Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
  • C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
  • C02F1/56—Macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/72—Treatment of water, waste water, or sewage by oxidation
  • C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2101/00—Nature of the contaminant
  • C02F2101/10—Inorganic compounds
  • C02F2101/103—Arsenic compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/06—Contaminated groundwater or leachate
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2303/00—Specific treatment goals
  • C02F2303/18—Removal of treatment agents after treatment
  • C02F2303/185—The treatment agent being halogen or a halogenated compound

Definitions

• the invention relates to a composition for purification of water, particularly for purifying water containing Arsenic.
• Arsenic, Mercury, Lead, Manganese, Copper and Iron are some of the most toxic heavy metals which are found in ground water. In some areas the drinking water contains as high as 300 parts per billion (ppb) Arsenic.
• the World Health Organisation [WHO] and the US Environmental Protection Agency recommends that drinking water should not contain more than 10 ppb Arsenic.
• ppb Arsenic As contaminated water often contains microbes, a robust water purification technology should also provide for removal or deactivation of cysts, bacteria and virus. According to the US Environmental Protection Agency, the minimum standards are log-6 removal of bacteria, log 4 of virus and log 3 removal of cysts.
• JP2002079015A (Eric Winchester e.al.,) discloses a filter for removal of Arsenic which is made of fired diatomaceous earth and 5 to 30% by weight of ferric ions bonded to the earth.
• US20030089665 A1 discloses a medium for removing Arsenic from water.
• This medium is a mixture of activated Bauxite, Aluminum trihydrate and Ferric compound selected from the group consisting of Ferric hydroxide, Ferric oxyhydroxide, Ferric hydroxyoxide and mixtures thereof. It provides removal to the extent of about 90%.
• CN101591056A Zhejiang Sunda Ater Co Ltd
• CN101591056A provides a flocculating agent for treating water. It contains bentonite, electrolytic Aluminium waste residue and ferrous sulphate.
• WO0200557 A1 discloses that certain combinations of inorganic coagulants and water-soluble or water-dispersible polymers remove greater amount of heavy metals and micro-organism. It discloses a water purification composition which includes a primary coagulant selected from the group consisting of water-soluble, multivalent inorganic salts and mixtures thereof; a bridging flocculent selected from the group consisting of water-soluble and water dispersible anionic and non-ionic polymers having a weight average molecular weight of at least about 2000000 Daltons, a coagulant aid selected from the group consisting of water-soluble and water dispersible cationic polymers having a weight average molecular weight of less than about 1500000 Daltons.
• a primary coagulant selected from the group consisting of water-soluble, multivalent inorganic salts and mixtures thereof
• a bridging flocculent selected from the group consisting of water-soluble and water dispersible anionic and non-ionic polymers having a weight average molecular weight
• CN1227192A (Zeng Zhaoxiang) provides a compound coagulant for treating waste water consisting of soluble compounds of Iron, Calcium, Magnesium and Alumnium such as Ferrous sulfate, Calcium oxide, Magnesium chloride and Aluminum sulfate and difficultly soluble aluminosilicates including bentonite, kaolin, diatomite and slag.
• the compound coagulant is added into waste water before the pH value of the waste water is regulated with alkali solution to 7 to 9, so that organic matter in the waste water is ion-adsorbed by the compound coagulant.
• JP10028808A provides solid fine powdery flocculent composition prepared from a water soluble aluminum salt or Iron salt type inorganic flocculant, a self-pH regulator, a polymeric flocculant finer than a usually used one and other essential component in a powdery granule form and is directly added to waste water to be treated alone to complete flocculation under stirring and formed floes stable in form and excellent in dehydration properties are separated to be excluded out of the system.
• US201 1/0139724A1 (Siemens Water Technologies Corp., 201 1 ) discloses a composition and method for reducing a concentration of chlorite in water.
• the composition includes a mixture of ferrous iron and a polyaluminium chloride.
• the application requires the iron to be in the ferrous state which reduces chlorite to chloride.
• CN10231 1 160 A discloses a water purifying agent for aquaculture pools.
• the agent includes industrial grade diatomite,
• polyaluminium chloride polymeric ferric sulfate and clinoptilolite powder.
• Arsenic In addition is also needed a composition which can be used to reduce turbidity and other contaminants including residual aluminum.
• composition having a balance between total Iron and total Aluminium and in which the compound of Aluminium has certain minimum basicity.
• composition for purification of water comprising a compound of Iron and a compound of Aluminium wherein the ratio of total Iron to total Aluminium is in the range of 1 :0.1 to 1 :150 and basicity of said compound of Aluminium is at least 40%.
