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首页> 外文期刊>Journal of industrial and engineering chemistry >An analysis method for degradation kinetics of lowly concentrated PAH solutions under UV light and ultrasonication
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An analysis method for degradation kinetics of lowly concentrated PAH solutions under UV light and ultrasonication

机译：紫外光和超声作用下低浓度多环芳烃溶液降解动力学的分析方法

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Degradation of lowly concentrated PAHs with small numbered aromatic rings has been investigated in aspect of kinetics under irradiation energy such as UV and ultrasonication. The conventional kinetic analysis for both of phenanthrene and pyrene showed that their degradation simply followed a pseudo first order reaction regime at the low bulk concentrations of the PAHs. Meanwhile, overall reaction orders estimated on a basis of half-life time were 0th for phenanthrene and -0.4th for pyrene, regardless of any energy irradiation, respectively. The discrepancy arising from these two analyses on reaction orders might suggest that there could be a certain 'molecular agglomeration' in extremely dilute solutions containing 'solvent-repellent solute molecules.' Also the ring cleavage reaction was found to be more retarded with higher ring numbers even if the rate gaps were small. Those findings drove us to speculate that hydrophobicity could increase as the hydrophobic PAH molecules swamped in order to form some kind of agglomerates. Consequently, the agglomeration and the number of aromatic rings were likely to be closely related to higher hydrophobicity exerted by them. Under this postulation we demonstrated an explanation that the reaction rate constants would decrease with increasing number of molecules partly due to agglomeration of hydrophobic molecules in aqueous environment. Ultrasonic irradiation was less effective than UV photolysis possibly owing to the larger energy dissipation.
机译：在辐射能（如紫外线和超声波）下的动力学方面，已经研究了具有少量芳环的低浓度PAHs的降解。菲和pyr的常规动力学分析表明，它们的降解简单地遵循了在低堆积浓度的PAHs下的拟一级反应机制。同时，以半衰期为基础估计的总反应阶数对于菲为0，对于pyr为-0.4，而与任何能量辐射无关。这两种分析在反应顺序上的差异可能表明，在含有“排斥溶剂的溶质分子”的极稀溶液中，可能存在一定的“分子团聚”。另外，即使速率差距较小，也发现在较高的环数下，环裂解反应更受阻。这些发现促使我们推测，疏水性可能会随着疏水性PAH分子的浸入而增加，从而形成某种附聚物。因此，团聚和芳环的数目很可能与它们施加的较高的疏水性密切相关。在这种假设下，我们证明了一种解释，即反应速率常数将随着分子数量的增加而降低，部分原因是由于水性环境中疏水性分子的团聚。超声波辐照不如紫外线光解有效，这可能是因为能量散布更大。

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