Different types of desiccant dehumidifiers function in other ways, but the principle course of action they use to extract humidity with the air is possibly absorption or adsorption. Absorption happens if the desiccant material dissolves as it will require humidity with the air, as is the situation with dampness absorbers. https://dstdehumidifiers.co.uk/case-studies/desiccant-dehumidifiers-in-cold-stores/