Spectroscopic Characteristics of Hydrophilic/Hydrophobic Fractions of Natural Organic Matters at Various Critical Retention Factors
MU Si-tu1,2, LIU Chun2, WANG Shu3, FAN Hui-ju3, HAN Bing-jun1, XIAO Kang1*
1. College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
2. School of Environmental Science and Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China
3. State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
Abstract：Adsorption resin chromatography obtains wide application in characterizing the distribution of hydrophilic/hydrophobic fractions in natural organic matters. As a basic parameter of chromatography, the critical retention factor has a potential impact on results of adsorption and separation. In this study, water samples from a reservoir were fractionated into hydrophilic substances (HIS), hydrophobic acids (HOA), hydrophobic bases (HOB) and hydrophobic neutrals (HON) under the conditions of various critical retention factors (k′cr=5, 10, 25, 50, 100). The distribution of the hydrophilic/hydrophobic fractions were systematically characterized, with special attention placed to their spectroscopic properties. The results showed that the relative proportions of hydrophilic/hydrophobic fractions depended on the value of k′cr, and the proportion of hydrophobic components and the degree of hydrophobicity increased with the increase of k′cr value. In wavelength range of 250~280 nm, the UV absorbance of HIS increased with increasing k′cr, while the absorbance of hydrophobic fractions performed in the reserved trend. The difference in UV spectra between the hydrophilic and hydrophobic fractions was enlarged with increasing k′cr value. The specific UV absorbance (i. e. UV absorbance per unit concentration) of the hydrophobic fractions was found to be sensitive to the value of k′cr, indicating that the critical retention factor may affect the properties of aromatic functional groups in the obtained fractions. Three dimensional excitation-emission matrix fluorescence spectroscopy was further conducted to characterize the hydrophilic/hydrophobic fractions, with the spectral data analyzed using fluorescence regional integration and fluorescence index techniques. The results revealed that the fluorescence peak appearance (peak location and intensity), fluorescence regional distribution and fluorophore density were related to the value of k′cr, meanwhile the fluorescence indices of BIX, HIXem and Peak T/C were sensitive to the value of k′cr. It is speculated that the critical retention factor may have profound impact on the chemical compositions and transformation behaviors of the resultant hydrophilic/hydrophobic fractions. Therefore, it is suggested that particular attention should be paid to the setting of the critical retention factor and indicating its value clearly when conducting separating and characterizing of the distribution of hydrophilic/hydrophobic fractions.
穆思图，刘 春，王 舒，樊慧菊，韩秉均，肖 康. 不同临界保留因子下天然有机物亲疏水组分光谱特性[J]. 光谱学与光谱分析, 2018, 38(07): 2221-2226.
MU Si-tu, LIU Chun, WANG Shu, FAN Hui-ju, HAN Bing-jun, XIAO Kang. Spectroscopic Characteristics of Hydrophilic/Hydrophobic Fractions of Natural Organic Matters at Various Critical Retention Factors. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2018, 38(07): 2221-2226.
[1] Leenheer J A, Croué J P. Environmental Science & Technology, 2003, 37(1): 18A.
[2] Van Oss C J, Giese R F, Docoslis A. Journal of Dispersion Science and Technology, 2005, 26(5): 585.
[3] Shen Y, Zhao W, Xiao K, et al. Journal of Membrane Science, 2010, 346(1): 187.
[4] Liang S, Liu C, Song L. Water Research, 2007, 41(1): 95.
[5] Shen Y X, Xiao K, Liang P, et al. Journal of Membrane Science, 2012, 415-416：336.
[6] HU Meng-liu, LIN Jie, XU Guang-hong, et al(胡孟柳, 林 洁, 许光红, 等). Environmental Science(环境科学), 2013, 34(1): 169.
[7] Xiao K, Shen Y X, Liang S, et al. Journal of Membrane Science, 2014, 467(467): 206.
[8] Imai A, Fukushima T, Matsushige K, et al. Water Research, 2002, 36(4): 859.
[9] Xiao K, Sun J Y, Shen Y X, et al. RSC Advances, 2016, 6(29): 24050.
[10] SONG Shu-bin, GAO Ya, ZHANG Wei-jun, et al(宋数宾, 高 雅, 张伟军, 等). Chinese Journal of Environmental Engineering(环境工程学报), 2013, 7(10): 3890.
[11] Chen W, Westerhoff P, Leenheer J A, et al. Environmental Science & Technology, 2003, 37(24): 5701.
[12] Coble P G, Lead J, Baker A, et al. Aquatic Oganic Matter Fluorescence. New York: Cambridge University Press，2014.
