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首页> 外文会议>International conference on remediation of contaminated sediments >A DIFFERENTIAL HYSTERESIS COEFFICIENT FOR CHARACTERIZING THE ADSORPTIVE-DESORPTIVE BEHAVIOUR OF CONTAMINANTS IN SEDIMENTS
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A DIFFERENTIAL HYSTERESIS COEFFICIENT FOR CHARACTERIZING THE ADSORPTIVE-DESORPTIVE BEHAVIOUR OF CONTAMINANTS IN SEDIMENTS

机译：用于表征沉积物中污染物的吸附 - 去膜行为的差分滞后系数

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In this work, a new hysteresis coefficient is proposed and its usefulness for determining the adsorption-desorption behavior of pollutants on sediments and soils is examined. In sediment pollution and remediation, the adsorption and desorption play a key role on pollutants availability and transport. For several pollutants and solid matrices such as sediments, the desorption pathway is different from that of the adsorption. This phenomenon is known as hysteresis. Here, we define a hysteresis coefficient CH as the ratio of the slope (derivative) of the adsorption curve and the slope of the desorption curve in a given point (C_j, q_j) of interest. We demonstrate that: ⅰ) CH is dimensionless; ⅱ) when hysteresis is not important, CH=1, i.e., the adsorption is reversible; ⅲ) when hysteresis is important, CH>1, i.e., the adsorption is irreversible; ⅳ) the greater the hysteresis, the greater the CH; ⅴ) the CH can be determined at any convenient point (C_j, q_j) of interest of the adsorption curve, peforming a few consecutive desorption steps, and there is no need to determine the full adsorption-desorption cycle; ⅵ) the CH is consistent (i.e. C_H ≥1) for the most common isotherm models (linear, Freundlich and Langmuir); ⅶ) there exist also analytical, particular, simple equations for finding CH for the linear, Freundlich and Langmuir isotherm models; ⅷ) the CH shows several advantages over the well known hysteresis indices defined by Huang and Weber (1997) and Ma et al. (1993). Using experimental data from refereed literature, we also show that the CH provides a quantitative basis for ⅰ) comparing the irreversibility of the adsorption of different individual pollutants on a given soil; ⅱ) comparing the irreversibility of the adsorption of a given pollutant on different soils; ⅲ) determining the effect of aging and weathering on adsorption irreversibility. Overall, the CH allows for the quantitative determination of pollutant availability and this, in turn, could be a valuable tool for estimating the remediation potential of polluted sediments.
机译：在这项工作中，提出了一种新的滞后系数，并研究了确定污染物对沉积物和土壤的吸附 - 解吸行为的有用性。在泥沙污染和修复中，吸附和解放在污染物可用和运输方面发挥着关键作用。对于几种污染物和沉积物如沉积物，解吸途径与吸附的不同。这种现象被称为滞后。这里，我们将滞后系数CH定义为吸附曲线的斜率（衍生）与感兴趣的给定点（C_J，Q_J）中的解吸曲线的斜率的比率。我们证明：Ⅰ）CH是无量纲的; Ⅱ）当滞后不重要时，CH = 1，即吸附是可逆的; Ⅲ）当滞后是重要的时，CH> 1，即吸附是不可逆转的; ⅳ）滞后越大，CH越大; ⅴ）CH可以在吸附曲线的兴趣的任何方便的点（C_J，Q_J）处确定，Peforming几个连续的解吸步骤，并且不需要确定完全吸附 - 解吸周期; ⅵ）最常见的等温模型（即，C_H≥1）一致（即C_H≥1）（Linear，Freundlich和Langmuir）; ⅶ）还存在分析，特别简单的方程，用于查找线性，Freundlich和Langmuir等温线模型的CH; ⅷ）CH显示出在黄色和韦伯（1997）和MA等人定义的众所指知的滞后指数上的几个优点。 （1993）。利用来自裁判文献的实验数据，我们还表明CH提供了Ⅰ的定量基础，比较了不同个体污染物对给定土壤的吸附的不可逆性; Ⅱ）比较不同土壤上给定污染物的吸附的不可逆性; Ⅲ）测定老化和风化对吸附不可逆性的影响。总的来说，CH允许定量测定污染物可用性，而这可能是估算污染沉积物的修复潜力的有价值的工具。

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