Key information

Title
A method for removal of impurities from a liquid by coagulation using a composition of dissolved chitosan and zirconium salt
Application number
20161973
Case type
National
Status
30.09.2019 Patent meddelt (B1)
Filed
13.12.2016
Effective date
13.12.2016
Publicly available
14.06.2018
Next annual fee due
31.12.2026
Applicant
TETA VANNRENSING AS (NO)
Owner
TETA VANNRENSING AS (NO)
Inventor
Tor Håkonsen (NO) et al.
Agent
DEHNS NORDIC AS (NO)
Granted
30.09.2019
Patent number
344181
Expiry date
13.12.2036

Abstract and drawing

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content.
A method for removal of impurities from a liquid comprising the step of; adding a composition of chitosan and zirconium salt to the liquid, followed by particle removal. The invention also relates to a coagulation composition comprising chitosan and zirconium salt.

Publications

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 04.01.2023 02-01 Endring av fullmektig 2022/20250 UT GH Forespørsel DEHNS NORDIC AS
 30.12.2022 01-03 Endring av fullmektig 2022/20250 INN NIPO Dehns PAT change search-29122022 (1) DEHNS NORDIC AS
 30.12.2022 01-02 Endring av fullmektig 2022/20250 INN 2022-12-29 Dehns AS transfer to Dehns Nordic AS DEHNS NORDIC AS
 30.12.2022 01-01 Endring av fullmektig 2022/20250 INN Generell henvendelse DEHNS NORDIC AS
 30.04.2020 18-01 Saksbehandling 20161973 UT PT Påminnelse om ikke betalt årsavgift (3329) (PT20161973)
03.10.2019 17-01 Saksbehandling 20161973 UT PT Registreringsbrev Nasjonal Patent (15) (PT20161973)
24.07.2019 16-01 Saksbehandling 20161973 UT PT Meddelelse om patent DEHNS AS
 17.06.2019 15-07 Saksbehandling 20161973 INN Krav merket engelsk DEHNS AS
 17.06.2019 15-06 Saksbehandling 20161973 INN Beskrivelse ren DEHNS AS
 17.06.2019 15-05 Saksbehandling 20161973 INN Beskrivelse merket DEHNS AS
 17.06.2019 15-04 Saksbehandling 20161973 INN Hovedbrev DEHNS AS
 17.06.2019 15-03 Saksbehandling 20161973 INN Krav ren norsk DEHNS AS
 17.06.2019 15-02 Saksbehandling 20161973 INN Krav ren engelsk DEHNS AS
 17.06.2019 15-01 Saksbehandling 20161973 INN Korrespondanse (Hovedbrev inn) DEHNS AS
 20.05.2019 14-01 Saksbehandling 20161973 UT Realitet patent DEHNS AS
 15.05.2019 13-01 Saksbehandling 20161973 INN epost korrespondanse
07.05.2019 12-01 Saksbehandling 20161973 UT PT Påminnelse om ikke betalt årsavgift (3329) (PT20161973)
11.03.2019 02-01 Endring av fullmektig 2019/03119 UT GH Forespørsel DEHNS AS
 28.02.2019 11-05 Saksbehandling 20161973 INN Krav merket DEHNS AS
 28.02.2019 11-04 Saksbehandling 20161973 INN Krav ren DEHNS AS
 28.02.2019 11-03 Saksbehandling 20161973 INN Fullmakt DEHNS AS
 28.02.2019 11-02 Saksbehandling 20161973 INN Hovedbrev DEHNS AS
 28.02.2019 11-01 Saksbehandling 20161973 INN Korrespondanse (Hovedbrev inn) DEHNS AS
 28.02.2019 01-02 Endring av fullmektig 2019/03119 INN Fullmakt DEHNS AS
 28.02.2019 01-01 Endring av fullmektig 2019/03119 INN Generell henvendelse DEHNS AS
 08.11.2018 10-01 Saksbehandling 20161973 UT Henlagt manglede svar TANDBERG INNOVATION AS
 01.11.2018 09-01 Saksbehandling 20161973 UT PT Varsel om betaling av første årsavgift (3317) (PT20161973)
30.07.2018 08-01 Saksbehandling 20161973 UT Realitet patent TANDBERG INNOVATION AS
 09.03.2018 07-04 Saksbehandling 20161973 INN Krav ren TANDBERG INNOVATION AS
 09.03.2018 07-03 Saksbehandling 20161973 INN Hovedbrev TANDBERG INNOVATION AS
 09.03.2018 07-02 Saksbehandling 20161973 INN Krav merket TANDBERG INNOVATION AS
 09.03.2018 07-01 Saksbehandling 20161973 INN Korrespondanse (Hovedbrev inn) TANDBERG INNOVATION AS
 09.01.2018 06-02 Saksbehandling 20161973 INN Hovedbrev Tandberg Innovation AS
 09.01.2018 06-01 Saksbehandling 20161973 INN Korrespondanse (Hovedbrev inn) Tandberg Innovation AS
 08.11.2017 05-02 Saksbehandling 20161973 INN Hovedbrev Tandberg Innovation AS
 08.11.2017 05-01 Saksbehandling 20161973 INN Korrespondanse (Hovedbrev inn) Tandberg Innovation AS
 09.05.2017 04-02 Saksbehandling 20161973 UT PT report 12:26:26
09.05.2017 04-01 Saksbehandling 20161973 UT Realitet patent Tandberg Innovation AS
 14.03.2017 03-03 Saksbehandling 20161973 INN Fullmakt Tandberg Innovation AS
 14.03.2017 03-02 Saksbehandling 20161973 INN Erklæring Søkers rett til oppfinnelse Tandberg Innovation AS
 14.03.2017 03-01 Saksbehandling 20161973 INN Korrespondanse (Hovedbrev inn) Tandberg Innovation AS
 15.12.2016 02-01 Saksbehandling 20161973 UT Formalia 1 Tandberg Innovation AS
 13.12.2016 01-02 Saksbehandling 20161973 INN Beskrivelse Tandberg Innovation AS
 13.12.2016 01-01 Saksbehandling 20161973 INN Søknadsskjema Patent Tandberg Innovation AS

