CA2110458A1 - Quaternary polyallylamine water treatment agents - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Quaternized polyallylamines and their use for water clarification is disclosed.

Description

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QUATERNARY POLYALLYLAMINE WATER TREATMENT AGENTS

FIELD OF THE INVENTION

The present invention relates to quaternized polyallylamines and their use for water treatment. More S particularly, the present invention relates to the usa of quaternized polyallylamines for the flocculation of suspended solids in water purification or wastewater clarification systems.

BACKGROUND OF THE INVENTION

The present invention relates to the clarification of raw water for use in industrial or domestic applications, or for the clarlficatlon of wastewater for reuse or disposal.
Raw water such as from rivers, lakes, or underground usually contains suspended matter. The suspended matter can consist of large sollds, settleable by gravity alone without any external aid and nonsettleable material often colloidal in nature. `

Removal of nonsettleable material is generally accom-plisbed by coagulation9 f10cculation and sedimentation. In com-bination, these three processes are referred to as conventional clarification. See the Betz Handbook of Industrial Water Con-ditioning, 9th Edition, 1991, Betz Laboratories, Inc., Trevose, PA, pages 23 through 30.

Coagulation is the process of destabilization by charge neutralization. Once neutralized, particles no longer repel each other and can be brought together. Coagulation is necessary for the removal of the colloidal sized suspended matter. Flocculation is the process of bringing together of the destabilized or "coagulated" particles to form a larger agglomeration or floc.
Sed~mentation or settling, refers to the physical removal of particles from suspension that occurs once the particles have been coagulated and flocculated. Sedimentation alone~ without prior coagulation results ln the removal of only relatively coarse suspended solids.

Naturally occurring suspended particles are predominently negatlvely charged. Polyelectrolytes are traditionally used for influent and wastewater clarification. For low turbidity waters, inorganic palyelectrolytes, such as alum, or organic polyelectro-lytes such as melamine formaldehydes are traditionally employed.
For higher turbidity waters, high charge cationic polyelectro-lytes, such as polyamines, formed by the condensatlon reaction of epichlorhydrin and dimethylamine can be used. High turbidity 2 ~

waters are generally considered those having greater than 60 NTU (nepholometric turbidity units). In low turbidity waters, those with turbidity less than 60 NTU, there are generally not enough particles to form a settleable floc when the water is treated with cationic polymers alone. Inorganic coagulants such as alum, aluminum sulfate, polyaluminum chloride, ferric sulfate, ferric chloride, sodium aluminate and melamine formaldehydes are used.

It is an object of the present invention to provide materials and methods for clarifying water which are more effective than the present commercially available products.

The use of monoallylamines to coalesce suspended par-ticulate matter in aqueous dispersions ls disclosed in U.S.
Patent No. 4,661,263. Vlnylamine copolymers as flocculating agents are described in U.S. Patent Nos. 4,957,977 and 4,808,6~3.

U.~. Patent Nos. 4,504,640 and 4,528,347 disclose pro-cesses for the production of monoallylamine by polymerizing an ~;
inorganic salt of monoallylamine in a polar solvent in the presence of a radical initiator or polymerizing monoallylamineusing a monomer of inorganic acid salts of monoallylamine in the presence of an azo type radical initiator.

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SUMMARY OF THE INVENTION

The present invention is directed to a water treatment agent comprising quaternary polyallylamine and a method of clarifying water whi h employs quaternary polyallylamines~
Quaternary polyallylamines are obtained from the reaction of allylamine polymers and a quaternizing agent such as methyl (ethyl) chloride or dimethyl (ethyl) sulfate with aqueous sodium hydroxide.

The quaternary polyallylamines of the present invention were found to provide improved clarification of raw water. The h quaternized polyallylamines are effective in amounts which vary depending upon the particular system being treated. The treat-ment levels can range from about 1 to 50 parts per million parts of water, depending upon functions such as turbidity, pH, temper-ature, water quanti~y, and respective contaminents in the water.

