| Summary: | 碩士 === 國立成功大學 === 資源工程學系碩博士班 === 91 === The traditional methods of surface area measurements are BET method (Branouer, Emmet and Teller method), EG method (Ethylene glycol method), EGME method (Ethylene glycol monoethyl ether method) and MB method (Methylene blue method). BET method has been recognized that it can not measure the total surface areas of expandable clays due to nitrogen does not interact with or have access to the interlayer surfaces. The surface area measurement result of EG, EGME methods are influenced by the species of exchangeable cation within clay. MB method has been used to measure surface area of clay in solution, still the result is influenced by CEC (Cation Exchange Capacity) of clays samples. The determination of surface areas of expandable clay by PEO (Polyethylene oxide) adsorption in aqueous solution is the main research topic in this study. Our discussion is focus on the feasibility of using ethylene oxide chain to determine the surface areas of expandable clay.
Experimental results indicate that the ethylene oxide chain of PEO is coating on the interlamellar space of montmorillonite fully, which is composed predominately of a SiO2 (Si tetrahedral sheets) surface. Consequently, we can use the area of a single ethylene oxide chain unit to calculate the surface area of expandable clay. The surface areas of montmorillonite sample A, B, C, D determined by PEO adsorption method were 337 m2/g, 116 m2/g, 187 m2/g and 198 m2/g respectively. In this study, we also found that the surface areas of expandable clays in aqueous solution are related to particle size but not to CEC. Conclusively, we found that PEO adsorption is suitable way to measure the surface area expandable clays in solution.
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