WO2013044299A1

WO2013044299A1 - Water treatment composition and method

Info

Publication number: WO2013044299A1
Application number: PCT/AU2012/001162
Authority: WO
Inventors: Ross Leslie Palmer; Alan Miller
Original assignee: Poolrite Research Pty Ltd
Priority date: 2011-09-26
Filing date: 2012-09-26
Publication date: 2013-04-04

Abstract

A swimming pool additive composition is provided comprising (i) a fruit acid and/or a sugar acid; and (ii) an inorganic agent and/or a carboxylic acid to help maintain a desired pool chemistry, particularly pH level, and/or impart a therapeutic quality to the pool water.

Description

WATER TREATMENT COMPOSITION AND METHOD

FIELD OF THE INVENTION

The present invention relates to the field of water treatment. More particularly, this invention relates to treatment of swimming pool water to provide a suitable and beneficial swimming environment.

BACKGROUND OF THE INVENTION

Swimming pools (also referred to herein as "pools") are popular for exercising and relaxing in but if they are to be maintained so as to provide a safe and healthy swimming environment then the pool water must undergo regular treatment to remain clear, clean and free from pathogens. Electrolytic, or saltwater, chlorinators are a common means for producing free chlorine to oxidise such pathogens. This requires the addition of salt (sodium chloride) to the pool and electrolysis is achieved by passing the salt water solution through an electrolytic cell which converts sodium chloride in the water into chlorine gas which, when dissolved in water becomes sodium hypochlorite (liquid chlorine).

The pool owner must monitor the level of salt within the pool and ensure that it is maintained at an appropriate level to provide sufficient chlorine to kill pathogens. There is also an optimal pH range of about 7.4 to 7.6 at which pool water should be maintained to provide maximum comfort for bathers and to minimise precipitation of inorganic salts onto the electrodes of the electrolytic cell. Total alkalinity and water hardness are also factors which must be monitored and kept within specified ranges.

It would therefore be useful to simplify the regimen of pool water maintenance for a pool owner or otherwise reduce the need for or frequency of addition of one or more chemicals.

Further, bathers may spend relatively long periods of time in their swimming pool and so it would be desirable to include in the pool chemistry any agents which can improve the comfort of the bather in the water, increase the satisfaction obtained from the swimming pool experience or impart health benefits to the bather during their immersion.

OBJECT OF THE INVENTION It is an object of the invention to overcome or alleviate one or more of the above disadvantages or provide the consumer with a useful or commercial choice.

SUMMARY OF THE INVENTION

In one broad form, the present invention resides in a swimming pool additive composition comprising (i) a fruit acid and/or a sugar acid and (ii) an inorganic agent and/or a carboxylic acid.

In a first aspect, although it need not be the only or indeed the broadest form, the invention resides in a swimming pool additive composition comprising:

(a) ascorbic acid and/or a fruit acid selected from the group consisting of citric acid, isocitric acid, glycolic acid, malic acid, tartaric acid and lactic acid; and

(b) a carboxylic acid and/or an inorganic agent selected from the group consisting of an inorganic salt, an inorganic mineral and a mineral acid.

Preferably, the fruit acid is citric acid.

The inorganic salt may be selected from the group consisting of sodium chloride, magnesium chloride, potassium chloride, sodium sulphate, sodium bisulphate, magnesium sulphate and potassium bisulfate.

The inorganic mineral may be a carbonate, oxide, sulphate or hydroxide of sodium, magnesium, calcium or potassium.

Suitably, the inorganic mineral may be selected from the group consisting of calcium carbonate, sodium bicarbonate and potassium bicarbonate.

It will be understood that the inorganic mineral, if present, will be a separate agent to the mineral acid and so the inorganic mineral, if acidic when dissolved, will not be a strong acid by comparison to the known mineral acids.

The mineral acid may be selected from the group consisting of hydrochloric acid, sulphuric acid, nitric acid and phosphoric acid.

Preferably, the mineral acid is hydrochloric acid. The carboxylic acid is preferably a dicarboxylic acid.

Preferably, the dicarboxylic acid is oxalic acid.

The composition may further comprise a formulating agent, excipient, aroma agent and/or binding agent.

In one preferred embodiment, the composition comprises a fruit acid selected from the group consisting of citric acid, isocitric acid, glycolic acid, malic acid, tartaric acid and lactic acid in combination with an inorganic salt.

