Department of Biotechnology, Chemistry and Environmental Engineering, Aalborg University, Niels Bohrs Vej 8, DK-6700 Esbjerg, Denmark.
Chemosphere. 2012 Mar;86(11):1092-7. doi: 10.1016/j.chemosphere.2011.12.011. Epub 2012 Jan 2.
Chloride and carbonates have the potential to impact pathway, kinetics, and efficiency of oxidation reactions, both as radical scavengers and as metal complexing agents. Traditionally, it is assumed that they have an overall negative impact on the activated persulfate performance. This study investigated the influence of carbonates and chloride on the reactivity of persulfate for three different activation techniques to produce reactive free sulfate radicals; heat, alkaline and iron activation. By using p-nitrosodimethylaniline as model target compound, it was demonstrated that iron activation at neutral pH was not affected by Cl(-) or HCO(3)(-), alkaline activation was enhanced by Cl(-) and even more by CO(3)(2-), and heat activation was enhanced by Cl(-), and no effect from HCO(3)(-) was observed. At pH 2 destruction of perchloroethylene by iron activated persulfate was significantly affected by chloride. Reaction rates decreased, but the overall oxidation efficiency was unaffected up to 28 mM Cl(-). The effect of chloride and carbonates is caused by direct attack of produced reactive chlorine, or carbonate species or by catalysis of the propagation reactions resulting in more sulfate radicals. These results show that carbonate and chloride might play an important role in activated persulfate applications and should not strictly be considered as scavengers.
氯盐和碳酸盐有可能影响氧化反应的途径、动力学和效率，既是自由基清除剂，又是金属络合剂。传统上，人们认为它们对过硫酸盐的活性有整体的负面影响。本研究考察了碳酸盐和氯盐对三种不同的过硫酸盐活化技术产生的活性游离硫酸根自由基的反应性的影响；热、碱性和铁活化。通过使用对硝基二甲苯胺作为模型目标化合物，证明中性 pH 下的铁活化不受 Cl(-)或 HCO(3)(-)的影响，Cl(-)增强了碱性活化，而 CO(3)(2-)的增强作用更大，HCO(3)(-)则没有影响。在 pH 2 时，过氧单硫酸盐通过铁活化对全氯乙烯的破坏受到氯离子的显著影响。反应速率下降，但在 28 mM Cl(-) 以下，整体氧化效率不受影响。氯离子和碳酸盐的影响是由产生的活性氯、碳酸盐物种的直接攻击或引发反应的催化作用引起的，导致更多的硫酸根自由基。这些结果表明，碳酸盐和氯盐在过硫酸盐的应用中可能起着重要作用，不应严格将其视为清除剂。
