Carbonation degassers, typically used in the beverage industry, remove dissolved gases from liquids through membrane-based separation techniques devised by chemical engineers. Courtesy Membrana.
Most food ingredients and processed foods contain unwanted contaminants, such as
- Suspended solids,
- Dissolved salts,
- Metals,
- Bacteria,
- Fungi, and
- Other pathogens.
Chemical engineers have invented a variety of processes to remove these substances, thereby improving food quality, safety, and aesthetics. One of the most widely used processes today is membrane-based separation.
Membrane-based separation
This technique uses pressure during food processing to force unwanted impurities out through a semipermeable membrane. Differences in size, shape, or surface charge determine what is and is not removed.
Semipermeable membrane materials developed by chemical engineers include cellulose acetate, ceramics, and polymers. Numerous physical membrane configurations have been devised to separate unwanted solids and dissolved compounds from foods and beverages on a commercial scale. Membrane-based separation provides significant cost and performance advantages compared with such traditional separation techniques as centrifugation, vacuum filtration, and sand or diatomaceous earth filtration.
Different types of membrane-based separators use reverse osmosis, microfiltration, ultrafiltration, or nanofiltration systems based on the size and structure of the membrane pores. The size of the pores regulates the size of the solid particles or liquid droplets that can be removed.
While numerous commercial designs are currently available, chemical engineers are constantly striving to develop even more advanced membrane-based separation systems that are more efficient, effective, and cost-effective.
Copyright © 2009 American Institute of Chemical Engineers and Chemical Heritage Foundation. All rights reserved.