Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210023, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
J Environ Sci (China). 2019 Jun;80:5-13. doi: 10.1016/j.jes.2018.06.015. Epub 2018 Jun 30.
This work studied the structural effects of hematite (α-FeO), 2-line ferrihydrite (HFO) and goethite (α-FeOOH) on diethyl phthalate ester (DEP) degradation. The results showed that the degradation of DEP was faster under 365 nm light irradiation than in the dark in the presence of iron (hydr)oxides. The apparent kinetic rates of DEP degradation followed the order HFO > goethite ≈ hematite in the dark and HFO > hematite > goethite under 365 nm light irradiation. Two pathways governed HO decomposition efficiency on iron (hydr)oxide surfaces: (1) forming OH on inherent surface hydroxyl groups (Fe-OH) and (2) producing O and HO on the surface oxygen vacancies. X-ray photoelectron spectroscopy (XPS) analyses indicated that HFO not only has high Fe-OH content but also has high Vo content, resulting in its low HO utilization efficiency (η). DEP was degraded through hydrogen abstraction and de-esterification, and the major products were (OH)-DEP, mono-ethyl phthalate (MEP), OH-MEP, and phthalate acid (PA). The study is important in understanding the transformation of phthalate esters in top surface soils and surface waters under ultraviolet light.
本研究考察了赤铁矿(α-FeO)、2 线水铁矿(HFO)和针铁矿(α-FeOOH)对邻苯二甲酸二乙酯(DEP)降解的结构效应。结果表明，在铁(氢)氧化物存在下，365nm 光照射下 DEP 的降解速度比黑暗中快。在黑暗中，DEP 降解的表观动力学速率顺序为 HFO>针铁矿≈赤铁矿，而在 365nm 光照射下，其顺序为 HFO>赤铁矿>针铁矿。HO 在铁(氢)氧化物表面分解效率受两条途径控制：(1)在固有表面羟基(Fe-OH)上形成 OH；(2)在表面氧空位上产生 O 和 HO。X 射线光电子能谱(XPS)分析表明，HFO 不仅具有高的 Fe-OH 含量，而且具有高的 Vo 含量，导致其 HO 利用率(η)较低。DEP 通过氢提取和去酯化降解，主要产物为(OH)-DEP、单乙基邻苯二甲酸酯(MEP)、OH-MEP 和邻苯二甲酸(PA)。本研究对于理解紫外光下表层土壤和地表水中间苯二甲酸酯的转化具有重要意义。
