NZ226868A - Reducing turbidity in aqueous systems by flocculation with aluminium chlorohydrate and a water-soluble cationic polymer - Google Patents

Description

New Zealand Paient Spedficaiion for Paient Number £26868 Priority Date(s): Complete Specification Filed: 1.1^.' d«.: "2 T5" 311 (TOT Publication Date: P.O. Journal, No: .J&&S: 22 NEW ZEALAND PATENTS ACT, 1953 No.: Date: COMPLETE SPECIFICATION FLOCCULATION OF SUSPENDED SOLIDS FROM AQUEOUS SOLUTIONS V -I/We, CALGON CORPORATION a corporation organized and existin'^ \,o under the laws of the State of Delaware, United States of Americans/ c D of Route 60-Campbell's Run, Robinson Township, State of Pennsylvania, United States of America, hereby declare the invention for which-I-/ we pray that a patent may be granted to p*e-/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - (followed by page la) 22 6 -ta - C-1447 TITLE OF THE INVENTION "FDOCCULATION OF SUSPENDED SOLIDS FROM AQUEOUS SOLUTIONS" BACKGROUND OF THE INVENTION This invention relates to methods of floculating, accelerating the rate of floculation and/or 5 accelerating the settling of solids which are suspended in aqueous media by addition thereto of a floculating composition.

U.S. 4,450,092 discloses compositions useful for 10 coagulating finely divided solids in turbid waters. These compositions are prepared by mixing inorganic water-soluble compounds such as aluminum chloride, aluminum sulfate, ferric chloride and ferric sulfate with a polymer of diallyl dimethyl ammonium chloride 15 having a molecular weight of at least 2,000. The weight ratio of the inorganic component to the organic component ranges from 0.75:1 to about 4:1. 22 6 8 6 8 C-1447 US Patent 4,582,627 discloses flocculating agents which are reaction products of sulfate ion-containing polymeric aluminum hydroxy chloride and one or more cationic polymers such as polyacrylic amide, polyamide 5 amine and polyethylene imine.

US Patent 4,137,165 discloses the use of low molecular weight acrylamide polymers which contain quaternized dimethylamino methyl groups for 10 clarification of turbid waters.

US Patent 3,489,681 discloses the use of water-soluble copolymers of diacetone acrylamide as flocculating agents.

The term flocculation, as used herein, is synonymous with the term coagulation. Flocculation refers to the settling of suspended solid particles from aqueous systems. Turbidity, as used herein, is 20 defined as the cloudiness or haziness of a solution caused by finely suspended particles. Turbidity is measured using NTU's, (nephelometric turbidity units). As used herein, low turbidity systems are systems having a low solids concentration (on a weight 25 basis), i.e., a solids weight percent of 0.1 or less. As a general rule, this corresponds to an approximate turbidity of 50 NTU's or less, but may vary due to the nature of the suspended or dissolved color matter.

High solids suspensions include those systems 3 0 containing in excess of 0.1 weight percent suspended solids, which generally corresponds to a turbidity of 22 - 3 - C-1447 greater than 50 NTU's. While the instant compositions are especially effective in low turbidity waters, it is not intended that their use be so restricted. In fact, the instant compositions are useful in a wide 5 variety of raw waters and in concentrated wastewaters.

Many flocculants are known, including alum (A^SO^)^ X ^0, wherein X is about 14), poly(aluminum chloride), sodium aluminate, iron 10 compounds such as ferric chloride and ferric sulfate, lime and various cationic organic polymers, including but not limited to poly (alkaline amines), poly(diallyl dimethyl ammonium chloride), poly(2-hydroxy propyl-1-N-methyl ammonium chlorides) and quaterized 15 poly (N-N-dimethylaminomethacrylate). The novel compositions of the instant invention are not, however, known or suggested in the art.

SUMMARY OF THE INVENTION The instant invention relates to synergistic flocculation compositions of aluminum chlorohydrate and at least one water-soluble cationic polymer selected from the group consisting of water-soluble 25 polyamines and water-soluble dialkyl diallyl ammonium polymers, wherein the weight ratio of aluminum chlorohydrate to polymer is at least 5:1, on an active basis.

