Hur Jin, Schlautman Mark A
Department of Environmental Engineering and Science, Clemson University, Anderson, SC 29625-0919, USA.
J Colloid Interface Sci. 2003 Aug 15;264(2):313-21. doi: 10.1016/S0021-9797(03)00444-2.
Molecular weight (MW) fractionation of Suwannee River fulvic acid (SRFA) and purified Aldrich humic acid (PAHA) by adsorption onto kaolinite and hematite was investigated in equilibrium and rate experiments with a size-exclusion chromatography system using ultraviolet (UV) light detection. The extent of adsorptive fractionation based on UV detection was positively correlated with the percent carbon adsorption for both humic substances (HS), although the specific fractionation pattern observed depended on the particular HS and mineral used. Higher MW fractions of SRFA, an aquatic HS, were preferentially adsorbed to both kaolinite and hematite whereas the fractionation trends for PAHA, a terrestrial peat HS, differed for the two minerals. The contrasting fractionation patterns for SRFA versus PAHA can be explained reasonably well by the different structural trends that occur in their respective MW fractions and the underlying adsorption processes. Rate studies of adsorptive fractionation revealed an initial rapid uptake of smaller HS molecules by the mineral surfaces, followed by their replacement at the surface by a much slower uptake of the larger HS molecules present in aqueous solution.
通过使用紫外（UV）光检测的尺寸排阻色谱系统，在平衡和速率实验中研究了通过吸附到高岭石和赤铁矿上对苏万尼河富里酸（SRFA）和纯化的奥尔德里奇腐殖酸（PAHA）进行分子量（MW）分级。基于紫外检测的吸附分级程度与两种腐殖质（HS）的碳吸附百分比呈正相关，尽管观察到的特定分级模式取决于特定的HS和所用矿物。水生HS——SRFA的较高MW级分优先吸附到高岭石和赤铁矿上，而陆地泥炭HS——PAHA的分级趋势在两种矿物上有所不同。SRFA与PAHA的对比分级模式可以通过它们各自MW级分中出现的不同结构趋势和潜在的吸附过程得到合理的解释。吸附分级的速率研究表明，矿物表面最初快速吸收较小的HS分子，随后水溶液中存在的较大HS分子以慢得多的吸收速率在表面取代它们。
