Kazpard V, Lartiges B S, Frochot C, d'Espinose de la Caillerie J B, Viriot M L, Portal J M, Görner T, Bersillon J L
University of Nancy, LEM-ENSG/INPL-CNRS, Pôle de l'Eau 15 Avenue du Charmois, BP 40, 54501 Vandoeuvre Cedex, France.
Water Res. 2006 Jun;40(10):1965-74. doi: 10.1016/j.watres.2006.03.014. Epub 2006 May 5.
A model of a humic substance (MHS) obtained from auto-oxidation of catechol and glycine, was aggregated at pH 6 and 8 with Al(13) polycations. The fate of Al(13) coagulant species upon association with MHS functional groups was studied using solid state (27)Al Magic-angle spinning (MAS) NMR and CP-MAS (13)C NMR. Electrophoretic measurements and steady-state fluorescence spectroscopy with pyrene as a fluoroprobe, were combined to investigate structural re-organization of humic material with aluminum concentration. MAS (27)Al NMR revealed that the coagulant species are Al(13) polycations or oligomers of Al(13) units at both pHs. CP MAS (13)C spectra indicated that, at low Al concentration, hydrolyzed aluminum species bind selectively to carboxylic groups at pH 6 and to phenolic moieties at pH 8. At higher coagulant concentrations, the remaining functional groups also interact with hydrolyzed Al to yield similar CP MAS (13)C spectra in the optimum concentration range. Negative values of electrophoretic mobility were obtained at optimum coagulant concentrations even though an overall charge balance was achieved between MHS anionic charge and Al(13) cationic charge at pH 6. The polarity-sensitive fluorescence of pyrene revealed that the interaction of Al(13) coagulant species with MHS functional groups induces the formation of intramolecular hydrophobic microenvironments. Such structural changes were reversed upon further addition of Al(13) polycations.
通过邻苯二酚和甘氨酸的自动氧化获得的腐殖质模型（MHS），在pH值为6和8时与Al(13)多阳离子发生聚集。使用固态（27）Al魔角旋转（MAS）核磁共振和CP-MAS（13）C核磁共振研究了Al(13)混凝剂物种与MHS官能团结合后的命运。结合电泳测量和以芘为荧光探针的稳态荧光光谱，研究了腐殖质材料随铝浓度的结构重组。MAS（27）Al核磁共振表明，在两个pH值下，混凝剂物种均为Al(13)多阳离子或Al(13)单元的低聚物。CP MAS（13）C光谱表明，在低铝浓度下，水解铝物种在pH值为6时选择性地与羧基结合，在pH值为8时与酚基部分结合。在较高的混凝剂浓度下，剩余的官能团也与水解铝相互作用，在最佳浓度范围内产生相似的CP MAS（13）C光谱。即使在pH值为6时MHS阴离子电荷与Al(13)阳离子电荷之间实现了总体电荷平衡，但在最佳混凝剂浓度下仍获得了负的电泳迁移率值。芘的极性敏感荧光表明，Al(13)混凝剂物种与MHS官能团的相互作用诱导了分子内疏水微环境的形成。进一步添加Al(13)多阳离子后，这种结构变化得以逆转。
