天然産アロフェン表面酸/塩基特性の表面錯形成モデリングによる解析

概要

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The variable surface charges of natural allophane were measured by the potentiometric titration at the three ionic strengths (I=0.001, I=0.01 and I=0.1) under C0_2 free system. The results showed that the total charge of natural allophane strongly depended on the ionic strength and that the point of zero charge was pH=5.0. The titration curve obtained at I=0.1 system was analyzed by means of surface complexation modeling. The results of the modeling revealed that the surface charge of allophane was originated from the combinative contribution of protonation/deprotonation of aluminol site and deprotonation of silanol site. The contribution of aluminol to the total surface charge was 5 times larger than that of silanol. The acidity constants and surface site densities estimated from I=0.1 system successfully described the charging behavior of I=0.01 system, confirming the validity of proposed mechanism of the surface reaction.
日本粘土学会の論文
2004-05-26