ZA200005116B - Water treatment product and method. - Google Patents
Water treatment product and method. Download PDFInfo
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- ZA200005116B ZA200005116B ZA200005116A ZA200005116A ZA200005116B ZA 200005116 B ZA200005116 B ZA 200005116B ZA 200005116 A ZA200005116 A ZA 200005116A ZA 200005116 A ZA200005116 A ZA 200005116A ZA 200005116 B ZA200005116 B ZA 200005116B
- Authority
- ZA
- South Africa
- Prior art keywords
- water treatment
- treatment product
- water
- particulate material
- alumina
- Prior art date
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims description 70
- 238000000034 method Methods 0.000 title claims description 21
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 37
- 239000011236 particulate material Substances 0.000 claims description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 24
- 229910052785 arsenic Inorganic materials 0.000 claims description 19
- 239000011248 coating agent Substances 0.000 claims description 16
- 238000000576 coating method Methods 0.000 claims description 16
- 229910052742 iron Inorganic materials 0.000 claims description 14
- 229910001570 bauxite Inorganic materials 0.000 claims description 12
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 claims description 11
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 11
- 239000002245 particle Substances 0.000 claims description 7
- 239000007788 liquid Substances 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 3
- 229910001385 heavy metal Inorganic materials 0.000 claims description 3
- 239000011368 organic material Substances 0.000 claims description 3
- 150000004684 trihydrates Chemical class 0.000 claims description 3
- 239000002253 acid Substances 0.000 claims description 2
- 150000001450 anions Chemical class 0.000 claims description 2
- 150000001768 cations Chemical class 0.000 claims description 2
- 229910052711 selenium Inorganic materials 0.000 claims description 2
- 238000002791 soaking Methods 0.000 claims description 2
- 239000000047 product Substances 0.000 description 22
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 17
- 239000000243 solution Substances 0.000 description 16
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 11
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 9
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 7
- 150000003839 salts Chemical class 0.000 description 7
- 229910021653 sulphate ion Inorganic materials 0.000 description 7
- 239000002002 slurry Substances 0.000 description 6
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 5
- 239000012141 concentrate Substances 0.000 description 5
- 239000012153 distilled water Substances 0.000 description 5
- 238000002474 experimental method Methods 0.000 description 5
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000000356 contaminant Substances 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 4
- 239000003651 drinking water Substances 0.000 description 3
- 235000020188 drinking water Nutrition 0.000 description 3
- 229910052500 inorganic mineral Inorganic materials 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000011707 mineral Substances 0.000 description 3
- 238000001179 sorption measurement Methods 0.000 description 3
- 239000002351 wastewater Substances 0.000 description 3
- MHUWZNTUIIFHAS-XPWSMXQVSA-N 9-octadecenoic acid 1-[(phosphonoxy)methyl]-1,2-ethanediyl ester Chemical compound CCCCCCCC\C=C\CCCCCCCC(=O)OCC(COP(O)(O)=O)OC(=O)CCCCCCC\C=C\CCCCCCCC MHUWZNTUIIFHAS-XPWSMXQVSA-N 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000003463 adsorbent Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 229910010272 inorganic material Inorganic materials 0.000 description 2
- 239000011147 inorganic material Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000011148 porous material Substances 0.000 description 2
- 239000012266 salt solution Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 229940047047 sodium arsenate Drugs 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- 238000004131 Bayer process Methods 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910021536 Zeolite Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001479 atomic absorption spectroscopy Methods 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- JYYOBHFYCIDXHH-UHFFFAOYSA-N carbonic acid;hydrate Chemical compound O.OC(O)=O JYYOBHFYCIDXHH-UHFFFAOYSA-N 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052570 clay Inorganic materials 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 239000013065 commercial product Substances 0.000 description 1
- 238000011437 continuous method Methods 0.000 description 1
- GDVKFRBCXAPAQJ-UHFFFAOYSA-A dialuminum;hexamagnesium;carbonate;hexadecahydroxide Chemical compound [OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[OH-].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Mg+2].[Al+3].[Al+3].[O-]C([O-])=O GDVKFRBCXAPAQJ-UHFFFAOYSA-A 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 229910001657 ferrierite group Inorganic materials 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 150000004678 hydrides Chemical class 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 229910001701 hydrotalcite Inorganic materials 0.000 description 1
- 229960001545 hydrotalcite Drugs 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- LDHBWEYLDHLIBQ-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide;hydrate Chemical compound O.[OH-].[O-2].[Fe+3] LDHBWEYLDHLIBQ-UHFFFAOYSA-M 0.000 description 1
- 238000002386 leaching Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052680 mordenite Inorganic materials 0.000 description 1
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000008213 purified water Substances 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 229910052665 sodalite Inorganic materials 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Landscapes
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Description
© wo sersois2 PCT/GB99/01026
WATER TREATMENT PRODUCT & METHOD
As discharge limits for metals tighten, adsorption processes for high level treatment of metal bearing wastes becomes increasingly attractive. Adsorption is capable of removing many metals over a wider pH range and to much lower levels than precipitation. Additionally, adsorption can often remove complexed metals which would not be checked by conventional treatment processes.
