Method of water treatment using polyacrylamide-phosphonate flocculants
AssigneeDiatec Polymers
InventorLeo E. Nagan
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Abstract
A method of treating an aqueous system is disclosed. The method may be used to treat sewage streams as well as aqueous streams in pulp and paper mill processing. The method includes the steps of adding a polymeric composition to an aqueous stream. The composition is an anionically modified acrylamide polymer in an aqueous medium. The polymer is formed by reacting an acrylamide polymer with phosphorous acid, and has at least 5 mole percent phosphonate groups based on the acrylamide content of the polymer, and has a molecular weight of at least about 40,000. the pH of the composition is adjusted to at least about 7.7.
Claims12
A method of water treatment comprising the step of adding a polymeric composition to an aqueous system having a pH of about 5.6 or above, said composition comprising, in an aqueous medium, an anionically modified acrylamide polymer formed by reacting an acrylamide polymer with phosphorous acid, said modified polymer having at least 5 mole percent phosphonate groups based on the acrylamide content of the acrylamide polymer and having a molecular weight of at least about 40,000, the pH of said composition being adjusted to at least about 7.7.
A method of water treatment comprising the step of adding an aqueous composition having a pH of about 7.7 to about 8.4 to a paper machine system for manufacturing alkaline-sized papers using calcium carbonate as a filler, said system having a pH of at least about 5.6, said composition comprising an anionically modified acrylamide polymer formed by reacting an acrylamide polymer with phosphorous acid, said modified polymer having about 5 mole percent to about 100 mole percent phosphonate groups based on the acrylamide content of the acrylamide polymer and having a molecular weight of about 40,000 to about 18,000,000.
Dependencies are inferred from the claim text.