Drying air and using the dry air for food dehydration? Probably don't want to bubble/sparge the air through sulfuric acid then. Standard dessicants like silica gel calcium sulfate that can be "recharged" by heating should be adequate for dehydrating foods. Potatoes? Gonna be slow. If you've got refrigeration capacity, you could run the air through a cold trap; maintenance and prevention of Legionaire's, or other organisms in a cold trap might get FDA or public health departments involved.
Silica gel, calcium sulfate, phosphorus pentoxide, Karl Fischer reagent, various temperature cold traps, molecular sieves, come to mind immediately, and various combinations. Some of these can be re-used, some can't.