NZ776421A - Methods and uses for hypochlorite concentrates - Google Patents
Methods and uses for hypochlorite concentratesInfo
- Publication number
- NZ776421A NZ776421A NZ776421A NZ77642121A NZ776421A NZ 776421 A NZ776421 A NZ 776421A NZ 776421 A NZ776421 A NZ 776421A NZ 77642121 A NZ77642121 A NZ 77642121A NZ 776421 A NZ776421 A NZ 776421A
- Authority
- NZ
- New Zealand
- Prior art keywords
- hypochlorite
- concentrate
- concentration
- ocl
- aqueous
- Prior art date
Links
- WQYVRQLZKVEZGA-UHFFFAOYSA-N Hypochlorite Chemical compound Cl[O-] WQYVRQLZKVEZGA-UHFFFAOYSA-N 0.000 title claims abstract description 284
- 239000012141 concentrate Substances 0.000 title claims abstract description 84
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 50
- 239000003651 drinking water Substances 0.000 claims abstract description 19
- 230000000249 desinfective Effects 0.000 claims abstract description 12
- 235000012206 bottled water Nutrition 0.000 claims abstract description 11
- 238000011012 sanitization Methods 0.000 claims abstract description 9
- 239000000463 material Substances 0.000 claims abstract description 7
- VLTRZXGMWDSKGL-UHFFFAOYSA-M Perchlorate Chemical compound [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 claims description 55
- XTEGARKTQYYJKE-UHFFFAOYSA-M chlorate Chemical compound [O-]Cl(=O)=O XTEGARKTQYYJKE-UHFFFAOYSA-M 0.000 claims description 52
- ZAMOUSCENKQFHK-UHFFFAOYSA-N chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 50
- 239000000460 chlorine Substances 0.000 claims description 48
- 229910052801 chlorine Inorganic materials 0.000 claims description 48
- 239000011780 sodium chloride Substances 0.000 claims description 41
- 229910052708 sodium Inorganic materials 0.000 claims description 36
- 238000005649 metathesis reaction Methods 0.000 claims description 30
- 229910052700 potassium Inorganic materials 0.000 claims description 27
- 150000003839 salts Chemical class 0.000 claims description 23
- 229910052744 lithium Inorganic materials 0.000 claims description 19
- 239000012535 impurity Substances 0.000 claims description 17
- 241000894007 species Species 0.000 claims description 12
- 238000003860 storage Methods 0.000 claims description 11
- 125000002340 chlorooxy group Chemical group ClO[*] 0.000 claims description 10
- 229910045601 alloy Inorganic materials 0.000 claims description 8
- 239000000956 alloy Substances 0.000 claims description 8
- 230000036499 Half live Effects 0.000 claims description 5
- 229910001914 chlorine tetroxide Inorganic materials 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminum Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 239000000919 ceramic Substances 0.000 claims description 2
- 229910052802 copper Inorganic materials 0.000 claims description 2
- 239000010949 copper Substances 0.000 claims description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 2
- 229920001971 elastomer Polymers 0.000 claims description 2
- 239000011521 glass Substances 0.000 claims description 2
- 229910052759 nickel Inorganic materials 0.000 claims description 2
- 239000004033 plastic Substances 0.000 claims description 2
- 229920003023 plastic Polymers 0.000 claims description 2
- 239000005060 rubber Substances 0.000 claims description 2
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 239000010936 titanium Substances 0.000 claims description 2
- 229910052719 titanium Inorganic materials 0.000 claims description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 2
- 239000002023 wood Substances 0.000 claims description 2
- 239000012611 container material Substances 0.000 claims 5
- NHYCGSASNAIGLD-UHFFFAOYSA-N chlorine monoxide Inorganic materials Cl[O] NHYCGSASNAIGLD-UHFFFAOYSA-N 0.000 claims 2
- 239000004567 concrete Substances 0.000 claims 1
- 239000004575 stone Substances 0.000 claims 1
- 239000011575 calcium Substances 0.000 description 46
- 238000000034 method Methods 0.000 description 45
- 238000003843 chloralkali process Methods 0.000 description 37
- 239000011734 sodium Substances 0.000 description 36
- SUKJFIGYRHOWBL-UHFFFAOYSA-N Sodium hypochlorite Chemical compound [Na+].Cl[O-] SUKJFIGYRHOWBL-UHFFFAOYSA-N 0.000 description 35
- 238000006243 chemical reaction Methods 0.000 description 25
- ZKQDCIXGCQPQNV-UHFFFAOYSA-N Calcium hypochlorite Chemical compound [Ca+2].Cl[O-].Cl[O-] ZKQDCIXGCQPQNV-UHFFFAOYSA-N 0.000 description 21
- -1 Salt sodium hypochlorite Chemical class 0.000 description 20
- 239000005708 Sodium hypochlorite Substances 0.000 description 20
- 239000000047 product Substances 0.000 description 18
- 229910019093 NaOCl Inorganic materials 0.000 description 16
- 229910052783 alkali metal Inorganic materials 0.000 description 16
- VTYYLEPIZMXCLO-UHFFFAOYSA-L calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 14
- FAPWRFPIFSIZLT-UHFFFAOYSA-M sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 14
- 229910052791 calcium Inorganic materials 0.000 description 12
- AXCZMVOFGPJBDE-UHFFFAOYSA-L Calcium hydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 11
- OYPRJOBELJOOCE-UHFFFAOYSA-N calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 11
- 239000000920 calcium hydroxide Substances 0.000 description 11
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 11
- 235000011116 calcium hydroxide Nutrition 0.000 description 11
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 11
- 239000007787 solid Substances 0.000 description 11
- 238000007323 disproportionation reaction Methods 0.000 description 10
- 239000004744 fabric Substances 0.000 description 10
- 239000000203 mixture Substances 0.000 description 10
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L Calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 9
- 241000196324 Embryophyta Species 0.000 description 9
- 239000003513 alkali Substances 0.000 description 9
- 229910052925 anhydrite Inorganic materials 0.000 description 9
- 239000012153 distilled water Substances 0.000 description 9
- 239000003518 caustics Substances 0.000 description 8
- 238000004140 cleaning Methods 0.000 description 8
- 235000020188 drinking water Nutrition 0.000 description 8
- 235000010216 calcium carbonate Nutrition 0.000 description 7
- 229910000019 calcium carbonate Inorganic materials 0.000 description 7
- 238000002156 mixing Methods 0.000 description 7
- KWYUFKZDYYNOTN-UHFFFAOYSA-M potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 7
- 229910000831 Steel Inorganic materials 0.000 description 6
- INHCSSUBVCNVSK-UHFFFAOYSA-L lithium sulfate Chemical compound [Li+].[Li+].[O-]S([O-])(=O)=O INHCSSUBVCNVSK-UHFFFAOYSA-L 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000004659 sterilization and disinfection Methods 0.000 description 6
- 239000001110 calcium chloride Substances 0.000 description 5
- 235000011148 calcium chloride Nutrition 0.000 description 5
- 229910001628 calcium chloride Inorganic materials 0.000 description 5
- 238000004090 dissolution Methods 0.000 description 5
- 150000002500 ions Chemical class 0.000 description 5
- WMFOQBRAJBCJND-UHFFFAOYSA-M lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 239000000376 reactant Substances 0.000 description 5
- 239000004743 Polypropylene Substances 0.000 description 4
- 150000001450 anions Chemical class 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 4
- 238000005660 chlorination reaction Methods 0.000 description 4
- 230000001419 dependent Effects 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- 229920002635 polyurethane Polymers 0.000 description 4
- 239000004814 polyurethane Substances 0.000 description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- 229940112112 Capex Drugs 0.000 description 3
- MWRWFPQBGSZWNV-UHFFFAOYSA-N Dinitrosopentamethylenetetramine Chemical compound C1N2CN(N=O)CN1CN(N=O)C2 MWRWFPQBGSZWNV-UHFFFAOYSA-N 0.000 description 3
