GB2364047A

GB2364047A - Water treatment composition

Info

Publication number: GB2364047A
Application number: GB0015569A
Authority: GB
Inventors: Philip Frank Souter; Colin Ure
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 2000-06-27
Filing date: 2000-06-27
Publication date: 2002-01-16
Also published as: GT200100128A; GB0015569D0

Abstract

A water treatment composition comprising (i) a polysaccharide material comprising an amine group, (ii) a second, substantially water-soluble polymeric material having an average molecular weight of at least 100,000. The composition may comprise an inorganic metal salt selected from iron sulphate, iron chloride, aluminium chloride, aluminium sulphate, manganese sulphate, manganese chloride, copper sulphate, copper chloride, poly- variations, and combinations thereof. The polysaccharide may be chitosan, modified chitosan, salts, or a combination thereof. The composition may comprise a disinfecting agent, a clay, or an alkali agent. The composition may be used to provide potable water.

Description

2364047 WATER TREATMENT COMPOSITION

FIELD OF THE INVENTION

The present invention relates to water treatment compositions, especially water purification compositions which are suitable for use in water purification processes.

BACKGROUND TO THE INVENTION

There is a need for potable water in all areas of the world In developed countries, water is purified and potable water is supplied on a large scale, typically by large national or multinational water management companies This water is typically supplied directly to the consumers homes in a potable form However, in some parts of the world, for example in some rural areas of developing countries, many people either do not have a direct water supply to their homes and only have access to a non- potable communal water supply such as a village well, or cannot be guaranteed that the water they do receive is potable Thus, there is a need for a water purification kit that allows the consumer to purify their own water, which produces potable water in a fast and efficient manner.

Current water purification compositions available on the market to date, consist mainly of disinfectants, e g sources of chlorine and/or iodine, and do not adequately purify water Water which is obtained after treatment by these water purification kits, may still comprise amounts of water impurities, e g heavy metal ions such as arsenic, which, when continually consumed for a prolonged period of time, may lead to health problems Thus, there is a need to provide a water purification composition which removes water-impurities like heavy metal ions, more efficiently and effectively than current water purification kits.

The Inventors have surprisingly found that a water purification composition comprising (i) a polysaccharide which comprises an amine group; and (ii) a second polymeric material which is substantially water-soluble and has a weight average molecular weight of at least 100000; and optionally (iii) an inorganic metal salt, removes greater amounts of water impurities, like heavy metal ions, from water compared to current water purification compositions.

Also, current water purification compositions do not adequately remove, kill or inactive micro-organisms such as bacteria, viruses and cysts, which are present in the water Thus, there remains a need to provide a water purification composition which does adequately remove, kill or inactive these micro-organisms.

The Inventors have surprisingly found that when the composition of the present invention comprises a disinfecting agent, said composition removes, kills or inactivates a surprisingly larger amount of micro-organisms such as bacteria, viruses and cysts compared to water purification compositions known in the art.

In addition, the water which is to be purified by a water purification composition typically comprises a large amount of water-soluble organic content When bleach, especially chlorine based bleach, is comprised by current water purification compositions, said bleach acts on this water-soluble organic content and produces by-products in the water, like chlorine derivatives such as chloroacetic acid or chloroform, which are harmful to human and animal health Thus, there is a need to provide a water purification method which produces purified water comprising a low amount of disinfection by-products.

The Inventors have surprisingly found that by purifying water using a combination of (i) the composition of the present invention and (ii) a disinfecting agent, typically by using a method comprising the steps of (a) contacting a wgaer purification composition of the present invention to water to obtain a solution comprising solid matter; and (b) removing at least part of said solid matter from said solution to obtain partially purified water; and (c) adding a disinfecting agent to said partially purified water to obtain purified water, a surprisingly low amount of water purification by- products like chlorine derivatives are present in the water after treatment.

SUMMARY OF THE INVENTION

In a first embodiment of the present invention, a water purification composition is provided which comprises (i) a polysaccharide which comprises an amine group; and (ii) a second polymeric material which is substantially water-soluble and has a weight average molecular weight of at least 100000; and optionally (iii) an inorganic metal salt selected from the group consisting of iron sulphate, iron chloride, aluminium chloride, aluminium sulphate, manganese sulphate, manganese chloride, copper sulphate, copper chloride, poly variations thereof or a combination thereof.

