Adsorptive Removal of Cadmium (II) from Aqueous Solution by Multi-Carboxylic-Functionalized Silica Gel: Equilibrium, Kinetics and Thermodynamics

2017 3rd International Conference on Environmental Science and Material Application

生态环境科学;材料科学

Li, Min^1 ; Meng, Xiaojing^1 ; Yuan, Jinhai^1 ; Deng, Wenwen^1 ; Liang, Xiuke^1

Department of Chemical Engineering, Chongqing University of Science and Technology, Chongqing

401331, China^1

关键词: Free energy of adsorption;    Freundlich and Langmuir isotherms;    Kinetics and thermodynamics;    Pseudo second order kinetics;    Pseudo-first order kinetic model;    Pseudo-first order kinetics;    Pseudo-second-order kinetic models;    Thermodynamics parameters;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/108/2/022015/pdf
DOI  :  10.1088/1755-1315/108/2/022015

来源: IOP

【 摘 要 】

In the present study, the adsorption behavior of cadmium (II) ion from aqueous solution onto multi-carboxylic-functionalized silica gel (SG-MCF) has been investigated in detail by means of batch and column experiments. Batch experiments were performed to evaluate the effects of various experimental parameters such as pH value, contact time and initial concentration on adsorption capacity of cadmium (II) ion. The kinetic data were analyzed on the basis of the pseudo-first-order kinetic and the pseudo-second-order kinetic models and consequently, the pseudo-second-order kinetic can better describe the adsorption process than the pseudo-first-order kinetic model. Equilibrium isotherms for the adsorption of cadmium (II) ion were analyzed by Freundlich and Langmuir isotherm models, the results indicate that Langmuir isotherm model was found to be credible to express the data for cadmium (II) ion from aqueous solution onto the SG-MCF. Various thermodynamics parameters of the adsorption process, including free energy of adsorption (ΔG0), the enthalpy of adsorption (ΔH0) and standard entropy changes (ΔS0), were calculated to predict the nature of adsorption. The positive value of the enthalpy change and the negative value of free energy change indicate that the process is endothermic and spontaneous process.