• a packaged water purification product comprising a sachet comprising a first compartment holding the composition of the first aspect and a second compartment holding a disinfectant.
• a composition of the first aspect for purification of water comprising Arsenic to provide purified water having not greater than 10 ppb Arsenic.
• a composition of the first aspect for providing purified water having turbidity value less than 1 NTU.
• a method of purifying water comprising the steps of:
• the disclosed composition which provides a solution to the problems, includes a compound of Iron and a compound of Aluminium wherein the ratio of total Iron to total Aluminium is in the range of 1 :0.1 to 1 :150. At the broad range, the composition is effective usable and effective against input water from some representative sources.
• this ratio is 1 :0.3 to 1 :25. In more preferred compositions it is 1 :2 to 1 :10.
• the ratio between the total iron content to the total aluminium content is a ratio by weight between the weight of the metal calculated using the corresponding chemical formula and molecular weights.
• coagulating compositions fail to provide robust results under variable conditions. For example, it is found that a composition which provides good results with input water of a particular quality, does not provide same results when the quality changes. With a change in the parameters of input water (e.g. pH and TDS), sometimes the composition does not give desired performance. We found that the preferred and more preferred compositions were robust and their performance was not significantly different with input water of different quality.
• the basicity of the compound of Aluminium is at least 40%. Preferably it is in the range of 45 % to 100 %. Basicity is an important feature of Aluminium compounds, especially Polyaluminium compounds. It is directly proportional to the degree of hydrolysis and also the "B" value.
• Basicity is a major factor in determining the molecular species distribution; low-basicity favors low molecular weight species and high-basicity favors high molecular weight species. Temperature and concentration also effect the molecular species distribution but in less predictable ways.
• High basicity products have a higher positive charge and are more efficient in coagulating negatively charged contaminants.
• PAC can be broadly divided into three groups of basicities based on the manufacturing techniques used for their production.
• Low basicity PAC with basicity from -1 % to -45 % is manufactured by the well known reaction of aluminum trihydrate (Al 2 0 3 3H 2 0) with hydrochloric acid or aluminum chloride.
• High-basicity PAC with basicity of -45 % to about -65 % is manufactured by the reaction of aluminum chloride or low-basicity PAC with a base.
• Ultra high-basicity PAC (including ACH) with basicity of -65 % to -83 % is manufactured by the oxidation process (i.e., the reaction of hydrochloric acid or aluminum chloride or low-basicity PAC with aluminum metal).
• Aluminium based coagulants are produced by controlled reaction of Aluminium salts with a base. They are typically characterized by their degree of neutralisation (r), or basicity.
• the total Aluminium content is 1 to 20 wt%. More preferably it is 2 to 10 wt%.
• the total Iron content of the composition is 0.1 to 15 wt%. I more preferred compositions it is 0.5 to 15wt% and more preferably 0.5 % to 10 wt% and most preferably it is 0.5 to 8 wt%.
• a preferred compound of Aluminium is selected from, Polyaluminium chloride,
• Polyaluminum chloride is the most preferred. Also preferred is Aluminium
• Disclosed compound of aluminium can generally be defined by the formula:
• q is the charge of anion X, and typically 0 ⁇ n/m ⁇ 3.
• X can be one type of anion or a combination of anions. Suitable examples of these ions include Chloride, Sulphate, and Silicate.
• the degree of neutralization of a pre-hydrolysed aluminium compound is represented by B value.
• B value is a molar ratio of OH content to Al content of the prehydrolysed aluminium compound that is represented by the formula:
• the basicity is linked to B value and is directly proportional to B value of the compound.
• the compound of iron is a ferric compound and the ferric compound is in an
• B value is a molar ratio of OH content to Fe content of a prehydrolysed iron compound that is represented by the formula:
• a ferric compound in an unhydrolysed state has a B value of 0.
• Ferric compounds in unhydrolysed state typically are salts of trivalent iron, i.e. Fe(lll) that would dissociate in aqueous solutions. Therefore, a preferred compound of Iron is selected from Ferric sulphate, Ferric chloride, Ferric nitrate, Ferric acetate and other Ferric halides.
• compositions also include a flocculation aid.
• adsorbent clay which is capable of adsorbing more of water and other impurities.
• examples of clay which may be included are montmorillonite clay (dioctheydral smectite clay), laponite, hectorite, nontronite, saponite, volkonsite, sauconite, beidellite, allevarlite, illite, halloysite, attapulgite, mordenite, kaolines, and bentonite.
• Highly preferred clay belongs to the class of aluminosilicate clay. Bentonite is particularly preferred.
• the composition contains 10 to 50%, preferably 20 to 40 wt% flocculation aid.
