不同地域天然伊利石表面酸碱特性的比较

The acid-base characteristics of different natural illits

利用电位滴定技术和恒定容量表面络合模式表征不同来源天然伊利石的表面酸碱性质 .鉴于固体基质在酸量滴定过程中发生溶解 ,相应的滴定上清液被视为体系空白 .考虑到水解铝、硅酸和伊利石表面活性位之间的表面络合或沉淀反应 ,提出两种表面质子反应模型 .对其中的特例 ,还考虑了表面离子交换反应 .模拟程序的拟合结果显示两种模型对水解伊利石体系的滴定行为均可获得满意的描述 .

The acid\|base characteristics of different natural illites were investigated by potentiometric titrations, and interpreted using the constant capacitance surface complexation model. The acidimetric supernatant was regarded as the system blank, due to considerable release of Al and Si from illite substrate. The surface complexation or precipitation between soluble aluminum species, silicic acid and active sites on illite surface, was taken into account. Two surface proton\|reaction models were proposed. The ion exchange reaction was also considered for a special case. Optimization results indicated that both models could provide a good description of the titration behavior for all aqueous illite systems in this study. The similar intrinsic acidity constants for the different illites showed some generalities in their acid\|base properties.