Preferably, the fruit acid is citric acid.

Preferably, the inorganic salt is one or more of sodium chloride, potassium chloride or magnesium chloride.

In a further preferred embodiment, the composition comprises ascorbic acid in combination with a mineral acid.

Preferably, the mineral acid is hydrochloric acid.

In yet a further preferred embodiment, the composition comprises ascorbic acid, citric acid and oxalic acid.

In a second aspect, the invention resides in a method of treating a body of water, the method including the steps of:

(a) combining a fruit acid and/or a sugar acid with an inorganic agent and/or a carboxylic acid to form a treatment composition; and

(b) introducing an effective amount of the treatment composition into the body of water,

to thereby treat the body of water.

The fruit acid may be selected from the group consisting of citric acid, isocitric acid, glycolic acid, malic acid, tartaric acid and lactic acid.

Preferably, the fruit acid is citric acid.

Suitably, the sugar acid is ascorbic acid.

The inorganic agent may be selected from the group consisting of an inorganic salt, an inorganic mineral and a mineral acid.

The carboxylic acid may be a dicarboxylic acid such as oxalic acid.

The method may result in a decrease in the pH of the body of water and/or a reduction in the concentration of free metal ions in the body of water.

In one preferred embodiment, the treatment composition comprises citric acid and a salt.

Suitably, the salt is selected from the group consisting of sodium chloride, magnesium chloride and potassium chloride.

Suitably, the body of water is a swimming pool.

The treatment composition may be a swimming pool additive composition.

In a third aspect, the invention resides in a method of treating a subject, the method including the steps of:

(a) combining a fruit acid and/or a sugar acid with an inorganic agent and/or a carboxylic acid to form a treatment composition;

(b) adding an effective amount of the treatment composition into a body of water; and

(c) exposing the subject to the body of water,

to thereby treat the subject.

In one embodiment, the treatment composition comprises ascorbic acid and a mineral acid.

In a further embodiment, the treatment composition comprises ascorbic acid, citric acid and a dicarboxylic acid.

The method may be suitable for treating a subject suffering from a condition associated with vitamin C deficiency.

Alternatively, the method may be suitable for treating a subject in need of a skin treatment such as a chemical peel.

Throughout this specification, unless the context requires otherwise, the words "comprise", "comprises" and "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the expression "swimming poof is also intended to embrace the analogous use of spa baths, hot tubs and the like which are operated in a substantially identical manner to swimming pools. Unless contraindicated or noted otherwise, in these descriptions and throughout this specification, the terms "a" and "an" mean one or more, the term "or" means and/or.

As used herein, "subject" or "individual" or "patient" refers to any subject for whom or which therapy is desired, and generally refers to the recipient of the treatment to be practiced according to the invention. The subject will preferably be a mammal and, more preferably, the subject will be a human.

As used herein, unless the context demands otherwise, the term "treat," "treating," or "treatment" as used herein means to counteract a medical condition (e.g., a disorder sharing a physiological link to a lack of vitamin C) to the extent that the medical condition is improved according to clinically acceptable standard(s). This means to improve the disorder or relieve symptoms of the particular disorder in a patient. "Treat," 'treating," or "treatment" as used herein also includes prophylactic treatment unless the context requires otherwise.

The term "effective amount" or "therapeutically effective amount" means that amount of the relevant component that elicits the physical or medicinal response in a body of water or a subject.

The term "fruit acid" is used herein to refer generally to organic acids which may be isolated from one or more forms of fruit or other plant material or derived therefrom and include a-hydroxy acids such as citric acid, isocitric acid, glycolic acid, malic acid, tartaric acid and lactic acid.

The term "sugar acid" as used herein refers to monosaccharides having a carboxyl group and includes aldonic acids such as ascorbic acid.

Although the following discussion focuses on the use of the inventive composition and method in swimming pool water it will be understood that it is not so limited. The present invention may be applied mutatis mutandis to other bodies of water requiring similar treatment.

The present invention is predicated on the use of a swimming pool additive composition comprising (i) a fruit acid and/or a sugar acid and (ii) an inorganic agent and/or a carboxylic acid to help maintain a desired pool chemistry, particularly pH level, and/or impart a therapeutic quality to the pool water.