- 150000001340 alkali metals Chemical class 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000005755 formation reaction Methods 0.000 description 3
- 235000015203 fruit juice Nutrition 0.000 description 3
- 230000036541 health Effects 0.000 description 3
- GLXDVVHUTZTUQK-UHFFFAOYSA-M lithium;hydroxide;hydrate Chemical compound [Li+].O.[OH-] GLXDVVHUTZTUQK-UHFFFAOYSA-M 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- AYJRCSIUFZENHW-UHFFFAOYSA-L Barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- QWPPOHNGKGFGJK-UHFFFAOYSA-N Hypochlorous acid Chemical compound ClO QWPPOHNGKGFGJK-UHFFFAOYSA-N 0.000 description 2
- 241000229754 Iva xanthiifolia Species 0.000 description 2
- LWXVCCOAQYNXNX-UHFFFAOYSA-N Lithium hypochlorite Chemical compound [Li+].Cl[O-] LWXVCCOAQYNXNX-UHFFFAOYSA-N 0.000 description 2
- OTYBMLCTZGSZBG-UHFFFAOYSA-L Potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 2
- 241000605112 Scapanulus oweni Species 0.000 description 2
- 210000003491 Skin Anatomy 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- 239000000356 contaminant Substances 0.000 description 2
- 230000000875 corresponding Effects 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 235000012055 fruits and vegetables Nutrition 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
- 238000006703 hydration reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006011 modification reaction Methods 0.000 description 2
- 229920000915 polyvinyl chloride Polymers 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- 239000011591 potassium Substances 0.000 description 2
- 235000015320 potassium carbonate Nutrition 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- 229910052939 potassium sulfate Inorganic materials 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- HPEWZLCIOKVLBZ-UHFFFAOYSA-N Barium hypochlorite Chemical compound [Ba+2].Cl[O-].Cl[O-] HPEWZLCIOKVLBZ-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical compound OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- NLZUEZXRPGMBCV-UHFFFAOYSA-N Butylhydroxytoluene Chemical compound CC1=CC(C(C)(C)C)=C(O)C(C(C)(C)C)=C1 NLZUEZXRPGMBCV-UHFFFAOYSA-N 0.000 description 1
- YALMXYPQBUJUME-UHFFFAOYSA-L Calcium chlorate Chemical compound [Ca+2].[O-]Cl(=O)=O.[O-]Cl(=O)=O YALMXYPQBUJUME-UHFFFAOYSA-L 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate dianion Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 241000287828 Gallus gallus Species 0.000 description 1
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M Lithium chloride Chemical class [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 1
- ZLNQQNXFFQJAID-UHFFFAOYSA-L Magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L Magnesium hydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000007832 Na2SO4 Substances 0.000 description 1
- 239000004698 Polyethylene (PE) Substances 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 210000001685 Thyroid Gland Anatomy 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- RQPZNWPYLFFXCP-UHFFFAOYSA-L barium dihydroxide Chemical compound [OH-].[OH-].[Ba+2] RQPZNWPYLFFXCP-UHFFFAOYSA-L 0.000 description 1
- 235000015278 beef Nutrition 0.000 description 1
- 238000004061 bleaching Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000004641 brain development Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- KZBUYRJDOAKODT-UHFFFAOYSA-N chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 231100001010 corrosive Toxicity 0.000 description 1
- 231100000078 corrosive Toxicity 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000004059 degradation Effects 0.000 description 1
- 239000007857 degradation product Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002635 electroconvulsive therapy Methods 0.000 description 1
- 231100000049 endocrine disruptor Toxicity 0.000 description 1
- 239000000598 endocrine disruptor Substances 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 239000011152 fibreglass Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- PEDCQBHIVMGVHV-UHFFFAOYSA-N glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 1
- 235000011187 glycerol Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- XMBWDFGMSWQBCA-UHFFFAOYSA-M iodide Chemical compound [I-] XMBWDFGMSWQBCA-UHFFFAOYSA-M 0.000 description 1
- 229910052740 iodine Inorganic materials 0.000 description 1
- PNDPGZBMCMUPRI-UHFFFAOYSA-N iodine Chemical compound II PNDPGZBMCMUPRI-UHFFFAOYSA-N 0.000 description 1
- 239000011630 iodine Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011776 magnesium carbonate Substances 0.000 description 1
- 235000014380 magnesium carbonate Nutrition 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 235000012254 magnesium hydroxide Nutrition 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000010813 municipal solid waste Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 235000015277 pork Nutrition 0.000 description 1
- 235000021395 porridge Nutrition 0.000 description 1
- 238000004445 quantitative analysis Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 230000001105 regulatory Effects 0.000 description 1
- 150000003385 sodium Chemical group 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 230000001954 sterilising Effects 0.000 description 1
- 238000004642 transportation engineering Methods 0.000 description 1
Abstract
The present invention relates to methods of sanitising and/or disinfecting a water source, which may be a potable water source or a body of water such as a pool or spa. The present invention also relates to methods of surface sanitization, which may be a biological or non-biological surface. The main sanitisation /disinfectant material contemplated is an aqueous hypochlorite solution, prepared initially as a hypochlorite concentrate. he main sanitisation /disinfectant material contemplated is an aqueous hypochlorite solution, prepared initially as a hypochlorite concentrate.
Description
The present ion relates to methods of sanitising and/or ecting a water source, which
may be a potable water source or a body of water such as a pool or spa. The present invention
also relates to methods of surface sanitization, which may be a biological or non-biological surface.
The main sanitisation /disinfectant material contemplated is an aqueous hypochlorite solution,
prepared initially as a hypochlorite concentrate.
NZ 776421
METHODS AND USES FOR HYPOCHLORITE CONCENTRATES
Field
The present invention s to methods of sanitising and/or disinfecting a water source, which
may be a potable water source or a body of water such as a pool or spa. The present invention
also relates to s of e sanitization, which may be a biological or non-biological
surface. The main sation /disinfectant material contemplated is an aqueous hypochlorite
solution, prepared initially as a hypochlorite concentrate.
Background
Abbreviations:-
OSG = On Site Generator by CAP process.
CAP = ChlorAlkali Process
HSLS= High Strength Low Salt sodium hypochlorite belonging to Powell
Manufacturing.
HRL = Highest Recommended Level
HAL = Highest ble Level
CAPEX = Capital Expenditure
OPEX = Operating Expenditure
RESIDUAL IONIC STRENGTH (RI) =
RI = Total Ionic Strength (IT) – [Ionic strength of Hypochlorite species]
SALT METATHESIS = a reaction between two inorganic salts where one
product is insoluble in water. The reactants need not be highly soluble for the
reaction to take place, but may take a longer time for the reaction to reach
completion.
Drinking water disinfecting has traditionally been achieved using chlorination via liquefied
ne gas delivered in bulk, drums, or cylinders. Transporting and handling large volumes
of liquefied ne gas is an g safety issue, and to solve this problem water treatment
plants have been transitioning to using bulk CAP aqueous sodium hypochlorite (12.5 % w/w).
