不同吸附模型分析天然有机物的吸附特征

Analysis of adsorption characteristics on natural organic matter by different adsorption models

为探讨活性炭吸附土壤溶出天然有机物(NOM)的最佳模型,利用Langmuir模型、Freundlich模型和Modified Freundlich模型分别对活性炭吸附不同浓度土壤(农田和森林)溶出NOM的数据进行拟合分析,发现与前两种模型相比,Modified Freundlich模型更适合用于对土壤溶出非均质复杂混合物NOM吸附过程的描述。用UV260表征溶出NOM的浓度的情况下,当农田和森林土壤溶出NOM的浓度范围分别在53.4~109.2/m和50.6~185.9/m时,低浓度的土壤溶出NOM更适合用于NOM吸附特性的分析。此外,在三种模型中与吸附强度相关参数(b、K和k)的分析中,K与b线性关系的具有高度相关性(R2=0.9857),而k与K(R2=0.0775)和k与b(R2=0.1429)的相关性较低,即Langmuir模型和Freundlich模型在描述NOM单层吸附过程中具有较好的一致性。

The Langmuir model, Freundlich model and modified Freundlich model were employed to fit the adsorption data of natural organic matter(NOM)released from agricultural and forest soils, under different initial concentrations, for exploring the best model for NOM adsorption. And the modified Freundlich model was proved to be the best one in the three models for describing the adsorption process of heterogeneous compounds of NOM. In the range of 53.4~109.2/m and 50.6~185.9/m by using UV260 value represented the NOM concentrations for agricultural and forest soils, respectively, lower initial concentration is more suitable for the investigation of adsorption analysis of NOM released from soils. Moreover, the linear correlations of adsorption capacity parameters for three models were also conducted, the high correlation coefficient between K and b(R2=0.9857)and the low values of k and K(R2=0.0775)as well as k and b(R2=0.0775) demonstrated that the Langmuir and Freundlich models possessed good consistency in describing the NOM monolayer adsorption process.