PURPOSE: To obtain a water treating method with less toxicity by which dissolved oxygen in a boiler water is removed and the surface of steel is passivated by adding at least one kind of carbohydrazone selected from carbohydrazone compds. expressed by a specified formula in an enough amt. to remove oxygen to the boiler.
CONSTITUTION: In the removing method of dissolved oxygen from a boiler water at alkali pH, at least one kind of carbohydrazone compd. selected from carbohydrazone compds. expressed by formula I, formula II and formula III is added in an amt. to remove oxygen to the boiler In formulae I, II and III, R1, R2, R3, R4, R5, R6, R7 and R8 are independently hydrogen, alkyl groups, substd. alkyl groups, aryl groups or substd. aryl groups. By this method, dissolved oxygen can be removed from the boiler water at alkali pH.
DEBORA EMU ROJIYAASU
FUREDERITSUKU JIEI SUUIICHINSU
