Zhang Guangzhi, Hu Hao, Sun Weiling, Ni Jinren
Department of Environmental Engineering, Peking University, The Key Laboratory of Water and Sediment Sciences, Ministry of Education, Beijing 100871, China.
J Environ Sci (China). 2009;21(6):795-800. doi: 10.1016/s1001-0742(08)62343-8.
Kinetics and isotherms of Triton X-100 sorption on soil, base-extracted soil (BE), humic acid (HA) and humin (HM) were investigated respectively to get better understanding on characteristics of the surfactant sorption onto different soil organic matters (SOMs). It was demonstrated that the kinetics results could be satisfactorily described by the pseudo-second order model. The half of the time to reach equilibrium (t1/2) for different sorbents followed the sequence of soil > HA > BE > HM. Furthermore, the calculated equilibrium sorption capacity (C(eq)) was found in the sequence of HA > BE > HM > soil, which agreed well with the experimental results. The isotherms of Triton X-100 sorption on soil and HA could be well described by the S-type isotherm, but BE and HM by the L-type. The isotherms of all the four sorbents were found reasonably fitted to the Langmuir equation. The K(d) value, defined as the ratio of Triton X-100 in sorbent and in the equilibrium solution for given concentrations, generally followed the order of HM > HA > soil > BE. Separated HM and HA showed high affinity for Triton X-100, but the HA and HM in soil and BE were tightly bounded by the minerals. Thus, the HA on the soil surface might dominate the sorption, whereas the bounded HM would play a key role upon the surfactants being penetrated inside the soil.
分别研究了Triton X-100在土壤、碱提取土壤（BE）、腐殖酸（HA）和胡敏素（HM）上的吸附动力学和等温线，以更好地了解表面活性剂在不同土壤有机质（SOMs）上的吸附特性。结果表明，伪二级模型能够很好地描述动力学结果。不同吸附剂达到平衡的时间的一半（t1/2）遵循土壤>HA>BE>HM的顺序。此外，计算得到的平衡吸附容量（C(eq)）顺序为HA>BE>HM>土壤，这与实验结果吻合良好。Triton X-100在土壤和HA上的吸附等温线可用S型等温线很好地描述，而BE和HM的可用L型等温线描述。所有四种吸附剂的等温线都能较好地拟合Langmuir方程。K(d)值定义为给定浓度下吸附剂和平衡溶液中Triton X-100的比值，一般遵循HM>HA>土壤>BE的顺序。分离出的HM和HA对Triton X-100表现出高亲和力，但土壤和BE中的HA和HM被矿物质紧密结合。因此，土壤表面的HA可能主导吸附，而结合的HM在表面活性剂渗透到土壤内部时将起关键作用。
