1.1 Technology Overview

Synthetic membrane processes perform versatile functions. In liquid separations, for example, they are used to separate particles that span four orders of magnitude from dissolved ions to bacteria (Figure 1.1). More than 95% of sales are for liquid separations. Since 1965, membrane technology has transformed from laboratory development to proven industrial applications. Membranes are used for desalination of seawater and brackish water, potable water production, and for treating industrial effluents. Membrane processes are used for the concentration of and purification of food and pharmaceutical products, in the production of base chemicals, and energy conversion devices such as fuel cells. Membranes are also used in medical devices such as haemodialysis, blood oxygenators, and controlled drug delivery products. Membrane separation processes are being increasingly integrated with conventional technologies as hybrid membrane systems to make products energy efficiently and with minimum environment impact.

Figure 1.1: Membrane process solute size

Four developments are widely considered to be responsible for transferring membrane science from the laboratory to commercial reality since 1960:

1. development of high-efficiency cross-flow membrane elements (modules) with large surface areas;

2. creation of advanced materials with controllable capabilities to separate molec-ularly similar components (e.g. gases, salts, colloids, proteins);

3. tailoring membrane morphology for controlling microscopic transport phenomena; and

4. manufacturing membrane elements economically and reliably. ^[1]

Continuing advances in development of new membranes with better thermal, chemical, and improved transport properties have led to many new possible applications. Development...