催化过氧化氢对石油烃污染土壤的氧化能力

摘要

Regarding to the petroleum hydrocarbon polluted sites that are remediated with H2 O2 based ex-situ chemical oxidation, the oxidizing capacity and reactive process of catalyzed H2 O2 were studied with different H2 O2 mass fractions and oxidant to catalyst∕stabilizer ratios. It is found that hydroxyl radical and superoxide anion are the major oxidation groups. The H2 O2 mass fraction of 0. 50%-1. 00% and the oxidant to catalyst∕stabilizer ratio of 75∶1-100∶1 provide higher total petroleum hydrocarbon ( TPH) degradation rate. The results demonstrated that high H2 O2 concentration and low oxidant to catalyst∕stabilizer ratio may lead to rapid H2 O2 decomposition that reduce the contact time between oxidant and contaminant and decrease the oxidizing efficiency. In addition, it is also found when H2 O2 is under rapid decomposition, it tends to oxidize hydrocarbon molecules with less carbon number.%针对催化过氧化氢对石油烃污染场地土壤进行异位氧化修复，通过使用不同浓度过氧化氢及不同摩尔比的过氧化氢和催化稳定剂与污染土壤进行反应，比较过氧化氢在不同条件下对石油烃的氧化降解性能。结果表明：催化过氧化氢反应过程中产生的中间产物羟基自由基和超氧阴离子为最主要的氧化基团；当过氧化氢浓度为0．50%~1．00%，氧化剂与催化稳定剂摩尔比为75∶1~100∶1时，总石油烃的降解率较高；过高的过氧化氢浓度或过低的氧化剂与催化稳定剂摩尔比会导致过氧化氢分解过快，氧化剂与污染物的接触时间降低，从而达不到理想的污染物去除率；过氧化氢在快速分解时，优先氧化碳数较低的石油烃。