An adsorbent commonly present in metal treatment processes is an amorphous iron oxide called ferrihydrite. A disadvantage of such treatment is that ferrihydrite forms a sludge product from which it is difficult to recover purified water. In order to address this problem, a water treatment product has been described which consists of washed sand coated with ferrihydrite (M Edwards and M M Benjamin, Jnl. Water Poll
Control Fed, Vol 61, Part 9, 1989, pages 1523-1533). That product has also been tested for removal of arsenic from drinking water (F G A
Vagliasindi et al, Proceedings Water Quality Technology Conference, Part 2, New Orleans, 12-16 November 1995, pages 1829-1853). in Europe and USA the pemitted quantities of arsenic in drinking water have been, or will shortly be, reduced from 200 ug/l to 50 pg/l and on to 20 or 10 ug/l. As a water treatment product for removing arsenic, activated alumina has been proposed (Canadian patent 2,090,989). The particles of activated alumina are robust and readily separable from treated water. Although activated alumina is by itself an active adsorbent of arsenic and other heavy metals, there is a need for an even better material. This need has been addressed in WO 96/37438, which proposes water treatment compositions comprising lanthanum oxides and alumina. But lanthanum oxides would be prohibitively expensive for the treatment of very large volumes of water.
CN
According to the present invention there is provided a water treatment product which is a particulate material having a specific surface area of at least 1.0 m?/g, or an artefact formed by bonding together such particulate material, and having an insoluble ferric iron coating. Preferably, the particulate material is porous and may have through pores, closed pores or both. The artefacts formed from the particulate material are typically cylindrical or brick shaped.
The particulate material is preferably non-metallic and a mineral or inorganic material. Preferred materials which may act predominantly as substrates for the ferric iron coating, include Zeolites,
Ferrierite, Mordenite, Sodalite, pillared clays and activated clays. Preferred are alumina-based materials including alumina itself and bauxite. The particulate material or the artefact formed therefrom is preferably robust, resistant to crushing, and does not form a fine powder or sludge during use.
The individual particles in the particulate material, which may be accretions of fine particles, need to be sufficiently large to be easily separable from treated water. The individual particles may be as fine as having a mean size of 5 um or 10 um, although coarse particles are more readily separated from the treated water. Preferably the individual particles have a mean size of 100 pm to 5000 um, e.g. from 200 pm — 1000 um.
They may be formed by agglomeration or pelleting or crushing.
The particulate material used herein may be of alumina trihydrate as produced by the Bayer process, or calcined alumina.
Preferably there is used activated alumina, a product formed by heating alumina trihydrate at 300-800°C. Activated alumina has the advantage of a large specific surface area. Thus for example the commercial product
AA400G has a specific surface area of 260 — 380 m?/g. Alternatively, the porous medium may be of bauxite, or other alumina-containing mineral ‘such as zeolite, clay or hydrotalcite. The non-volatile content of bauxite comprises from 40 or 50 — 95 wt% of alumina together with from 3 or 5 = 25 oo WO 99/50182 PCT/GB99/01026 wt% of ferric oxide. Activated bauxite is a preferred material which may be formed by heating the mineral at a temperature in the range 300 — 800°C, and may typically have a specific surface area of from 100 or 150 — 200 m?/g. Because the iron content of bauxite is present in, rather than v on, the particle surface, it is generally not counted as part of the insoluble ferric iron coating of this invention.
