Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, PR China; Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Ministry of Agriculture/Tianjin Key Laboratory of Agro-environment and Safe-product, Tianjing, 300191, PR China.
Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, PR China.
Chemosphere. 2019 Aug;229:200-205. doi: 10.1016/j.chemosphere.2019.04.135. Epub 2019 Apr 24.
In the present study, ascorbic acid (AA) induced persulfate activation was investigated for the further exploration of organic pollutants oxidation by persulfate. We interestingly found that AA showed a significant catalytic activity to persulfate. Under neutral pH and room temperature condition, about 71.3% of pentachlorophenol (PCP, 10 mg L) was decomposed in 180 min with 40 mmol L persulfate and 1.0 mmol L AA, while only 15.4% and 3.2% of PCP was removed by alone persulfate and AA respectively. The result of EPR spectra identified sulfate radical (SO) and hydroxyl radical (OH) were generated during the reaction between persulfate and AA. Quenching experiments confirmed that both SO and OH contributed to the decomposition of PCP. With the addition of AA augmented from 0 to 1 mmol L, the PCP degradation ratio continuously increased. However, excess AA could consume the generated reactive oxygen species (ROSs) that led to the inhibition of PCP degradation. Meanwhile, the PCP degradation by persulfate-AA was strongly pH dependent. The PCP degradation rate was declined as the initial pH increased from 3.5 to 10.5. At pH above 12.5, the base activation began to predominate over AA activation of persulfate. Furthermore, it was observed that the AA inducing persulfate activation was related to the extent of AA ionization, while CHO promoted the highest persulfate activation for the PCP degradation, and CHO induced the lowest persulfate activation. This study indicates the high potential of AA induced persulfate activation for treatment of organochlorine contaminated water.
在本研究中，考察了抗坏血酸（AA）诱导过硫酸盐活化以进一步探索过硫酸盐氧化有机污染物。我们有趣地发现 AA 对过硫酸盐表现出显著的催化活性。在中性 pH 和室温条件下，在 40 mmol/L 过硫酸盐和 1.0 mmol/L AA 存在下，约 71.3%的五氯苯酚（PCP，10 mg/L）在 180 min 内分解，而单独使用过硫酸盐和 AA 时，PCP 的去除率分别为 15.4%和 3.2%。EPR 光谱结果表明，在过硫酸盐与 AA 的反应过程中生成了硫酸根自由基（SO）和羟基自由基（OH）。淬灭实验证实，SO 和 OH 都有助于 PCP 的分解。随着 AA 从 0 增加到 1 mmol/L，PCP 的降解率不断增加。然而，过量的 AA 会消耗生成的活性氧物质（ROSs），从而导致 PCP 降解的抑制。同时，过硫酸盐-AA 体系中 PCP 的降解强烈依赖于 pH 值。当初始 pH 值从 3.5 增加到 10.5 时，PCP 的降解速率下降。在 pH 值高于 12.5 时，开始出现碱基活化，超过 AA 对过硫酸盐的活化作用。此外，观察到 AA 诱导过硫酸盐活化与 AA 离解程度有关，而 CHO 对 PCP 降解的促进作用最大，CHO 对过硫酸盐的活化作用最小。本研究表明，AA 诱导过硫酸盐活化在处理有机氯污染水方面具有很大的潜力。
