Over mhea I found that coffee grounds were the only thing that could get the smell of spoiled milk out of my car. So I started researching coffee grounds and it turns out they are a widely used deodorizer. What is the chemistry behind how they deodorize?
Because coffee is an adsorbent. http://ias.vub.ac.be/General/Adsorption.html
Why? There are many phenolic hydroxyl and carboxyl groups on the surface of coffee grounds, and many aromatic molecules cling tightly to these groups when they encounter them.
A better understanding of the attraction between these groups and aromatic molecules can be had in many fine Organic Chemistry courses at your local colleges and universities.
A phenol is a benzene with an alcohol on it, so what is a phenol with a hydroxyl on it? Is it a phenol with multiple alcohols?
Oddly, we are going over aromatic compounds right now in organic II and what I learned is that aromatic rings do not interact well with other molecules without a catalyst. Maybe something in the coffee performs this function.
Here’s a picture of a phenolic hydroxyl group. http://www.tetrahydrocurcuminoids.com/images/pg_clinical_fig1.gif
And if you’re taking organic now, you’ll grok the stuff far better than I, who hasn’t paid it serious attention since neuropharmacology class, over two decades ago! 