Yuhong Li, Weidong Gao, Kongshuang Zhao, Gang Yang, Zhonghe Zhu, Rongjing Cui
Jiangsu Laboratory of Advanced Functional Materials, School of Chemistry and Material Engineering, Changshu Institute of Technology, Changshu, 215500, China.
The journal of physical chemistry. B 2013 Mar 28The adsorption process of salicylic acid (SA) onto chitosan membrane is monitored in real time by the dielectric relaxation spectroscopy (DRS) method. A unique dielectric relaxation, which is related to the macroscale concentration polarization layers (CPLs) in the SA solution caused by the adsorption, is observed. By modeling the measured systems composed of the membrane, the CPLs, and the SA solution, the dielectric spectra are analyzed systematically on the basis of the interfacial polarization theory. The parameters about the constituent phases, i.e., the dielectric constant εm and the conductivity κm of the chitosan membrane, the conductivity distribution (κ1 to κ2), and the thickness dCPL of the CPL, are obtained. The time-dependent εm and κm give insight into the microstate of the chitosan membrane during the adsorption. Furthermore, the time evolution of the conductivity gradient of the CPL, Δκ/dCPL, is combined to interpret the adsorption mechanism. It is suggested that the noninvasive dielectric monitoring may be applied to many adsorption and release processes.
Yuhong Li, Weidong Gao, Kongshuang Zhao, Gang Yang, Zhonghe Zhu, Rongjing Cui. Real-time monitoring on the adsorption process of salicylic acid onto chitosan membrane using dielectric spectroscopy: macroscale concentration polarization and dynamics. The journal of physical chemistry. B. 2013 Mar 28;117(12):3337-44
PMID: 23441927
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