Description:FIELD OF THE INVENTION:
The present invention relates to the compositions for the regeneration of cation exchange resins commonly used in household or industrial contexts for the softening of water. The invention also provides a method for regenerating the cation exchange resins of water softener unit.

BACKGROUND OF THE INVENTION:
Domestic water softeners consist of cation-exchange resin that saturate after a certain period. Saturation decreases the efficiency of the cation exchange resin and needs frequent regeneration. The regeneration process involves treating the resin with brine solution. In some instances, where the water quality is very bad, the resin gets saturated beyond regeneration. In such instances, the resin must be replaced. The situation is particularly worrisome for home appliances such as dishwashers where the entire softener chamber must be replaced. This replacement is an additional expense to consumers and adds to recycling/disposal load of the organisations with an impact on environment too. Some of the prior art discussing the regeneration of ion-exchange resins have been listed below.

EP3103770B1 discloses a method to provide brine for regenerating an ion-exchange material and water softening. The brine tank comprises of a solid salt, brine compartment, separation element, inlet, outlet and water level control device. The regeneration takes place frequently and the brine tank is refilled with water thereby having a positive effect regarding microbial contamination.

US5474704A discloses an improved composition for regeneration of cation exchange resin beds in water softening system. The water softening system is usually a household or industrial system where the improved composition comprises of salts of gluconic acid and alkali metal salt. The alkali metal salts comprise of salt of citric acid.

Even though various methods of rejuvenating/regenerating the exhausted or saturated resins have been reported in literature of relevance and are time-tested and effective. However, in the context of domestic dishwashers, only one standard in-built process of regeneration using brine is available at consumer’s and service technician’s disposal. Indian water conditions are dynamic and range from very soft to very hard with several places reporting water hardness well above 1000 ppm as expressed in calcium carbonate. Additionally, the ground water also contains iron and manganese that fouls the cation exchange resin. Iron and manganese are known to foul the resin and reduce the ion-exchange capacity, thus impacting the performance of the dishwasher. The softening device in domestic appliances like dishwashers is a compact assembly, that cannot be dismantled by users/technicians and usually is a 2-chamber assembly with resin in one and brine in another compartment. The flow patterns and paths of water and brine are pre-defined and cannot be altered in a household setup even with trained technicians. Thus, there is a need to regenerate the depleted resin in the existing hydrodynamic setup of the water softener and needs a method/process and product/composition that can do this in a simple and consumer-centric way, and which can be implemented in day-to-day life of consumers and technicians.

OBJECTIVE OF THE INVENTION:
It is a primary objective of the present invention to provide a composition for regenerating the depleted cation exchange resin of a water softening unit.

It is another objective of the present invention to provide a method for regenerating the depleted cation exchange resin of a water softening unit.

SUMMARY OF THE INVENTION:
The present invention provides a composition for regenerating a cation exchange resin comprising:
1 to 10 wt% of an acid selected from an organic acid, an inorganic acid or a combination thereof; and
5 to 15 wt% of a metal salt selected from an alkali metal salt, an alkaline earth metal salt or a combination thereof.

The composition optionally comprises a chelant, the chelant is an electron donor compound selected from Methylglycine di-acetic acid Tri sodium salt, Glutamic Acid Diacetate Tetrasodium salt or a combination thereof

The organic acid is selected from citric acid, oxalic acid, maleic acid, acetic acid or a combination thereof, and the inorganic acid is selected from sulfuric acid, hydrochloric acid or a combination thereof.

The alkali metal salt is selected from sodium chloride and potassium chloride, or a combination thereof and the alkaline earth metal salt is selected from magnesium sulfate, magnesium chloride, calcium chloride, calcium sulfate or a combination thereof.

The combination of organic acid and inorganic acid is in a ratio in range of 2:1 to 1:0.1.