In a second embodiment of the present invention, a combination of; (a) a water purification composition comprising (i) a polysaccharide which comprises an amine group; and (ii) a second polymeric material which is substantially water- soluble and has a weight average molecular weight of at least 100000; and optionally (iii) an inorganic metal salt selected from the group consisting of iron sulphate, iron chloride, aluminium chloride, aluminium sulphate, manganese sulphate, manganese chloride, copper sulphate, copper chloride, poly variations thereof or a combination thereof; and (b) a disinfecting agent, for simultaneous or sequential use in water purification, is provided.

In a third embodiment of the present invention a method of purifying water is provided, said method comprises the steps of; (a) contacting a water purification composition comprising (i) a polysaccharide which comprises an amine group; and (ii) a second polymeric material which is substantially water-soluble and has a weight average molecular weight of at least 100000; and optionally (iii) an inorganic metal salt selected from the group consisting of iron sulphate, iron chloride, aluminium chloride, aluminium sulphate, manganese sulphate, manganese chloride, copper sulphate, copper chloride, poly variations thereof or a combination thereof, to water to obtain partially purified water comprising solid matter; and (b) removing at least part of said solid matter from said partially purified water by; (i) filtration; or (ii) decanting; or (iii) sedimentation; or (iv) flotation; or (v) a combination thereof, to obtain purified water.

DETAILED DESCRIPTION OF THE INVENTION

Polysaccharide The water purification composition herein referred to as "composition" comprises a polysaccharide which comprises an amine group The polysaccharide is selected on the basis that it can act as a flocculent and causes the aggregation of water-insoluble particles into larger water-insoluble aggregated complexes known as flocs The polysaccharide may also adsorb or coagulate oils, fats and other organic or inorganic matter, and may sequester heavy metal ions.

The term "amine group" is defined herein as including primary amine groups, secondary amine groups, tertiary amine groups, quaternary amine groups such as quaternary ammonium groups, but the term "amine group" does not include amide groups Said amine group is preferably present as a side group of the polysaccharide.

Preferably, the polysaccharide is substantially water-insoluble "Substantially water- insoluble" is defined herein as having at least 10 % by dry total weight of undissolved material present as determined by the following method:

lg material is added to 1 litre of distilled water at a p H of between 6 0 and 8 0, at C and stirred vigorously for 24 hours The water is then filtered through a 3 micrometer filter, and the undissolved material which is collected by the filter step is dried at 80 C until constant weight, typically for 24 to 48 hours The weight of this undissolved material is then determined and the % dry weight of this undissolved material can be calculated.

The amine group of the polysaccharide is preferably protonated when the polysaccharide comes into contact with water, typically this protonation reaction occurs at a p H of below 9 0, and preferably at a p H of from 3 to 8 Thus, preferably the polysaccharide is cationic when in a solution of water at a p H of below 9.

Alternatively, the amine group of the polysaccharide may already be in a charged state, for example a substituted or protonated state The amine group of the polysaccharide may be a cationic quaternary ammonium group.

The polysaccharide preferably comprises a starch or substituted starch comprising an amine group Preferably the polysaccharide comprises a cationic starch For example, starch such as, and/or cationic starch obtained from, potato starch, waxy maize starch, corn starch, wheat starch and rice starch More preferably, the polysaccharide comprises an amine group which is bound directly to the monomer saccharide backbone unit of said polysaccharide More preferably the polysaccharide comprises a polymer of glucosamine where all the monomer saccharide backbone units are connected in a linear conformation via beta-1-4-glycosidic bonds More preferably, the polysaccharide comprises a modified chitin, such as chitosan, modified chitosan, or salts thereof Most preferably the polysaccharide comprises chitosan or modified chitosan The polysaccharide may be an impurity of chitin, and therefore, chitin may be a preferred source of polysaccharide for use herein.

Chitosan suitable for use herein is typically derived from the chitin of crustacea such as crabs, lobsters and shrimps Chitosan derived from the chitin of fungi can also be used herein The chitosan for use herein is typically found in the shells of crustacea and can be extracted by any technique known in the art, for example by using the extraction techniques described in U 53533940, U 53862122, U 53922260 and U 54195175.

