Treating microbe contamination in water with THP salts and polymeric biopenetrants

Abstract

A synergistic composition comprising a THP salt and a biopenetrant, in which the biopenetrant comprises a polymer of an unsaturated carboxylic acid or a copolymer of an unsaturated carboxylic acid with a sulphonic acid, said polymer or copolymer being terminated by a mono- or diphosphonated unsaturated carboxylic acid group or having such monomers incorporated into the polymer backbone. This composition acts synergistically to enhance the biocidal efficacy of the THP salt against both planktonic (free-swimming) and sessile (attached) bacteria, and also acts synergistically to enhance the efficacy of the THP salt in the dissolution of iron sulphide scale.

Claims

1. A method of treating a freshwater system contaminated with microbes, the method comprising the step of adding to said system separately or together, a biocidally active amount of a THP salt and a biopenetrant, wherein the biopenetrant comprises a copolymer of an unsaturated carboxylic acid with a sulfonic acid, said copolymer being terminated by vinylidene-1,1-diphosphonic acid (VDPA) or having such monomers incorporated into the polymer backbone, thereby killing at least some of said microbes.

2. The method according to claim 1, wherein the THP salt is tetrakis(hydroxymethyl) phosphonium sulfate.

3. The method according to claim 1, wherein the THP salt is a tetrakis(hydroxymethyl) phosphonium phosphite, a tetrakis(hydroxymethyl) phosphonium bromide, a tetrakis(hydroxymethyl) phosphonium fluoride, a tetrakis(hydroxymethyl) phosphonium chloride, a tetrakis(hydroxymethyl) phosphonium phosphate, a tetrakis(hydroxymethyl) phosphonium carbonate, a tetrakis(hydroxymethyl) phosphonium formate, a tetrakis(hydroxymethyl) phosphonium citrate, a tetrakis(hydroxymethyl) phosphonium borate or a tetrakis(hydroxymethyl) phosphonium silicate.

4. The method according to claim 1, wherein the copolymer of the biopenetrant is an acrylate/sulfonate copolymer.

5. The method according to claim 4, wherein the acrylate/sulfonate copolymer has a molecular weight of 5000-6000.

6. The method according to claim 1, wherein the proportion of the VDPA copolymer to THP salt is from 1% to50% by weight, relative to the total weight of the composition.

7. The method according to claim 6, wherein the proportion is from 1% to 25% by weight, relative to the total weight of the composition.

8. The method according to claim 7, wherein the proportion is from 1% to 5% by weight, relative to the total weight of the composition.

9. The method of claim 1, wherein the microbes are bacteria, fungi or algae.

10. A method of treating a seawater system contaminated with microbes, the method comprising the step of adding to said system separately or together, a biocidally active amount of a THP salt and a biopenetrant, wherein the biopenetrant comprises a polymer of an unsaturated carboxylic acid, said polymer being terminated by vinylphosphonic acid (VPA) or having such monomers incorporated into the polymer backbone, thereby killing at least some of said microbes.

11. The method according to claim 10, wherein the THP salt is tetrakis(hydroxymethyl) phosphonium sulfate.

12. The method according to claim 10, wherein the THP salt is a tetrakis(hydroxymethyl) phosphonium phosphite, a tetrakis(hydroxymethyl) phosphonium bromide, a tetrakis(hydroxymethyl) phosphonium fluoride, a tetrakis(hydroxymethyl) phosphonium chloride, a tetrakis(hydroxymethyl) phosphonium phosphate, a tetrakis(hydroxymethyl) phosphonium carbonate, a tetrakis(hydroxymethyl) phosphonium formate, a tetrakis(hydroxymethyl) phosphonium citrate, a tetrakis(hydroxymethyl) phosphonium borate or a tetrakis(hydroxymethyl) phosphonium silicate.

13. The method according to claim 10, wherein the polymer of the biopenetrant is polyacrylate polymer.

14. The method according to claim 13, wherein the polyacrylate polymer has a molecular weight of about 4000.

15. The method according to claim 10, wherein the proportion of the VPA polymer to THP salt is from 1% to 50% by weight, relative to the total weight of the composition.

16. The method according to claim 15, wherein the proportion is from 1% to25% by weight, relative to the total weight of the composition.

17. The method according to claim 16, wherein the proportion is from 1% to5% by weight, relative to the total weight of the composition.

18. The method of claim 10, wherein the microbes are bacteria, fungi or algae.

Description

(1) The present invention will be illustrated by way of the following examples.

(2) In the examples, the various abbreviations have the following meaning: VPA polymer: a vinylphosphonic acid-terminated polyacrylate of molecular weight about 4000 VDPA copolymer: a vinylidene-diphosphonic acid-terminated acrylate/sulphonate copolymer of molecular weight 5000-6000 GHB: general heterotrophic bacteria SRB: sulphate reducing bacteria WHO water: World Health Organisation Standard Hardness Water (see TABLE I below) SMOW water: Standard Mean Ocean Water (see TABLE II below) THPS: a 50% aqueous solution of tetrakis(hydroxymethyl)phosphonium sulphate WSCP: copolymer of N, N, N, N-tetramethyl-1,2-diamino ethane and bis(2-chloroethyl)ether.

