Sähköosmoosi

Sähköosmoosi, also known as electroosmosis, is a physical phenomenon that occurs when an electric field is applied across a porous material containing a fluid. This process results in the movement of the fluid through the pores due to the electrical charges present on the pore surfaces.

In a typical setup, an electric potential difference is established between two electrodes embedded within the porous medium. The pore walls usually carry a net electrical charge. This charge attracts ions of opposite sign from the surrounding fluid, forming an electrical double layer. When the electric field is applied, the mobile ions within this double layer are forced to move, dragging the bulk fluid along with them. The direction of fluid flow is determined by the polarity of the applied voltage and the charge of the pore surfaces.

Sähköosmoosi has several practical applications. It is used in dewatering processes, such as in civil engineering for soil consolidation and in waste treatment to remove water from sludges. The principle is also employed in analytical chemistry for capillary electrophoresis, where it contributes to the overall movement of the analyte solution within a capillary. Furthermore, sähköosmoosi plays a role in biological systems, particularly in the movement of fluids across cell membranes and in kidney filtration. Research continues to explore its potential in areas like microfluidics and targeted drug delivery.