pH影响下小麦根吸附极性有机物的行为研究  

Effect of pH on Sorption of Polar Organic Compounds to Wheat Root

作　　者：杨玲[1] 黄杰勋[1] 李非里[1] 邱宇平[1] 

机构地区：[1]浙江工业大学生物与环境工程学院,浙江杭州310032

出　　处：《环境科学与技术》2013年第4期9-13,共5页Environmental Science & Technology

基　　金：国家重点基础研究发展计划"973"子课题(2009CB421603)

摘　　要：文章以标准纤维素为对照吸附剂,以菲为对照吸附质,采用批量平衡振荡法进行吸附实验,研究不同pH条件下,小麦根吸附极性污染物(2,4-二氯苯酚和硝基苯)的行为差异。结果表明:污染物吸附以疏水性分配为主,吸附系数(K_d)值随化合物疏水性的增强而增强;非解离型极性污染物(硝基苯)的吸附与疏水性污染物(菲)类似,吸附等温线呈线性,相关系数(R^2)均大于0.98,同时pH对吸附的影响无显著性差异(P>0.05);解离型极性污染物(2,4-二氯苯酚)的吸附随pH增加而降低,仅在pH 5.0时呈现吸附线性,在pH 7.0和8.0时均呈非线性,等温线逐渐向浓度轴弯曲,这源于疏水作用以及解离的2,4-二氯苯酚与吸附剂之间静电作用的共同影响。根的吸附能力大于纤维素,这与根中含有类脂物质有关。Under various pH conditions, the sorption differences of polar contaminants such as 2,4-dichlorophenol and nitrobenzene on the dried wheat root were studied with batch equilibration techniques, with standard cellulose as the control sorbent and phenanthrene as the control sorbate. Results indicated that the hydrophobic partition played a primary role in pollutants sorption, and their sorption coefficient increased with the enhancement of hydrophobicity of the sorbates. The sorption of unionized polar contaminants including nitrobenzene was similar with hydrophobic contaminants such as phenanthrene, which was characterized with linear isotherm and with no significant difference between pH and sorption（P〉0. 05）. However, for the dissociated polar pollutants such as 2,4-dichlorophenol, the sorption decreased with increase of solution pH. The sorption isotherm was linear at pH 5.0, while was nonlinear with a concave-downward shape at pH 7.0 or 8.0, owing to the combined effect of electrostatic repulsion and hydrophobie interaction. The sorption on the wheat roots was greater than that on the celluloses, owing to higher lipid contents in the roots.

关 键 词：小麦根 纤维素 吸附 极性有机物 PH 

分 类 号：X503[环境科学与工程—环境工程]