Thus, the instant method utilizes a synergistic composition comprising aluminum chlorohydrate and at least one water-soluble cationic polymer to accomplish clarification objectives. The novel compositions of this invention are stable when blended together and synergistically settle fine suspended matter from aqueous systems. The instant compositions are especially effective in low-turbidity, low-alkalinity waters, but they are also effective in other waters. Low-alkalinity waters, as used herein, are waters having total alkalinity values of 150 ppm or less.

Additionally, the instant compositions are convenient to use since only one product must be added to the system being treated, instead of two or more.

DETAILED DESCRIPTION OF THE INVENTION The instant invention relates to a composition useful for reducing turbidity in aqueous systems which comprises: (a) aluminum chlorohydrate; and (b) at least one water-soluble cationic polymer selected from the group consisting of water-soluble polyamines and water-soluble dialkyl diallyl ammonium polymers, wherein the weight ratio of (a) to (b) is at least 5:1, and preferably ranges from 10:1 to about 100:1, most preferably 10:1 to about 30:1.

Any water soluble polyamine may be used. As used herein, the term polyamine includes any water-soluble product having the following structure: h j+ I *2 wherein R^ different, are C-^-Cg straight and R^, which may selected from the or branched alkyl be the same or group consisting and hydrogen and of 226868 - 5 wherein. R is selected from the group consisting of straight or branched C^-Cg alkylene and hydroxy-substituted straight or branched C-^-Cg alkylene, and wherein n ranges from 2 to 50,000. Preferably, the molecular 5 weight should range from about 500 to about 200,000, as determined by gel permeation chromatography.

Polymers having molecular weights ranging from about 10,000 - 150,000 are more preferred. The most preferred polyamines are .epichlorohydrin-dimethylamine 10 polymers.

Any water soluble di C-^g diallyl ammonium polymer can be used. The preferred polymers are polydimethyl diallyl ammonium chloride 15 (polyDMDAAC), polydiethyldiallyl ammonium chloride (polyDEDAAC), polydimethyl diallyl ammonium bromide (polyDMDAAB) and polydiethyl diallyl ammonium bromide (polyDEDAAB). The most preferred dialkyl diallyl ammonium polymer is a homo polymer of dimethyl diallyl 2 0 ammonium chloride.

The molecular weight of the dialkyl diallyl ammonium polymer preferably ranges from about 1,000 to about 5,000,000, as determined by gel permeation 25 chromatography.

The ratio of aluminum chlorohydrate to polymer is critical, and should be at least 5:1, by weight, on an active basis. Preferably, the ratio should range from 30 10:1 to about 100:1, and most preferably from 10:1 to about 30:1. These compositions synergistically reduce turbidity in aqueous systems, particularly low-turbidity, (i.e., systems containing 0.1 or less weight percent of suspended solids), low-alkalinity systems (i.e., 150 ppm or less). 226868 The instant invention is additionally directed to a method for reducing turbidity in an aqueous system which comprises adding to said system an effective amount of a composition comprising: (a) aluminum 5 chlorohydrate; and (b) at least one cationic polymer as defined above; wherein the weight ratio of (a) to (b) is at least 5:1, preferably 10:1 to about 100:1, and most preferably 10:1 to about 30:1.

As used herein, the phrase "effective amount" refers to that amount of an aluminum chlorohydrate/polymer composition which is necessary to reduce turbidity in the system being treated.

Generally, the effective amount will range from substantially ^^ 0.1 ppm of the instant compositions, on an active basis, to substantially 100 ppm of the instant conpositions.

The key to this invention is that the inventors have discovered a synergistic relationship between aluminum chlorohydrate and certain cationic polymers.

While use of these components, individually, is known in the art, the use of the instant compositions is not known. The synergistic benefit of the combined components, as demonstrated by the examples, is 2 5 surprising and unexpected.

The instant conpositions are especially effective in low turbidity, low alkalinity waters. However, the inventors do not intend that the instant compositions 3 0 be restricted to use in such systems, as the instant conpositions are effective flocculants in a wide range of aqueous systems. *0- \ ^1- ■ * 9/ E tU/' 22 6 8 - 7 - C-1447 Other important aspects of the instant invention are that the components of the conpositions are compatible and that the instant conpositions are stable. Additionally, the instant conpositions afford 5 the advantages of using one product instead of many products.