The polysaccharide for use herein typically has an amine modification degree of at least 0 1, more preferably at least 0 2, or preferably at least 0 3, or preferably at least 0.4, or preferably at least 0 5, or preferably at least 0 6, or preferably at least 0 7, or preferably at least 0 8, or preferably at least 0 9, or preferably at least 1 0 Said modification degree is an indication of the amount of amine groups present in the polysaccharide and is defined as the number ratio of the number of amine groups present in the polysaccharide per monomer unit of the polysaccharide.

Preferably, the polysaccharide has a weight average molecular weight of at least 10000, or preferably at least 25000, or preferably at least 50000, or preferably at least 75000, or preferably at least 100000.

The composition herein preferably comprises (by weight) from 0 1 %, or preferably from 0 5 %, or preferably from 1 %, or preferably from 1 5 %, or preferably from 2 %, or preferably from 2 5 %, and preferably to 50 %, or preferably to 40 %, or preferably to 30 %, or preferably to 20 %, or preferably to 10 %, or preferably to 5 %, or preferably to 4 % polysaccharide.

Second polymeric material The composition herein comprises a second polymeric material which is substantially water-soluble and has a weight average molecular weight of at least 100000 The second polymeric material is selected on the basis that it can act as flocculent and causes the aggregation of water-insoluble particles into larger water- insoluble aggregated complexes known as flocs It is believed that the ability of the second polymeric material to act as a flocculent, is due to the combination of its molecular weight, structure, and water-solubility properties.

The term "substantially water-soluble" means having less than 10 % by total dry weight of undissolved material present as determined in the following test:

The second polymeric material does not comprise a polysaccharide and/or does not comprise an amine group and therefore is different to, and is not, the polysaccharide of the composition of the present invention Preferably the second polymeric material comprises an amide group More preferably the second polymeric material is a polyacrylamide The second polymeric material may comprise a cationic polyacrylamide Preferred cationic polyacrylamides for use herein include those known under the trade names as Zetag 89, Praestol 611 BC, Calfloc 1552, Calfloc 1506, Calfloc 1508, Magnafloc LT 22, Magnafloc LT 22 S, Magnafloc LT 27 and Polymin KP 97.

Preferably, the second polymeric material for use herein is nonionic or anionic, preferably anionic, more preferably the second polymeric material contains at least 0.02, or preferably at least 0 05, or preferably at least 0 1 anionic groups per monomer unit.

The second polymeric material for use herein is typically a polyacrylamide, especially preferred are anionic or nonionic polyacrylamides Typical anionic and nonionic polyacrylamides for use herein are those from the Magnafloc range supplied by Allied Colloids Of these polyacrylamides, especially preferred are those known under the trade name as Magnafloc LT 20, Magnafloc LT 25, Magnafloc LT 255, Magnafloc LT 26, Magnafloc LT 28, Magnafloc 351 and Magnafloc 919.

It is preferred that a low amount of substantially water-soluble organic content is present in the composition herein The term "low amount of substantially water- soluble content" can be determined by the following method:

500 mg of said composition is added to 1 litre of deionised water which comprises no detectable amounts of substantially water-soluble organic content, to form a solution.

Said solution is left for 30 minutes and is then filtered through Whatman GF/C paper having an average pore size of 1 2 micrometers to obtain purified water The level of total organic content (TOC) of said purified water is determined using the ISO method 8245:1999 A composition comprising "a substantially low amount of water-soluble content" is defined as a composition which gives a TOC of said purified water of less than 1 Oppm, preferably less than 7 ppm, when determined using this method.

Thus, the composition herein preferably comprises an amount of second polymeric material such that a low amount of substantially water-soluble organic content, as defined hereinbefore, is present in the composition herein In addition, the second polymeric material is preferably selected so that a low amount of substantially water- soluble organic content, due to the presence of the second polymeric material, is present in the water after treatment with the composition herein Preferably, the second polymeric material does not comprise a polysaccharide and more preferably the second polymeric material does not comprise a carboxymethyl cellulose or derivative thereof.

