The ability of monomolecular films of fatty alcohols in reducing evaporation of natural water samples collected from two reservoirs in São Paulo (Guarapiranga and Billings) was studied in the laboratory. Evaporation reductions were determined directly by measuring the volume of water evaporated from the test recipients after a certain period of time. Mixed films of hexadecanol and octadecanol showed high potential of evaporation reduction (up to 57%) and persistence on the water surface of ca. 48 hours. A brief discussion on the better efficiency of these mixed films in reducing water evaporation is also presented.
water; evaporation; fatty alcohols; monomolecular films; surface tension
