Parametric evaluation of flux decline during ultrafiltration of protein solutions

Ultrafiltration is finding wide application in many industrial separation processes. We have investigated the application of ultrafiltration for the concentration and separation of protein solutions. Flux decline, varying both initial fluid properties and operating conditions, was experimentally studied using cellulose acetate hollow fibre modules. In addition, some methods for reducing flux decline, including backwash, backflush and chemical cleaning have been tested. Results indicate that flux decline is mainly due to macrosolutes from the feed. However, moderate ultrafiltration pressure may lead to a slow flux decline in spite of low initial permeation rates. Appropriate operational cycles were selected based on specific fluid properties as well as operating conditions. The use of chemical cleaning agents, especially sodium hypochlorite, proved to be highly effective in increasing the permeation rate to almost initial levels. Process design and scaling-up conditions are discussed.