Preferably, the weight average molecular weight of the second polymeric material is at least 250000, or preferably at least 500000, or preferably at least 1000000, or preferably at least 2000000, or preferably at least 3000000, or preferably at least 5000000, or preferably at least 10000000.

Preferably, the composition herein comprises (by weight) from 0 1 %, or preferably from 0 2 %, or preferably from 0 5 %, or preferably from 1 %, and preferably to 30 %, or preferably to 20 %, or preferably to 10 %, or preferably to 5 %, or preferably to 3 % second polymeric material.

Inorganic metal salt In a highly preferred embodiment of the present invention, the composition herein comprises an inorganic metal salt selected from the group consisting of iron sulphate, iron chloride, manganese sulphate, manganese chloride, copper sulphate, copper chloride, aluminium sulphate, aluminium chloride, poly variations thereof, and combinations thereof The inorganic metal salt of the composition of the present invention is selected on the basis that it can act as a coagulant and can interact with charged water-soluble impurities in such a manner so as to neutralise the charge of said water-soluble impurity to form a water-insoluble impurity, usually to form a water-insoluble salt of said impurity, which precipitates out of solution The inorganic salt of the composition of the invention can also lower the turbidity of the water by increasing the particle size of the water-insoluble impurities possibly causing sedimentation or facilitating the removal of these waterinsoluble impurities by filtration or other water-insoluble matter removal techniques such as flotation or decanting The inorganic salts selected herein, can also co-precipitate heavy metal ions out of water, and can also lower the total organic content present in the water by coagulating or adsorption of this organic content onto the water- insoluble impurities which have been formed in the water.

Preferably the inorganic metal salt of the composition of the invention is a multivalent, preferably a di or tri-valent, inorganic metal salt such as, aluminium III sulphate, iron II (ferrous) sulphate or iron III (ferric) sulphate A most preferred inorganic metal salt for use herein is iron III sulphate The term "inorganic metal salt" includes all poly variations thereof such as polyaluminum chloride and polyferric material, but does not include compounds comprising methyl or ethyl groups The inorganic metal salt is preferably free of carbon atoms The term "inorganic metal salts which are free of carbon atoms" includes sources of inorganic metal salts which comprise minor amounts of carbon impurity such as often found in naturally occurring inorganic metal salt sources For example, preferred inorganic metal salts of the composition of the invention comprise (by weight of said salt) less than 5 %, more preferably less than 3 %, more preferably less than 1 %, even more preferably less than 0 1 %, even more preferably less than 0 01 % carbon atoms.

Particularly preferred are those inorganic metal salts which are a source of acid, such as aluminium III sulphate or iron sulphate This is especially true when the composition herein also comprises a source of carbonate such as sodium carbonate, since the acid source, and carbonate source, may react together to form a gas This process is known as effervescence and helps to disperse the composition herein, especially when the composition herein is in the form of a tablet.

The composition herein preferably comprises (by weight) from 1 %, or preferably from 5 %, or preferably from 10 %, or preferably from 15 %, or preferably from 20 %, or preferably from 25 %, and preferably to 50 %, or preferably to 40 %, or preferably to 30 % inorganic salt selected from the group consisting of iron sulphate, iron chloride, manganese sulphate, manganese chloride, copper sulphate, copper chloride, aluminium sulphate, aluminium chloride, poly variations thereof, and combinations thereof.

Disinfecting agent The composition herein preferably comprises a disinfecting agent The disinfecting agent may comprise any compound which disinfects or sanitises water The disinfecting agent may be inorganic such as silver salts, colloidal silver, nanosilver, ozone, chlorine dioxide, chlorine, sodium hypochlorite or chloramine The disinfecting agent may also be organic such as a quaternary ammonium compound.

Preferred disinfecting agents include inorganic chlorine based disinfectants, wherein the chlorine is in a formal oxidation state that is not minus one, preferably above minus one Preferred sources of chlorine comprise hypochlorites and organic sources of chlorine such as isocyanurates Other preferred disinfecting agents comprise iodine and sources of iodine such as polyiodide resins.