• the composition includes a flocculating agent which is a high molecular weight polymeric water soluble material. It aids the formation of larger floes and boosts the kinetics of flocculation.
• flocculating agents are examples of flocculating agents.
• polysaccharides (dextane celluloses), proteins, modified celluloses
• polyacrylamides preferably high molecular weight polyacrylamide. It is especially preferred that the polyacrylamide is either anionic or non-ionically modified, more preferably anionically modified. Suitable molecular weight of these polyacrylamides is in the range of 10 5 to 10 7 .
• a preferred flocculating agent is Superfloc® (from Cytec).
• the flocculating agent is from 1 to 10 wt%, more preferably from 2 to 5 wt% and most preferably from 2 to 4 wt%.
• polyacrylamides are particularly preferred flocculating agents.
• Anionic polyacrylamides are the most preferred.
• Such coagulating compositions may also be used in tandem with disinfecting compositions, such as halogen based disinfecting compositions. In such cases, it often becomes necessary to quench any excess halogen present in the purified water.
• compositions also includes a quencher which is capable of reacting, in particular, with chlorine based disinfectants, thereby making the water further more safe for consumption.
• Preferred quenchers include sodium thiosulphate and ascorbic acid.
• Compositions containing a quencher preferably include 1 to 20 wt%, more preferably from about 2 to 12 wt% thereof.
• a packaged water purification product having a sachet having a first compartment holding the composition of the first aspect and a second compartment holding a disinfectant. The two portions are spatially separated.
• the external surface area of the second compartment is less than the external surface area of the first compartment.
• the reason for using the surface area relationship is because the surface area available for ingress of moisture needs to be minimal to ensure minimal ingress of moisture for maximum stability. Details of such a sachet may be found in WO2008/1 16724 A1 (Unilever).
• Halogenated compounds are preferred disinfectants. More preferred halogen compounds are those of chlorine or iodine, more preferably those of chlorine. Suitable chlorine compounds are inorganic compounds like sodium hypochlorite, Calcium hypochlorites, chlorine dioxide, or chloramines, or organic chlorine compounds like sodium dichloro-isocyanurates, or trichloroisocyanuric acid. Calcium hypochlorite is a commonly used solid inorganic chlorine based disinfectant. It is generally available in two forms. The more common form has the formula Ca(OCI)CI which is referred to as stabilized bleaching powder (SBP). Commercially available bleaching powder generally contains 30 to 35 % available Chlorine. SBP is generally available in fine powder form and at low moisture content of less than 1 wt%. The other form of Calcium hypochlorite is called high-strength hypochlorite and has the chemical formula Ca(OCI) 2 . This can be commercially procured at available Chlorine in the range of 60 to 65 wt%.
• Chlorine based disinfectants deactivate the microorganisms, in particular bacteria and virus, and oxidise the As +3 ions.
• the second compartment preferably has 1 to 15 wt% disinfectant; the balance being comprised of other ingredients.
• the disinfectant is preferably present in an amount in the range of from 1 to 20%, more preferably from about 2 to 12% by weight of the composition. Most preferred disinfectant is Calcium hypochlorite.
• the disinfectant part of the sachet also includes a buffering agent.
• a buffering agent Calcium oxide, Sodium carbonate, Sodium bicarbonate, Calcium hydroxide, Magnesium oxide and Magnesium hydroxide are preferred buffers. Buffering agents neutralize the protons generated during hydrolysis of metal salts of Aluminium and Iron. Whenever present, the buffering agent is from 5 to 25 wt% and preferably from 5 to 15 wt%.
• the first compartment includes 0.5 to 10 g, more preferably 1 to 5 g of the composition of the first aspect.
• the composition of the first aspect of the invention and the packaged water purification product may be used for daily consumer use at domestic level. It may also be used at a community level, especially for large-scale disaster relief operations.
• Solid form is the most suitable form of the composition of the first aspect. Suitable solid forms include powder, granule and tablet forms; most preferred form being the powder form. In the case of the packaged water purification product, the most preferred form is the powder form for the first and the second compartments.
• the water purification composition of the invention is preferably delivered in amounts in the range of 0.5 to 10 g, more preferably in the range of 1 to 5 g. These may be suitably added to 5 to 20 litres of water.
• the water purification composition of the first aspect may be delivered to the consumer in any known suitable packaging form.
• the packaging When formed as tablets, the packaging may be metalized laminate or blister packing.
• a suitable packaging When formed as powders, a suitable packaging is metalized laminate.
• composition of the first aspect for purification of water comprising Arsenic to provide purified water comprising not greater than 10 ppb Arsenic. This is from an input Arsenic content of 300 ppb according to standard NSF protocol.
