MECHANISM OF REMOVING MONODISPERSE GOLD PARTICLES FROM A SUSPENSION USING CUPRAMMONIUM REGENERATED CELLULOSE HOLLOW FIBER (BMM HOLLOW FIBER)

In order to clarify the mechanism of removing viruses with cuprammonium regenerated cellulose hollow fiber (BMM hollow fiber), monodisperse gold particles were used. The dependences of the concentration of gold particles in the filtrate on the particle concentration and the particle size were investigated. The particles were considered to be caught by BMM through two mechanisms, that is, plugging of capillaries and trapping within voids. Here, the capillaries stand for the narrow pathway among neighboring cellulose particles which construct the membrane and the voids the bulky space surrounded by the aggregated cellulose particles. In the initial stage, the plugging of the capillaries causes decrease in the particle concentration. On the other hand, trapping leads to the occupation of spaces within the voids. When the voids near the inner surface are occupied by gold particles, the particles proceed inwards through channels formed by voids and finally fiow out from the outer surface of the membrane. This leads to increase in the particle concentration in the preceding stage. The removability of the particles depends both on the relative size bewtween the capillary (or the void) and the particle and on the trapping capacity. © 1990 The Society of Polymer Science, Japan.