CA1067627A - Removal of arsenic from water - Google Patents
Removal of arsenic from waterInfo
- Publication number
- CA1067627A CA1067627A CA259,608A CA259608A CA1067627A CA 1067627 A CA1067627 A CA 1067627A CA 259608 A CA259608 A CA 259608A CA 1067627 A CA1067627 A CA 1067627A
- Authority
- CA
- Canada
- Prior art keywords
- water
- support material
- porous support
- arsenic
- ferric
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/30—Processes for preparing, regenerating, or reactivating
- B01J20/32—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating
- B01J20/3231—Impregnating or coating ; Solid sorbent compositions obtained from processes involving impregnating or coating characterised by the coating or impregnating layer
- B01J20/3234—Inorganic material layers
- B01J20/3236—Inorganic material layers containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
-
- 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
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- 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
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Organic Chemistry (AREA)
- Analytical Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Water Treatment By Sorption (AREA)
Abstract
ABSTRACT
A process and apparatus for removing arsenic from water intended for drinking purposes in which the water is passed through a bed or column of a porous support material having impregnated thereon a sub-stantially water insoluble ferric compound. Preferably the ferric com-pound is ferric hydroxide, which is produced in situ on the support material, and the treatment is carried out at a pH of 4-8.3. Optimum removal of arsenic occurs at pH 4.4.
A process and apparatus for removing arsenic from water intended for drinking purposes in which the water is passed through a bed or column of a porous support material having impregnated thereon a sub-stantially water insoluble ferric compound. Preferably the ferric com-pound is ferric hydroxide, which is produced in situ on the support material, and the treatment is carried out at a pH of 4-8.3. Optimum removal of arsenic occurs at pH 4.4.
Description
10~71~27 This lnvention relates to the puri~icatlon o~ water and more partlcularly to the removal of arsenic ~rom drinking water.
Certain sources of drlnklng water have, in certain geographi-cal areas, been found to be contaminated with arsenlc ln amounts which could be in~urious to life and health if the water is consumed by an individual over a long period. Such contamination 18 believed due to a natural leaching action from arsenical rocks and strata through which the water percolates. As is well known, arsenic is a cumulatiYe poison in the body, that ls lt is not eliminated by normal body functions, and hence it tends to accumulate until it reaches a suffici-ent level to cause illness or even death. It i8, therefore important that drinking water sources should be as free as pos~ible of arsenical ions. The Canadian Government publication entitled "Public Health - A
Handbook and Objectives", published in 1968, sets a series of Canadian Drink-ing Water Standards which specify 0.05 ppm maximum for arsenic in ~afe drinking water. Certain wells are known to contain 3.8 ppm and even re arsenic and it is clear that water from such wells must be treated before it is safe for human consumption. Iron sulfides, ion exchangers and activated charcoal have been used to remove arsenic from water but are not entirely satisfactory for reasons of cost, contamination by introduction of other ions or foreign matter, and difficulty of achieving contact between the arsenical water and the removal agent.
Arsenic in well water is believed to be present primarily as arsenate, and also as arsenite and a consideration of arsenate salts, particularly of Group II metals such as Ba, Sr, Ca and Mg, shows that arsenate~ generally decrease in solubility with a decrease in size of the cation. Ferric ions are, therefore, particularly suitable for remov-ing arsenic from drinking water.
An obJect of the present invention is, therefore to provide a method for removing arsenic from drin~ing water by reaction of arsenic, gen--1- ~
10~i'7~'7 .... .
erally in t~le ~orm of arsenaLe, wlth ~erric lons, p~eferably in the form of a suhstantially water insoluble ferrLc compound such as ferric hydroxide.
Another ob~ect of this inv?ntion is to provide an apparatus for the removal of arsenic from drinking water which is suitable for domestic use.
