Interaction between 6PPD/6PPD-Q and natural Fe-Mn nodules: Performance and mechanism of adsorption and oxidative transformation

作者：Jiaqi Shi, Yan Li, Qi Wei, Xin Zhu, Shaohua Cao, Wenyi Xie, Yang Guo, Jing Wei, Zekai Li, Tao Long · 发表于：Environment International · 年份：2025 · DOI：10.1016/j.envint.2025.109438 · 被引用次数：18 · 研究领域：Geochemistry and Elemental Analysis、Radioactive element chemistry and processing、Catalytic Processes in Materials Science

The widely used rubber antioxidant N-(1,3-Dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) and its ozonated product, 6PPD-quinone (6PPD-Q), are highly toxic to aquatic life, yet understanding on their environmental behaviors is limited. This study comprehensively investigated their adsorption and transformation processes on natural Fe-Mn nodules (NFMN), which commonly exist in sediments and soils through a combination of diverse experimental and computational methods. The maximum adsorption capacity of 6PPD-Q (719.2 μg·g −1 ) is significantly higher than that of 6PPD (133.8 μg·g −1 ) at 293 K, and it is more difficult to desorb. They follow different kinetic and isothermal adsorption models, and environmental conditions (including temperature, pH, and anions) exert distinct influences on the adsorption of the two substances. Adsorption mechanisms involving electrostatic attraction, charge transfer, hydrogen bonding, and Lewis acid-base complexation were unveiled. For 6PPD, electrostatic adsorption and Lewis acid-base complexation contribute significantly to its adsorption. Conversely, for 6PPD-Q, the contribution of Lewis acid-base complexation outweighs that of hydrogen bonding, while the effect of electrostatic adsorption is relatively negligible. The stronger electrostatic attraction, more efficient charge transfer, and a greater number of binding sites for hydrogen bonding and Lewis acid-base complexation with NFMN results in more robust adsorption of 6PPD-Q. Furthermor...