Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China.
Chemosphere. 2014 Apr;101:15-20. doi: 10.1016/j.chemosphere.2013.11.063. Epub 2013 Dec 25.
Efficiencies of 2,4,4'-trichlorobiphenyl (PCB28) degradation in a goethite-catalyzed Fenton-like system under various conditions were investigated. Up to 99% of PCB28 was degraded in the Fenton-like system after 48 h. The hydroxyl radical was responsible for the degradation of PCB28 at pH 3-7. Degradation of PCB28 and H2O2 followed pseudo-first-order kinetics. The rate of PCB28 degradation decreased when the pH increased from 3 to 7, but increased with increasing concentration of goethite and H2O2. The rate of H2O2 decomposition increased at higher pH and goethite concentration, and decreased at lower H2O2 concentration. The half-lives of 4-chlorobiphenyl, 4,4'-dichlorobiphenyl, 2,4,4'-trichlorobiphenyl, and 2,2',4,4'-tetrachlorobiphenyl were 1.8, 3.5, 4.1, and 11h, respectively; therefore, the number of chlorine atoms in the biphenyl molecule determined the chemical reactivity of PCBs. By gas chromatography-mass spectrometry, one monochlorobiphenyl, three dichlorobiphenyl, and two hydroxytrichlorobiphenyl derivatives were identified as major products of PCB28 degradation. The decrease in pH of the reaction mixture after 48h reaction revealed that acidic products might be formed during degradation.
研究了在不同条件下针铁矿催化芬顿样体系中 2,4,4'-三氯联苯（PCB28）的降解效率。在芬顿样体系中，经过 48 小时，PCB28 的降解率高达 99%。在 pH 值为 3-7 时，羟基自由基是 PCB28 降解的原因。PCB28 和 H2O2 的降解符合准一级动力学。当 pH 值从 3 增加到 7 时，PCB28 的降解速率降低，但随着针铁矿和 H2O2 浓度的增加而增加。在较高的 pH 值和针铁矿浓度下，H2O2 的分解速率增加，而在较低的 H2O2 浓度下，H2O2 的分解速率降低。4-氯联苯、4,4'-二氯联苯、2,4,4'-三氯联苯和 2,2',4,4'-四氯联苯的半衰期分别为 1.8、3.5、4.1 和 11h，因此联苯分子中的氯原子数决定了 PCBs 的化学活性。通过气相色谱-质谱联用仪，鉴定出 PCB28 降解的主要产物为一种单氯联苯、三种二氯联苯和两种羟基三氯联苯衍生物。48 小时反应后反应混合物的 pH 值下降表明在降解过程中可能形成了酸性产物。