It has been found that the addition of salts into a saltwater pool may cause fluctuations in the pH level. Particularly, the pH will generally increase following the addition of sodium chloride due to consequent reactions after passage through the electrolytic cell. This effect and the issues it raises for pool chemistry has not been previously realised and thus it would be useful to treat or prevent the pH rise at the same time as adding the salt. In this respect, the combination of a fruit acid and an inorganic salt is envisaged.

Preferably, the fruit acid is citric acid.

Preferably, the inorganic salt is sodium chloride or magnesium chloride.

Further components, such as an aroma agent, may also be added. Sufficient quantities of the citric acid will be added with the salt to counteract a pH increase of approximately 0.1 to 1.0, preferably to lower the pH by 0.1 to 0.6. It will be appreciated that the actual pH change observed will depend on the exact quantity of citric acid added, the pool volume and presence of other agents in the pool which may sequester the citric acid, such as high levels of free metals. By way of an illustrative example, it has been shown that a 27000 litre pool at pH 7.9 and total alkalinity (carbonate- based buffer) can be dosed with 400g of citric acid (anhydrous) to provide a lowering of pH to 7.3.

The citric acid may also provide other benefits to the pool environment. For example, citric acid is an effective cleaning agent and may assist in reducing the extent of or removing any local staining due to the deposition of metal-containing compounds. Citric acid is also a useful chelating agent and so may aid in reducing the levels of potentially problematic free metals in the pool water to thereby lessen the incidence of staining.

In addition to the pH and pool chemistry control provided by the addition of a fruit acid, such as citric acid, certain health benefits may also be provided. Fruit acids are known to be beneficial in the treatment of certain skin conditions. For example, fruit acids have been used to remove layers of skin in a process sometimes referred to as chemical peeling to improve the appearance, tone and texture of skin. The cleansing effect provided by this treatment also helps to reduce the severity of acne and like skin conditions. The levels of the fruit acid which would likely be attained in the pool would be considerably lower than those used by healthcare providers during a chemical peel procedure but the longer time spent by a pool user within the pool water, and hence exposed to the treatment environment, should ensure at least a portion of the health benefits are imparted.

Alternatively, the fruit acid may be provided in a pool additive composition in combination with a strong acid, such as hydrochloric or sulphuric acids. Preferably, this composition will be formulated as a convenient solid additive which can simply be dropped by the user into the pool to slowly dissolve and release the fruit and mineral acids to lower the pH of the pool water and provide the further benefits discussed above.

The formulation may require an internal compartment which can hold the liquid mineral acid and which is formed from a substance which will dissolve in water. Alternatively, the mineral acid may be held within or associated with the solid crystals of the fruit acid and other formulating agents to thereby be released upon dissolution. Even in this scenario, due to the caustic nature of the acids, a polymeric barrier or the like would be provided to encapsulate the active components to protect the user during handling before conveniently dissolving in the pool water.

This pool additive is a convenient means for balancing the pool pH and may be used separate to or in conjunction with other embodiments comprising the fruit acid in combination with inorganic salts, such as sodium chloride and magnesium chloride.

In a further embodiment of the invention, the pool additive composition may comprise ascorbic acid in addition to or instead of the fruit acid component. Ascorbic acid is a form of vitamin C and is known to be useful in chelating metals, such as iron, and therefore may be used as part

c

of a pool additive composition to reduce the incidence of or remove metal stains from, the swimming pool surface.

Ascorbic acid, in suitable levels within the pool water, may also provide health benefits to bathers. Vitamin C deficiency has been linked to a range of disease processes such as scurvy, heart disease, high blood pressure, osteoarthritis, age-related macular degeneration and even certain forms of cancer. Given that it is a water-soluble vitamin it is possible to absorb therapeutically effective amounts of it transdermal^ when a bather is exposed to sufficient concentrations of ascorbic acid in pool water for an appropriate period of time.

In one general embodiment, the composition comprises ascorbic acid in combination with a mineral acid.

Preferably, the mineral acid is hydrochloric acid.

This embodiment will possess the pH lowering and free metal concentration/cleaning benefits of that discussed above employing a fruit acid but will additionally provide the health benefits associated with vitamin C intake.

Further embodiments of the invention may comprise a carboxylic acid, preferably a dicarboxylic acid, in addition to or as a replacement for a mineral acid as a pH lowering agent.