The combination of alkali metal salt and alkaline earth metal salt is in a ratio in range of 2:1 to 10:1.
The composition is in the form of solid, liquid or a mixture of both solid and liquid.

The composition in solid form is selected from powder, granules, tablet or a combination thereof.

The present invention also provides a method for regenerating a cation exchange resin using the said composition, the method comprises:
introducing the said composition into the resin bed;
keeping the said composition in the resin bed for 1 to 30 minutes; and
flushing the resin bed with water till the salinity of output water is similar to the salinity of input water.

The method for regenerating the cation exchange resin is performed manually or automated in a compact machine.

The method for regenerating the cation exchange resin is performed after 6 to 8 intervals.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS/FIGURES:
Figure 1 depicts a flowchart for method to regenerate a depleted/exhausted cation exchange resin bed.

DETAILED DESCRIPTION OF THE INVENTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.

Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.

It must be noted that as used herein and in the appended claims, the singular forms "a", "and", and "the" include plural referents unless the context dictates otherwise. Thus, for example, reference to "a compound" includes a plurality of such compounds, and reference to "the step" includes reference to one or more steps and equivalents thereof known to those skilled in the art, and so forth.

The term “some” as used herein is defined as “none, or one, or more than one, or all”. Accordingly, the terms “none”, “one”, “more than one”, “more than one, but not all” or “all” would all fall under the definition of “some”. The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments”.

The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.

More specifically, any terms used herein such as but not limited to “includes”, “comprises”, “has”, “consists” and grammatical variants thereof is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. The specification will be understood to also include embodiments which have the transitional phrase “consisting of” or “consisting essentially of” in place of the transitional phrase “comprising”. The transitional phrase “consisting of” excludes any element, step, or ingredient not specified in the claim, except for impurities associated therewith. The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention.

Whether or not a certain feature or element was limited to being used only once, either way it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element”. Furthermore, the use of the terms “one or more” or “at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there NEEDS to be one or more” or “one or more element is REQUIRED”.

Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having an ordinary skill in the art.

Reference is made herein to some “embodiments”. It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility and non-obviousness.

Use of the phrases and/or terms such as but not limited to “a first embodiment”, “a further embodiment”, “an alternate embodiment”, “one embodiment”, “an embodiment”, “multiple embodiments”, “some embodiments”, “other embodiments”, “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.

In an aspect, the present invention provides a composition for regenerating a cation exchange resin comprising:
1 to 10 wt% of an acid selected from an organic acid, an inorganic acid or a combination thereof; and
5 to 15 wt% of a metal salt selected from an alkali metal salt, an alkaline earth metal salt or a combination thereof.

In an embodiment of the present invention, the composition optionally comprises a chelant, the chelant is an electron donor compound selected from Methylglycine di-acetic acid Tri sodium salt, Glutamic Acid Diacetate Tetrasodium salt or a combination thereof.

In an embodiment of the present invention, the organic acid is selected from citric acid, oxalic acid, maleic acid, acetic acid or a combination thereof, and the inorganic acid is selected from sulfuric acid, hydrochloric acid or a combination thereof.

In an embodiment of the present invention, the alkali metal salt is selected from sodium chloride, potassium chloride or a combination thereof, and the alkaline earth metal salt is selected from magnesium sulfate, magnesium chloride, calcium sulfate or a combination thereof.

In an embodiment of the present invention, the combination of organic acid and inorganic acid is in a ratio in range of 2:1 to 1:0.1.

In an embodiment of the present invention, the combination of alkali metal salt and alkaline earth metal salt is in a ratio in range of 2:1 to 10:1.
In an embodiment of the present invention, the composition is in the form of solid, liquid or a mixture of both solid and liquid.

In an embodiment of the present invention, the composition in solid form is selected from powder, granules, tablet or a combination thereof.

In another aspect, the present invention provides a method for regenerating a cation exchange resin using the said composition, the method comprises:
introducing the said composition into the resin bed;
keeping the said composition in the resin bed for 1 to 30 minutes; and
flushing the resin bed with water till the salinity of output water is similar to the salinity of input water.