Hypochlorites are very effective, cheap sanitizers which provide a valuable ection service
to humanity. The largest use for hypochlorite is for drinking water disinfection. Its use for this
application however has been hindered due to its low strength; CAP sodium hypochlorite
(12.5%w/w) is mostly ed of water, and is thus expensive to transport at scale. Some
plants have installed sodium hypochlorite OSGs to reduce the transport cost, and Powell has
developed a HSLS process to make a more concentrated CAP sodium hypochlorite (30% w/w).
At this time the HSLS s, in , can produce the most stable aqueous hypochlorite
with the resultant lowest disproportionation rate to te and perchlorate. The disadvantages
of the HSLS process are:-
1.1 The ntial OPEX and CAPEX required.
1.2 The need to locate the process adjacent to a ne plant or alternatively to
continue transporting liquefied chlorine gas in bulk, drums or ers to the
manufacturing site.
1.3 The continuing transport cost of 30%w/w sodium hypochlorite. (70% water, and a
more Dangerous Good than CAP hypo; also more corrosive to road tankers)
All aqueous hypochlorites to some degree are unstable and disproportionate into undesirable
chlorates and perchlorates. Instability increases with an increase in hypochlorite concentration.
Upon heating, exposure to UV light or simply storage over time, hypochlorite will
portionate to a mixture of chloride, oxygen, chlorates and perchlorates:
2 ClO- → 2 Cl- + O2
3 ClO- → 2 Cl- + ClO-3
OCl- +ClO32- → ClO4- + Cl-
Recently, as a result of improved analytical capability, orates derived from hypochlorite
have been shown to be a major human health issue. Perchlorate has been found to both interfere
with brain development in children and present a dose -related risk to iodine uptake in healthy
adults, as an endocrine disruptor of the human thyroid system. Perchlorate ination of
drinking water is a major global concern and the US EPA has recently proposed (in 2018) to
regulate the perchlorate level in drinking water via a maximum contaminant level goal
[MCLG]. Currently the US EPA has levels for drinking water set at:-
HRL Chlorate: 210 µg/L
HAL Perchlorate: 15 µg/L
Whilst the limit set by the World Health Organization is 70 µg/L for chlorate (2016).
To partly ameliorate this issue, the current practice is focussed on better management
techniques and guidelines for handling and storing hypochlorite to t disproportionation.
For example, some of the key recommendations are to dilute hypochlorite solutions on delivery
since halving the concentration decreases the disproportionation rate by a factor of 7, to store
hypochlorite solutions at lower temperatures as reducing temperature by 5 ˚C decreases
disproportionation rate by a factor of 2, to keep the pH between 11 and 13 even after dilution,
and importantly, to avoid extended storage times by, using fresh hypochlorite solutions when
possible.
The most common aqueous hypochlorite is sodium lorite which is made by the Chlor
Alkali Process (CAP) shown by on (I)
Cl2 + 2NaOH = NaOCl + NaCl + H2O (CAP) (I)
Another method for aqueous hypochlorite preparation is by salt metathesis reactions such as:-
Ca(OCl)2 + Na2CO3 = 2NaOCl + CaCO3 (II)
)2 + Na2SO4 = 2NaOCl + CaSO4 (III)
Although the ation of aqueous hypochlorites by metathesis has been known for many
decades, the process has never achieved commercial success. The lack of application is due to
the fact that Chlor Alkali Plants (CAP) must produce aqueous hypochlorite as a by-product.
As the demand for chlorine has sed (eg PVC manufacture), in turn producing more CAP
hypochlorite, aqueous hypochlorite produced by metathesis has not been required, and hence
this process has never been developed or commercialized.
Also as bleaching activity sed, emphasis was placed upon the development of solid
hypochlorites to avoid the costly transport of water which is the main component of sodium
hypochlorite.
Only lithium hypochlorite, calcium hypochlorite and barium hypochlorite have been isolated
as pure anhydrous solids.
Processes for the cture of solid calcium lorite have been in development since
the early 1950’s, and today there are two main processes:-
A) The sodium process based on the following reaction:-
CaCl2 + 2NaOCl = 2NaCl + Ca(OCl)2 (IV)
B) The calcium process based on the reaction:-
2Cl2 + 2Ca(OH)2 = CaCl2 + Ca(OCl)2 + 2H2O (V)
Both processes are widely used, gh product from the sodium process seems to be
dominant in the market.
A major problem with the use of solid calcium hypochlorite is storage and handling of large
quantities because of its self reactivity.
It is well known that if a single drop of organic liquid such as glycerin or brake fluid were to
fall into a drum of solid calcium hypochlorite it can start an exothermic decomposition causing
the whole contents to heat up and bubble like boiling porridge.
There have been numerous fatalities and fires on board ships which have been carrying large
quantities of solid calcium hypochlorite in c lined steel drums.
The disproportionation reaction of solid hypochlorite by a hydration reaction is rmic and
in the case of concentrated solid hypochlorites, such as LiOCl and Ca(OCl)2, can lead to
ous thermal runaway reactions and potentially explosions. As a result, solid hypochlorite
is classified as a dangerous good by the criteria of the Australian Dangerous Goods Code (ADG
Code) for Transport by Road and Rail. This makes it expensive to ort and store large
quantities of solid hypochlorite as many safety precautions must be followed. To further
mitigate the risk of fire caused by the self reactivity of calcium hypochlorite on ships,
government authorities rely on standard tests performed under the UN Protocol or the US
NFPA to classify into different risk categories, m hypochlorite depending on its strength,
degree of hydration and t concentrations.
Restrictive regulations associated with the storage, transport and handling of calcium
hypochlorite have increased the cost of its use for water treatment and these reasons have
prevented the material from being used as a esis feedstock.
Considerable work has been done over the last 50 years to find a way to reduce the self
reactivity of solid Ca(OCl)2. The following methods have been investigated:-
1 Maintaining a level of moisture in the Ca(OCl)2
2 Reducing the available chlorine level in the product
3 Adding non hydrated ts to the product
4 Coating the product with hydroscopic materials
ingly, there is an urgent need to improve upon the current practices for both domestic
and commercial ations of hypochlorites.
Summary
The present disclosure is predicated on the discovery that bodies of water can be more
efficiently sanitised and/or disinfected with aqueous hypochlorite concentrates differentiated
from previously used concentrates by low level salt impurities. In particular, and without being
bound by theory, the inventors have fied methods of using aqueous hypochlorite
concentrates of Li, K, or Na differentiated by low levels of salt ties. These hypochlorite
concentrates exhibit superior stabilities and generate less Chlorates and Perchlorates than
hypochlorite concentrates made by the conventional CAP process, and are similar to and in
some cases superior to hypochlorite concentrates produced by the more ive and capital
ive HSLS process. The above applications also extend to the use of said concentrates in
sanitising surfaces.
In particular, when you make hypochlorite by the CAP and the HSLS process, the reaction
forms an equimolar quantity of NaCl and NaOCl. The formed NaCl which is highly soluble
and though somewhat ult to remove, is easily avoided by using the esis process as
highlighted in the present invention. For instance, in the HSLS process, the methods currently
adopted uses refrigeration and fugation to remove the NaCl which adds an extra burden
in on to CAPEX and OPEX. In contrast, the residue CaSO4 or CaCO3 uct from
the hypochlorite produced in the present invention can be d by simple filtration
processes. The inventors have realised that these reactions already produce products having
very low solubility anyway and so as a result the concentrate can be produced with very pure
hypochlorite (ie with very low levels of e salt impurities) compared with a CAP or HSLS
product.