Thus, by one aspect of this invention there is provided a process for treating arsenic-containing water intended for drinking purposes comprising adjusting pH of said arsenic-containing water to the range 4-8.3, and treating said water with ferric ions to precipitate ferric arsenate therefrom and thus produce drinking water containing below 0.05 ppm arsenic.
By another aspect of this invention there is provided an apparatus for use in treatment of water for drinking purposes, comprising means con-taining a bed of a porous support material having impregnated thereon ferric hydroxide.
By yet another aspect of this invention there is provided a water treatment system for removing arsenic from water intended for drinking purposes comprising:
(a) water supply means;
(b) container means for attachment to said water supply means; and (c) porous support material in said container means having impreg-nated thereon ferric hydroxide.
The invention will be described hereinafter in more detail with reference to the accompanying drawings in which:-Figure 1 is a sketch of a water treatment system employing the concepts of the present invention; and Figure 2 is a cross sectional view of a cartridge filter accordingto the present invention.
As noted hereinabove, arsenates decrease in solubility with a decrease in size of the cation and it can be shown quite readily that ferric ion forms an arsenate which has a solubility product of 10 20-24.
~erric hydroxide is a relatively non-hazardous material and is sub-.
,- lo~t7~ '7 ~Lant i~lly ln~oluble in water 80 ~hat it 1~ hlghly ~ultable a~ a means uf lntroduclnK ferrlc ions. Further, ferrlc hydroxlde has the advant-age of removlng arsenic wlthout lntroducinK foreign matter lnto the water, l.e. the r~moval of arHenlc by mesn~ of ferric hydroxide adds more water, as a product of the reactlon, to the water.
( )3 ~3 A~4 ~ FeAR04 ~ 3H20 or: Fe 3 + 3~2A~04 1 ~ Fe~H2~sO4)3 followed by: Fe(H2A~04)3 - Fe(AB03)3 + 3H20 Araenate ln acidic water hydrolyse~ to form the ions hydrogen arAenate and dlhydrogen arsenate. A con~lderation of the dlssociatlon constants of these ions, the ~olubllity products of ferrlc arsenate and ferrlc hydroxlde inticates that the removal of arsenic from drinking water ~` should take place at a pH in the range 4-8.3 and that the optimum pH i9 about 4.4. Having determined that ferrlc lon i8 a particularly efficaclous ion for the removal of arsenlc from drlnking water, there remalns the problem of lntroduclng ferrlc ion6 to a water purlfication syfitem. It has been found that thls problem may be overcome by carrylng - the ferrlc ions, preferably in the form of ferrlc hydroxlde, on a porous,flnely divided inorganlc, support materlal, f9uch as montmorillonite, scheelite, kie~elguhr, fùllers earth, vermlcullite, diatomite, alumlna or the like. Molecular sleves may also be employed as the support material but are expenslve. The ~upport materlal, generally in the size range 50-60 mesh, can then he contained in a cartridge for attach-ment to a domestic drinklng water supply. Such cartridges generally containing sterlllzing, deotorlzlng and clariflcation agents are9 of course, well known in the art. It has been found preferable to generate the ferrlc hydroxide ln sltu on the Rupport material, the method to be employed dependlng, at least in part, upon the Ypecific support materlal employed. I~ is known~ for example9 that montmorillonite con-tains 3-4% of Fe and addltional Fe may not be required. Ln general, how-ever, the support materlal i~ lmpregnated with an aqueous solution of a water soluble salt, such ag ferrlc chloride, ferric nitrate or ferrous sulphate, and the ferrlc ion 18 preclpitated by the addition of sufficiellt ....
10~7~ 7 base such as alkali or alkaline earth metal hydroxides or ammonium hydroxide to increase the pH sufficiently to form ferric hydroxide.
The resultlng Fe(0H)3 impregnated porous ~upport material is then washed with water to remove excess reagent and can then be loaded into a filter bed or cartridge in known manner.
In Figure 1 there is shown, diagrammatically a subterranean well 1 from which water is pumped via pump 2 to a storage tank 3.
