Electroanalysis of Layer Charge Character on Clay Minerals

• Main Authors: Shih-Kun Cheng, 鄭世堃
• Other Authors: 陳鴻基
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/13860663127189917937

碩士 === 中興大學 === 土壤環境科學系所 === 95 === Abstract Structure and system are improved recently due to progress of transistor and integrated circuit. Screen printed electrode has advantage of low cost, easy modification and disposability that promote rapid development of electroanalysis. We studied three subjects of electroanalysis on clay minerals. 1. Electroanalysis of Surface Charge of Alkylammonium Intercalated Smectites Electroanalysis of surface charge of alkylammonium intercalated smectites. In this subject, surface charge of alkylammonium intercalated smectites was studied by using electrochemical technique coupled with X-ray and IR instruments. The electrochemical behavior of paraquat clearly indicated an apparent difference of surface charge between Na-montmorillonite and ferruginous smectite, originated from octahedral and tetrahedral charge. Intercalated alkylammonium could change the surface charge characteristics of these two montmorillonite. The effect of alkylammonium in surface charge was found to increase with the carbon number of alkylammonium. The surface charge of ferruginous smectite was most affected by alkylammonium. 2. Application of electrochemical technique to study the catalysis of catechol by clay minerals Application of electrochemical technique to study the catalysis of catechol by clay minerals. In this subject, the catalysis and polycondensation of catechol and glycine by clay minerals using screen-printed carbon electrode coupled with cyclic voltammetry. The results indicated electroanalytical technique is a rapid and convenient method in studying catalysis and polycondensation of catechol. The order of catalytic ability was ferruginous smectite > kaolinite > Na-montmorillonite. Ferruginous smectite had larger oxidative and reductive power due to the existence of Fe2+/3+ in octahedral layer, and hence its catalysis for catechol was much obvious than other clay minerals. Furthermore, porosity of clay film might affect clay-modified electrode in studying catalysis and polycondensation of catechol. Overall, cyclic voltammetry at different scan rate could be a rapid and convenient method in catalytic study of clay minerals. Porosity of clay film might affect clay-modified electrode in studying catalysis and polycondensation of catechol. Overall, cyclic voltammetry at different scan rate could be a rapid and convenient method in catalytic study of clay minerals. 3. Effects of clay minerals on electroanalysis of copper-plated screen printed electrode Effects of clay minerals on electrochemical character of copper-plated screen printed electrode. In this subject, we modified copper-plated screen printed electrode with ferruginous smectite, Na-montmorillonite and kaolinite. Oxidative and reductive signals increased due to the adsorption of copper ion on clay minerals. We study the movement of paraquat in clay film. The results indicated the order of the signals of paraquat was ferruginous smectite > Na-montmorillonite > kaolinite. The Rpc and Rpa of clay modified copper-modified screen printed electrode were more than that of clay modified screen printed electrode. When paraquat was added, the order of the signals for copper was kaolinite > Na-montmorillonite > ferruginous smectite. That indicated electrochemistry od copper was affected by adsorption of copper ion on clay minerals and layer charge of clay minerals. Clay modified copper-plated screen printed electrode could determine larger current of paraquat, and movement of paraquat in clay film of clay modified copper-plated screen printed electrode was more than that of clay modified carbon electrode. Clay modified copper-plated screen printed electrode has larger potential for determination of some analytic compounds. Electroanalysis has rapid, convenient, variable and inexpensive characters, and that has larger potential for studying clay minerals. Electroanalysis is a advantaged technique for development and popularization.