Effect of aluminum speciation and structure characterization on preferential removal of disinfection byproduct precursors by aluminum hydroxide coagulation.
Effect of aluminum speciation and structure characterization on preferential removal of disinfection byproduct precursors by aluminum hydroxide coagulation.
复制标题
DOI：
10.1021/es8034347
复制
发表时间：
2009-05
影响因子：
11.4
通讯作者：
He Zhao;Huijuan Liu;Chengzhi Hu;J. Qu
中科院分区：
文献类型：
--
作者：
He Zhao;Huijuan Liu;Chengzhi Hu;J. Qu
研究了不同pH条件下氯化铝和聚合氯化铝对腐殖酸的混凝效果。采用电喷雾质谱（ESI-MS）结合固体27 Al魔角旋转核磁共振（MASNMR）技术对铝的形态进行了详细的研究。采用傅里叶变换红外光谱（FTIR）和固体13 C交叉极化魔角自旋（CPMAS）NMR对混凝沉淀的冷冻干燥絮体进行了分析。本研究还评估了混凝过程中PACI和AlCl 3混凝对消毒副产物（DBP）前体的去除情况。特别强调了铝的形态和结构表征的作用，在优先去除前体混凝。结果表明，混凝过程中预水解或原位生成的Al 13物种对具有相关结构的DBP前体物具有优先去除作用。一方面，对于具有芳香族和羧基结构的DBP前体，原位Al 13物种优先结合到这些DBP前体。因此，更多的DBP前体与芳香族和羧基结构被去除AlCl 3比那些由PAC在pH 5.0。另一方面，对于具有脂肪族结构的DBP前体，铝凝聚不负责还原这些前体。然而，低聚铝物种和预先形成的Al 13物种弱优先结合DBP前体与脂肪族结构。
Humic acid was coagulated by aluminum chloride and pokyaluminum (PACl) at different pH conditions. Aluminum speciation was investigated in details through combining electrospray ionization mass spectrometer (ESI-MS) with solid-state 27Al magic-angle spinning nuclear magnetic resonance (MAS NMR). Freeze-dried flocs from coagulation precipitates were analyzed by Fourier transform infrared (FTIR) and solid-state 13C cross-polarization magic angle spinning (CPMAS) NMR. This study also evaluated removal of disinfection byproduct (DBP) precursors by PACI and AlCl3 coagulation during coagulation process. Particular emphasis was paid to the role of aluminum speciation and structure characterization in the preferential removal of precursors by coagulation. The results indicated that prehydrolyzed or in situ formed Al13 species during coagulation process exhibited preferential removal for corresponding DBP precursors with relative structures. On one hand, for DBP precursors with aromatic and carboxylic structures, in situ Al13 species were preferentially bound to these DBP precursors. Thus, more DBP precursors with aromatic and carboxylic structures were removed by AlCl3 than those by PACl at pH 5.0. On the other hand, for DBP precursors with aliphatic structures, aluminum coagulation was not responsible for reducing these precursors. However, oligomeric aluminum species and preformed Al13 species were weak preferentially bound to DBP precursors with aliphatic structures.