In an embodiment of the present invention, the method for regenerating the cation exchange resin is performed manually or automated in a compact machine.

In an embodiment of the present invention, the method for regenerating the cation exchange resin is performed after 6 to 8 intervals.

Technical advantages of the present invention:
In some embodiments, advantages of the present invention over the prior arts include but are not limited to the following:
 The present invention provides a method/process and product/composition that can regenerate the depleted resin in the existing hydrodynamic setup of the water softener in a simple and consumer-centric way.
 The present invention provides a method/process and product/composition that can be implemented in day-to-day life of consumers and technicians.

The present invention is further illustrated by reference to the following examples which is for illustrative purpose only and does not limit the scope of the invention in any way. These examples are not intended to be inclusive of all aspects of the subject matter disclosed herein, but rather to illustrate representative features, methods, compositions, and results. These examples are not intended to exclude equivalents and variations of the present invention, which are apparent to one skilled in art.

EXAMPLES:
The below examples are provided to demonstrate the invention but are not intended to limit the scope of the invention.

Example 1: A method to regenerate a depleted/exhausted cation exchange resin bed.
The said composition is made to pass through the resin bed and stay in bed for a period of 1 minute to 30 minutes. The resin bed is then flushed with water as per service flow and the flushing is repeated till the salinity of output water is similar to salinity of input water. The method can be manual or automated in a compact machine such as a household dishwasher to achieve the desired output (figure 1).

Example 2: Compositions to regenerate depleted/exhausted cation exchange resin bed.
Composition Components
Composition 1 10 wt% of NaCl + 5 wt% of Citric Acid
Composition 2 10 wt% of NaCl + 4 wt% of Hydrochloric Acid , Claims:WE CLAIM:

1. A composition for regenerating a cation exchange resin comprising:
1 to 10 wt.% of an acid selected from an organic acid, an inorganic acid or a combination thereof; and
5 to 15 wt.% of a metal salt selected from an alkali metal salt, an alkaline earth metal salt or a combination thereof.

2. The composition as claimed in claim 1, wherein the composition optionally comprises a chelant, wherein the chelant is an electron donor compound selected from Methylglycine di-acetic acid Tri sodium salt, Glutamic Acid Diacetate Tetrasodium salt or a combination thereof.

3. The composition as claimed in claim 1, wherein the organic acid is selected from citric acid, oxalic acid, maleic acid, acetic acid or a combination thereof, and wherein the inorganic acid is selected from sulfuric acid, hydrochloric acid or a combination thereof.

4. The composition as claimed in claim 1, wherein the alkali metal salt is selected from sodium chloride, potassium chloride or a combination thereof, and wherein the alkaline earth metal salt is selected from magnesium sulfate, magnesium chloride, calcium sulfate or a combination thereof.

5. The composition as claimed in claim 1, wherein the combination of organic acid and inorganic acid is in a ratio in range of 2:1 to 1:0.1 and wherein the combination of alkali metal salt and alkaline earth metal salt is in a ratio in range of 2:1 to 10:1.

6. The composition as claimed in claim 1, wherein the composition is in the form of solid, liquid or a mixture of both solid and liquid.

7. The composition as claimed in claim 1, wherein the composition in solid form is selected from powder, granules, tablet or a combination thereof.

8. A method for regenerating a cation exchange resin using the composition defined in claim 1, the method comprises:
introducing the said composition into the resin bed;
keeping the said composition in the resin bed for 1 to 30 minutes; and
flushing the resin bed with water till the salinity of output water is similar to the salinity of input water.

9. The method as claimed in claim 8, wherein the method for regenerating the cation exchange resin is performed manually or automated in a compact machine.

10. The method as claimed in claim 8, wherein the method for regenerating the cation exchange resin is performed after 6 to 8 intervals.