A preferred dicarboxylic acid is oxalic acid due to its high acid strength although any carboxylic acid showing similar acid strength may be suitable. Oxalic acid is a dry acid, i.e. it can purchased as a solid, and so a dry pool additive formulation can be achieved by combining oxalic with a fruit acid, such as citric acid, and/or a sugar acid, such as ascorbic acid.

In one general embodiment, a pool additive composition may be provided comprising oxalic acid, citric acid and ascorbic acid. Such a composition will provide the chelating, cleaning and therapeutic properties as previously discussed and will also have a strong pH lowering effect due to the acid strength of oxalic acid. Thus the same effects are achieved as with compositions employing a mineral acid but the formulation, storage and handling aspects of the composition are simplified due to the absence of any strongly acidic liquid components. The composition may be added directly to the pool water or added to a smaller volume of water, for example 20 L, for dissolution prior to addition to the pool.

Embodiments of the present invention which comprise a non-mineral acid for pH control provide benefits in simplifying the overall balance of the pool chemistry. It is known that mineral acids, such as hydrochloric acid, destroy or lower total alkalinity in the local region of the pool water into which they are administered due to their extremely high acid strength. Other acids provided with certain embodiments of the present invention including one or more of citric acid, ascorbic acid and possibly even oxalic acid provide the benefits of pH lowering but are sufficiently weaker than hydrochloric acid such that they do not have a comparable reducing effect on the total alkalinity.

.

Other embodiments of the present invention comprise a combination of an inorganic mineral with a fruit acid and/or a sugar acid. The inorganic mineral may be selected from the group consisting of calcium carbonate, sodium bicarbonate and potassium bicarbonate. The fruit acid is, preferably, citric acid and the sugar acid is, preferably, ascorbic acid. Such embodiments may be used to provide the pH lowering, cleaning, chelating and therapeutic benefits discussed previously in combination with the effects achieved by adding preferred inorganic minerals, such as water softening effects or the provision of further health benefits associated with natural minerals found in health spas and the like.

EXAMPLES

The formulations presented below are non-limiting examples of suitable compositions for the purposes listed. The key, effective, ingredients are listed but it will be understood by a person of skill in the art of formulation chemistry and analogous fields that certain other components may be necessary to present a final product such as binders, excipients or other 'glues' to maintain the ingredients in close association. Additional ingredients such as cyanuric acid (as a stabilizer), an algaecide and a clarifier may also be included to provide additional benefits to the pool water and allow for convenient single dosing to balance a number of pool chemistry factors.

1. 9.875 Kg - Sodium chloride

0.125 Kg - Citric acid

Optionally, 1 -50 ml_ of an aroma agent (citrus oils such as limonene)

The above pH control formulation may be applied separately to but in conjunction with a second composition as follows:

2. 9.5 Kg - Magnesium chloride (typically as the hexahydrate)

0.5 Kg - Boric acid

When used in conjunction, one lot of formula 2 may be applied per three lots of formula 1 per 10,000 L of pool water.

3. 20 L of aqueous Hydrochloric acid at a pH of approximately 1.35 2 Kg - Sodium chloride

0.5 Kg - Potassium chloride

0.125 Kg - Citric aid

0.125 Kg - Ascorbic acid 4. 1.0 Kg - Ascorbic acid

0.5 L - Hydrochloric acid

This composition may be applied per 50,000 L of pool water.

This composition will contain binders to hold the hydrochloric acid and prevent seepage. It may come in a sealed container which dissolves in the pool water, for example a water soluble polymeric coating displaying good acid resistance.

5. 0.5 Kg - Oxalic acid

0.1 Kg - Citric acid

0.2 Kg - Ascorbic acid

The above three dry acid components could be formulated into solid pellets or the like, optionally with the use of binders or other formulation agents, and then added to 20 L of water prior to use. This provides a convenient to handle and store dry formulation which can be used both for pH control and to provide certain health benefits in terms of vitamin C exposure and skin treatment.

The present invention provides a range of pool additive compositions which can be tailored to provide a desired pH level within a pool without the need for separate administration and adjustment of a strong pH lowering agent, such as a mineral acid. The compositions of the invention may also provide health benefits to bathers due to the presence of skin treatment agents such as fruit acids and a vitamin C source such as ascorbic acid. The advantages which can be achieved by such compositions in maintaining appropriate pool chemistry and the therapeutic effects which may be provided have not hitherto been realized.

