts within its interlayers.
View Article and Find Full Text PDFChemSusChem
January 2025
Universita degli Studi di Ferrara, Dipartimento di Scienze Chimiche e Farmaceutiche, Via Borsari 46, 44121, Ferrara, ITALY.
Direct photochemical conversion of CO2 into a single carbon-based product currently represents one of the major issues in the catalysis of the CO2 reduction reaction (CO2RR). In this work, we demonstrate that the combination of an organic photosensitizer with a heptacoordinated iron(II) complex allows to attain a noble-metal-free photochemical system capable of efficient and selective conversion of CO2 into CO upon light irradiation in the presence of N,N-diisopropylethylamine (DIPEA) and 2,2,2-trifluoroethanol (TFE) as the electron and proton donor, respectively, with unprecedented performances (ΦCO up to 36%, TONCO > 1000, selectivity > 99%). As shown by transient absorption spectroscopy studies, this can be achieved thanks to the fast rates associated with the electron transfer from the photogenerated reduced dye to the catalyst, which protect the dye from parallel degradation pathways ensuring its stability along the photochemical reaction.
View Article and Find Full Text PDFOrg Lett
January 2025
Key Laboratory for Green Pharmaceutical Technologies and Related Equipment of Ministry of Education, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, P. R. China.
Herein, a -phenylphenothiazine-based hyper-cross-linked polymer (PTH-HCP) was finely designed and constructed, which serves as a metal-free heterogeneous photocatalyst for organic transformations. Characterization experiments have shown that this polymer demonstrates outstanding stability, extensive surface area, and exceptional photoelectric response properties. Moreover, PTH-HCP showed good catalytic efficiency and recyclability in the photochemically driven difluoromethylation/cyclization reactions.
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