University of Rhode Island, Department of Geosciences. Kingston, RI, USA.
University of Rhode Island, Department of Chemistry. Kingston, RI, USA.
J Hazard Mater. 2019 Dec 15;380:120875. doi: 10.1016/j.jhazmat.2019.120875. Epub 2019 Jul 13.
This research investigates the formation of free radical intermediates in an advanced oxidation processes (AOP) capable of destroying recalcitrant contaminants. The AOP studied is marketed as OxyZone® and relies on the premise of successful persulfate activation by peroxone (hydrogen peroxide plus ozone) and the formation of free radicals. The goal of this research was to determine which radicals are involved in the treatment of the model contaminant, 1,4-dioxane, which is a ubiquitous, recalcitrant organic groundwater pollutant difficult to destroy by conventional oxidants. In a parallel study, the peroxone activation persulfate (PAP) solution investigated herein rapidly degraded 1,4-dioxane. The degradation rates of 1,4-dioxane were measured as a function the oxidant:contaminant ratio. Its degradation products or mechanism were not investigated, however. Electron paramagnetic resonance (EPR) spectroscopy spin trapping was used to identify radicals produced in the oxidant solution, its active ingredients, and their possible interplay. The data presented herein indicate that the combination of hydrogen peroxide and dissolved ozone in the presence of persulfate results in the co-occurrence hydroxyl and sulfate radicals and possibly superoxide/hydroperoxyl radicals. These findings progress our understanding of the chemical radicals formed during PAP treatment of aqueous phase contaminants, such as 1,4-dioxane.
本研究调查了一种高级氧化工艺（AOP）中自由基中间体的形成，该工艺能够破坏难处理的污染物。所研究的 AOP 以 OxyZone® 为品牌，其原理是成功地通过过氧单硫酸盐（过氧化氢加臭氧）激活过硫酸盐，并形成自由基。本研究的目的是确定哪种自由基参与了模型污染物 1,4-二恶烷的处理，1,4-二恶烷是一种普遍存在的、难处理的有机地下水污染物，难以被传统氧化剂破坏。在一项平行研究中，本文所研究的过氧单硫酸盐（PAP）溶液迅速降解了 1,4-二恶烷。1,4-二恶烷的降解速率被测量为氧化剂：污染物比值的函数。然而，没有研究其降解产物或机制。电子顺磁共振（EPR）光谱自旋捕获用于鉴定氧化剂溶液中产生的自由基、其有效成分及其可能的相互作用。本文提供的数据表明，在过硫酸盐存在的情况下，过氧化氢和溶解臭氧的组合导致羟基和硫酸根自由基的共同出现，并且可能还有超氧自由基/过氧自由基。这些发现推进了我们对 PAP 处理水相污染物（如 1,4-二恶烷）过程中形成的化学自由基的理解。
