Di-(2-ethylhexy)-phthalate在细菌及细菌-矿物复合体表面的吸附解吸行为

Adsorption and desorption behaviors of Di-(2-ethylhexy)-phthalate on bacterium and bacterium-minerals associations

以土壤中分离出的邻苯二甲酸二异辛酯(DEHP)高耐性细菌(伯克霍尔德菌,Burkholderia sp.)及3种常见矿物为实验材料,研究Burkholderia sp.及其矿物复合体对DEHP的吸附解吸行为,包括吸附动力学、吸附等温曲线、pH的影响、FTIR分析等.结果显示,Burkholderia sp.能在较短时间内完成对DEHP的吸附;DEHP在细菌表面的吸附符合Langmuir等温吸附方程(R2>0.97);Burkholderia sp.吸附DEHP的最适pH为7.0~8.0.蒙脱石、针铁矿、高岭土及细菌对DEHP的吸附能力大小依次为:蒙脱石>针铁矿>伯克霍尔德菌>高岭土;同时,蒙脱石-细菌复合体系对DEHP结合能力最强,而高岭土和针铁矿-细菌复合体系对DEHP的结合强度较小.FTIR分析结果表明细菌表面的蛋白质及脂质部分在DEHP吸附过程中的作用较大,而疏水性作用等是DEHP与细菌及复合体相互结合的主要作用力.这些结果都与DEHP在环境中的迁移转化行为密切相关,对评估该类化合物的环境生态风险以及控制环境污染都具有重要的指导意义.

A Di-（2-ethylhexy）-phthalate （DEHP）-tolerant bacterium （Burkholderia sp. ） and three bacterium-minerals （montmorillonite, goethite and kaolinite） associations were applied in the DEHP absorption. The adsorption kinetic, adsorption isotherm, the effect of initial pH, and Fourier transform infrared spectroscopy （FTIR） analysis were conducted to investigate the adsorption and desorption behaviors of DEHP on the bacterium or associations. Results show that Burkholderia sp. exhibited rapid biosorption of DEHP. The adsorption isotherms of DEHP were well fitted with the Langmuir isothermal model and the order of DEHP adsorption capacity was montmorillonite 〉 goethite 〉 Burkholderia sp. 〉 kaolinite. Furthermore, the affinity of bacterium- montmorillonite to DEHP was stronger than that of bacterium-goethite and bacterium-kaolinite associations. The optimum pH for DEHP adsorption by bacterium was observed to be 7.0 ~ 8.0. FTIR spectra suggested that cell wall proteins and lipid involved in DEHP adsorption on Burkholderia sp. Moreover, hydrophohic interaction might play an important role in the DEHP adsorption by the bacterium or bacterium-minerals associations. Data obtained in this study would provide valuable information for a better understanding of the migration and transformation behavior of DEHP in the contaminated environment, and be significant to evaluate the ecological risk and control the environment pollution.