The present methods described herein have been found to have the following advantageous
properties:
1 Lower Chlorates and Perchlorates make metathesized based hypochlorites safer to
use for pools and spas (hot tubs).
2 Lower Chlorates and Perchlorates are also an advantage for drinking water
chlorination fecting). Chlorination using the metathesis process described
herein is also the cheapest method for drinking water ent. (see Table 3).
3 Hypochlorites made via the present metathesis process have better high
temperature stability than other comparable hypochlorites, making them
especially suitable for use in spas (hot tubs).
4 Since metathesis hypochlorites are more stable than conventional hypochlorites,
they have or time based efficacy.
Potassium and sodium based metathesized hypochlorites containing exceedingly
low c levels (which is only added to the hypochlorite as a stability booster)
are environmentally ly spa sanitisers. [High c concentrations in
conventional hypochlorites presents a disadvantage to their use in spas (hot tubs)
because of corrosion to spa (hot tub) surfaces.].
6 Lower Chlorates and Perchlorates levels in metathesised hypochlorites make them
more suitable for sanitising biological surfaces like fruit and vegetables.
7 Potassium and sodium based metathesized hypochlorites containing exceedingly
low caustic levels (which is only added to the hypochlorite as a stability booster)
are environmentally friendly surface sanitisers. [Caustic levels in conventional
hypochlorites prevent their use on some surfaces because of corrosion to said
surfaces.].
Accordingly, the resultant aqueous sodium hypochlorite concentrates produced by metathesis
as described herein can be formed easily and cheaply and are safe to store and handle, while
also minimising the aqueous tration of the chlorate and/or perchlorate by-products
which are reduced to a previously un-achievable minimal level.
Accordingly, in one aspect the present invention es a method for sanitizing a body of
water (including pools and spas) using an aqueous hypochlorite concentrate of Li, K or Na,
wherein the concentrate is characterized with a low level of salt impurities defined by a
“residual” ionic strength of between 0.2 and 1.7 gram moles per litre of concentrate, n
the method includes the step of administering said concentrate to the body of water to provide
an available chlorine level in the treated water of between 1 and 20 ppm (w/v), and wherein
the hypochlorite is produced via Metathesis reaction.
In a r second aspect the ion also provides a method for disinfecting a potable water
source using an aqueous hypochlorite concentrate of K or Na, wherein the concentrate is
characterized with a low level of salt impurities defined by a ual” ionic strength of
between 0.2 and 1.7 gram moles per litre of concentrate, wherein the method es the step
of administering said concentrate to the potable water source to provide an available chlorine
level in the treated water of between 0.1 and 10 ppm (w/v), and wherein the hypochlorite is
produced via Metathesis on.
In one aspect the ion provides a method for sanitizing a non-biological surface using an
aqueous hypochlorite concentrate of Li, K or Na, wherein the concentrate is characterized with
a low level of salt impurities defined by a “residual” ionic strength of between 0.2 and 1.7 gram
moles per litre of concentrate, wherein the method includes the step of applying said
concentrate, or a diluted solution f, to said non-biological surface to provide an available
chlorine level on said surface of between 10 and 10000 ppm (w/v), and wherein the
hypochlorite is produced via Metathesis reaction.
In another aspect the invention provides a method for zing a biological surface using an
aqueous hypochlorite concentrate of Li, K or Na, wherein the concentrate is characterized with
a low level of salt impurities defined by a “residual” ionic strength of between 0.2 and 1.7 gram
moles per litre of concentrate, wherein the method includes the step of ng said
concentrate, or a d on thereof, to said biological surface to provide an available
chlorine level on said surface of between 10 and 10000 ppm (w/v), and wherein the
hypochlorite is produced via Metathesis reaction.
The Ca(OCl)2 feedstock used in the esis reaction to produce the lorite trate
as used herein is characterised with a high available chlorine content of from 65-80%,
preferably about 70%, 71%, 72%, 73%, 74%, 75%, or about 76%.
In some embodiments, if the calcium hypochlorite feedstock is produced from a reaction of
chlorine and calcium hydroxide (calcium process, reaction V), the sodium hypochlorite
solution or hypochlorite solution can have a half-life about 20% to about 50% more than that
of a lorite solution produced from a reaction of calcium hypochlorite produced by
reacting m chloride and sodium hypochlorite (sodium process, reaction IV).
In one embodiment the surface is a ological surface selected from selected from stainless
steel and other ferrous alloys, copper and its alloys, nickel and its , titanium and its alloys,
aluminium and its alloys, plastics, rubbers, glass, wood, or ceramic.
In another embodiment the surface is a biological surface selected from fruit and vegetables,
processed animal skin (eg chicken, beef or pork) and human skin.
Brief description of the drawings
Embodiments of the present invention will now be described, by way of non-limiting example,
with reference to the drawings in which:
Figure 1 illustrates a comparison of NaOCl stabilities made by metathesis reaction with two
different calcium hypochlorites. (one made by Na process, the other by the Ca process).
Figure 2 illustrates a comparison of stabilities of hypochlorite solution of the present ion
compared to other methods.
Figure 3 illustrates the degradation of sodium hypochlorite solutions of the present invention
compared to the CAP process.
Figure 4 illustrates the formation of chlorate from sodium hypochlorite solutions of the present
invention compared to the CAP process.
Figure 5 illustrates the formation of perchlorate from sodium hypochlorite solutions of the
present invention compared to the CAP process.
Figure 6 rates a comparison of ation of sodium hypochlorite solutions at 52 ˚C.
Figure 7 illustrates a comparison of commercial and lithium hypochlorite ons of the
present invention, compared with simulation results of a high th low salt (HSLS) sodium
hypochlorite belonging to Powell Manufacturing.
Figure 8 a table which compares hypochlorite solutions made using different processes.
Figure 9 a table showing the economics associated with drinking water chlorination.
Detailed description
In one , the present invention is predicated on the discovery that aqueous hypochlorite
trates of Li, K, or Na made by the metathesis reaction are produced with low levels of
salt ties. As concentrates they are then mixed further with water, (i.e, required dilution)
and such resultant lorites are more stable than CAP and HSLS (by Powell)
hypochlorites, and have, in a pre diluted state, a residual ionic concentration less than 1.7
g.mole/litre and as low as 0.2 g mole/litre.
To solve the problem of the safe transportation storage, and domestic use of Li, K or Na
hypochlorites, the inventors have developed methods based on aqueous trates which
allow for a new way to disinfect a portable water source or sanitize a pool or spa, or a e.
Advantageously, the metathesis process can allow for the preparation of fresh hypochlorites
y includes Na, Li, and K) at the point of use.
In other embodiments, the hypochlorite concentrates have a lower chlorate concentration
governed by the total ionic concentration but more particularly by a residual ionic concentration
of less than 1.7 M, down to about 0.2 M.
The chlorate content will still be dependent upon time, temperature history, strength of the
hypochlorite on and starting chlorate concentration, but will always be less than CAP
hypochlorite and, in some instances, HSLS hypochlorites because of the age of the
lowest residual ionic strength.
In other embodiments the hypochlorite concentrates are characterised by a lower perchlorate
concentration governed by the total ionic concentration but more particularly by the al
ionic concentration of less than 1.7 M, down to about 0.2 M
The perchlorate content will still be dependent upon time, temperature history, strength of the
hypochlorite solution and starting perchlorate concentration, but will always be less than CAP
hypochlorite and, in some instances, HSLS hypochlorites e of the advantage of the
lowest residual ionic strength.
