平板型颗粒在非对称电解质中的电位分布

THE POTENTIAL DISTRIBUTIONS OF PLATE COLLOIDAL PARTICLES IN ASYMMETRIC ELECTROLYTES

根据扩展的朗格缪尔方法 ,推导出在不对称电解质中平板型颗粒在中低电位条件下的电位分布表达式。在距板较近的范围内 ,此表达式与文献值相比较吻合程度较好。对于相同类型的电解质 ,平板型颗粒表面电位越高 ,曲线重叠越好 ;不同类型的电解质 ,当b∶a越大时 ,电位曲线的重叠程度越好。在表面电位相同时 ,对于a∶b型电解质 ,a值相同时 ,b值越大电位分布曲线衰减越快 ;b值相同时 ,a值越小电位分布曲线衰减越快。在表面电位为 4时 ,2∶3,1∶3和 1∶2型电解质的相对误差分别为 2 .9% ,2 .76 %和 2 .4 5 % ;表面电位为 3时 ,2∶3,1∶3和 1∶2型电解质的相对误差分别为 3.11% ,2 .95 %和 2 .92 % ;表面电位为 2 .5时 ,2∶3,1∶3和 1∶2型电解质的相对误差分别为3.37% ,3.19%和 3.39% ;表面电位为 2时 ,2∶3,1∶3和 1∶2型电解质的相对误差分别为 3.87% ,3.6 3%和 4 .2 2 %。

Using the extended Langmuir's method, an approximate expression of surface potential distributions was derived with the plate distance for asymmetric electrolytes in the case of low and moderate constant surface potential. It was found that this approximation worked quite well for small plate separations for asymmetric electrolytes at low and moderate surface potentials. For the same type of electrolytes, the higher the surface potentials were, the better the potential curves overlapped; for different electrolytes, the larger the b∶a, the more accurate the results were. At the same potential, the larger the value of b for a fixed a, the faster the potential curve decreased and the smaller the value of a for a fixed b, the faster the potential curve decreased. For y_0=4, the relative errors are 2.9%, 2.76% and 2.45% for 2∶3, 1∶3 and 1∶2 cases respectively. For y_0=3, the relative errors are 3.11%, 2.95% and 2.92%. For y_0=2.5, the relative errors are 3.37%, 3.19% and 3.39%. For y_0=2, the relative errors are 3.87%, 3.63% and 4.22%.