Chen Baoliang, Johnson Elizabeth J, Chefetz Benny, Zhu Lizhong, Xing Baoshan
Department of Plant, Soil and Insect Sciences, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Environ Sci Technol. 2005 Aug 15;39(16):6138-46. doi: 10.1021/es050622q.
In both forest and agricultural soils, plant derived cuticular materials can constitute a significant part of soil organic matter. In this study, the sorption of nonpolar (naphthalene and phenanthrene) and polar (phenol and 1-naphthol) aromatic organic pollutants to aliphatic-rich cuticularfractions of green pepper (Capsicum annuum) (i.e., bulk (PC1), dewaxed (PC2), nonsaponifiable (PC3), nonsaponifiable-nonhydrolyzable (PC4), and dewaxed-hydrolyzed residue (PC5)) were examined to better understand the influence of polarity and accessibility on their sorption behavior. The polarity and structures of cuticular fractions were characterized by elemental analysis, Fourier transform infrared spectroscopy, and solid-state 13C NMR. The sorption isotherms fit well to the Freundlich equation. Sorption of the tested organic compounds to PC4, which had more condensed domains, was nonlinear (Freundlich N(s) values of 0.766-0.966). For naphthalene and phenanthrene, the largest sorption capacity (K(oc)) occurred in PC5, which contained the highest paraffinic carbons (63%) and the lowest polarity: approximately 2 and aproximately 3 times higher than the respective carbon-normalized octanol-water partition coefficient (K(owc)), indicating that PC5 was a powerful sorption medium. For phenol and 1-naphthol, the largest K(oc) values occurred in PC4 with polar aromatic cores: approximattely 17 and approximately 7 times higher than the respective K(owc), suggesting that PC4 was much more accessible and compatible to polar aromatic pollutants than nonpolar aromatic pollutants. There was little or no correlation of K(oc) with either aliphatic or aromatic components of the tested aliphatic-rich sorbents because the polarity and accessibility apparently played a regulating role in the sorption of organic contaminants.
在森林土壤和农业土壤中，植物衍生的角质层物质都可能构成土壤有机质的重要组成部分。在本研究中，研究了非极性（萘和菲）和极性（苯酚和1-萘酚）芳香族有机污染物对青椒（辣椒）富含脂肪族的角质层组分（即本体（PC1）、脱蜡（PC2）、不皂化（PC3）、不皂化-不可水解（PC4）和脱蜡-水解残渣（PC5））的吸附情况，以更好地了解极性和可及性对其吸附行为的影响。通过元素分析、傅里叶变换红外光谱和固态13C核磁共振对角质层组分的极性和结构进行了表征。吸附等温线与Freundlich方程拟合良好。测试的有机化合物对具有更多缩合域的PC4的吸附是非线性的（Freundlich N(s)值为0.766 - 0.966）。对于萘和菲，最大吸附容量（K(oc)）出现在PC5中，PC5含有最高比例的链烷烃碳（63%）且极性最低：分别比相应的碳归一化正辛醇-水分配系数（K(owc)）高约2倍和约3倍，表明PC5是一种强大的吸附介质。对于苯酚和1-萘酚，最大的K(oc)值出现在具有极性芳香核的PC4中：分别比相应的K(owc)高约17倍和约7倍，这表明PC4对极性芳香污染物的可及性和兼容性远高于非极性芳香污染物。K(oc)与测试的富含脂肪族吸附剂的脂肪族或芳香族组分几乎没有相关性，因为极性和可及性显然在有机污染物的吸附中起调节作用。