To solve the problem of high generation of chlorates and perchlorates in CAP hypochlorates,
the inventors have ered a new family of extremely stable aqueous hypochlorite ts
made by a salt metathesis process.
In an aspect, the present invention provides a family of extremely stable aqueous hypochlorite
products ing Na, K, and Li which have a al ionic strength of less than 1.7 M.
The stability and rate of disproportionation of aqueous hypochlorites is markedly dependant on
the concentration of the hypochlorite molecules in solution. In order to understand the impact
of impurities upon hypochlorite stability it is necessary to devise a way of removing
hypochlorite concentration from consideration. This was done by comparing hypochlorites
based on their residual ionic strengths instead of the conventional total ionic strength. As a
result, it was discovered that the stability of hypochlorites could be reliably indicated by
calculating their al ionic strengths (or calculating from experimental measurements).
Furthermore, for the first time, it was found that al ionic th was a quantitative
method of defining a family of hypochlorite products that are markedly different (greater
stability) to standard CAP lorite which has a residual ionic strength greater than about
1.7 M.
Residual ionic strength (RI) is first d.
Aqueous hypochlorites are difficult to describe as they have variable parameters such as:-
1 Metallic parent, ( Ca, Ba, Mg, Na, K, and Li )
2 Strength, which may be measured as gpl of available chlorine
3 Method of preparation (CAP and Salt Metathesis)
4 Impurities, e.g. NaCl, CaCl2, LiCl salts etc.
An important ter influencing the stability of an aqueous hypochlorite is its ionic
strength. The Total Ionic strength for s alkali metal hypochlorites is expressed as
IT =1/2∑mizi2 = ½(m1z12 + m2z22 +.......+ mnzn2) where (V1)
n = total number of different ionic species in solution
m = molal tration, in this case molar.
z = Charge on the ion of specific species i
IT = Ionic Strength as defined by G.N. Lewis
ine earth hypochlorites require a different expression for ionic strength to reflect
complex multivalent ionic interactions.)
e the Total Ionic strength represented by on VI es the concentrations of the
anion and cation of the hypochlorite s, the total ionic strength is a function of the
hypochlorite strength. If the ionic strength of the hypochlorite species is removed from the total
ionic strength calculation then a new function called “residual ionic strength (RI)” is newly
defined.
RI = Total Ionic Strength (IT) – [Ionic strength of Hypochlorite species]
This new parameter “Residual Ionic Strength” is only dependent on :-
1) The purity of the reactants involved in its production
2) The type of anion bound to the alkali metal reactant, used in the salt metathesis reaction.
3) The solubility of the salt produced by the metathesis reaction.
4) The solubility of salts produced as by-products or impurities associated with the
reactants of the metathesis reaction.
The term ual Ionic Strength” can therefore be used to define a new family of
hypochlorite products, produced by metathesis, which have residual ionic strengths below 1.7
g mole/litre, which is the minimum residual ionic strength of ional CAP lorite.
The concentrates of the present invention provides a sodium hypochlorite solution that has a
residual ionic concentration of less than about 1.7 molarity.
This embodiment defines a new family of aqueous hypochlorite products, including Li, Na,
and K, d by their exceedingly low residual ionic strengths, which contributes to improved
stability and the associated lowest rate of disproportionation into chlorates and orates.
(See equations VII, and VIII)
The problem with the Chlor Alkali Process (CAP) for making hypochlorites Reaction (1) is
product instability (due to amongst other things the co-generation of salt) and the associated
generation of harmful by-products, such as chlorates and perchlorates. (see Figure 2).
To mitigate this m, aqueous hypochlorite concentrates of the present invention are
produced from a esis on. The hypochlorites produced by metathesis contain
chlorate levels about 25% lower, and perchlorate levels about 50% lower than the equivalent
CAP hypochlorite.
In some embodiments, the metathesized hypochlorite concentrates have a residual ionic
concentration less than about 1.7 molarity, down to about 0.2 ty. In other embodiments,
the residual ionic concentration is from about 0.2 M (g mole/l) to about 1.7 M. In other
embodiments, the residual ionic concentration is from about 0.2 M to about 1.5 M, about 0.2
M to about 1.4 M, about 0.2 M to about 1.3 M or about 0.2 M to about 1.0 M.
A feature of this family of very stable aqueous hypochlorite aqueous concentrates, which
include LiOCl, NaOCl and KOCl, is their very low residual ionic concentrations. Residual
Ionic trations as low as about 0.2 gm mole/litre, can be obtained by judicious choice of
reactants and their levels of contaminant impurities.
Hypochlorites made by using Ca(OCl)2 (Ca) which has been made by the calcium process, (
reaction (V)) are more stable than ts made by using Ca(OCl)2 (Na) which has been made
by the sodium process ( reaction (IV)). (see Figure 1).
Table 1: Common impurities in calcium hypochlorite produced by the sodium or calcium
process, including the %w/w of available ne.
Impurities Sodium Process Calcium Process Solubility
% w/w on (IV) %w/w equation (V) (g/100g in H2O at
°C)
ble chlorine 65-80 65 (minimum)
Ca(OH)2 5 (typical) 6 (maximum) 0.165
CaCO3 1 (typical) 1 (typical) 0.0014
NaCl (soluble) 20 (max) 0 35.7
CaCl2 0 9 (maximum) 74.5
Ca(ClO3)2 0 1 (maximum) (soluble)
H2O 10 (max) 4 (max)
MgCO3 Trace Trace 0.01
Mg(OH)2 Trace Trace 0.0009
BaCO3 Trace Trace 0.0022
Ba(OH)2 Trace Trace 1.67
It is believed that the increased stability of aqueous metathesis hypochlorites formed from
Ca(OCl)2 (Ca) made by the m process is due to a smaller quantity of CaCl2 in the t
from the calcium process compared with the NaCl content of product from the sodium process.
Further, the general insolubility of calcium impurities resulting in a purer aqueous hypochlorite
and ingly has a better aqueous stability as compared to the one made using the sodium
process. A lower rate of formation of chlorate/perchlorate in the NaOCl made by Ca(OCl)2
(Ca) as compared to that made by using Ca(OCl)2 (Na), was also found.
ageously, this further improves the purity of the resultant sodium hypochlorite solution,
which has better stability with respect to lower disproportionation rates into chlorate and/or
perchlorate.
In some embodiments, the aqueous hypochlorite trate has a tration of greater than
% w/w, greater than 10 % w/w, r than 15 % w/w, or greater than 20 % w/w. of the
hypochlorite species.
The disproportionation products of hypochlorites are chlorates and perchlorates. The inventors
have further investigated the hypochlorite, te, perchlorate and O2 content of the solution
and determined that these concentrations are dependent on several factors such as temperature,
starting chlorate, hypochlorite and ionic strengths. By regulating these factors, the
disproportionation products of the composition can be controlled to a minimum.
In some ments, the calcium hypochlorite is produced from a reaction of chlorine and
calcium hydroxide (calcium process). The sodium hypochlorite solution or hypochlorite
solution can have a half-life about 20% to about 50% more than that of a hypochlorite solution
produced from a reaction of calcium hypochlorite ed by the reaction of calcium de
and sodium hypochlorite (sodium process).