Tank 3 may, of course, be of the gravity or pressure type and is normally connected to a distrlbution system 4. One arm 5 of the distribution system is provided wlth a suitable coupling for connection of the inlet side 11 (Figure 2) of a cartr$dge filter 6 of the present invention.
Outlet side 12 of cartridge 6 i~ connected to a faucet 7 which provides drinking water. As shown more clearly in Figure 2 the impregnated porous support material 8 18 retained in cartridge 6 by means of mesh screens 9 and 10 at the inlet and outlet ends respectively. Inlet and outlet ends 11 and 12 are provided with any suitable quick coupling devices such as captive cap couplings 13 and 14 respectively to facilitate removal and exchange of the cartridge 6.
In operation the pH of the water in the system is measured, at any suitable point, for example in tank 3, and adjusted as necessary by the addition of an acid or alkali to ensure that the pH is within the normally operative range 4-8.3 and preferably at about 4.4. It will be appreciated that the present invention may be employed in both municipal and private water treatment systems and is particularly suit-able for smell domestic systems where it is unlikely that sophisticated laboratory facilities will be found. Measurement of pH can, however, be carried out quickly and inexpensively by unskilled personnel using any of the known colorimetric methods readily a~ailable on the market.
Example 1 100g of 30-40 Mesh molecular sieve material 5A by Fisher ~O~ 7 . .
Sclentiflc Company was impregnated with 4.6g of Fe~ as Fe(OH) The impregnated molecular sieve was then formed lnto a column l5.5~
long and l" diameter. 6810 mls of water with a pH of 4.7 and contain-ing 3.8 ppm arsenic was passed through the column at a flow rate of 30 ml/min. The effluent was found to contaln 0.042 ppm arsenic and 0.3 ppm Fe which i8 well below the recommended safe limits of 0.05 ppm As and 0.3 ppm Fe.
Example 2 80 g Of 30-80 me~h diatomite containing 0.97% Fe as Fe(OH)3 was loaded into a column 12" long and l" diameter. 4546 mls of water with a pH of 3.9 and containing 0.59 ppm arsenic was passed through the column at a flow rate of 100 ml/min. The effluent was found to contain less than 0.03 ppm arsenic, which i8 well below the recommended safe limit for drinking water.
As will be appreciated molecular sieves are relatively expensive and not therefore economically feasible for use in domestic water systems.
Other support materials such as vermicullite and diatomite are, however, very much cheaper and,as indicated in Example 2,equally effective as a ~upport material, so that it is anticipated that filter cartridges containing Fe(OH)3 impregnated support materials will be available at acceptable commercial cost.
A~ previously indicated it is contemplated that cartridges of the present invention will be provided for domestic use and therefore no provision forregeneration of the cartridges has been made for safety reasons. It is contemplated that, depending on water throughput, a cartridge will be of sufficient size to have a useful life of 3-5 years and will normally be discarded after say l 1/2 - 2 112 years. It is ~5-; ., ~
10~71~'~7 of course, important that the cartridge does not reach saturation before discard and hence the relatively large safety factor to be allowed. The discarded cartridges wlll obviously contain a relatively large amount of arsenic and disposal thereof will require considerable care and attention. Municipal and industrial u6ers may, of course, regeneratethe column materials and otherwise dispose of the recovered arsenic.
Other modifications and advantages of the present invention will be apparent to those skilled in the art, without departing fro~
the scope of this invention which is to be construed only by reference to the appended claims.
