Mora Verónica C, Rosso Janina A, Carrillo Le Roux Galo, Mártire Daniel O, Gonzalez Mónica C
Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas, Facultad de Ciencias Exactas, Universidad Nacional de La Plata, CONICET. C.C. 16, Suc. 4, (1900) La Plata, Argentina.
Chemosphere. 2009 Jun;75(10):1405-9. doi: 10.1016/j.chemosphere.2009.02.038. Epub 2009 Mar 13.
The kinetics and mechanism of the thermal activation of peroxydisulfate, in the temperature range from 60 to 80 degrees C, was investigated in the presence and absence of sodium formate as an additive to turn the oxidizing capacity of the reaction mixture into a reductive one. Trichloroacetic acid, TCA, whose degradation by a reductive mechanism is well reported in the literature, was used as a probe. The chemistry of thermally activated peroxydisulfate is described by a reaction scheme involving free radical generation. The proposed mechanism is evaluated by a computer simulation of the concentration profiles obtained under different experimental conditions. In the presence of formate, SO(4)(-) radicals yield CO(2)(-), which are the main species available for degrading TCA. Under the latter conditions, TCA is more efficiently depleted than in the absence of formate, but otherwise identical conditions of temperature and [S(2)O(8)(2-)]. We therefore conclude that activated peroxydisulfate in the presence of formate as an additive is a convenient method for the mineralization of substrates that are refractory to oxidation, such as perchlorinated hydrocarbons and TCA. This method has the advantage that leaves no toxic residues.
在60至80摄氏度的温度范围内，研究了过二硫酸盐热活化的动力学和机理，研究是在添加和不添加甲酸钠的情况下进行的，添加甲酸钠是为了将反应混合物的氧化能力转变为还原能力。文献中已充分报道了通过还原机理降解的三氯乙酸（TCA）被用作探针。热活化过二硫酸盐的化学过程由一个涉及自由基生成的反应方案描述。通过对在不同实验条件下获得的浓度分布进行计算机模拟，对所提出的机理进行了评估。在甲酸盐存在的情况下，硫酸根自由基（SO(4)(-)）生成甲酸根离子（CO(2)(-)），这是可用于降解TCA的主要物质。在上述条件下，与不存在甲酸盐但温度和过二硫酸盐浓度（[S(2)O(8)(2-)]）相同的情况相比，TCA的消耗效率更高。因此，我们得出结论，在添加甲酸盐的情况下，活化过二硫酸盐是一种方便的方法，可用于使难氧化的底物（如全氯烃和TCA）矿化。该方法的优点是不会留下有毒残留物。