Preferably, the instant conpositions are applied as aqueous solutions. Thus, an aluminum 10 chlorohydrate/cationic polymer composition is added to water, forming an aqueous solution. The maximum weight percent of the composition in water depends upon its solubility limit; generally, however, it is preferred that the aqueous solution contain from about 15 0.1 to about 20%, by weight, of the instant aluminum chlorohydrate/cationic polymer composition, wherein the weight ratio of aluminum chlorohydrate to cationic polymer is at least 5:1, on an active basis.

EXAMPLES The following examples demonstrate the invention in greater detail. These examples are not intended to limit the scope.of the invention in any way.

In the examples, the following products were used: Aluminum chlorohydrate solution, available from Reheis Chemical Company (50 weight % active), Cortlic 30 Industries (50 weight % active) and Laporte Chemical Conpany (38 weight % active).

Alum is a 50% active aqueous solution of aluminum sulfate, Al2 (S04)3 . 14 H20. 2 2 - 8 - C-1447 High MW PolyDMDAAC is 20 weight % active polydimethyl diallyl ammonium chloride (MW = 1,000,000-2,000,000), available from Calgon Corporation as Cat-Floc L.

Medium MW Poly DMDAAC is 20 weight % active polydimethyl diallyl airmonium chloride (MW = 150,000 + 50,000), available from Calgon Corporation as Cat-Floc TL.

Low MW Poly DMDAAC is 30 weight % active polydimethyl dially ammonium chloride (MW = 3,000 -4,000), available from Calgon Corporation as Varikem 110.

Dry Poly DMDAAC is 100% active polydimethyl diallyl arranonium chloride (MW = approximately 200,000), available from Calgon Corporation as E-921.

High MW Polyamine is a 50 weight % active epichlorhydrin - dimethylamine polymer (MW = 100,000), available from American Cyanamid as CA-260.

Low MW Polyamine is a 50 weight % active epichlorohydrin dimethylamine polymer (MW = 20,000), available from American Cyanamid as CA-250.

Alum/Medium MW PolyDMDAAC (5:1) is Cat Floe K-5, available from Calgon Corporation, which is 5 parts, by weight, a 50% alum solution (by weight) and 1 part Cat-Floc C, a 40%, by weight, active polyDMDAAC having a molecular weight of approximately 150,000. 22 6 - 9 - C-1447 Alunv/Medium MW PolyDMDAAC (10:1) is Cat Floe K-10, available from Calgon Corporation, which is 10 parts, by weight, a 50% alum solution (by weight) and 1 part Cat-Floc C, a 40%, by weight, active polyDMDAAC having 5 a molecular weight of approximately 150,000.

Examples 1-22 In Examples 1-22, jar tests were run on Watauga 10 River water having an initial turbidity of 4.0 - 4*5 NTU's. The water had a total alkalinity of 60-70 ppm.

The jar tests were run under the following conditions: 1 min § 100 rpm 20 min @ 45 rpm 10 min @ 0 rpm 2 0 After a 10 minute settling period, 30 ml samples of supernatant were drawn, and turbidity was measured using a Bausch & Lomb Mini-20 Spect r ophotometer/Nephelomete r. 2 5 For filtration index measurements, 100 ml samples of supernatant were drawn, and the time was measured for each 100 ml sanple to pass through a sheet of 0.3 micron filter paper. The filtration index values were then calculated by dividing the time obtained by the 3 0 time required for 100 mis of deionized water to pass through a sheet of 0.3 micron filter paper.

Results are shown in Table I. -10- C-1447 TABLE I 226868 Supernatant Example As Product Clarity (NTU'S) Filtration Number Flocculant Dosage (ppm) (10 min.) Index 1* Alum 2* Alum 3* Alum 4* Alum * Alum 6* Alum 7* Alum/DMDAAC (10:1)** 8* Alum/DMDAAC (10:1) 9* Alum/DMDAAC (10:1) * Alum/DMDAAC (10:1) 11* Aluminum Chlorohydrate+ 12* Aluminum Chlorohydrate 13* Aluminum Chlorohydrate 14* Aluminum Chlorohydrate Aluminum Chlorohydrate/ High MW DMDAAC (5:1) 16 Aluminum Chlorohydrate/ High MW DMDAAC (10:1) 17 Aluminum Chlorohydrate/ High MW DMDAAC (20:1) 18 Aluminum Chlorohydrate/ Medium MW DMDAAC (10:1) 19 Aluminum Chlorohydrate/ Low MW DMDAAC (10:1) Aluminum Chlorohydrate/ Low MW Polyamine (5:1) 21 Aluminum Chlorohydrate/ Low MW Polyamine (10:1) 22 Aluminum Chlorohydrate/ Low MW Polyamine (20:1) 4.4 4.0 2.37 3.7 2.30 2.4 2.22 40 2.4 50 2.9 4.3 3.6 2.9 1.93 2.3 1.8 1.55 0.45 1.40 0.52 1.40 0.64 1.30 1.26 1.50 1.30 1.60 1.26 1.50 1.50 1.60 1.26 1.40 1.30 1.40 1.26 * Comparison example + Aluminum Chlorohydrate was supplied by Reheis.