The composition herein preferably comprises (by weight) from 0 01 %, or preferably from 0 1 %, or preferably from 0 2 %, or preferably from 0 5 %, or preferably from 0 7 %, or preferably from 1 0 %, or preferably from 1 2 %, or preferably from 1 5 %, and preferably to 20 %, or preferably to 10 %, or preferably to 5 %, or preferably to 4 %, or preferably to 2 5 % disinfecting agent.

Clay The composition herein preferably comprises a clay The clay acts as a seed particle onto which water-insoluble impurities can aggregate to form flocs The presence of clay in the composition improves the rate of floc formation and allows the formation of larger flocs compared to when clay is absent from the composition herein The clay may also act as a swelling agent, and if the composition herein is in the form of a tablet, the clay improves the rate at which the tablet disintegrates on contact with water by swelling upon contact with water so that the components of the tablet are pushed apart by the swollen clay particles The clay can also act as a desiccant within the tablet The clay may also act as a cationic exchange agent to remove metal ions from the water and the clay can also remove colour and some organic material from water by adsorption.

The clay is preferably a smectite clay, preferably a dioctahedarl smectite clay such as montmorillonite clay or a trioctahedral smectite clay such as hectorite clay Those clays found in bentonite clay deposits are also preferred Particularly preferred clays for use herein include laponite clay, hectorite, montmorillonite, nontronite, saponite, volkonsite, sauconite, beidellite, allevarlite, illite, halloysite and attapulgite.

The composition herein preferably comprises (by weight) from 1 %, or preferably from 5 %, or preferably from 10 %, or preferably from 15 %, or preferably from 20 %, or preferably from 25 %, and preferably to 80 %, or preferably to 50 %, or preferably to 35 % clay.

Aluminosilicate Aluminosilicates may be used herein in place of, or in addition to, clay The aluminosilicate can act as a cationic exchange agent to remove metal ions from water, and can also act as a seed particle to enhance floc formation The aluminosilicates for use herein are preferably in hydrated form Preferred aluminosilicates for use herein include zeolite A, zeolite X, zeolite Y, zeolite P and zeolite beta.

The composition herein preferably comprises (by weight) from 1 %, or preferably from 5 %, or preferably from 10 %, or preferably from 15 %, or preferably from 20 %, or preferably from 25 %, and preferably to 80 %, or preferably to 50 %, or preferably to 35 % aluminosilicate.

A third polymeric material The composition herein may comprise a third polymeric material Said third polymeric material does not contain an amine group and is substantially water insoluble The term "substantially water insoluble" is defined hereinbefore Thus, the third polymeric material is different to, and is not, the polysaccharide or the second polymeric material of the composition of the present invention The third polymeric material is selected on the basis that it can act as a seed particle to enhance floc formation The third polymeric material can be used in place of, or in addition to, clay or zeolite.

Preferably the third polymeric material comprises cellulose, more preferably the third polymeric material is an unmodified cellulose Most preferably the third polymeric material comprises powdered cellulose.

The composition herein preferably comprises (by weight) from 1 %, or preferably from 5 %, or preferably from 10 %, or preferably from 15 %, or preferably from 20 %, or preferably from 25 %, and preferably to 80 %, or preferably to 50 %, or preferably to 35 % third polymeric material.

Alkali agent The composition herein may comprise an alkali agent The alkali agent can be any compound which gives alkalinity when contacted to water The alkali agent for use herein is not a polymeric material The composition herein preferably comprises an amount of alkali agent such that when the composition herein is contacted to water to form a solution, said solution has a p H of from 6 0 to 8 5.

Preferred alkali agents are selected from the group consisting of sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium oxide, calcium carbonate, calcium bicarbonate, calcium hydroxide, calcium oxide, potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium oxide and combinations thereof.

Particular alkali agents which are a source of carbonate when contacted to water, for example sodium carbonate or sodium bicarbonate may be preferred for used herein.

If the composition herein comprises a source of acid, for example an inorganic salt of the composition of the present invention such as iron sulphate, said alkali agent which is a source of carbonate can interact with said acid source in the presence of water to produce a gas This process is known as effervescence, and improves the rate at which the composition disperses, especially when the composition herein is in the form of a tablet.

The composition herein typically comprises (by weight) from 1 % to 50 %, preferably from 10 %, or preferably from 15 %, or preferably from 20 %, or preferably from 25 %, and preferably to 45 %, or preferably to 40 %, or preferably to 35 % alkali agent.

