Claret Francis, Schäfer Thorsten, Brevet Julien, Reiller Pascal E
Commissariat à l'Energie Atomique, CE Saclay, DEN/DANS/DPC/SECR/Laboratoire de Speciation des Radionucléides et des Molécules, Bâtiment 391-P.C. 33, F-91191 Gif-sur-Yvette CEDEX, France.
Environ Sci Technol. 2008 Dec 1;42(23):8809-15. doi: 10.1021/es801257g.
Sorptive fractionation of Suwannee River Fulvic Acid (SRFA) and Purified Aldrich Humic Acid (PAHA) on alpha-Al2O3 at pH 6 was probed in the supernatant using different spectroscopic techniques. Comparison of dissolved organic carbon (DOC) analysis with UV/vis spectrophotometric measurements at 254 nm, including specific UV absorbance (SUVA) calculation, revealed a decrease in chromophoric compounds for the nonsorbed extracts after a 24 h contact time. This fractionation, only observable below a certain ratio between initial number of sites of humic substances and of alpha-Al2O3, seems to indicate a higher fractionation for PAHA. C(1s) near-edge X-ray absorption fine structure spectroscopy (NEXAFS) confirmed this trend and points to a decrease in phenolic moieties in the supernatant and to an eventual increase in phenolic moieties on the surface. Time-resolved luminescence spectroscopy (TRLS) of Eu(III) as luminescent probe showed a decrease in the ratio between the (5)D0-->(7)F2 and (5)D0-->(7)F1 transitions for the fractionated organic matter (OM) that is thought to be associated with a lower energy transfer from the OM to Eu(III) due to the loss of polar aromatics. These modifications in the supernatant are a hint for the modification of sorbed humic extracts on the surface.
利用不同的光谱技术，在pH值为6的上清液中研究了苏万尼河富里酸（SRFA）和纯化的奥尔德里奇腐殖酸（PAHA）在α-Al2O3上的吸附分级。通过溶解有机碳（DOC）分析与254 nm处的紫外/可见分光光度测量（包括计算比紫外吸光度（SUVA））进行比较，结果表明，接触24小时后，未吸附提取物中发色化合物减少。这种分级现象仅在腐殖物质与α-Al2O3的初始位点数量存在一定比例以下时才可见，这似乎表明PAHA的分级程度更高。C(1s)近边X射线吸收精细结构光谱（NEXAFS）证实了这一趋势，并表明上清液中酚类部分减少，而表面酚类部分最终增加。以铕（III）作为发光探针的时间分辨发光光谱（TRLS）显示，分级后的有机物质（OM）中(5)D0→(7)F2和(5)D0→(7)F1跃迁之间的比率降低，这被认为是由于极性芳烃的损失导致从OM到铕（III）的能量转移降低。上清液中的这些变化暗示了表面吸附的腐殖提取物的变化。
