Shao Hongyun, Shen Jia, Jiang Zili, Ruan Xiuxiu
School of Environmental and Chemical Engineering, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China; Center of green urban mining & industry ecology, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China.
School of Environmental and Chemical Engineering, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China; Center of green urban mining & industry ecology, Shanghai University, No.99 Shangda Road, Shanghai 200444, PR China.
J Hazard Mater. 2025 Sep 15;496:139319. doi: 10.1016/j.jhazmat.2025.139319. Epub 2025 Jul 20.
To develop a long-term oxidative technology, peroxydisulfate intercalated magnesium aluminum layered double hydroxide (Mg/Al-PDS LDH) was prepared for in-situ oxidation of sulfamethoxazole (SMX) in soil. In the airtight system, Mg/Al-PDS LDH exhibited 99.54 % SMX removal in solution, as most PDS was retained within the LDH interlayers. However, SMX removal rate was reduced to 77.66 % in the open system, since PDS was rapidly released by the replacement of CO (formed from dissolved CO). When Mg/Al-PDS LDH was applied to the bottom layer of SMX-contaminated soil column, the effluent SMX concentration remained below 0.21 mg/L with a total removal rate of 98.72 %. In contrast, top-layer application yielded only 10.7 % removal, indicating the effectiveness of solid-phase oxidation as SMX percolated through the LDH layer. Density functional theory and Raman analyses evidenced that intercalated PDS had an elongated O-O bond with decreased bond energy, facilitating its activation by the base sites of LDH. Mechanism analysis confirmed that surface-bound SO and •OH were the dominant active species for SMX oxidation. CO derived from degradation-generated CO was intercalated into LDH, proving the carbon sequestration capability of Mg/Al-PDS LDH. This study provides new insights into the long-lasting oxidation mechanism of Mg/Al-PDS LDH for soil remediation.
为开发一种长期氧化技术，制备了过二硫酸盐插层的镁铝层状双氢氧化物（Mg/Al-PDS LDH）用于土壤中磺胺甲恶唑（SMX）的原位氧化。在密闭系统中，Mg/Al-PDS LDH对溶液中SMX的去除率达99.54%，因为大部分PDS保留在LDH层间。然而，在开放系统中，SMX去除率降至77.66%，这是由于PDS被溶解的CO形成的CO取代而迅速释放。当将Mg/Al-PDS LDH应用于SMX污染土壤柱的底层时，流出液中SMX浓度保持在0.21 mg/L以下，总去除率为98.72%。相比之下，顶层应用的去除率仅为10.7%，这表明当SMX渗透通过LDH层时，固相氧化是有效的。密度泛函理论和拉曼分析证明，插层的PDS具有伸长的O-O键且键能降低，有利于其被LDH的碱性位点活化。机理分析证实，表面结合的SO和•OH是SMX氧化的主要活性物种。降解产生的CO衍生的CO被插入LDH中，证明了Mg/Al-PDS LDH的碳固存能力。本研究为Mg/Al-PDS LDH用于土壤修复的长效氧化机理提供了新的见解。
