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The photodegradation of chlorothalonil, a polychlorinated aromatic fungicide widely used in agriculture, was investigated under ultraviolet-visible irradiation in the presence and absence of different humic substances that significantly enhance the chlorothalonil phototransformation. On the basis of a kinetic model, an analytical study, the effect of scavengers, the chlorothalonil phosphorescence measurement, and varying irradiation conditions, it was possible to demonstrate that this accelerating effect is due to their capacity to reduce the chlorothalonil triplet state via H-donor reaction and to energy transfer from the triplet humic to ground state chlorothalonil. Energy transfer occurs at wavelengths below 450 nm and accounts for up to 30% of the reaction in deoxygenated medium upon irradiation with polychromatic light (300-450 nm). This process is more important with Elliott humic and fulvic acids and with humic acids extracted from natural carbonaceous material than with Nordic NOM and Pahokee peat humic acids. The obtained results are of high relevance to understanding the processes involved in chlorothalonil phototransformation and the photoreactivity of humic substances. Chlorothalonil is one of the rare molecules shown to react by energy transfer from excited humic substances.

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Oxygenated additives have been the subject of much research because they notably improve the fuel characteristics and combustion performance. Moreover, there is a tendency to use oxygenated additives derived from biomass. In the case of glycerol, previous studies have shown that oxygenated compounds are generated by dehydration, decomposition and isomerization reactions from glycerol and its intermediaries, where the selected route of these reactions depends on the type of catalyst used. In this work, the liquid phase obtained during the catalytic glycerol decomposition at 400°C using a basic catalyst was characterized by GC and GC-MS. This phase is constituted mostly by highly oxygenated compounds of known energetic use. After a drying process, the effect of the glycerol condensates as an additive in diesel-biodiesel (B5) engines at the 0.2% (v/v) concentration was evaluated. The physical properties of the fuel and the mechanic, thermodynamic, and environmental performance of the stationary diesel engine were analyzed in the current study. The presence of the additive decreased the pour point of diesel and the amount of particulate matter generated during combustion.

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