| abstract |
A method for cleaning a microfiltration or ultrafiltration membrane comprising the step of contacting said membrane with a hydroxyl radical. The method is particularly suited for oxidation resistant membranes, such as Halar, with biological or organic fouling. The hydroxyl radicals for example are generated from an aqueous solution of transition metal ions, such as molybdenum, chromium, cobalt, copper, tungsten or more particularly iron, in conjunction with hydrogen peroxide under acidic conditions. The method is particularly suited to hollow fibre membranes where oxygen bubo es foamed in the course of the reaction create a flow that draws more liquid in through a wall of a vertical hollow fibre membrane and pushes water out of the top of the lumen, and where oxygen bubbles act to self agitate the solution which can break up a filter cake, where present, on the microfiltration or ultrafiltration membrane surface. |