What is Adsorption?

We know that the air in our homes can have unwanted contaminants in it; that’s why we use filters. But not all filters were created equally. High-efficiency furnace filters and portable air purifiers do a great job removing things like pollen and pet dander from the air. Unfortunately, even though pollen and pet dander are small from our perspective, in terms of air quality they are actually rather big when compared to other air contaminants. Other hazards like bacteria, viruses, and irritating chemicals are much, much smaller. Trying to capture these hazards with conventional filters is the microscopic equivalent of trying to catch minnows with a tuna net.  The chemicals we can’t capture using filters are often the most noticeable indicators of air quality in the form of malicious odors. When Zipper the cat pees on the carpet or your collard greens go bad it’s easy to notice that your air quality is suffering.

When air passes through a filter, big particles like dust and pet hair get caught in the filter fibers. But, small chemicals pass through the filters and into the ‘clean’ air.

There is a solution, though. Some filters can trap these small bacteria, viruses, and chemicals. But what does it mean for a filter to trap these tiny chemical molecules?  What traps them? And do they stay trapped? The answer to all of these questions is adsorption.

Molecular Velcro

Adsorption is a process where a substance in a gas or liquid becomes attached to a solid surface. Of course, if you’re not a chemist this doesn’t mean much. Instead of thinking about the scientific definition, think about Velcro. Some things stick to Velcro and some don’t—and the things that do stick tend to stay stuck.

Courtesy of Amazon.com

Adsorption works kind of like Velcro. The surface of a solid acts as the Velcro, and the tiny chemical molecules in the air act as the things that get stuck in Velcro. So, when air passes over the right kind of solid surface, chemical molecules in the air get stuck to that surface and the cleaned air passes over. And once the molecules are stuck to the surface, they don’t come back off.

When molecules in the air pass over an adsorptive surface, they get stuck to the surface and cleaned air passes over the surface.

There are lots of materials with this special, molecular-Velcro surface. The most common one is activated carbon. Activated carbon is similar to charcoal and naturally has this molecular-Velcro surface, which makes it really good at removing chemicals from the air. But, no one wants piles of charcoal sitting in their home to remove chemicals. So what can the average homeowner use instead to make sure they’re removing unwanted chemicals from their air?

Coated Filters

The answer to this question is a coated filter. Think about a typical home furnace filter. These filters are really good at removing ‘big’ particles like dust and pet dander, but not so good at removing chemicals. But, with the addition of a coating that gives the filter the same molecular-Velcro surface that occurs naturally in activated carbon, a standard filter can remove chemicals, too.

When the filter fibers are coated to make their surface adsorptive, airborne chemicals stick to the fibers. That way, all of the contaminants—including small chemicals—are trapped.

Colorfil makes filters like this. At Colorfil, we’ve created a powerful combination of specialized air filter materials so that our filters not only filter out the big stuff that typical filters handle but also the tiny chemicals that cause odors and irritation. With this combination of features, our filters ensure fresh, clean air in your home.

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