Method for treating reverse osmosis membranes

Claim 2

In a method in accordance with claim 1, said imbibing solution wherein said anionic surface active agent is sodium sulfate derivative of 7-ethyl-2-methyl-4-undecanol.

Claim 3

In a method for treating a cellulose ester or ether reverse osmosis membrane comprising immersing such a membrane in a water-wet condition in an imbibing solution, and then removing and drying said membrane, the improvement wherein said imbibing solution is a single phase temperature independent imbibing solution which remains homogeneous at imbibing temperatures without coacervation and without causing substantial loss of desalination parameters by said membrane, said solution consisting essentially of: about 30 to 60 percent of glycerin; about 25 to 55 percent of water; about 3 to 10 percent of a nonionic first surface active agent; and about 0.1 to 5 percent of a second surface active agent selected from the group consisting of anionic and cationic surface active agents, all percentages being by weight, said nonionic surface active agent being (a) a product formed by condensing one or more alkylene oxides of two to four carbon atoms alone or with other alkylene oxides with a relatively hydrophobic compound selected from a fatty alcohol, fatty acid, sterol, fatty glyceride, fatty amide, fatty mercaptan or tall oil fatty acids, or (b) a product formed by condensing one or more lower alkyl alcohol amines with a fatty acid; said anionic surface active agent being selected from sulfates and sulfonated alkyl, aryl, alkyl-aryl hydrocarbons and alkali-metal salts thereof; and said cationic surface active agent being an alkyl dimethyl benzyl ammonium chloride wherein said alkyl group has eight to 18 carbon atoms.

Claim 4

In a method in accordance with claim 4, an imbibing solution wherein said second surface active agent is an alkyl dimethyl benzyl ammonium chloride wherein said alkyl group has 8 to 18 carbon atoms, as a cationic surface active agent.

Claim 5

In a method in accordance with claim 4, an imbibing solution wherein said second surface active agent is the dioctyl ester of sodium sulfosuccinic acid, as an anionic surface active agent.

Claim 6

In a method in accordance with claim 4, an imbibing solution wherein said second surface active agent is the sodium sulfate derivative of 7 ethyl-2 methyl-4-undecanol, as an anionic surface active agent.

Claim 7

In a method in accordance with claim 4, an imbibing solution wherein said nonionic surface active agent is a polyethylene glycol ether of C11-C15 linear alcohol; wherein said anionic surface active agent is selected from the group consisting of the dioctyl ester of sodium sulfosuccinic acid and the sodium sulfate derivative of 7 ethyl-2 methyl-4-undecanol; and said cationic surface active agent is an alkyl dimethyl benzyl ammonium chloride wherein said alkyl group has eight to 18 carbon atoms.