Particulate materials having a high specific surface area show ! a high capacity for adsorbing contaminants and removing them from water. :
The water treatment product of this invention preferably has a specific ; surface area of 1.0 — 400 m?/g, e.g. at least 10 m?/g, particularly at least 1 100 mg. :
The particulate material may be provided with a precipitated : insoluble ferric iron coating by soaking it in a ferric solution, e.g. an aqueous solution of ferric sulphate or ferric chloride. Then the water is removed by evaporation or otherwise and the product dried at elevated : temperature, e.g. of 50 - 500°C and preferably 50 - 200°C, to convert ferric salts to an insoluble ferric iron coating, probably a hydrated ferric oxide or ferrihydrate. The preparative technique described in the M Edwards reference noted above is suitable. The ferric iron coating may constitute from 0.01% to 50%, preferably 0.1% to 10%, by weight of the water treatment prodact.
An alternative method of making a water treatment product according to the invention comprises treating a ferruginous ore with acid liquid so as to leach out iron from the ore, and then raising the pH of the ; liquid so as to form a precipitated ferric iron coating on the surface of the : ore. For example, the ore may be treated with hydrochloric acid at a pH of around 3, and the pH subsequently raised to about 7 by use of sodium oe ! hydroxide. The resulting product is filtered, washed and dried preferably at i elevated temperature as before. Also included within the scope of the } invention is a water treatment product which is a ferruginous ore having a ! precipitated ferric iron coating on its surface. Preferably the ore is bauxite, \ J
~4- particularly activated bauxite.
As demonstrated in the examples below, the water treatment product of this invention has a combination of useful properties: excellent capacity and avidity for rapidly adsorbing inorganic contaminants from ct 5 water being treated; robust material which is easily separable from treated water and can be treated to recover inorganic contaminants and so permit reuse without losing its structure.
The invention also includes a water treatment method, which method comprises contacting water to be treated with the water treatment product herein described, and thereafter recovering treated water containing a reduced concentration of an organic material or cation or anion particularly at least one heavy metal or As or Se or F. Batch treatment typically involves agitating the water to be treated with an aliquot of the water treatment product, the amount of which is chosen in order to 15s achieve a desired degree of water purification in a desired time, typically less than 1 hour. Continuous methods are also possible as well known in the art.
Optimum conditions for removal of organic materials and of inorganic materials are generally different. Depending on the nature of the contaminant to be removed, it may be advantageous to adjust the pH of the water in order to improve the performance of the water treatment product.
Thus for example, arsenic is best removed at a pH of 5 to 7 preferably 5.5, while fluoride is best removed at a pH of 6 to 8 preferably 7. 2s Example
Doping Procedure
As ferric salt solutions the chloride and sulphate were initially used. Both the ferric chloride and ferric sulphate solutions are classified as drinking water grades, which are suitable in potable, water treatment. The ferric chloride solution was supplied as 10.58 w% Fe ion and the ferric a sulphate solution was supplied as 12.0 w% Fe ion.
f © WO 99/50182 PCT/GB99/01026
Activated alumina AA400G (28x48 mesh size; 0.3-0.6 mm) was doped in ferric salt solutions according to the following samples:
Sample 1: 9.5 g of the ferric chloride concentrate was diluted to 1000 ml with distilled water. 1000 g of AA400G were added to this solution and the slurry was stirred to ensure an even coating of the salt on the alumina.
Once the alumina had taken up (adsorbed) all of the liquid, the sample was transferred to a tray and dried in an oven at 160°C for 3 hours. After this period of drying all of the samples were free flowing. After drying, the samples were washed to remove surface dust. Preferably they are then immersed in water/sodium carbonate solution for 24 hours to ensure almost complete hydrolysis of the ferric salt and to prevent any iron salt leaching out. The product contained approximately 0.15 wt% Fe as FezO;.
Sample 2: 47.2 g of the ferric chloride concentrate was diluted to 1000 mi with distilled water. 1000 g of AA400G were added to this solution and the slurry was stirred to ensure an even coating of the salt on the alumina. This was then followed up as in Sample 1. The product contained 0.61 wt% Fe as Fe;0as.
Sample 3: 8.3 g of the ferric sulphate concentrate was diluted to 1000 mi with distilled water. 1000 g of AA400G were added to this solution and the slurry was stirred to ensure an even coating of the salt on the alumina.
This was then followed up as in Sample 1. The product contained approximately 0.15 wt% Fe as Fe;0s.