Certain sources of drlnklng water have, in certain geographi-cal areas, been found to be contaminated with arsenlc ln amounts which could be in~urious to life and health if the water is consumed by an individual over a long period. Such contamination 18 believed due to a natural leaching action from arsenical rocks and strata through which the water percolates. As is well known, arsenic is a cumulatiYe poison in the body, that ls lt is not eliminated by normal body functions, and hence it tends to accumulate until it reaches a suffici-ent level to cause illness or even death. It i8, therefore important that drinking water sources should be as free as pos~ible of arsenical ions. The Canadian Government publication entitled "Public Health - A
Handbook and Objectives", published in 1968, sets a series of Canadian Drink-ing Water Standards which specify 0.05 ppm maximum for arsenic in ~afe drinking water. Certain wells are known to contain 3.8 ppm and even re arsenic and it is clear that water from such wells must be treated before it is safe for human consumption. Iron sulfides, ion exchangers and activated charcoal have been used to remove arsenic from water but are not entirely satisfactory for reasons of cost, contamination by introduction of other ions or foreign matter, and difficulty of achieving contact between the arsenical water and the removal agent.
Arsenic in well water is believed to be present primarily as arsenate, and also as arsenite and a consideration of arsenate salts, particularly of Group II metals such as Ba, Sr, Ca and Mg, shows that arsenate~ generally decrease in solubility with a decrease in size of the cation. Ferric ions are, therefore, particularly suitable for remov-ing arsenic from drinking water.
An obJect of the present invention is, therefore to provide a method for removing arsenic from drin~ing water by reaction of arsenic, gen--1- ~
10~i'7~'7 .... .
erally in t~le ~orm of arsenaLe, wlth ~erric lons, p~eferably in the form of a suhstantially water insoluble ferrLc compound such as ferric hydroxide.
Another ob~ect of this inv?ntion is to provide an apparatus for the removal of arsenic from drinking water which is suitable for domestic use.
Thus, by one aspect of this invention there is provided a process for treating arsenic-containing water intended for drinking purposes comprising adjusting pH of said arsenic-containing water to the range 4-8.3, and treating said water with ferric ions to precipitate ferric arsenate therefrom and thus produce drinking water containing below 0.05 ppm arsenic.
By another aspect of this invention there is provided an apparatus for use in treatment of water for drinking purposes, comprising means con-taining a bed of a porous support material having impregnated thereon ferric hydroxide.
By yet another aspect of this invention there is provided a water treatment system for removing arsenic from water intended for drinking purposes comprising:
(a) water supply means;
(b) container means for attachment to said water supply means; and (c) porous support material in said container means having impreg-nated thereon ferric hydroxide.
The invention will be described hereinafter in more detail with reference to the accompanying drawings in which:-Figure 1 is a sketch of a water treatment system employing the concepts of the present invention; and Figure 2 is a cross sectional view of a cartridge filter accordingto the present invention.
As noted hereinabove, arsenates decrease in solubility with a decrease in size of the cation and it can be shown quite readily that ferric ion forms an arsenate which has a solubility product of 10 20-24.
~erric hydroxide is a relatively non-hazardous material and is sub-.
,- lo~t7~ '7 ~Lant i~lly ln~oluble in water 80 ~hat it 1~ hlghly ~ultable a~ a means uf lntroduclnK ferrlc ions. Further, ferrlc hydroxlde has the advant-age of removlng arsenic wlthout lntroducinK foreign matter lnto the water, l.e. the r~moval of arHenlc by mesn~ of ferric hydroxide adds more water, as a product of the reactlon, to the water.
