High flux, chlorine resistant coating for sulfate removal membranes

A coated filtration membrane, comprising:

• a filtration membrane,
• a coating on said membrane, said coating comprising:
• a hydrophilic polymer;
• a surfactant;
• and
• one or more charged compounds, each containing one or more sulfonate functionalities and one or more linkable functionalities selected from the group consisting of amine, monochlorotriazine, and dichlorotriazine;
• wherein the hydrophilic polymer comprises at least one material selected from the group consisting of polydopamine and its copolymers, poly (dopamine-acrylamide) and its copolymers, polyethylene, polyvinyl alcohol, hydroethyl cellulose, hydroxyl propyl cellulose, methyl cellulose poly (hydroxyethyl methacrylate) and its copolymers, styrene-maleic anhydride copolymer, methyl vinyl ether-maleic anhydride copolymer, polyethylenimine, carboxy methyl cellulose, locust bean gum, bean gum, carrageenan, agar, polyvinylpyrrolidone, sulfonate polysulfone, polyethylene oxide and copolymers, polyethylene glycol, polyacrylamide, and polysaccharide;
• and
• wherein the surfactant comprises at least one hydrocarbon chain having at least 16 carbon atoms.

A conformal chlorine-resistant, fouling resistant, and permeate flux-enhancing coating for a membrane, comprising:

• dopamine HCl;
• a surfactant;
• a first charged compound;
• and
• a second charged compound containing one or more sulfonate functionalities and one or more linkable functionalities from the group consisting of amine, monochlorotriazine, and dichlorotriazine;
• wherein said surfactant is 40% sodium lauryl ether sulfate in water, said first charged compound is a solution of 0.1% benzopurpurine 4B, and said second charged compound is a solution of 0.4% 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid Na salt hydrate.