In many industrial processes, such as in bioreactors that produce fuels or pharmaceuticals, foam can get in the way.
In many industrial processes, such as in bioreactors that produce fuels or pharmaceuticals, foam can get in the way. Frothy bubbles can take up a lot of space, limiting the volume available for making the product and sometimes gumming up pipes and valves or damaging living cells. Companies spend an estimated $3 billion a year on chemical additives called defoamers, but these can affect the purity of the product and may require extra processing steps for their removal.
Now, researchers at MIT have come up with a simple, inexpensive, and completely passive system for reducing or eliminating the foam buildup, using bubble-attracting sheets of specially textured mesh that make bubbles collapse as fast as they form. The new process is described in the journal Advanced Materials Interfaces, in a paper by recent graduate Leonid Rapoport PhD ’18, visiting student Theo Emmerich, and professor of mechanical engineering Kripa Varanasi.
The new system uses surfaces the researchers call “aerophilic,” which attract and shed bubbles of air or gas in much the same way that hydrophilic (water-attracting) surfaces cause droplets of water to cling to a surface, spread out, and fall away, Varanasi explains.
Read more at Massachusetts Institute of Technology
Image: In a beaker with a constant stream of bubbles, inserting a piece of the new textured material developed by the MIT team (gray object extending into the surface at top) causes the foam buildup at the top of the beaker to dissipate almost completely within ten minutes. Courtesy of the Varanasi Lab