( )3 ~3 A~4 ~ FeAR04 ~ 3H20 or: Fe 3 + 3~2A~04 1 ~ Fe~H2~sO4)3 followed by: Fe(H2A~04)3 - Fe(AB03)3 + 3H20 Araenate ln acidic water hydrolyse~ to form the ions hydrogen arAenate and dlhydrogen arsenate. A con~lderation of the dlssociatlon constants of these ions, the ~olubllity products of ferrlc arsenate and ferrlc hydroxlde inticates that the removal of arsenic from drinking water ~` should take place at a pH in the range 4-8.3 and that the optimum pH i9 about 4.4. Having determined that ferrlc lon i8 a particularly efficaclous ion for the removal of arsenlc from drlnking water, there remalns the problem of lntroduclng ferrlc ion6 to a water purlfication syfitem. It has been found that thls problem may be overcome by carrylng - the ferrlc ions, preferably in the form of ferrlc hydroxlde, on a porous,flnely divided inorganlc, support materlal, f9uch as montmorillonite, scheelite, kie~elguhr, fùllers earth, vermlcullite, diatomite, alumlna or the like. Molecular sleves may also be employed as the support material but are expenslve. The ~upport materlal, generally in the size range 50-60 mesh, can then he contained in a cartridge for attach-ment to a domestic drinklng water supply. Such cartridges generally containing sterlllzing, deotorlzlng and clariflcation agents are9 of course, well known in the art. It has been found preferable to generate the ferrlc hydroxide ln sltu on the Rupport material, the method to be employed dependlng, at least in part, upon the Ypecific support materlal employed. I~ is known~ for example9 that montmorillonite con-tains 3-4% of Fe and addltional Fe may not be required. Ln general, how-ever, the support materlal i~ lmpregnated with an aqueous solution of a water soluble salt, such ag ferrlc chloride, ferric nitrate or ferrous sulphate, and the ferrlc ion 18 preclpitated by the addition of sufficiellt ....
10~7~ 7 base such as alkali or alkaline earth metal hydroxides or ammonium hydroxide to increase the pH sufficiently to form ferric hydroxide.
The resultlng Fe(0H)3 impregnated porous ~upport material is then washed with water to remove excess reagent and can then be loaded into a filter bed or cartridge in known manner.
In Figure 1 there is shown, diagrammatically a subterranean well 1 from which water is pumped via pump 2 to a storage tank 3.
Tank 3 may, of course, be of the gravity or pressure type and is normally connected to a distrlbution system 4. One arm 5 of the distribution system is provided wlth a suitable coupling for connection of the inlet side 11 (Figure 2) of a cartr$dge filter 6 of the present invention.
Outlet side 12 of cartridge 6 i~ connected to a faucet 7 which provides drinking water. As shown more clearly in Figure 2 the impregnated porous support material 8 18 retained in cartridge 6 by means of mesh screens 9 and 10 at the inlet and outlet ends respectively. Inlet and outlet ends 11 and 12 are provided with any suitable quick coupling devices such as captive cap couplings 13 and 14 respectively to facilitate removal and exchange of the cartridge 6.
In operation the pH of the water in the system is measured, at any suitable point, for example in tank 3, and adjusted as necessary by the addition of an acid or alkali to ensure that the pH is within the normally operative range 4-8.3 and preferably at about 4.4. It will be appreciated that the present invention may be employed in both municipal and private water treatment systems and is particularly suit-able for smell domestic systems where it is unlikely that sophisticated laboratory facilities will be found. Measurement of pH can, however, be carried out quickly and inexpensively by unskilled personnel using any of the known colorimetric methods readily a~ailable on the market.
Example 1 100g of 30-40 Mesh molecular sieve material 5A by Fisher ~O~ 7 . .
Sclentiflc Company was impregnated with 4.6g of Fe~ as Fe(OH) The impregnated molecular sieve was then formed lnto a column l5.5~
long and l" diameter. 6810 mls of water with a pH of 4.7 and contain-ing 3.8 ppm arsenic was passed through the column at a flow rate of 30 ml/min. The effluent was found to contaln 0.042 ppm arsenic and 0.3 ppm Fe which i8 well below the recommended safe limits of 0.05 ppm As and 0.3 ppm Fe.
Example 2 80 g Of 30-80 me~h diatomite containing 0.97% Fe as Fe(OH)3 was loaded into a column 12" long and l" diameter. 4546 mls of water with a pH of 3.9 and containing 0.59 ppm arsenic was passed through the column at a flow rate of 100 ml/min. The effluent was found to contain less than 0.03 ppm arsenic, which i8 well below the recommended safe limit for drinking water.