** Composition ratios in this table are on a product:product (as product) basis. 22 6 8 6 8 - 11 - C-1447 Examples 23-74 In Examples 23-74, jar tests were run on feed water having a turbidity of approximately 12 NTU's. 5 Total alkalinity was approximately 150 ppm.

The jar tests were run under the following conditions: l min @ 100 rpm 3 min @ 50 rpm 6 min @ 20 rpm 5 min @ 0 rpm After a 5 minute settling period, 10 ml samples of supernatant were drawn, and turbidity was measured using a Bausch & Lorn Mini-20 Spectrophotometer/ Nephelometer.

Results are shown in Table II. 23 24 26 27 28 29 31 32 33 34 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 -12-TABLE II I TS 8 6 8 Active Dosage Supernatant (As product dosage) Clarity (NTU's) Flocculant (ppm) (5 min.) High MW Polyamine 0.5 8.6 High MW Polyamine 2.5 8.8 High MW Polyamine 10.0 8.8 High MW Polyamine 25.0 9.6 Low MW Polyamine 0.5 8.8 Low MW Polyamine 2.5 8.6 Low MW Polyamine 10.0 8.8 Low MW Polyamine 25.0 8.9 High MW PolyDMDAAC 0.4 9.4 High MW PolyDMDAAC 4.0 8.9 High MW PolyDMDAAC 8.0 9.0 High MW PolyDMDAAC 20.0 9.8 Medium MW PolyDMDAAC 0.4 9.2 Medium MW PolyDMDAAC .4.0 9.2 Medium MW PolyDMDAAC ■ 8.0 9.0 Medium MW PolyDMDAAC 20.0 9.6 Low MW PolyDMDAAC 0.4 9.1 Low MW PolyDMDAAC 4.0 9.5 Low MW PolyDMDAAC 8.0 9.2 Low MW PolyDMDAAC 20.0 9.8 Dry PolyDMDAAC 1.0 9.6 Dry PolyDMDAAC 5.0 9.4 Dry PolyDMDAAC 10.0 9.4 Dry PolyDMDAAC 25.0 10.1 Reheis Aluminum Chlorohydrate 2.0 6.2 Reheis Aluminum Chlorohydrate 2.5 4.6 Reheis Aluminum Chlorohydrate 3.0 2.3 Reheis Aluminum Chlorohydrate 4.0 1.2 Reheis Aluminum Chlorohydrate 5.0 0.9 Reheis Aluminum Chlorohydrate 10.0 0.6 Cortlic Aluminum Chlorohydrate 2.0 7.0 Cortlic Aluminum Chlorohydrate 2.5 5.8 Cortlic Aluminum Chlorohydrate 3.0 3.3 Cortlic Aluminum Chlorohydrate 4.0 2.3 Cortlic Aluminum Chlorohydrate 5.0 1.9 Cortlic Aluminum Chlorohydrate 10.0 0.9 -13- C-1447 TABLE II (Continued) 22 6 8 6 8 Active Dosage Supernatant Example (As product dosage) Clarity (NTU's) Number Flocculant (ppm) (5 min.) 59 Aluminum Chlorohydrate*/High MW (20) 5,4 PolyDMDAAC (5:1)* 60 Aluminum Chlorohydrate*/High MW (20) 4,6 PolyDMDAAC (10:1) 61 Aluminum Chlorohydrate*/High MW (20) 2.1 PolyDMDAAC (20:1) 62 Aluminum Chlorohydrate*/High MW (20) 1.9 PolyDMDAAC (20:1) 63 Aluminum Chlorohydrate*/High MW (20) 2.0 PolyDMDAAC (30:1) 64 Aluminum Chlorohydrate*/High MW (20) 2.3 PolyDMDAAC (50:1) 65 Aluminum Chlorohydrate*/Medium MW (20) 5.3 PolyDMDAAC (5:1) 66 Aluminum Chlorohydrate*/Medium MW (20) 2.0 PolyDMDAAC (20:1) 67 Aluminum Chlorohydrate*/Low MW (20) 5.4 PolyDMDAAC (5:1) 68 Aluminum Chlorohydrate*/Low MW (20) 2.1 PolyDMDAAC (20:1) 69 Aluminum Chlorohydrate/High MW (20) 4.0 Polyamine (5:1) 70 Aluminum Chlorohydrate/High MW (20) 3.8 Polyamine (10:1) 71 Aluminum Chlorohydrate/High MW (20) 3.9 Polyamine (20:1) 72 Aluminum Chlorohydrate/Low MW (20) 3.9 Polyamine (5:1) 73 Aluminum Chlorohydrate/Low MW (20) 4.0 Polyamine (10:1) 74 Aluminum Chlorohydrate/Low MW (20) 3.7 Polyamine (20:1) + Examples 23-58 are comparison examples.