In other embodiments, to ensure stability, the hypochlorite concentrate further comprises a
soluble alkali of about 0.1 g/L to about 0.5 g/L, and optionally an alkaline buffer ed from
carbonate, onate or a mixture thereof; and wherein the hypochlorite concentrate is
produced via a metathesis reaction.
In another embodiment, the ition is substantially free of impurities. This is especially
so if the calcium hypochlorite made by calcium process is used.
In another aspect, the present s utilise an aqueous concentrate comprising:
a) calcium hypochlorite having an available chlorine content of from 65-80% and a water
content of about 4% to about 10% w/w; and
b) an alkali metal salt;
wherein the mix of the alkali metal salt and calcium hypochlorite is in approximately
stoichiometric proportions; and
wherein a) and b) is react-able in water to form a lorite concentrate and a able salt.
The alkali metal can be selected from Na, Li or K.
In other embodiments, the anion associated with the alkali metal salt is selected from CO32-,
SO42-, PO43-, , H2PO4-, OH-, SO32-, HSO4-, HSO3- and S2O32-.
It will be appreciated the method described herein provides pool or water sanitisation by
applying the concentrate.
In certain ments the body of water is treated with the concentrate to provide an ble
chlorine level in the treated water of between 1 and 20 ppm (w/v), such as about 2, 4, 6, 8, 10,
12, 14, 16, 18 ppm (w/v) or any range in between. For producing a zed pool or spa (i.e.,
body of water) the present invention plates using aqueous hypochlorites of Li, K or Na,
and preferably Li.
In certain embodiments the potable water source is treated with the concentrate to provide an
available chlorine level in the treated water of between 0.1 and 20 ppm (w/v), such as about
0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
about 19 ppm (w/v), or any range in between. For producing a ected potable water source
the present invention only contemplates using aqueous hypochlorites of K or Na.
In another aspect, the present invention provides a method for preparing an aqueous
hypochlorite trate (to be used in the methods described herein), including mixing an
alkali metal salt (family includes Na, Li and K) with calcium hypochlorite having an available
chlorine content of from 65-80% and a water content of about 4% to about 10% w/w;
wherein the alkali metal salt and the calcium hypochlorite are in approximately stoichiometric
proportions; and
wherein the alkali metal salt and calcium hypochlorite is react-able in water to form a
hypochlorite concentrate.
In certain ments the biological surface is treated with the concentrate to provide an
available chlorine level in the treated water of between 1 and 20 ppm (w/v), such as about 2,
4, 6, 8, 10, 12, 14, 16, 18 ppm (w/v) or any range in between.
For sanitizing a biological surface the present invention contemplates using aqueous
hypochlorites of Li, K or Na, and preferably K or Na.
In certain embodiments this method includes the step of ng said concentrate, or a d
solution thereof, to said non-biological surface to provide an available ne level on said
surface of n 10 and 10000 ppm (w/v), and wherein the hypochlorite is produced via
Metathesis on.
For sanitizing a non-biological surface the present invention contemplates using aqueous
hypochlorites of Li, K or Na, and preferably Na or K.
In an embodiment the concentrate is used neat.
In another embodiment the tration is diluted prior to use.
In certain embodiments the surface is treated with the concentrate to provide an available
chlorine level in the treated water of between 0.1 and 20 ppm (w/v), such as about 0.2, 0.4, 0.6,
0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, about 19 ppm
(w/v), or any range in between.
In another aspect, the present invention provides a method for preparing an aqueous
hypochlorite trate (to be used in the surface sanitising methods described herein),
including mixing an alkali metal salt y includes Na, Li and K) with calcium hypochlorite
having an available chlorine content of from 65-80% and a water content of about 4% to about
% w/w;
wherein the alkali metal salt and the calcium hypochlorite are in approximately stoichiometric
proportions; and
wherein the alkali metal salt and calcium hypochlorite is react-able in water to form a
hypochlorite concentrate.
In an embodiment, the process further comprises adding a soluble alkali. The soluble alkali can
be sodium hydroxide. Other alkali can be potassium hydroxide, calcium hydroxide or lithium
hydroxide.
In another ment, the soluble alkali is t in an amount of about 0.1 g/L to about 0.5
g/L. In other embodiments, the tration is about 0.1 g/L to about 0.4 g/L, about 0.1 g/L
to about 0.3 g/L or about 0.1 g/L to about 0.2 g/L. Advantageously, the e alkali acts to
further stabilise the hypochlorite solution.
In r embodiment, the process further comprises a step of adding an alkaline buffer to the
sodium hypochlorite, wherein the alkaline buffer is selected from ate, onate or a
mixture thereof.
In another embodiment, the metathesis reaction is performed at room temperature, or at about
1°C to about 35°C.
The metathesized based metal lorite concentrate, as used herein is characterised by the
metal hypochlorite concentrate having an residual ionic concentration less than 1.7 molarity,
the metal hypochlorite solution having an available chlorine content of about 90 g/L to about
160 g/L; and wherein the metal is selected from Na, K or Li.
In some embodiments, the metathesized hypochlorite concentrate has a residual ionic
concentration less than about 1.7 molarity. In other ments, the residual ionic
concentration is from about 0.2 M (g.mole/L) to about 1.7 M. In other embodiments, the
residual ionic concentration is from about 0.2 M to about 1.6 M, about 0.2 M to about 1.5 M,
about 0.2 M to about 1.4 M or about 0.2 M to about 1.2 M. In some embodiments, the
hypochlorite solution has a residual ionic concentration of about 0.2 M to about 1 M.
Advantageously, the metathesized metal hypochlorite concentrate has approximately 50%
reduction of perchlorate when compared with CAP hypochlorite exposed to the same
conditions and at the same concentrations.
In other embodiments, the metathesized alkali metal hypochlorite concentrate comprises a
soluble alkali of about 0.1g/l to about 0.5 g/l. In other embodiments, the concentration is of
about 0.1g/l to about 0.4 g/l or about 0.2g/l to about 0.4 g/l.
In other embodiments, the metathesized alkali metal hypochlorite concentrate comprises an
alkaline buffer selected from a ate/bicarbonate mixture.
In other embodiments, the metathesized hypochlorite concentrate has a half-life of at least 1.4
times greater than that of Chlor Alkali Plant (CAP) hypochlorites. Preferably, the ife is at
least 1.7 time greater than that of CAP hypochlorites.
In other embodiments, the metathesized hypochlorite solution is produced from an alkali metal
salt or its corresponding hydrated form.
In other embodiments, the anion associated with the alkali metal salt or its corresponding
hydrated form is ed from CO32-, SO42-, PO43-, HPO42-, H2PO4-, OH-, SO32-, HSO4-, HSO3-
and .
It will be appreciated that many further modifications and permutations of various aspects of
the described embodiments are possible. ingly, the described aspects are intended to
embrace all such alterations, modifications, and variations that fall within the spirit and scope
of the appended .
hout this specification and the claims which follow, unless the context requires
otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be
understood to imply the inclusion of a stated integer or step or group of integers or steps but
not the exclusion of any other integer or step or group of rs or steps.
The nce in this specification to any prior publication (or information derived from it), or
to any matter which is known, is not, and should not be taken as an acknowledgment or
admission or any form of tion that that prior publication (or information derived from
it) or known matter forms part of the common general knowledge in the field of endeavour to
which this specification relates.
