Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Casilla de Correo 16, Sucursal 4, 1900 La Plata, Argentina.
Chemosphere. 2011 Aug;84(9):1270-5. doi: 10.1016/j.chemosphere.2011.04.062. Epub 2011 May 23.
The ability of thermal activated peroxydisulfate (PS) of mineralizing phenol at 70°C from contaminated waters is investigated. Phenol in concentrations of 10(-4) to 5×10(-4)M is quantitatively depleted by 5×10(-3) to 10(-2)M activated PS in 15 min of reaction. However, mineralization of the organic carbon is not observed. Instead, an insoluble phenol polymer-type product is formed. A reaction mechanism including the formation of phenoxyl radicals and validated by computer simulations is proposed. High molecular weight phenolic products are formed by phenoxyl radical H-abstraction reactions. This is not the case for the room temperature degradation of phenol by sulfate radicals where sulfate addition to the aromatic ring mainly leads to the generation of hydroxycyclohexadienyl radicals leading to hydroxybenzenes and oxidized open chain products. Therefore, a change in the reaction mechanism is observed with increasing temperature, and thermal activation of PS at 70°C does not lead to the mineralization of phenol. Thus PS activation at 70°C may be considered a potential method to reduce the load of phenol in polluted waters by polymerization.
研究了在 70°C 下热激活过二硫酸盐 (PS) 矿化受污染水中苯酚的能力。在 15 分钟的反应中，浓度为 10(-4) 至 5×10(-4)M 的苯酚被 5×10(-3) 至 10(-2)M 的激活 PS 定量消耗。然而，没有观察到有机碳的矿化。相反，形成了不溶性的苯酚聚合物型产物。提出了一种包括酚氧自由基形成的反应机制，并通过计算机模拟进行了验证。高相对分子质量的酚类产物是通过酚氧自由基的 H 原子夺取反应形成的。对于室温下硫酸盐自由基降解苯酚的情况则不是如此，其中硫酸盐主要加成到芳环上，主要生成羟基环己二烯基自由基，导致生成羟基苯和氧化开链产物。因此，随着温度的升高，反应机制发生了变化，70°C 下 PS 的热激活不会导致苯酚的矿化。因此，70°C 下 PS 的激活可以被认为是通过聚合减少受污染水中苯酚负荷的潜在方法。
