The material referred to as molecular sieve is called Zeolite. Today zeolite is made synthetically but was originally described by the Greeks. Zeolite is Greek for “Boiling stone”. When the Greeks “discovered” this mineral the observed when water contacted the stone the water the stone would heat up and steam would rise. This is because when water is adsorbed on zeolite the heat of adsorption is between 1800 and 2700 BTU for ever pound of water adsorbed.
This is because when water is adsorbed on zeolite the heat of adsorption is between 1800 and 2700 BTU for every pound of water adsorbed. This energy transfer is fundament physical chemistry force that makes these materials so useful is so many industrial and commercial applications.
Self-warming hand cream and facial mask are made by mixing fine particle zeolite with emollients. When applied to the skin the moisture reacts with the zeolite to emit heat, act as stringent and exfoliant. Zeolite heat of adsorption is 1800-2700 BTU per pound of water adsorbed.