As will be appreciated molecular sieves are relatively expensive and not therefore economically feasible for use in domestic water systems.
Other support materials such as vermicullite and diatomite are, however, very much cheaper and,as indicated in Example 2,equally effective as a ~upport material, so that it is anticipated that filter cartridges containing Fe(OH)3 impregnated support materials will be available at acceptable commercial cost.
A~ previously indicated it is contemplated that cartridges of the present invention will be provided for domestic use and therefore no provision forregeneration of the cartridges has been made for safety reasons. It is contemplated that, depending on water throughput, a cartridge will be of sufficient size to have a useful life of 3-5 years and will normally be discarded after say l 1/2 - 2 112 years. It is ~5-; ., ~
10~71~'~7 of course, important that the cartridge does not reach saturation before discard and hence the relatively large safety factor to be allowed. The discarded cartridges wlll obviously contain a relatively large amount of arsenic and disposal thereof will require considerable care and attention. Municipal and industrial u6ers may, of course, regeneratethe column materials and otherwise dispose of the recovered arsenic.
Other modifications and advantages of the present invention will be apparent to those skilled in the art, without departing fro~
the scope of this invention which is to be construed only by reference to the appended claims.
Claims (19)
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for treating arsenic-containing water intended for drinking purposes comprising adjusting pH of said arsenic-containing water to the range 4-8.3, and treating said water with ferric ions to precipitate ferric arsenate therefrom and thus produce drinking water containing below 0.05 ppm arsenic.
2. A process as claimed in claim 1 wherein said water is treated with ferric hydroxide.
3. A process as claimed in claim 2 wherein said ferric hydroxide is deposited on a porous support material.
4. A process as claimed in claim 3 wherein said porous support material is a finely divided inorganic material selected from the group comprising: scheelite, kieselguhr, vermicullite, fullers earth, alumina, diatomite and montmorillonite.
5. A process as claimed in claim 3 wherein said porous support material is a molecular sieve.
6. A process as claimed in claim 2, 3 or 4 wherein the pH is in the range 4.4-4.7.
7. A process as claimed in claim 3, 4 or 5 wherein said ferric hydroxide is produced in situ on said porous support material.
8. A process as claimed in claim 3, 4 or 5 wherein said porous support material is impregnated with an aqueous solution of a water soluble ferric salt and ferric hydroxide is precipitated therefrom by addition of a sufficient quantity of a base.
9. A process for removing a substantial proportion of arsenic from water for drinking purposes comprising passing said water, at a pH in the range 4-8.3, through a bed of a porous support material having impregnated thereon ferric hydroxide.
10. A process as claimed in claim 9 wherein the pH is in the range 4.4-4.7.
11. Apparatus for use in treatment of water for drinking purposes comprising means containing a bed of a porous support material having impregnated thereon ferric hydroxide.
12. Apparatus as claimed in claim 11 wherein said means comprises a cartridge means, containing a column of said porous material, having an inlet and an outlet, adapted for attachment to a water distribution system.
13. Apparatus as claimed in claim 11 or 12 wherein said porous support material comprises a finely divided inorganic material selected from the group comprising: scheelite, kieselguhr, vermicullite, fullers earth, alumina, diatomite and montmorillonite.
14. Apparatus as claimed in claim 11 or 12 wherein said porous support material is a molecular sieve.
15. A water treatment system for removing arsenic from water intended for drinking purposes comprising:
(a) water supply means;
(b) container means for attachment to said water supply means; and (c) porous support material in said container means having impregnated thereon ferric hydroxide.
(a) water supply means;
(b) container means for attachment to said water supply means; and (c) porous support material in said container means having impregnated thereon ferric hydroxide.
16. A system as claimed in claim 15 wherein said container means comprises a cartridge, having inlet and outlet means, containing a column of said porous support material.