Composition The composition herein is preferably in a solid form, most preferably in a tablet or powder form The composition herein is preferably packaged so that it is protected from environmental conditions such as moisture Preferably the composition herein is packaged in a water impermeable material such as polypropylene.

Method for use The composition herein can be used to purify water using a method comprising the steps of (a) contacting the composition herein to water to obtain partially purified water comprising solid matter; and (b) removing at least part of said solid matter from said partially purified water by; (i) filtration; or (ii) decanting; or (iii) sedimentation; or (iv) flotation; or (v) a combination thereof, to obtain purified water.

The composition herein can be in the form of a tablet or solid powder which is added to water, typically to form partially purified water comprising solid matter such as flocs This solid matter can be removed or separated from the remaining part of the partially purified water by any technique, typically by filtration but decanting, sedimentation and flotation may also be used By filtration it is meant passing the partially purified water through a filter Filtration can occur by pouring means, for example by pouring said partially purified water through a filter to remove at least part of the solid matter from said partially purified water Filtration can also occur by centripetal force means, for example by total enclosing the partially purified water by a filter and spinning said partially purified water and said filter so that said partially purified water passes through said filter and at least part of said solid matter is separated from said partially purified water Filtration can also occur by plunging means, for example by plunging or moving a filter through said partially purified water so that at least part of said solid matter is separated from said partially purified water.

Filters typically used include cloth filters, filter paper and polishing filters, such as filters comprising activated carbon, glass fibre, zeolite, ion exchange media, or a combination thereof, which remove residual water-impurities, e g organic matter, heavy metal ions and residual disinfectant from the water Filters suitable for use may be impregnated with silver or other biostatic components so that bacteria cannot grow on said filter and the filter can be reused several times without contaminating the water being filtered Sand filters can also be used, and more than one filter may be used in combination herein.

Preferably, from 1 Omg, or preferably from 50 mg, or preferably from 75 mg, or preferably from 100 mg, or preferably from 150 mg, or preferably from 200 mg, or preferably from 250 mg, or preferably from 300 mg, and preferably to 2000 mg, or preferably to 100 mg, or preferably to 750 mg of composition herein is added to 1 litre of water The amount of composition herein which is added to the water depends on the impurity of said water For example, less composition is needed to adequately purify water whichis not very impure compared to the amount of composition herein which is needed to purify very impure water.

Combination In a preferred embodiment of the present invention, the composition herein is used in combination with a disinfecting agent for simultaneous or sequential use in the purification of water When used in combination with the composition herein, the disinfecting agent is preferably not comprised by said composition and therefore is not an integral component of said composition Thus, it is not essential that the composition herein when used in combination with a disinfecting agent comprises a disinfecting agent, since the composition can be used in combination with a disinfecting agent simultaneously or sequentially, preferably sequentially, to purify water It may be preferred that the composition herein when used in combination with a disinfecting agent, does comprise an additional disinfecting agent in addition to the separate disinfecting agent that is not comprised by the composition herein, this additional disinfecting agent may also be the same type of disinfecting agent as the separate disinfecting agent.

In a highly preferred embodiment of the present invention, the composition herein is used in combination with a disinfecting agent by contacting said composition to water to form partially purified water comprising solid matter, removing at least part of said solid matter from the remaining part of said partially purified water by filtration, decanting, sedimentation, flotation or a combination thereof, to form purified water, wherein said disinfecting agent is preferably added to the water after the solid matter removal step In this particular embodiment of the present invention, the disinfecting agent is not substantially removed from the water by the solid matter removal step and thus a greater amount of said disinfecting agent remains in the water after said removal step which keeps said water sterile In addition, the solid matter removal step removes a substantial amount of organic matter from the water, and thus the water obtained after said removal step comprises a lower amount of organic matter, so that when the disinfecting agent is then added to the water after the solid matter removal step, there is less organic matter present in this water for the disinfecting agent to interact with, and therefore a lower amount of harmful by- products such as chlorine-derivatives, are generated by the disinfecting agent interacting with this lower amount of organic matter.

