Fate of coagulant species and conformational effects during the aggregation of a model of a humic substance with Al13 polycations.
Fate of coagulant species and conformational effects during the aggregation of a model of a humic substance with Al13 polycations.
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DOI：
10.1016/j.watres.2006.03.014
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发表时间：
2006-06
期刊：
影响因子：
12.8
通讯作者：
V. Kazpard;Bruno Lartiges;Céline Frochot;J. B. D. D. L. Caillerie-J.-B.-D.-D.-L.-Caillerie-2275097272;M. Viriot;Jean-Michel Portal;Tatiana Görner;J. Bersillon
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文献类型：
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作者：
V. Kazpard;Bruno Lartiges;Céline Frochot;J. B. D. D. L. Caillerie-J.-B.-D.-D.-L.-Caillerie-2275097272;M. Viriot;Jean-Michel Portal;Tatiana Görner;J. Bersillon
邻苯二酚和甘氨酸自氧化生成的腐殖物质（MHS）模型在pH 6和8时与Al 13聚阳离子发生聚集。利用固体27 Al魔角旋转（MAS）NMR和CP-MAS 13 C NMR研究了与MHS官能团缔合后Al 13凝结剂物种的命运。结合电泳测量和稳态荧光光谱与芘作为荧光探针，研究了腐殖物质的结构重组与铝浓度。MAS 27 Al NMR表明，在两种pH值下，混凝剂物种为Al 13聚阳离子或Al 13单元的低聚物。CP MAS 13 C光谱表明，在低Al浓度下，水解铝物种在pH 6下选择性地与羧基结合，在pH 8下与酚部分结合。在较高的混凝剂浓度下，其余的官能团也与水解的Al相互作用，在最佳浓度范围内产生类似的CP MAS 13 C光谱。在最佳混凝剂浓度下，即使在pH 6时MHS阴离子电荷和Al 13阳离子电荷之间达到总体电荷平衡，电泳迁移率仍为负值。芘的偏振敏感荧光显示，Al 13凝聚剂与MHS官能团的相互作用诱导了分子内疏水微环境的形成.这种结构的变化被逆转后，进一步添加Al 13聚阳离子。
A model of a humic substance (MHS) obtained from auto-oxidation of catechol and glycine, was aggregated at pH 6 and 8 with Al13polycations. The fate of Al13coagulant species upon association with MHS functional groups was studied using solid state27Al Magic-angle spinning (MAS) NMR and CP-MAS13C 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. MAS27Al NMR revealed that the coagulant species are Al13polycations or oligomers of Al13units at both pHs. CP MAS13C 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 MAS13C 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 Al13cationic charge at pH 6. The polarity-sensitive fluorescence of pyrene revealed that the interaction of Al13coagulant species with MHS functional groups induces the formation of intramolecular hydrophobic microenvironments. Such structural changes were reversed upon further addition of Al13polycations.