Sample 4: 41.2 g of the ferric sulphate concentrate was diluted to 1000 ml with distilled water. 1000 g of AA400G were added to this solution and the slurry was stirred to ensure an even coating of the salt on the s alumina. This was then followed up as in Sample 1. The product contained 0.63 wt% Fe as Fe;0a.
Sample 5: 412 g of the ferric sulphate concentrate was diluted to 1000 mil with distilled water. 1000 g of AA400G were added to this solution and the slurry was stirred to ensure an even coating of the salt on the alumina. This was then followed up as in Sample 1. The product contained 6.0 wt% Fe as Fez0as.
Jar Test Experiments a) A jar test was carried out at room temperature (~20°C). The particulate materials used included activated alumina AA400G and
AA400G iron doped according to the above mentioned procedures. A prefixed amount of the particulate material, in a range of 0.05g,0.1g,05¢ and 1g, was weighed into a 250 ml conical flask equipped with a magnetic follower. To this, 200 mi of raw water (contaminated water) was added and stirred magnetically for a period of time of 10 minutes to several days.
After stirring, the solutions were filtered using 0.2 pm membrane filters. b) 5 g of the particulate material were placed in a flask equipped with a magnetic follower. To this, 1000 m! of raw water (contaminated water) was added and stirred magnetically for a period of 1 hour, during which, at intervals of 1, 5'and 10 minutes, samples were withdrawn and were filtered using 0.2 pm membrane filters.
Y . 7 WO 99/50182 PCT/GBY9/01026
Analysis
Arsenic in solution is measured by atomic absorption spectrometry (hydride generation-atomic absorption method), which can detect trace limit of 2 ug/l or under favourable conditions as low as 0.5 ug/l.
Example 2
Use of iron oxide coated activated alumina to remove fluoride
To examine the effectiveness of the iron oxide coated activated alumina to remove fluoride compared with untreated activated alumina, the following test was conducted. 1. A solution containing ~20 mg/l F was prepared and analysed for fluoride concentration using a selective ion electrode. 2. 0.05 g, 0.1 g and 0.5 g samples of the various particulate materials were placed in containers. 3. 200 mi of the fluoride solution was added to each container. 4. Using magnetic stirrers, the containers were stirred overnight at room temperature. 5. Approximately 50 mi of the slurry was syringed from each container and filtered. 6. The fluoride concentration of each filtered solution was analysed using a selective ion electrode.
Media tested were . AA400G - commercially available activated alumina. ° Sample 2 eo Sample 4 . Sample S.
Results
The starting fluoride concentration was 21 mg/l F. The results shown in the table below are the final concentrations of F in mg/l.
y
Particulate Material Addition oss | ote | 08s pons
Conclusions
The use of iron coated activated alumina enabled greater fluoride removal than untreated activated alumina particularly at media s addition levels of 0.1 g and above. Increasing the amount of iron oxide present on the activated alumina surface increased the amount of fluoride removed.
Example 3
A jar test experiment was done as described in Example 1.
The water tested was wastewater containing 26 mg/l of arsenic. The particulate materials tested were the product of sample 5 (Example 1 containing 6.0 wt% Fe as Fe,0s) here referred to as AAFSS50, and (for comparison) commercial activated alumina AA400G. 1.5g or 2g of particulate material were maintained in contact with 200 ml of wastewater for 30 or 60 minutes. The results are set out in Table 1 below.
C
© WO 99/50182 PCT/GB99/01026
Table 1: Arsenic removal from wastewater using Iron coated
Activated alumina
Media wt of particulate | Contact Time Final Arsenic material (minutes) Concentration (9) (mg)
FS is | wom
ARTIS es | ow | os mas |Z | ® | om
Example 4 s Jar test experiments were performed as described in
Example 1, using borehole water containing an initial arsenic content concentration of 14.7 ug/l. 200mi samples of the water were stirred with various different quantities of the particulate material for various different contact times. The results are set out in Table 2.
