Method for producing stabilized hypobromous acid composition, stabilized hypobromous acid composition, and slime inhibition method for separation membrane

A slime inhibition method for a separation membrane, the method comprising:

• incorporating, in a feed water or a wash water supplied to a membrane separation device containing the separation membrane, a stabilized hypobromous acid composition selected from the group consisting of A), B) or C), wherein A), B) and C) are as defined below:
• A) a stabilized hypobromous acid composition obtained from a method for producing a stabilized hypobromous acid composition, the method comprising:
• inducing a reaction by adding bromine, under an inert gas atmosphere, to a mixed solution comprising water, an alkali hydroxide and sulfamic acid, wherein
• a proportion of bromine added is not more than 25 wt% relative to a total weight of the composition;
• B) a stabilized hypobromous acid composition comprising a reaction product of a bromine-based oxidizing agent and a sulfamic acid compound;
• and
• C) a stabilized hypobromous acid composition comprising a reaction product of a sulfamic acid compound with a reaction product of a bromine compound and a chlorine-based oxidizing agent;
• and
• contacting the separation membrane with said stabilized hypobromous acid composition and/or passing said stabilized hypobromous acid composition through the separation membrane, wherein
• the separation membrane is a reverse osmosis membrane composed of a polyamide-based polymer membrane or a nanofiltration membrane composed of a polyamide-based polymer membrane,
• the bromine-based oxidizing agent is bromine or bromine chloride, and
• a ratio of the equivalent weight of the sulfamic acid compound relative to the equivalent weight of the bromine-based oxidizing agent or the reaction product of a bromine compound and a chlorine-based oxidizing agent is 1 or greater.