Preferably, the weight ratio of composition herein to disinfecting agent when used in combination is from 10000:1, or preferably from 5000:1 or preferably from 1000:1, or preferably from 500:1, and preferably to 2:1, or preferably to 10:1, or preferably to 25:1, or preferably to 50:1, or preferably to 100:1.

EXAMPLES

Example 1

The following compositions are in accord with the present invention:

Ingredient Composition A B C D E F G H I J K Chitosan 3 5 4 1 5 3 15 1 2 3 1 5 Cationic modified 3 1 potato starch Magnafloc LT 22 S 2 5 10 1 Magnafloc LT 25 1 5 2 1 3 3 Magnafloc LT 28 3 1 5 1 5 Aluminium 32 15 10 30 45 25 10 35 sulphate Iron III sulphate 30 22 25 Calcium 2 0 5 1 hypochlorite Iodine 1 Hectorite clay 40 15 20 40 25 Montmorillonite 30 32 55 5 70 clay Zeolite X 12 70 20 Sodium carbonate 30 25 15 10 30 10 25 Sodium 22 45 25 35 bicarbonate Miscellaneous to to to to to to to to to to to 100 100 100 100 100 100 100 100 100 100 Example 2

500 mg of the compositions A to K from example 1 were added in powder or tablet from to 1 litre of water, respectively The water was then agitated or stirred briefly.

The water was left to stand for 5 minutes, after which said water was stirred or agitated for a further minute and then left to stand for another 20 minutes During this time, water-insoluble flocs formed in the water The was then poured through a tightly woven cloth filter to remove said water-insoluble flocs, and the remaining part of the water was collected This remaining part of the water is purified water.

Example 3

500 mg of the compositions A, C, F, G, I, J and K were added in powder or tablet from to 1 litre of water, respectively The water was then agitated or stirred briefly.

The water was left to stand for 10 minutes, after which said water was stirred or agitated for a further minute and then left to stand for another 20 minutes During this time, water-insoluble floes formed in the water The was then poured through a tightly woven cloth filter to remove said water-insoluble flocs, and the remaining part of the water was collected lmg calcium hypochlorite was then added to the collected water, and the collected water was agitated or stirred briefly This collected water is purified water.

Claims

1 A water purification composition comprising; (i) a polysaccharide which comprises an amine group; and (ii) a second polymeric material which is substantially water-soluble and has a weight average molecular weight of at least 100000; and optionally (iii) an inorganic metal salt selected from the group consisting of iron sulphate, iron chloride, aluminium chloride, aluminium sulphate, manganese sulphate, manganese chloride, copper sulphate, copper chloride, poly variations thereof, or a combination thereof.

2 A water purification composition according to claim 1, whereby said polysaccharide comprises chitosan, modified chitosan, salts thereof or a combination thereof.

3 A water purification composition according to any preceding claim, whereby said inorganic metal salt comprises a member selected from the group consisting of iron sulphate, aluminium sulphate, iron chloride, poly-variations thereof, or a combination thereof.

4 A water purification composition according to any preceding claim, whereby said composition comprises a disinfecting agent.

A water purification composition according to any preceding claim, whereby said composition comprises clay, preferably smectite clay.

6 A water purification composition according to any preceding claim, whereby said composition comprises aluminosilicate.

7 A water purification composition according to any preceding claim, whereby said composition comprises an alkali agent, preferably said alkali agent comprises sodium carbonate, sodium bicarbonate, sodium hydroxide, sodium oxide, calcium carbonate, calcium oxide, calcium hydroxide, potassium carbonate, potassium bicarbonate, potassium hydroxide, potassium oxide or a combination thereof.

8 A combination of a water purification composition of claims 1-7 and a disinfecting agent, for simultaneous or sequential use in the purification of water.

9 A method of purifying water comprising the steps of; (a) contacting a water purification composition of claims 1-7 to water to obtain partially purified water comprising solid matter; and (b) removing at least part of said solid matter from said partially purified water by; (i) filtration; or (ii) decanting; or (iii) sedimentation; or (iv) flotation; or (v) a combination thereof; to obtain purified water.

A method of purifying water according to claim 9, comprising the step of adding a disinfectant agent to water prior to, during or after step (b), preferably after step (b).