It will be appreciated by the skilled person that the present invention is not limited to the embodiments described in detail herein, and that a variety of other embodiments may be contemplated which are, nevertheless, consistent with the broad spirit and scope of the invention.

Claims

1. A swimming pool additive composition comprising:

(a) ascorbic acid and/or a fruit acid selected from the group consisting of citric acid, isocitric acid, glycolic acid, malic

5 acid, tartaric acid and lactic acid; and

2. The composition of claim 1 wherein the fruit acid is citric acid.

0 3. The composition of claim 1 or claim 2 wherein the inorganic salt is selected from the group consisting of sodium chloride, magnesium chloride, potassium chloride, sodium sulphate, sodium bisulphate, magnesium sulphate and potassium bisulfate.

4. The composition of any one of the preceding claims wherein the5 inorganic mineral is a carbonate, oxide, sulphate or hydroxide of sodium, magnesium, calcium or potassium.

5. The composition of claim 4 wherein the inorganic mineral is selected from the group consisting of calcium carbonate, sodium bicarbonate and potassium bicarbonate.

0 6. The composition of any one of the preceding claims wherein the mineral acid is selected from the group consisting of hydrochloric acid, sulphuric acid, nitric acid and phosphoric acid.

7. The composition of any one of the preceding claims wherein the carboxylic acid is a dicarboxylic acid.

5 8. The composition of claim 7 wherein the dicarboxylic acid is oxalic acid.

9. The composition of any one of the preceding claims further comprising one or more of a formulating agent, excipient, aroma agent and binding agent.

Q 10. The composition of any one of the preceding claims further comprising one or more of cyanuric acid, an algaecide and a clarifier.

11. The composition of claim 1 wherein the active ingredients consist of a fruit acid selected from the group consisting of citric acid, isocitric acid, glycolic acid, malic acid, tartaric acid and lactic acid in combination with an inorganic salt.

12. The composition of claim 11 wherein the fruit acid is citric acid.

13. The composition of claim 1 wherein the inorganic salt is selected from the group consisting of sodium chloride, potassium chloride and magnesium chloride.

14. The composition of claim 1 wherein the active ingredients consist of ascorbic acid in combination with a mineral acid.

15. The composition of claim 4 wherein the mineral acid is hydrochloric acid.

16. The composition of claim 14 comprising an acid resistant barrier for containment of the mineral acid.

17. The composition of claim 1 wherein the active ingredients consist of ascorbic acid, citric acid and oxalic acid.

18. A method of treating water in a swimming pool, the method including the steps of:

(a) combining a fruit acid and/or a sugar acid with an inorganic agent and/or a carboxylic acid to form a swimming pool additive composition; and

(b) introducing an effective amount of the swimming pool additive composition into the body of water, to thereby treat the swimming pool water.

19. The method of claim 18 wherein the fruit acid is selected from the group consisting of citric acid, isocitric acid, glycolic acid, malic acid, tartaric acid and lactic acid.

20. The method of claim 18 wherein the sugar acid is ascorbic acid.

21. The method of claim 18 wherein the inorganic agent is selected from the group consisting of an inorganic salt, an inorganic mineral and a mineral acid.

22. The method of claim 18 wherein the inorganic salt is selected from the group consisting of sodium chloride, magnesium chloride and potassium chloride.

23. The method of claim 18 wherein the carboxylic acid is a dicarboxylic acid.

24. The method of claim 18 wherein the treatment results in a decrease in the pH of the swimming pool water and/or a reduction in the concentration of free metal ions in the swimming pool water.

25. The method of claim 18 wherein the swimming pool additive composition consists of citric acid and a salt as the active components.

26. A method of treating a subject, the method including the steps of:

(c) exposing the subject to the body of water, to thereby treat the subject.

27. The method of claim 26 wherein the treatment composition is as described for the swimming pool additive composition of claims 1 to 17.

28. The method of claim 26 wherein the treatment is for suffering from a condition associated with vitamin C deficiency.

29. The method of claim 26 wherein the treatment is for a human in need of a skin chemical exfoliation treatment.

30. The method of claim 26 wherein the body of water is a swimming pool and the subject is exposed to the water by being at least partially immersed in the swimming pool.