The adsorption behaviors of different constituents within bulk humic substances (HS) on two nanoparticles, TiO₂ and ZnO, were examined by using two-dimensional correlation size exclusion chromatography (2D-CoSEC) and excitation emission matrix–parallel factor analysis (EEM-PARAFAC), which separated bulk HS into different size fractions and fluorescent components, respectively. Subtle changes in the size distributions of HS with increasing adsorbents were successfully identified and tracked via the 2D-CoSEC. From adsorption isotherm experiments, three different HS constituent groups with respect to sizes and fluorescence features were identified by the 2D-CoSEC and EEM-PARAFAC, respectively. The chromatographically separated HS size groups presented dissimilar adsorption behaviors in terms of adsorption affinity and isotherm nonlinearity. The sequence orders of adsorption, interpreted from the 2D-CoSEC, was consistent with those of the isotherm model parameters individually calculated for different HS size subfractions, signifying the promising application of 2D-CoSEC in obtaining an insight into the heterogeneous adsorption of HS in terms of molecular sizes. EEM-PARAFAC results also supported the major finding of the 2D-CoSEC as shown by the preferential adsorption of the fluorescent components associated with large molecular sizes.

中文翻译：

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使用二维相关尺寸排阻色谱（2D-CoSEC）和EEM-PARAFAC探索相对分子大小而言，腐殖质在纳米粒子上的非均相吸附行为

两种腐殖质（HS）中不同成分在两种纳米颗粒TiO ₂上的吸附行为通过使用二维相关尺寸排阻色谱法（2D-CoSEC）和激发发射矩阵-平行因子分析（EEM-PARAFAC），分别将大体积HS分离成不同的大小级分和荧光成分，对ZnO和ZnO进行了检测。通过2D-CoSEC成功地识别并跟踪了HS尺寸分布随吸附剂增加的细微变化。根据吸附等温线实验，分别通过2D-CoSEC和EEM-PARAFAC鉴定了三个不同的HS组成组，分别涉及尺寸和荧光特征。色谱分离的HS尺寸组在吸附亲和力和等温线非线性方面表现出不同的吸附行为。由2D-CoSEC解释的吸附顺序，与针对不同HS尺寸亚组分分别计算的等温线模型参数的那些相一致，这表明2D-CoSEC在从分子尺寸方面深入了解HS的异质吸附方面具有广阔的应用前景。EEM-PARAFAC的结果也支持了2D-CoSEC的主要发现，如与大分子大小相关的荧光成分的优先吸附所示。