Examples
Example 1
Li2SO4 + Ca(OCl)2 → 2LiOCl + CaSO4
A solution of Ca(OCl)2 was prepared using HY-CLOR Super-Shock ar pool chlorine
containing 700 g/kg of chlorine as Ca(OCl)2, by dissolving 72.0 g in 400 ml of distilled water
at 20 °C. The dissolution process was achieved by mixing with a Heidolph RZR 2041 variable
speed, polyurethane , steel, four blade, anchor style, 120 mm diameter, agitator at 305
rpm for 0.5 hours. 38.7 g of h AR grade Li2SO4 was slowly added to the previously
prepared unfiltered Ca(OCl)2 solution with nt ng for a period of 1 hour. The mixture
was then filtered using a Buchner funnel under vacuum h a polypropylene cloth filter.
The LiOCl solution was clean and bright and had an available ne content of 113.01 g/l.
A small quantity of LiOH was added to the product to impart stability. After washing with
distilled water, the CaSO4 was removed from the filter cloth, dried at 1500 °C for 8 hours and
weighed on a Sartorius electronic balance. The weight of CaSO4 was determined to be 47 g.
Yield is 98 % based on Li2SO4. The reaction ially goes to completion in stoichiometric
quantities.
Ionic strength of solution = 1.6503, pH=11
Example 2
2(LiOH.H2O) + Ca(OCl)2 = 2LiOCl + Ca(OH)2 +2H2O
A solution of Ca(OCl)2 was prepared using HY-CLOR Super-Shock granular pool chlorine
containing 700 g/kg of chlorine as Ca(OCl)2, by dissolving 72.0 g in 400 ml of distilled water
at 20 °C. The dissolution process was achieved by mixing with a Heidolph RZR 2041 variable
speed, polyurethane coated, steel, four blade, anchor style, 120 mm diameter, agitator at 305
rpm for 0.5 hours. 26.05 g of Helm AR grade LiOH.H2O was slowly added to the previously
prepared unfiltered )2 solution with constant ng for a period of 3 hour. The e
was then filtered using a Buchner funnel under vacuum through a polypropylene cloth filter.
The LiOCl solution was clean and bright and had an available chlorine content of 110 g/l. After
washing with distilled water, the Ca(OH)2 was removed from the filter cloth, dried at 800°C
for 8 hours and weighed on a Sartorius electronic balance. The weight of Ca(OH)2 was
determined to be 25 g. Yield is 95 % based on LiOH.H2O. The reaction essentially goes to
completion in stoichiometric quantities.
Ionic strength of on = 1.5978, pH=12
Example 3
K2SO4 + Ca(OCl)2 → 2KOCl + CaSO4
A solution of Ca(OCl)2 was ed using HY-CLOR Super-Shock ar pool chlorine
containing 700 g/kg of chlorine as Ca(OCl)2, by dissolving 72.0 g in 400 mL of distilled water
at 20 °C. The dissolution process was achieved by mixing with a Heidolph RZR 2041 variable
speed, ethane coated, steel, four blade, anchor style, 120 mm diameter, agitator at 320
rpm for 0.5 hours. 61.4 g of Merck AR grade K2SO4 was slowly added to the previously
prepared unfiltered Ca(OCl)2 solution with constant stirring for a period of 1 hour. The mixture
was then filtered using a Buchner funnel under vacuum through a polypropylene cloth filter.
The KOCl solution was clean and bright and had an available chlorine content of 123.4 g/L.
After washing with distilled water, the CaSO4 was removed from the filter cloth, dried at 150
°C for 8 hours and weighed on a Sartorius electronic balance. The weight of CaSO4 was
determined to be 46.1 g. Yield = 96% based on CaSO4. The reaction essentially goes to
completion in stoichiometric ties.
Example 4
K2CO3 + )2 → 2KOCl + CaCO3
As in example 1, a solution of Ca(OCl)2 was prepared using HY-CLOR Super-Shock granular
pool chlorine containing 700 g/kg of chlorine as Ca(OCl)2, by dissolving 72.0 g in 400 ml of
led water at 20 °C. The dissolution process was achieved by mixing with a Heidolph RZR
2041 variable speed, polyurethane coated, steel, four blade, anchor style, 120 mm er,
agitator at 305 rpm for 0.5 hours. 48.6 g of Mallinckrodt AR grade K2CO3 (anhydrous) was
slowly added to the previously prepared unfiltered Ca(OCl)2 solution with constant stirring for
a period of 1 hour. The mixture was then filtered using a Buchner funnel under vacuum through
a opylene cloth filter. The KOCl solution was clean and bright and had an available
chlorine content of 120.5 g/L. It was found that the hypochlorite formed by this reaction lacked
ity and it was necessary to add a small quantity of KOH to the product to impart ity.
After g with distilled water, the CaCO3 was removed from the filter cloth, dried at 1500
°C for 8 hours and weighed on a Sartorius electronic balance. The weight of CaCO3 was
determined to be 34.8 g. Yield is 98.8 % based on CaCO3. The reaction essentially goes to
completion in stoichiometric quantities.
Example 5
2KOH + Ca(OCl)2 → 2KOCl + Ca(OH)2
As in example 2, a solution of Ca(OCl)2 was prepared using R Super-Shock granular
pool chlorine containing 700 g/kg of chlorine as Ca(OCl)2, by dissolving 72.0 g in 400 mL of
distilled water at 20 °C. The dissolution process was achieved by mixing with a Heidolph RZR
2041 variable speed, polyurethane coated, steel, four blade, anchor style, 120 mm diameter,
agitator at 305 rpm for 0.5 hours. 39.6 g of Merck AR grade KOH (anhydrous) was slowly
added to the previously prepared unfiltered Ca(OCl)2 solution with constant stirring for a
period of 1 hour. The mixture was then filtered using a Buchner funnel under vacuum h
a polypropylene cloth filter. The KOCl solution was clean and bright and had an available
chlorine content of 144 g/L. After washing with distilled water, the Ca(OH)2 was removed
from the filter cloth, dried at 150 °C for 8 hours and weighed on a ius electronic balance.
The weight of Ca(OH)2 was determined to be 24.2 g. Yield is 92.6 % based on Ca(OH)2. Again
the reaction ially goes to completion in iometric quantities.
Example 6
Use of LiOCl from Example 2 for Spa Sanitising.
A fibreglass spa of 1300 litres was emptied, rinsed and filled with fresh Melbourne water.
180 mls of LiOCl concentrate from Example 2 which ned 110 g/litre of available chlorine
was added to the Spa and the temperature set to 25 deg C.
The available chlorine was measured before heat was applied and a reading of 14 mg/litre of
available chlorine was determined. (Shock Treatment)
The Spa was left for two days to reach equilibrium and the temperature was measured at 26
deg C. The available chlorine at this time read 0.5 mg/litre.
The Spa was then dosed with 22 mls of LiOCl concentrate and the available chlorine measured
2 mg/litre.
Two days later, the Spa having not been used, the temperature was at 25 deg C and the ble
chlorine analysed at 1.5 mg/litre.
The Spa displayed excellent ature control and the LiOCl displayed excellent ity.
Example 7
Use of KOCl from Example 3 for potable water disinfection.
In this example we will disinfect a 20,000 litre tank of rne rain water.
The tank filled with rain water is constructed of polyethylene. The tank fittings are also made
of PVC or hylene.
A petrol driven Honda ‘trash” pump is connected to allow the tank to be recycled using a layflat
discharge hose and a wire reinforced spiral wound suction hose, both being of c
construction.
970 mls of KOCl from Example 3, containing 123.4 g/litre of available chlorine were added to
the rain water tank.
The tank water was recirculated by using the Honda pump which ran for 3 hours.