• a composition of the first aspect for providing water having turbidity value less than 1 NTU. This is from an input turbidity content of 100 to 150 NTU.
• a method of purifying water comprising the steps of:
• the dispersion is allowed to separate by keeping it undisturbed for 30 seconds to 5 minutes, more preferably for 2 to 3 minutes. Thereafter, it is preferred that the supernatant is passed through a porous filter to get purified water.
• compositions (products) containing Polyaluminium chloride were made except that basicity of Polyaluminium chloride was varied in each composition.
• the four compositions were labeled as 1 a, 1 b and 1 c and 1 d and they were tested for Arsenic removal efficacy.
• the basic composition is shown in table 1 .
• the Arsenic content was measured using the Inductively Coupled Plasma Emission Spectroscopy / Mass Spectroscopy technique.
• the residual Aluminium and Iron content was also measured by the same method.
• the water samples (input / output) were acid digested using ICP grade (ultrapure) Hydrochloric acid and Nitric acid to convert all elements into its corresponding soluble forms and then measured for concentration.
• the data in table 2 illustrates the role of basicity of the compound of Aluminium on the Arsenic content.
• the data also indicates that the comparative compositions failed to meet the minimum threshold values for residual Aluminium and Iron content in purified water.
• the preferred composition (7d) did provide pure water meeting the minimum threshold values for residual Aluminium (max. 200 ppb) and Iron content (max 300 ppb).
• a packaged water purification product was made in the form of a two-compartment sachet.
• the first compartment was filled with compositions inside and outside the scope of the invention.
• the second compartment was filled with a disinfectant composition.
• Table-3 Detailed formulations of the respective first compartments are shown in table-3.
• PAC poly Aluminium chloride of basicity 80%
• FS Ferric sulphate
• PAM anionic polyacrylamide
• Clay means bentonite
• Form - means formulation
• Form-5 provides pure water containing less than 10 ppb Arsenic.
• Form-5 also provides water containing residual Aluminium and Iron levels within the regulatory limits.
• compositions containing varying Aluminium and Iron content were tested as described earlier. This was with the intent of studying the effect of varying Aluminium and Iron content on the performance of the composition. Details of the compositions are provided in table 5. Table 5
• the data in table 6 indicates that composition in which ratio of total Iron to total Aluminium is outside the claimed range (Form-9, 1 :0.07) is unable to keep the residual Arsenic content below 10 ppb.
• the data further indicates that at a broader ratio of Iron to Aluminium, (Form-8), the composition leaves behind greater amount of residual Aluminium as compared to compositions in which the ratio is narrower and within preferred limits.
• compositions containing ferrous sulphate and ferric sulphate and polymeric ferric were tested as described earlier. This was with the intent of studying the effect of oxidation and polymerization state of Iron content on the performance of the composition. Details of the compositions are provided in table 7.
• Table 8
• the data in table 8 indicates that composition in which the iron content is in the ferrous state is unable to keep the residual Arsenic content below 10 ppb. It is also seen that polymeric ferric sulphate gives arsenic removal however composition leaves behind higher levels of residual aluminium as compared to compositions having a non- polymeric ferric iron compound. It was observed that the residual aluminium in water treated with polymeric ferric sulphate is dependent on the water quality and the residual aluminium levels varied with the pH, TDS (Total dissolved salts), organics levels of the water.
• composition of the present invention provides treated water with less than 10ppb of Arsenic and less than 200ppb of residual aluminium and is independent of the quality of the water.
• the illustrated examples provide a robust composition for purification of water which gives purified water containing at the most ten ppb Arsenic. It also provides a composition which reduces turbidity and other contaminants and keeps residual metal content within regulated limits.

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)
• Removal Of Specific Substances (AREA)
• Treatment Of Water By Oxidation Or Reduction (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

Family

ID=49513844

Family Applications (1)

Country Status (7)

Cited By (5)

Citations (3)

Family Cites Families (5)

• 2014
  • 2014-10-17 BR BR112016009117A patent/BR112016009117A2/pt not_active Application Discontinuation
  • 2014-10-17 WO PCT/EP2014/072335 patent/WO2015062881A1/en active Application Filing
  • 2014-10-17 CN CN201480060108.8A patent/CN105849051A/zh active Pending
  • 2014-10-17 MX MX2016005531A patent/MX2016005531A/es unknown
  • 2014-10-17 EP EP14787147.9A patent/EP3063095A1/en not_active Withdrawn
  • 2014-10-17 EA EA201690909A patent/EA201690909A1/ru unknown
• 2016
  • 2016-04-29 PH PH12016500807A patent/PH12016500807A1/en unknown

Patent Citations (3)

Also Published As

Similar Documents

Legal Events