2,4-二氯苯酚在太湖沉积物中的吸附/解吸行为研究

Study on the Sorption/Desorption Behaviors of 2,4-Dichlorophenol in Tai Lake Sediments

采用吸附、解吸动力学实验方法,研究了太湖沉积物对2,4-二氯苯酚(2,4-Dichlorophenol)的吸附、解吸规律,同时探讨了环境因子如温度、pH值以及离子强度等对其吸附行为的影响。结果表明,2,4-DCP在太湖沉积物中的吸附/解吸在4h内快速达到平衡;线性等温式和Freundlich等温式都可以较好地描述太湖沉积物对2,4-DCP的吸附行为,即存在分配作用和表面吸附作用两种吸附机制;温度和离子强度的增加有利于沉积物对2,4-DCP的吸附,pH值对2,4-DCP吸附等温线的影响则不明显;2,4-DCP在贡湖沉积物中的吸附/解吸存在着明显的不可逆吸附,即吸附/解吸迟滞行为。

In the present research, 2,4-Dichlorophenol （2,4-DCP）, an ionizable organic contaminant priority-controlled in many countries, was selected to study their sorption/desorption properties and mechanisms in Tai Lake sediments. In addition, the effects of some environmental factors, such as temperature, pH value and ionic strength, on the sorption isotherm of 2,4-DCP were explored. All that we have done may provide some useful theoretical data for the development of remediation technologies of sediment in the organic-contaminated lakes or shellow groundwaters. Experimental results showed a rapid sorption/desorption equilibrium of 2,4-DCP in the Tai Lake sediments in 4 hours. Either linear or Freundlich sorption isotherm can describe the sorption behaviors of 2,4-DCP in Tai Lake sediments. Therefore, the possible sorption mechanisms may include partition and adsorption. Temperature and ionic strength seemed to promote the sorption of 2,4-DCP to the sediment of Gong Lake, while pH value showed negligible effects. Moreover, a lag between sorption and desorption （ i.e., irreversible sorption） was observed, while the qmax^irr is about 4 μg·g^-1.