Reverse Osmosis and Ultrafiltration

Abstract

Economic comparisons indicate reverse osmosis to be more cost effective than distillation for large operations [1]. Important progress has been made in synthetic semipermeable membranes, leading to a wider scope of reverse osmosis applications, including the purification of used water and saline water for drinking, the supply of ultra-pure water for the pharmaceutical and electronic industries and for feeding boilers [2]. Along with the mass transfer within the membrane surface is important. Reverse osmosis and ultrafiltration processes can be described by heat-transfer equations, but in contrast to the design of a heat exchanger, the equations for calculating flows and concentrations at membranes can only be solved iteratively. For the most important membrane configurations (tube, hollow-fiber, and spiral-wound modules) equations are given for describing their transfer characteristics [3].