17. A system as claimed in claim 15 wherein said support material is a finely divided inorganic material selected from the group comprising:
scheelite, kieselguhr, vermicullite, fullers earth, alumina, diatomite and montmorillonite.
scheelite, kieselguhr, vermicullite, fullers earth, alumina, diatomite and montmorillonite.
18. A system as claimed in claim 15 wherein said support material is a molecular sieve.
19. A system as claimed in claim 17 including means to control pH in a range 4-8.3.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA259,608A CA1067627A (en) | 1976-08-20 | 1976-08-20 | Removal of arsenic from water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA259,608A CA1067627A (en) | 1976-08-20 | 1976-08-20 | Removal of arsenic from water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1067627A true CA1067627A (en) | 1979-12-04 |
Family
ID=4106704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA259,608A Expired CA1067627A (en) | 1976-08-20 | 1976-08-20 | Removal of arsenic from water |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1067627A (en) |
Cited By (19)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0278830A1 (en) * | 1987-01-26 | 1988-08-17 | Hydro-Quebec | Process for treatment of water containing heavy metals, such as chromium |
| WO1998057893A1 (en) * | 1997-06-19 | 1998-12-23 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
| US6132623A (en) * | 1997-06-19 | 2000-10-17 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
| US6200482B1 (en) | 1997-08-12 | 2001-03-13 | Adi International Inc. | Arsenic filtering media |
| WO2001062670A1 (en) * | 2000-02-25 | 2001-08-30 | Capital Controls Ltd | Apparatus and method for water treatment by adsorption |
| US6387276B1 (en) | 1997-06-19 | 2002-05-14 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
| WO2003002462A1 (en) * | 2001-06-28 | 2003-01-09 | Ch2M Hill, Inc. | Carbon dioxide enhanced complex-adsorption process for metal or metalloid removal from water |
| WO2003043731A1 (en) * | 2001-11-15 | 2003-05-30 | Engelhard Corporation | Arsenic removal media |
| US6599429B1 (en) | 1998-04-01 | 2003-07-29 | Alcan International Limited | Water treatment product and method |
| WO2004101142A1 (en) * | 2003-05-15 | 2004-11-25 | Alcan International Limited | Method of preparing a water treatment product |
| WO2005058482A1 (en) * | 2003-12-16 | 2005-06-30 | Calgon Carbon Corporation | Adsorbents for removing heavy metals and methods for producing and using the same |
| WO2005092492A1 (en) * | 2004-03-04 | 2005-10-06 | The Regents Of The University Of California | Treated bottom ash medium and method of arsenic removal from drinking water |
| WO2005094577A1 (en) * | 2004-03-11 | 2005-10-13 | Aceto Corporation | Treatment of landfill gas |
| FR2881129A1 (en) * | 2005-01-26 | 2006-07-28 | Rhodia Chimie Sa | Purification of water, containing metals comprises passing water in a fixed aluminum doped silica bed |
| US7429551B2 (en) | 2001-08-27 | 2008-09-30 | Calgon Carbon Corporation | Adsorbents for removing heavy metals |
| US7429330B2 (en) | 2001-08-27 | 2008-09-30 | Calgon Carbon Corporation | Method for removing contaminants from fluid streams |
| EP2127740A1 (en) * | 2007-01-09 | 2009-12-02 | Badulin, Nikolay Aleksandrovich | Sorbent for removing heavy metal ions from water |
| US7892436B2 (en) | 2005-04-25 | 2011-02-22 | The Regents Of The University Of California | Compositions and methods for removing arsenic in water |
| CN113549777A (en) * | 2021-08-06 | 2021-10-26 | 武汉中地水石环保科技有限公司 | Device and method for reducing arsenic content of rock |
-
1976
- 1976-08-20 CA CA259,608A patent/CA1067627A/en not_active Expired
