Polymer flocculants with improved dewatering characteristics
AssigneeEcole Polytechnique Federale De Lausanne (Epfl)
InventorsJose Hernandez-Barajas, Christine Wandrey, David Hunkeler
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Abstract
A high molecular weight water soluble acrylamide based polymer having improved flocculating and dewatering properties is provided. The polymer is prepared by a process in which a small quantity of a chain branching agent is added to the polymerization reaction mixture continuously or stepwise while the monomers are polymerized. The polymer is useful in solid/liquid separations such as flocculants and coagulants in wastewater treatment applications, and as thickening agents.
Claims40
A process for preparing a water soluble polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable ethylenically unsaturated monomers;
- polymerizing the ethylenically unsaturated monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously, said semi-continuous addition further comprising at least two discrete additions.
A process for preparing an acrylic based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- polymerizing said acrylic monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously, said semi-continuous addition further comprising at least two discrete additions.
A process for preparing a water soluble polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable ethylenically unsaturated monomers;
- polymerizing the ethylenically unsaturated monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously in an amount of from about 1 to about 1000 ppm.
A process for preparing an acrylic based polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers;
- polymerizing said acrylic monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously in an amount of from about 1 to about 1000 ppm.
A process for preparing a water soluble polymer, comprising the steps of:
- (a) providing a polymerization reaction mixture comprising one or more polymerizable ethylenically unsaturated monomers;
- (b) polymerizing the ethylenically unsaturated monomers;
- and
- (c) adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously,
- wherein the water soluble polymer exhibits a viscosity that is at least about 10% higher than the viscosity achieved by performing the polymerization step (b) with the batch addition of one or more chain branching agents instead of continuous or semi-continuous addition.
A process for preparing a water soluble polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable ethylenically unsaturated monomers;
- polymerizing said ethylenically unsaturated monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously,
- wherein said water soluble polymer exhibits an intrinsic viscosity of greater than about 2 dl/g in 1M NaCl at 25° C. and a sedimentation coefficient within the soluble portion of greater than about 6.17 Svedberg in 0.05 M NaCl at 20° C.
A process for preparing a water soluble polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable ethylenically unsaturated monomers;
- polymerizing said ethylenically unsaturated monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously,
- wherein said water soluble polymer exhibits an intrinsic viscosity of greater than about 2.5 dl/g in 1M NaCl at 25° C. and an association to chain branching agent ratio of less than about 2.5 as measured in 0.005 M NaCl at 20° C.
A process for preparing a water soluble polymer, comprising the steps of:
- providing a polymerization reaction mixture comprising one or more polymerizable ethylenically unsaturated monomers;
- polymerizing said ethylenically unsaturated monomers;
- and
- adding to the reaction mixture during polymerization one or more chain branching agents either continuously or semi-continuously,
- wherein said adding step further comprises adding the one or more chain branching agents at a constant rate of between about 0.1 to about 20 weight percent per hour during polymerization, said weight percent based upon the total amount of the one or more chain branching agents added.
Dependencies are inferred from the claim text.