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BRIEF DESCRIPTION OF THE DRAWINGS
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Figures 1, 2 and 3 are graphs of turbidity versus polymer dose for Texas, Mississippi and Northwestern river waters respectively.
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Figures 4, 5 and 6 are graphs of ultraviolet absorbents (UVA at 254 nm) versus polymer dose for Texas, Mississippi and Northwestern river waters respectively.

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DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a composition and method of clarifying water. The composition of the present invention is a quaternary polyallylamine. The method of the present invention comprises treating water to be clarified with a quaternized poly--allylamine in an amount effective for the purpose of reducing turbidity and organic content.

The quaterni7ed polyallylamine of the present invention is preferably prepared from a polyallylamine hydrochloride. As - 10 disclosed in U.S. Patent Nos. 4,504,640 and 4,528,347, such a monoallylamlne may be prepared by polymerizing an inorganic acid ~
salt of monoallylamine in a polar solvent in the presence of a ~-radlcal inltlator having, in its molecule, an azo group and a group havlng catlonlc nltrogen atoms or polymerlzing monoallyl~
amlne using as a monomer, inorganic acld salts of monoallylamine ln the presence of an azo type radical initiator.
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The quaternlzed polyallylamines of the present tnvention can be prepared by polymer~zlng allylamine and isolat~ng the product accordlng to the teachings of Harada and Hasegawa in Makromol. Chem. Rapid Com~unlcation 5, 27 (1984). The allylamine polymers are then quaternized by co-feeding a quaternizing agent ~:
such as dlmethyl sulfate, methyl chloride or benzyl chloride with aqueous sodlum hydroxide according to Equation 1.

Equation_1 ~CH2 - CH t- + 3 CH3Cl + 3 NaOH
lH2 or NH2-HCl 3 CH3S04~H3 ~CH2 - CH-t- + 3 NaCl N~ (CH3)3 C1-or The resulting quaternary polyallylamine bas the general formula -~- CH2 - CH t-¢~l2 R1 - N - R2 X~

wherein R1 and R2 are lower alkyl or hydroxy alkyl groups of from 1 to 3 carbon atoms. R3 is an alkyl grnup of from 1 to 3 carbon atoms or benzyl and X~ is a water soluble anion such as Cl, Br, I, or CH3 S04. The molecular weight of the polyallylamine can range from about 500 to about 1 million, and is preferably from about 1,00C to 500,000.

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Regardless o~ the method of formation of the poly-allylamine hydrochloride9 the critical reaction for form;ng the material of the present invention is the quaternization reaction of Equation 1 above.

The resulting polymer is pref~erably concentrated and dialyzed to remove salts. The extent or degree of quaterni-zation can be substantiatPd by C-13 and N-15 NMR spectroscopy and a conventional colloid titration. ~he titration measures the degree of quaterni7ation (cationicity) as expressed in milliequivalents per gram of material (meq/g) using potassium polyvinylsulfate solution as titrant and toluidine blue as indicator.

While specific methods of preparing quaterni~ed poly-allylamines for use in the method of the present invention have been described, they are not intended to be limiting.
These described methods are only exemplary methods of preparing the quaternized polyallylamines used in the methnd of the present invention. Alternate methods of preparing quaternary polyallylamines may be employed to form the material used in the method of the present invention.

The following experimental procedures were employed to prepare the materials tested in the examples. Allylamine poly-mers were synthesized by homopolymerizing allylamine and isolating the product according to the teachings o~ Harada and Hasegawa and Makromol. Chem. Rapid Communication 5, 27 t1984).

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The allylamine polymers were then quaternized by cofeeding methyl chloride or dimethyl sulfate with aqueous sodium hydroxide. The addition was made over 90 minutes at less than 35C. Sodium hydroxlde feed was maintained slightly ahead of the methylating agent. The mixture was then heated to 60C for one hour. N-15 NMR analysis confirmed that quaternization occurred.

The spPcific polymers of this example are polytrimethyl-allyl ammonium salts (pTMAA). The flocculent activities of the specific polymers were measured by standard jar test procedures using both natural river waters and industrial oily wastewater as the test substrates.

