Electrical double layer on silver iodide. Influence of temperature and application to sol stability

Abstract

Results on the double layer charge and capacitance on AgI previously obtained have been improved and extended to include the temperature dependency between 5 and 85°C. At room temperature, alkali ions adsorb specifically on negative AgI, which gives rise to a marked ion specificity in the double layer capacitance and which is responsible for the lyotropic sequence in the coagulation concentrations. With increasing temperature, charge and capacitance decrease, with a concurrent decrease in specificity. At 65°C and above, the double layer is predominantly diffuse and nonspecific. The lyotropic sequence in the coagulation concentrations is then also lost. There is some evidence for a phase transition around 50°C in the adsorbed water layer.

On the impedance of the silicon dioxide/electrolyte interface

“…Most of the present knowledge of the electrical double layer stems frcm the study of these two systems. An important aspect of the silver iodide system is that its double-layer properties have been studied in two different ways: the measurement of charge on colloid suspensions [3], from which the double layer capacitance can be derived, and dtrect measurement of this capacitance with Ag/AgI solid electrodes, which confirms the value derived by the indirect method [2].…”

“…Most of the present knowledge of the electrical double layer stems frcm the study of these two systems. An important aspect of the silver iodide system is that its double-layer properties have been studied in two different ways: the measurement of charge on colloid suspensions [3], from which the double layer capacitance can be derived, and dtrect measurement of this capacitance with Ag/AgI solid electrodes, which confirms the value derived by the indirect method [2].Such a confirmation does not yet exist for the SiOJelectrolyte interface where H+ and OH-ions are potential determinin g ions (pdi). The only values of the double-layer capacitance on SiO, mentioned in the literature have been calculated 0022-0728/83/$03 00 0 1983 Eke&r !Zequola SA…”

Ice nucleation efficiency of AgI: review and new insights

“…The solubility decreases with decreasing temperature and reaches a value < 10 −17 at 273 K (Lyklema, 1966). Nevertheless, a small particle in a large droplet will dissolve to some degree.…”

“…For the liquid layer h, a value equal to the particle radius is often assumed (Sheng et al, 2008). Silver iodide is a sparingly soluble salt with a solubility product of around 10 −16 at 298 K (Hiemstra, 2012;Lyklema, 1966). The solubility decreases with decreasing temperature and reaches a value < 10 −17 at 273 K (Lyklema, 1966).…”

“…Silver iodide is a sparingly soluble salt with a solubility product of around 10 −16 at 298 K (Hiemstra, 2012;Lyklema, 1966). The solubility decreases with decreasing temperature and reaches a value < 10 −17 at 273 K (Lyklema, 1966). For an estimated saturation concentration of AgI in water of C s = 7.4 × 10 −10 g cm −3 at T < 273 K and assuming C t = 0, we obtain dM/ dt = 9 × 10 −19 g s −1 for a 200 nm particle and dM/ dt = 9 × 10 −20 g s −1 for a 20 nm particle.…”