A sample of rain water taken from the tank, analysed and found to contain 5 mg/litre of
available ne. This is an appropriate level of available chlorine to achieve potable water
disinfection.
Example 6
CIP (Cleaning-In-Place) Cleaning and Sterilisation of a Fruit Juice Plant.
1 Pre-Rinse
Rinse the pipework and equipment with clean water. Ensure that the flow through pipes and
valves is in the turbulent regime (3 m/s) Direct first flush to drain. The pre-rinse will remove
particulates and product residues.
2 Caustic Wash
Dilute trated c to approximately 1.5% (w/v) and heat to 80 deg C. Circulate hot
caustic solution for 15 minutes and return to feed tank ing filtration.
3 Water Wash
Heat the wash water to 75 deg C. Direct the first flush which will contain residual caustic to
drain. Continue recirculation for 15 s.
4 Sterilisation
Dilute the metathesised NaOCl concentrate (125 gpl available chlorine [125000 ppm w/v]) to
5000 ppm (w/v). Recirculate the diluted concentrate for 15 minutes. Check the available
chlorine before capturing the recycled ant for the next CIP clean.
Post Rinse
Do not heat this post rinse water before circulation. The purpose of this rinse is to remove the
residual NaOCl, so ue flushing to drain until Starch Iodide paper shows that all the
NaOCl has been flushed from the system.
6 Acid Rinse
This step may or not be required depending on the ability of the Post Rinse to remove any
alkaline residue from the Caustic Wash and the Sterilisation steps. Because Metathesised
hypochlorite contains much less caustic for stability control compared with CAP and HSLS
hypochlorites, the Post Rinse should be sufficient to remove final traces of caustic.
The Chlorate and Perchlorate is of a typical plant operation using CAP and Metathesised
NaOCl are compared below based on the authors simulation package.
Assumptions:-
Typically NaOCl (125 gpl ble chlorine) ex a chloralkali plant (CAP) is 3 days old.
NaOCl from the CAP plant may be stored at the Fruit Juice Processor for 2 weeks. (There being
a natural desire to reduce delivery frequencies)
Assume the NaOCl is stored at 25 deg C and the initial te concentration is 1 gpl.
Analysis at 0 days old
Source of Hypo Temp Total Ionic OCl’ ClO3’ ClO4’
Deg C Conc Conc Conc Conc
g moles/l
gpl gpl gpl
CAP NaOCl 25 4.494 131.25 1.0 0
Metathised NaOCl 25 1.65 131.25 1.0 0
Analysis at Analysis at 17 days old
Source of Hypo Temp Total Ionic OCl’ ClO3’ ClO4’
Deg C Conc Conc Conc Conc
g moles/l
gpl gpl gpl
CAP NaOCl 25 4.494 121.43 4.508 6.416*10-4
Metathised NaOCl 25 1.65 127.06 2.387 2.398*10-4
Conclusion:-
There is a significant reduction of Chlorate and Perchlorate concentrations in the Metathesised
sterilising concentrate, with a lower ial contamination, of the fruit juice, with these
degradation products which are harmful to human health.
Claims (10)
1. A method for sanitizing a body of water (including pools and spas) using an aqueous hypochlorite concentrate of Li, K or Na, wherein the concentrate is characterized with a low level of salt impurities defined by a ual” ionic strength of between 0.2 and 1.7 gram moles per litre of concentrate, wherein the method es the step of administering said concentrate to the body of water to provide an available chlorine level in the treated water of between 1 and 20 ppm (w/v), and wherein the lorite is produced via Metathesis reaction.
2. A method for disinfecting a potable water source using an aqueous hypochlorite concentrate of K or Na, wherein the concentrate is characterized with a low level of salt impurities defined by a “residual” ionic strength of between 0.2 and 1.7 gram moles per litre of concentrate, wherein the method includes the step of administering said concentrate to the potable water source to provide an available chlorine level in the treated water of between 0.1 and 10 ppm (w/v), and wherein the hypochlorite is produced via Metathesis reaction.
3. A method of claim 1 or claim 2 wherein the hypochlorite trate contains between 2 and 150 g/l of ble chlorine.
4. A method of anyone of claims 1 and 3 wherein the aqueous hypochlorite trate is a Li hypochlorite concentrate.
5. A method of any one of the claims 1-4 wherein the lorite concentrate has a half life about 1.4 to 1.7 times that of a CAP produced hypochlorite under the same conditions of concentration, temperature profile, exposure to light, storage time and container material, the concentration of the hypochlorite species at any time being expressed by the rate expression d(ClO’)/dt OCl’)2 ; or n the hypochlorite concentrate has a chlorate concentration at least 25% less than that of CAP produced hypochlorite under the same conditions of concentration, temperature profile, exposure to light, storage time and container material, the concentration of the chlorate species at any time being determined by the rate expression d(ClO3’)dt = 3K2[1/(3K2t +(OCl’)-1]2-K3(ClO3’)[1/(3K2t+(OCl’)-1]; or wherein the hypochlorite concentrate has a perchlorate concentration of at least 50% less than that of CAP produced hypochlorite under the same conditions of concentration, temperature e, exposure to light, storage time and ner material, the concentration of the perchlorate species at any time being determined by the rate expression d(ClO4’)dt = K3(ClO3’)(OCl’).
6. A method for sanitizing a biological or non-biological surface using an aqueous hypochlorite concentrate of Li, K or Na, wherein the concentrate is characterized with a low level of salt impurities defined by a “residual” ionic strength of between 0.2 and 1.7 gram moles per litre of concentrate, wherein the method includes the step of applying said concentrate, or a diluted solution thereof, to said non-biological surface to provide an available chlorine level on said surface of n 10 and 10000 ppm (w/v), and wherein the lorite is produced via Metathesis reaction.
7. A method of claim 6 n the hypochlorite concentrate contains between 2 and 150 g/l of available chlorine, and the aqueous hypochlorite concentrate is a Na or K hypochlorite trate.
8. A method of claims 6 to 7 wherein it includes the step of ng the K or Na concentrate, or d solution thereof, to said biological surface to provide an available chlorine level on said surface of between 0.1 and 20 ppm (w/v) and n the lorite is produced via Metathesis reaction.
9. A method of anyone of claims 6 to 8 wherein the surface is a non-biological surface is selected from stainless steel and other s alloys, copper and its alloys, nickel and its alloys, titanium and its alloys, aluminium and its alloys, plastics, rubbers, glass, wood, concrete, stone or ceramic.
10. A method of any one of the claims 6 to 9 wherein the hypochlorite concentrate has a half life about 1.4 to 1.7 times that of a CAP produced hypochlorite under the same conditions of concentration, ature profile, exposure to light, storage time and container material, the tration of the hypochlorite species at any time being expressed by the rate expression d(ClO’)/dt =-3K2(OCl’)2; or, wherein the hypochlorite concentrate has a chlorate concentration at least 25% less than that of CAP produced hypochlorite under the same conditions of concentration, temperature profile, re to light, storage time and container material, the concentration of the chlorate species at any time being determined by the rate expression ’)dt = 3K2[1/(3K2t +(OCl’)-1]2- K3(ClO3’)[1/(3K2t+(OCl’)-1]; or wherein the hypochlorite trate has a perchlorate tration of at least 50% less than that of CAP produced hypochlorite under the same conditions of concentration, temperature profile, exposure to light, storage time and container material, the concentration of the perchlorate species at any time being determined by the rate expression d(ClO4’)dt = K3(ClO3’)(OCl’). -
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