1,2-二氯苯在3种基质中的吸附研究

Adsorption of 1,2-Dichlorobenzene in three soil substrates from constructed wetlands

采用平衡振荡法研究了1,2-二氯苯在3种人工湿地基质中的吸附情况。结果表明,1,2-二氯苯在12 h达到吸附平衡,可由Lagergren一级吸附动力学模型得出3种土壤的吸附速率常数分别为0.3338 h-1、0.2679 h-1和0.2537 h-1,壤土的吸附效果明显好于细砂、粗砂。30℃的吸附等温线既符合Freudlich等温式又符合Langmuir等温式,结合壤土对1,2-二氯苯的吸附量随着温度的升高呈现先减小然后增大最后又下降的趋势,表明这一温度条件下的吸附实质上处于物理吸附向化学吸附过渡的状态。作为一种憎水性极强的非离子型有机化合物,1,2-二氯苯在酸性或碱性条件下的吸附量显著增加,吸附取决于分配作用。

The adsorption characteristics of 1,2-Dichlorobenzene in three kinds of soils substrates,which came from pilot constructed wetlands,were studied by balanced oscillation.The results showed that o-DCB achieved adsorption equilibrium in 12 hours,educing the first-order adsorption rate constants of three soils by Lagergren equation that were 0.3338 h-1,0.2679 h-1 and 0.2537 h-1,respectively,which indicated that the adsorption capacity of loam was higher than that of fine sand or coarse sand.The adsorption isothermal line on 30 ℃ could be described by Freudlich or Langmuir equation,which was actually a transition state from physisorption to chemisorption,considering the adsorption amount of o-DCB by loam firstly decreased then raised and finally declined with the increase of temperature.Being one of nonionic organic compounds with strong hydrophobicity,o-DCB adsorbed in soils was intensified under acidic or alkaline conditions,in which partitioning played a key role.