Table 2; Arsenic removal from borehole water using activated wt of particulate Contact Time AA400G AAFS50 material (g) (minutes) Final Arsenic Final Arsenic
Concentration Concentration (ug/l) (ng) or ow pes or ow ee or ow pw es or wm es ew or [we es pes os ow ew ee os ow | es es os wees [ew es wm pees pes os | wes es
I A EE EO wm pes es
Tw es ew wows es
Tw es es
/ © WO 99/50182 PCT/GB99/01026
Example 5
Jar test experiments were performed as described above, using de-ionised water spiked with about 31 to 33 ug/l of arsenic as sodium arsenate. The two particulate materials were those described previously, activated alumina AA400G, and an iron oxide coated activated alumina
AAFS50. Different amounts of each particulate material (0.1g, 0.5g and 1.0g) were stirred with 200 ml of the test water for different periods of time ~ (10, 20, 30, 60 minutes and 16 hours (960 minutes)). The results are set out in the accompanying Figures 1 and 2 which are graphs showing final arsenic concentration against contact time.
Example 6
Jar test experiments were performed as described above, using de-ionised water spiked with up to 1700 ug/i of arsenic as sodium arsenate. The two particulate materials were those described in Example 5 and used at 0.05 g of the material per 1000 ml of the arsenic solution and stirred for 960 minutes. The results are shown in Figure 3.
Claims (19)
1. A water treatment product which is a particulate material having a mean particle size of at least 5 um and a specific surface area of at least 10 m2/g, or an artefact formed by bonding together such particulate material, and having an insoluble hydrated ferric iron oxide coating.
2. The water treatment product of claim 1, wherein the particulate material has a mean particle size of 100 um to 5000 pm.
3. The water treatment product of claim 1 or claim 2, wherein the particulate material is an alumina-based material.
1s . 4 The water treatment product of claim 3, wherein the alumina- based material is selected from bauxite, alumina trihydrate and alumina.
5. The water treatment product of claim 3 or claim 4, wherein the alumina-based material is activated alumina or activated bauxite.
6. The water treatment product of any one of claims 1 to 5, wherein the particulate material has a specific surface area of at least 100 mg.
7. A method of making the water treatment product of any one of claims 1 to 6, which method comprises soaking the particulate material or an artefact formed from the particulate material in a ferric solution, and recovering and drying the coated particulate material or artefact.
1 0 0B10098 i PGT/GBISI01026 | SLMSPAMD. Lb Epo Vc 4 Mig, Ese -13- 0 8 Okt, 1999
8. The water treatment product of any one of claims 1 to 6, which is a ferruginous ore having a precipitated ferric iron coating on its surface. 5s
9 The water treatment product of claim 8, wherein the ore is bauxite.
10. The water treatment product of claim 9, wherein the bauxite is activated bauxite.
11. A method of making the water treatment product of any one of claims 8 to 10, which method comprises treating a ferruginous ore with acid liquid so as to leach out iron from the ore, and then raising the pH of the liquid so as to form a precipitated ferric iron coating on the surface of the ore.
12. A water treatment method, which method comprises contacting water to be treated with the water treatment product of any one of claims 1 to 6 or 8 to 10, and thereafter recovering treated water containing a reduced concentration of organic materials or cations or anions.
13. The water treatment method of claim 12, wherein the treated water has a reduced concentration of at least one heavy metal or As or Se orF.
14. The water treatment method of claim 13, wherein the treated water has a reduced As concentration of not more than 10 pg/l.
Cr. Cot PeT/ 94 /01020
15. A water treatment product according to claim 1, substantially as herein described and illustrated.
16. A method according to claim 7, substantially as herein described and illustrated.
17. A method according to claim 11, substantially as herein described and illustrated.
18. A method according to claim 12, substantially as herein described and illustrated.
19. A new water treatment product, a new method of making a water treatment product, or a new water treatment method, substantially as herein described. AMENDED SHEET
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9807071.7A GB9807071D0 (en) | 1998-04-01 | 1998-04-01 | Water treatment product and method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| ZA200005116B true ZA200005116B (en) | 2002-01-02 |
Family
ID=10829729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| ZA200005116A ZA200005116B (en) | 1998-04-01 | 2000-09-22 | Water treatment product and method. |
Country Status (2)
| Country | Link |
|---|---|
| GB (1) | GB9807071D0 (en) |
| ZA (1) | ZA200005116B (en) |
-
1998
- 1998-04-01 GB GBGB9807071.7A patent/GB9807071D0/en not_active Ceased
-
2000
- 2000-09-22 ZA ZA200005116A patent/ZA200005116B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| GB9807071D0 (en) | 1998-06-03 |
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