All polymers were dialyzed in 0.01% NaCl solution prior to testing, to remove excess salts.

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Oily wastewater effluent from a refinery API separator was clarified ~n a jar test. The test substrate had a pH of 10.3, and a turbidity of 142 NTU. The test cycle comprised adding the test treatment to refinery API separator water in a ~ar having a 1 inch by 3 inch paddle and stirring for 2 mlnutes at lOO rpm, 5 minutes at 40 rpm and 5 minutes of settling.
Thereafter, a portion of the effluent was drawn off and tested for turbidity and oil and grease content. The treatments tested included pTMAA quaternized with dimethyl sulfate (pTMAA MeS04), ::`::
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pTMMA quaternized with methyl chloride (pTMAA Cl) and a commer-cially available polydiallyldimethyl ammonium chloride (poly DADMAO) polymer clarification additive. Table 1 summarizes ~he results. Table l shows that the pTMAA polymers of the present q.
invention are more efficacious at lower treat~ent levels than a commercial clarification agent.

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Olarification of Refinery API Separator . Effluent Oily Wastewater Dosage Turbidity Oil & Grease Treatment (Ppm) (~m) (~pm) Blank 0 142 30.2 :;
po~y DADMAC 2 38 4 35 13.4 8 42 -~

16 64 -~

pTMAA MeS04 1 45 ----2 38 11.7 4 42 ____ 43 _ __ pTMM Cl 1 44 2 ~l 10.5 4 45 ___ `: ~
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Exam~le 2 The same test procedure described in Example 1 was employed to test the activity of pTMAA MeS04, pTMAA Cl, as compared to epichlorohydrin/dimethylamine copolymer and poly S DADMAC on Texas, Mississippi and northwestern river water.

Figures 1l 2 and 3 summarized the results of the tur-bidity measurements versus polymer dosage in parts per million active for Texas, Mississippi and northwestern river water re-spectively. In all cases, the pTMAA materials of the present invention were significantly more effective than poly DADMAC
or epichlorohydrin/dimethylamine copolymer.

Figures 4, 5 and 6 summari~es the r sults of the UVA
measurements at 254 nm (a measurement of natural and synthetic organics in the water) for the tested river waters. As can be seen, the pTMAA materials of the present invention are at least as effective as the commercial products in the removal of oil and grease.

While the present lnvention has been described with respect to partlcular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims and this invent~on generally should be construed to cover all such obvious forms and modificatlons which are within the true spirit and scope of the present inv~ntion.

Claims (10)

1. A method of reducing the organics content of an aqueous system comprising adding to the aqueous system an effective amount of a quaternary polyallylamine of the general formula:

wherein R1 and R2 are lower alkyl or hydroxy alkyl groups of from 1 to 3 carbon atoms, R3 is an alkyl group of from 1 to 3 carbon atoms or benzyl and X- is a water soluble anion.

2. The method of claim 1 wherein X- is a water soluble anion selected from the group consisting of Cl, Br, I and CH3 SO4.

3. The method of claim 1 wherein R1, R2, and R3 are CH3.

4. The method of claim 1 wherein said polyallylamine has a molecular weight of from about 500 to about 1 million.

5. The method of claim 1 wherein said polyallylamine has a molecular weight of from about 1,000 to about 500,000.

6. A composition for reducing the turbidity and organics content of an aqueous system comprising a quaternary polyallylamine of the general formula:

wherein R1 and R2 are lower alkyl or hydroxy alkyl groups of from 1 to 3 carbon atoms, R3 is an alkyl group of from 1 to 3 carbon atoms or benzyl and X- is a water soluble anion.

7. The composition of claim 6 wherein X- is a water soluble anion selected from the group consisting of Cl, Br, I, and CH3SO4.

8. The composition of claim 6 wherein R1, R2, and R3 are CH3.

9. The composition of claim 6 having a molecular weight of from about 500 to about 1 million.

10. The composition of claim 6 having a molecular weight of from about 1,000 to about 500,000.