Sorption Before a constant concentration of the fumigant can be maintained the sorptive capacity of the article under fumigation must be satisfied. It varied considerably with the article being treated. Sorption includes the terms adsorption, absorption and chemisorption. Adsorption is concerned with the loss of fumigant due to adhesion of impingement of the gas molecules to the surface of the materials under treatment. Absorption is concerned with loss of gas within the commodity due to capilary forces.
Chemisorption is a chemical reaction that takes place with a gas and commodity.
The process is irreversible. When chemisorption occurs, residues are formed. These residues are considered harmful in edible products. Desorption Desorption is the result of absorbed and adsorbed gas molecules. Desorption time varies with the commodities and conditions, but it can be complete.