Different types of desiccant dehumidifiers operate in different ways, but the principle process they use to extract dampness with the air is possibly absorption or adsorption. Absorption happens in the event the desiccant substance dissolves as it will require moisture from your air, as is the situation with humidity absorbers. https://dstdehumidifiers.co.uk/case-studies/desiccant-dehumidifiers-in-cold-stores/