(3) TABLE-US-00001 TABLE I WHO Standard Hardness Water 1 litre contains: CaCl.sub.2 (anhydrous) 0.305 g MgCl.sub.26H.sub.2O 0.139 g

(4) TABLE-US-00002 TABLE II Standard Mean Ocean Water 5 litres contain: NaCl 122.65 g MgCl.sub.26H.sub.2O 55.52 g Na.sub.2SO.sub.4 20.45 g CaCl.sub.22H.sub.2O 7.69 g KCl 3.48 g NaHCO.sub.3 1.00 g KBr 0.50 g pH adjusted to 8.2 by means of 0.1N NaOH

EXAMPLE 1

(5) Quantitative Suspension Test (Planktonic Bacteria) in WHO Water

(6) TABLE-US-00003 Log Reduction of General Heterotrophic Bacteria (based upon 50 ppm ai THPS) Contact period Test Product 1 hour contact 3 hour contact Control 0 0 Unformulated THPS 1 5.8 THPS/VPA polymer* 7.4 Total kill THPS/VDPA polymer* 7.4 Total kill THPS/0.7% WSCP 3.7 7.4

EXAMPLE 2

(7) Quantitative Suspension Test in De Inking Water

(8) TABLE-US-00004 Log reduction values for 75 ppm ai THPS/3 hour contact Test Product GHB SRB Control 0 0 Unformulated THPS 3.8 3 THPS/VPA polymer* 5.1 3

EXAMPLE 3

(9) Biofilm (Sessile) Tests: Freshwater (WHO)

(10) TABLE-US-00005 Viable bacteria (GHB) after 75 ppm ai Test Product THPS dosed for 3 hours Control 1 10.sup.5 Unformulated THPS 1 10.sup.5 THPS/VPA polymer* 1 10.sup.2 THPS/VDPA polymer* <10 THPS/2% sulphonated surfactant (a) 1 10.sup.3

EXAMPLE 4

(11) Biofilm Tests: Seawater (SMOW)

(12) TABLE-US-00006 Viable bacteria after 75 ppm ai THPS dosed for 3 hours Test Product GHB SRB Control 1 10.sup.4 1 10.sup.6 Unformulated THPS 1 10.sup.2 1 10.sup.4 THPS/VPA polymer* <10 <10 THPS/VDPA polymer* 1 10.sup.2 1 10.sup.2 THPS/5% quaternary ammonium compound(b) 1 10.sup.2 1 10.sup.3 *In each case, the ratio of THPS to polymer was 50% a.i. THPS to 5% polymer, the polymer comprising 25% solids as the sodium salt.

(13) (a) A di-sodium salt of a mixed mono- and di-alkyl disulphonated diphenyl oxide, available as DOWFAX 2A1.

(14) (b) An alkyl dimethyl benzyl ammonium chloride, available as EMPIGENBAC 50.

EXAMPLE 5

(15) Iron Sulphide Dissolution Tests

(16) The following solutions were made: (a)THPS:THPS (26.6g)+de-ionised water (73.4g) (b)VPA polymer:VPA polymer solution having 20% active ingredient (20g)+de-ionised water (80g) (c)VDPA polymer:VDPA polymer solution having 20% active ingredient (20g)+de-ionised water (80g) (d)THPS/5% VPA polymer:THPS (26.6g)+VPA polymer solution having 20% active ingredient (5g)+de-ionised water (68.4g) (e)THPS/5% VDPA polymer:THPS (26.6g)+VDPA polymer solution having 20% active ingredient (5g)+de-ionised water (68.4g) (f)THPS/20% VPA polymer:THPS (26.6g)+VPA polymer solution having 20% active ingredient (20g)+de-ionised water (53.4g) (g)THPS/20% VDPA polymer:THPS (26.6g)+VDPA polymer solution having 20% active ingredient (20g)+de-ionised water (53.4g)

(17) To each of these solutions was added 2g (accurately weighed) of an iron sulphide field scale (from a water injection system). The solutions were then stirred in a heated water bath for 20 hrs at 50 C., after this time they were filtered through a weighed filter paper. The filter paper and solids were then allowed to dry before re-weighing; the weight of solids remaining was therefore determined, and the % weight loss calculated.

(18) The iron concentrations in the filtered solutions were also measured using the iron method on the Hach DR2000 spectrophotometer.

(19) TABLE-US-00007 Fe.sup.2+ concentration Dissolver pH % wt loss in solution ppm (a)THPS 3.23 63 3120 (b)VPA polymer 4.54 60 1310 (c)VDPA polymer 3.28 47 1430 (d)THPS + 5% VPA 3.77 74 3320 polymer (e)THPS + 5% VDPA 3.13 78 3560 polymer (f)THPS + 20% VPA 3.94 76 3480 polymer (g)THPS + 20% VDPA 2.99 83 5260 polymer