关于固-液界面吸附中吸附剂浓度效应的表面组分活度模型研究

It has observed in the solid-liquid interface adsorption studies that the adsorption equilibrium constants obtained on the basis of the existing adsorption thermodynamics model associate with the sorbent concentration. This phenomenon was described as “sorbent concentration effect” (Cs-effect). This seems to contradict the thermodynamic equilibrium theory. The Cs-effect models have not been widely accepted. Our group proposed a new model, surface component activity (SCA) model, which will need to be improved. This project intends to choose different adsorption systems, considers the environmental factors (e. g. pH, temperature, ionic strength) for Cs-effect strength, investigates the applicability of the SCA model. We will discuss the physical meaning and influence factors of the model parameters, improve the determining method for model parameters and the SCA-thermodynamics equations, construct the SCA-kinetics equations and explore the micro mechanism of the sorbent concentration effect. This work has important theoretical significance and application value. It may deepen the scientific understanding of the solid-liquid interface adsorption phenomenon and provide the basis for related projects, such as wastewater treatment and soil restoration design.

在固-液界面吸附研究中发现，依据现有的吸附热力学模型得出的吸附平衡常数与吸附剂浓度有关，这一现象被称为 “吸附剂浓度效应”（Cs-effect），这与热力学平衡理论相悖，现还没有成熟的热力学模型描述或预测这种现象。本课题组提出了表面组分活度（SCA）模型，但尚需完善。本项目拟选取不同吸附体系进行吸附研究，系统考察环境因素（pH、温度、离子强度等）对Cs-effect强度的影响，重点考察SCA模型的适用性，通过探讨相关模型参数的物理意义和影响因素，改进模型参数值的测定方法及SCA热力学方程，并构建SCA动力学方程，根据实验数据对新方程进行验证，同时探讨Cs-effect的微观机理。这项工作具有重要的理论意义和应用价值，可加深对固-液界面吸附现象的科学认识，为吸附技术在相关工程（如废水处理和土壤修复）中的应用设计提供基础依据。

在固-液界面吸附研究中，发现一反常现象被称为 “吸附剂浓度效应”（Cs-effect），本课题组前期提出了表面组分活度（Surface component activity model，SCA）模型以解释这一现象。本项目优化完善了SCA模型，建立了相关模型参数（表面组分活度系数等）的测定（或拟合）方法，并构建了SCA动力学方程；实验研究了金属离子和有机污染物在固-液界面的吸附过程，皆表现出明显的Cs-effect，并证实了SCA方程的普适性；考察了 pH、离子强度、温度和特性吸附离子等因素对Cs-effect的影响，发现均不影响SCA方程所示的关系；阐释了吸附平衡和吸附速率与吸附剂浓度间的理论关系，加深了对固-液界面吸附特别是SCA模型适用性的认识；阐释了吸附剂浓度效应对固-液界面反应和吸附性能的影响规律及机理；为相关废水处理和土壤修复等工程的设计提供基础依据。