Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, PR China.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, PR China.
Chemosphere. 2020 Aug;253:126662. doi: 10.1016/j.chemosphere.2020.126662. Epub 2020 Apr 4.
In this study, pyrite (FeS) was used as a novel activator of calcium peroxide (CaO) for the degradation of diethyl phthalate (DEP) in both aqueous solution and soil. DEP (10 mg/L) in aqueous solution was completely degraded within 5.0 min by the FeS (0.30 g/L)/CaO (1.0 mM) system at pH 3.5. X-ray diffraction (XRD), scanning electron microscopy (SEM), electron paramagnetic resonance (EPR), free radical quenching, and X-ray photoelectron spectroscopy (XPS) were used to elucidate the mechanism of the catalytic decomposition of CaO, radical formation and DEP degradation in the presence of by pyrite. The results show that hydroxyl radicals (OH) are the dominant active species responsible for DEP degradation. Surface or lattice Fe(II) of FeS readily activates HO generated by CaO decomposition to produce OH, while the reducing sulfur species of FeS promotes the regeneration of surface of Fe(II) that catalyzes the production of additional OH, leading to the efficiently oxidative degradation of DEP. Although high concentration of common anions, such as Cl, NO, SO, and HCO, exert inhibitory effects on DEP degradation by pyrite/CaO, the reaction system can still efficiently degrade DEP in realistic soil. It was observed that 78% of DEP (25 mg kg) was degraded by 2.5% CaO (w/w) and 0.5% FeS (w/w) within 24 h. These results provide new insight into the mechanistic processes of CaO activation and OH formation by the novel FeS catalyst, demonstrating a promising alternative to the traditional HO-base Fenton process for contaminated soil remediation.
在这项研究中，黄铁矿（FeS）被用作一种新型的过氧化钙（CaO）活化剂，用于降解水溶液和土壤中的邻苯二甲酸二乙酯（DEP）。在 pH 值为 3.5 时，水溶液中 10 mg/L 的 DEP 在 5.0 min 内被 FeS（0.30 g/L）/CaO（1.0 mM）体系完全降解。X 射线衍射（XRD）、扫描电子显微镜（SEM）、电子顺磁共振（EPR）、自由基猝灭和 X 射线光电子能谱（XPS）用于阐明在黄铁矿存在下 CaO 的催化分解、自由基形成和 DEP 降解的机制。结果表明，羟基自由基（OH）是降解 DEP 的主要活性物质。FeS 的表面或晶格 Fe(II)容易激活由 CaO 分解生成的 HO 生成 OH，而 FeS 的还原硫物种促进表面 Fe(II)的再生，从而催化产生更多的 OH，导致 DEP 的有效氧化降解。尽管常见阴离子（如 Cl、NO、SO 和 HCO）的高浓度对黄铁矿/CaO 降解 DEP 有抑制作用，但反应体系仍能有效地在实际土壤中降解 DEP。结果表明，在 24 小时内，2.5% CaO（w/w）和 0.5% FeS（w/w）可使 78%的 25 mg/kg DEP 降解。这些结果为新型 FeS 催化剂对 CaO 活化和 OH 形成的机制过程提供了新的认识，为传统的 HO 基 Fenton 工艺修复污染土壤提供了一种有前途的替代方法。