* Composition ratios in this table are on a product:product (as product) basis. 226868

Claims (10)

WHAT WE CLAIM IS:

1. A conposition for reducing turbidity in aqueous systems comprising: (a) aluminum chlorohydrate; and (b) at least one water-soluble cationic polymer selected frcm the group consisting of: (i) water-soluble polyamines represented by structure I F1 (I> — R i* I n *2 wherein and R^, which may be the same or different, are selected from the group consisting of straight or branched C^-Cg alkyl and hydrogen; and wherein R is selected frcm the group consisting of straight or branched C^-Cg alkylene and hydroxy substituted straight or branched C^-Cg alkylene; and wherein n ranges frcm 2-50,000; and (ii) water-soluble dialkyl diallyl ammonium polymers; wherein the weight ratio of (a): (b) is at least 5:1, on an active basis. 22*5*8: b*? - 15 -

2. The conposition of Claim 1, wherein (b) is an epichlorohydrin dimethylamine polymer.

3. The conposition of Claim 1, wherein (b) is selected from the group consisting of polydimethyl diallyl ammonium chloride, polydiethyl diallyl ammonium chloride, polydimethyl diallyl ammonium bromide and polydiethyl diallyl ammonium bromide.

4. The composition of Claim 1, wherein (b) is polydimethyl diallyl ammonium chloride.

5. A method for reducing the turbidity of an aqueous system corrprising adding to said system an effective amount of a conposition comprising: (a) aluminum chlorohydrate; and (b) at least one water-soluble cationic polymer selected from the group consisting of: (i) water-soluble polyamines represented by structure I (I) i+ *2 wherein R± and which may be same or different, are selected from the group consisting of straight or branched C-^-Cg alkyl and hydrogen; and 226868 - 16 - wherein R is selected from the group consisting of straight or branched C^-Cg alkylene and hydroxy-substituted straight or branched C., -CD alkylene; and wherein n 5 ranges from 2-50,000; and (ii) water-soluble ^"Cg dialkyl diallyl ammonium polymers; wherein the weight ratio of (a) : (b) is at least 5:1, on an active basis.

6. The method of Claim 5, wherein (b) is an epichlorohydrin dimethylamine polymer.

^ 7. The method of Claim 5, wherein (b) is selected from the group consisting of polydimethyl diallyl ammonium chloride, polydiethyl diallyl airroonium chloride, polydimethyl diallyl ammonium bromide and polydiethyl diallyl ammonium bromide. 20

8. The method of Claim 5, wherein (b) is polydimethyl diallyl ammonium chloride. 25

9. The method of any one of Claims 5 to 8, wherein said aqueous system contains 0.1 weight precent, or less, suspended solids.

10. The method of any one of Claims 5 to 9, wherein said 30 effective amount is frcm substantially 0.1 to substantially 100 ppm of said conposition, on an active basis. BATtDTHIS O DAY Of I. 1*^1 A. I. PARK & SON PER agents FOR THE APPLICANT? 1*1 APRjpfy; mad