Search results for "UV–vis spectroscopy"
showing 2 items of 2 documents
Unraveling long-term changes in lake color based on optical properties of lake sediment
2020
A number of boreal surface waters have become browner over the last two decades. Recovery from acid rain is regarded as an important driver for this lake color increase, indicating a general browner lake color in preindustrial times. However, the lack of long-term monitoring data makes it challenging to unravel historical changes in lake color. In this study, we estimated long-term development in lake color (1800 to 2015) based on the optical properties of alkaline extractable dissolved organic matter (DOM) from sediment using UV–Vis and fluorescence spectroscopy. We found that the present lake color (2015) was significantly browner (four times higher in absorption coefficient) than for the…
Sulfur Dioxide Oxidation Catalyzed by Photosensitized Ytterbium Diphthalocyanine
2008
Oxidation of SO2 into SO3 was found effectively catalyzed by photosensitized ytterbium diphthalocyanine, YbPc2 (Pc = phthalocyanine ligand, C32H16N8) when performed in air-saturated dimethylformamide (DMF) solution at 20 °C. The process follows according to a multi-step complex mechanism involving chemical induction as its driving force. Excitation energy of the sandwich molecular system in YbPc2 is used to promote the reaction by creating a reactive intermediate form of the ytterbium complex hosting up to eight SO2 molecules. The conversion of SO2 proved complete.