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| Publication number | Priority date | Publication date | Assignee | Title |
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| EP0278830A1 (en) * | 1987-01-26 | 1988-08-17 | Hydro-Quebec | Process for treatment of water containing heavy metals, such as chromium |
| WO1998057893A1 (en) * | 1997-06-19 | 1998-12-23 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
| US6132623A (en) * | 1997-06-19 | 2000-10-17 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
| US6387276B1 (en) | 1997-06-19 | 2002-05-14 | The University Of Connecticut | Immobilization of inorganic arsenic species using iron |
| US6200482B1 (en) | 1997-08-12 | 2001-03-13 | Adi International Inc. | Arsenic filtering media |
| CZ301421B6 (en) * | 1998-04-01 | 2010-02-24 | Alcan International Limited | Water treatment method |
| US6599429B1 (en) | 1998-04-01 | 2003-07-29 | Alcan International Limited | Water treatment product and method |
| WO2001062670A1 (en) * | 2000-02-25 | 2001-08-30 | Capital Controls Ltd | Apparatus and method for water treatment by adsorption |
| WO2003002462A1 (en) * | 2001-06-28 | 2003-01-09 | Ch2M Hill, Inc. | Carbon dioxide enhanced complex-adsorption process for metal or metalloid removal from water |
| US6787041B2 (en) | 2001-06-28 | 2004-09-07 | Ch2M Hill, Inc. | Carbon dioxide enhanced complex-adsorption process for metal or metalloid removal from water |
| US7429330B2 (en) | 2001-08-27 | 2008-09-30 | Calgon Carbon Corporation | Method for removing contaminants from fluid streams |
| US7429551B2 (en) | 2001-08-27 | 2008-09-30 | Calgon Carbon Corporation | Adsorbents for removing heavy metals |
| WO2003043731A1 (en) * | 2001-11-15 | 2003-05-30 | Engelhard Corporation | Arsenic removal media |
| WO2004101142A1 (en) * | 2003-05-15 | 2004-11-25 | Alcan International Limited | Method of preparing a water treatment product |
| US7056537B2 (en) * | 2003-10-17 | 2006-06-06 | Aceto Corporation | Treatment of landfill gas |
| WO2005082523A1 (en) * | 2003-12-16 | 2005-09-09 | Calgon Carbon Corporation | Adsorbents for removing heavy metal cations and methods for producing and using these adsorbents |
| WO2005058482A1 (en) * | 2003-12-16 | 2005-06-30 | Calgon Carbon Corporation | Adsorbents for removing heavy metals and methods for producing and using the same |
| WO2005092492A1 (en) * | 2004-03-04 | 2005-10-06 | The Regents Of The University Of California | Treated bottom ash medium and method of arsenic removal from drinking water |
| US7820052B2 (en) | 2004-03-04 | 2010-10-26 | The Regents Of The University Of California | Method of arsenic removal from water |
| US7544636B2 (en) | 2004-03-04 | 2009-06-09 | The Regents Of The University Of California | Treated bottom ash medium and method of arsenic removal from drinking water |
| WO2005094577A1 (en) * | 2004-03-11 | 2005-10-13 | Aceto Corporation | Treatment of landfill gas |
| FR2881129A1 (en) * | 2005-01-26 | 2006-07-28 | Rhodia Chimie Sa | Purification of water, containing metals comprises passing water in a fixed aluminum doped silica bed |
| US7892436B2 (en) | 2005-04-25 | 2011-02-22 | The Regents Of The University Of California | Compositions and methods for removing arsenic in water |
| EP2127740A1 (en) * | 2007-01-09 | 2009-12-02 | Badulin, Nikolay Aleksandrovich | Sorbent for removing heavy metal ions from water |
| EP2127740A4 (en) * | 2007-01-09 | 2011-06-08 | Badulin Nikolay Aleksandrovich | Sorbent for removing heavy metal ions from water |
| CN113549777A (en) * | 2021-08-06 | 2021-10-26 | 武汉中地水石环保科技有限公司 | Device and method for reducing arsenic content of rock |
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