Membranes, Microfiltration, Microsieves, and More

Membranes generally refer to materials with controlled ability to pass or retain molecules or particles of specific sizes. Familiar applications include microfiltration, ultrafiltration, and reverse osmosis, differing in the scale of substances that are retained. Reverse osmosis membranes, for example, can retain ions such as sodium and chloride, permitting production of pure water from sea water.

Bacteria and yeast, on the other hand, are retained by microfiltration membranes, permitting sterili…