Consiglio Nazionale delle Ricerche - Istituto di Metodologie per l'Analisi Ambientale, C.da S. Loja, Zona Industriale, 85050 Tito Scalo (PZ), Italy.
J Hazard Mater. 2012 Jan 30;201-202:148-54. doi: 10.1016/j.jhazmat.2011.11.054. Epub 2011 Nov 25.
The aim of this work is to investigate the efficiency of the phyllomanganate birnessite in degrading catechol after mechanochemical treatments. A synthesized birnessite and the organic molecule were grounded together in a high energy mill and the xenobiotic-mineral surface reactions induced by the grinding treatment have been investigated by means of X-ray powder diffraction, X-ray fluorescence, thermal analysis and spectroscopic techniques as well as high-performance liquid chromatography and voltammetric techniques. If compared to the simple contact between the birnessite and the organic molecule, mechanochemical treatments have revealed to be highly efficient in degrading catechol molecules, in terms both of time and extent. Due to the two phenolic groups of catechol and the small steric hindrance of the molecule, the extent of the mechanochemically induced degradation of catechol onto birnessite surfaces is quite high. The degradation mechanism mainly occurs via a redox reaction. It implies the formation of a surface bidentate inner-sphere complex between the phenolic group of the organic molecules and the Mn(IV) from the birnessite structure. Structural changes occur on the MnO(6) layers of birnessite as due to the mechanically induced surface reactions: reduction of Mn(IV), consequent formation of Mn(III) and new vacancies, and free Mn(2+) ions production.
这项工作的目的是研究层状叶蜡石锰矿在机械化学处理后降解儿茶酚的效率。将一种合成的叶蜡石锰矿和有机分子在高能球磨机中一起研磨，通过 X 射线粉末衍射、X 射线荧光、热分析和光谱技术以及高效液相色谱和伏安技术研究了研磨处理诱导的异生物质-矿物表面反应。与叶蜡石锰矿和有机分子的简单接触相比，机械化学处理在降解儿茶酚分子的时间和程度上都显示出很高的效率。由于儿茶酚有两个酚基团和分子的小空间位阻，因此儿茶酚在叶蜡石表面的机械化学诱导降解程度相当高。降解机制主要通过氧化还原反应发生。这意味着在有机分子的酚基团和叶蜡石结构中的 Mn(IV)之间形成了表面双齿内球络合物。由于机械诱导的表面反应，叶蜡石的 MnO(6)层发生结构变化：Mn(IV)的还原，随后形成 Mn(III)和新的空位，以及游离的 Mn(2+)离子的生成。
