Abstract: The cellulosic hollow-fiber membranes of the invention are useful in fluid processing apparatus typically for artificial dialysis. Each fiber has a tubular microporous wall having micropores and defining a lumen. The micropores have an average pore diameter of about 55 to about 300 .ANG.. The cellulosic hollow fibers exhibit a percent removal of .beta..sub.2 -microglobulin through adsorption of up to 10% after a solution of 20 mg/l of .beta..sub.2 -microglobulin in water is circulated through the fiber lumen for 3 hours. They also exhibit a sufficient filtration fraction of .beta..sub.2 -microglobulin and a ultrafiltration rate to remove .beta..sub.2 -microglobulin from blood predominantly through filtration while preventing contamination of the membranes with .beta..sub.2 -microglobulin due to adsorption and controlling the amount of water removed from the blood.

Abstract: A hollow fiber membrane fluid processing apparatus comprising a housing, a fluid processing hollow fiber membrane bundle in the housing, partitions fluid tightly securing the opposed ends of the fiber bundle to the housing ends, a space being defined by the hollow fiber membrane outer surface, the housing inner surface, and the partitions, inlet and outlet ports for a first fluid disposed in the housing adjacent the opposed ends thereof in fluid communication with the space, and inlet and outlet ports for a second fluid disposed at the housing ends in fluid communication with the interior of the hollow fiber membranes is characterized in that the portion of the hollow fiber membranes in contact with each partition swells little upon contact with water-containing fluid.