Description, claims and drawings

Disclaimer: This text has been machine-scanned and may contain errors – please refer to "Publications" for legally binding content. Description
Field of the inventionThe present invention concerns a method for removal of impurities from a liquid and a coagulation composition comprising chitosan and zirconium salt.Background of the inventionChemical water treatment is a common water treatment process all over the world. It consists principally of 2 distinct steps:1. A chemical modification of the water causing impurities to precipitate in solid form.This is done by adding a coagulant in a specific dose under a specific pH.2. A particle separation step to remove the solids formed in step 1, usually by sedimentation or using a filter.Traditionally used coagulants in water treatment are almost exclusively salts of aluminum or ferric. These are supplied in the form of sulfates or chlorides (such as Al2(SO4)3, AlCl3, Fe(SO4)3 or their pre-polymerized forms (such as polyaluminum chloride or polyaluminum silicate sulfate). These metal salts work effectively, but their continued use is hampered by several side effects, specifically high residual waste (sludge) and metal residuals in the treated water.The present invention is to be used for water treatment. It consists of a specific composition of coagulants to be used to remove dissolved and suspended matter from water. Particles to be removed could be living particles such as bacteria, viruses, parasites, algea and amoeba, or other particles such as clay, dust, sand, metal hydroxides, asbestos and silica. Dissolved matter could be natural organic matter (NOM) from decaying vegetation, animals, organic soil and biological activity, metals and other organic or inorganic pollutants.Due to their surface charge, aquatic particles are often colloidally stable and resistant to aggregation (Duan & Gregory, 2003). The coagulation process is essential in order to destabilize suspended particles in the water, triggering formation of the aggregates that can be easily removed during water treatment by sedimentation or filtration. On account biodegradability, biocompatibility and non-toxicity, chitosan (C6H12O4N)n has turned attention of the researchers, interested to find an environmental friendly alternative to metal coagulants (Huang & Chen, 1996; Håkonsen, 2005; Kvinnesland, 2002; No & Meyers, 2000; Strand, Vandvik, Vårum, & Østgaard, 2001; Vogelsang et al., 2010; Zeng, Wu, & Kennedy, 2008). Some of the researches led to patent (US5543056, US3533940).However, while effective to reduce water turbidity (Divakaran & Pillai, 2001), chitosan has shown some limitations on NOM removal (Gadmar, 2005). In order to overcome the problem, it was proposed to apply chitosan along with metal coagulants (Kvinnesland, 2002; Vogelsang et al., 2010; patents US5393435; US6827874). The synergetic effect of chitosan together with metal coagulants allowed lowering the consumption of the last, thus, minimizing the environmental harm, while removed both turbidity and color effectively.The problem of NOM removal capacities at Norwegian water plants may be especially relevant, since significant increase in the content of NOM has been observed in several surface water sources in Norway during the past 10–12 years (Eikebrokk, Vogt, & Liltved, 2003; Skjelkvåle, 1988), and greater change can happen due to climate change.The interest in zirconium (Zr) as a coagulant is due to its chemical and physical properties, especially the valency of four, high ionic potential and atomic weight. Efficient coagulant properties of Zr for turbidity and NOM removals have been confirmed by the research data also (Jarvis, P. et al., 2012; Molinder, 2009). Different inventors also have been interested in Zr for waste water treatment (US4097377 and 4066542, WO/1992/021617) or purification of metal-contaminated waters (EP0471784).In ”Removal of fluoride from aqueous solution using Zr(IV) immobilizedcross-linked chitosan”, International journal of biological macromolecules, 77 (2015), 15-23, ISSN 1879-0003, Liu Qian et al. describe the combination of Chitosan and Zirconium oxychloride octahydrate in order to produce cross-linked particles capable of adsorbing fluorides. The means involved in preparing the adsorbing particles involve de-bubbling, coating, warming, cross-linking, washing, drying … i.e. sophisticated laboratory means not comparable to a simple pouring & stirring & dosing easier to manage for an operator on a water treatment plant. Further, Liu Qian et al. do not disclose a coagulation , but an adsorption. The present invention pertains to combine use of just mentioned coagulants to remove impurities from drinking water through a simple and robust method of preparation, achieving a synergetic effect and to join the best from the two.Summary of inventionThis is achieved according to the invention by providing a method for removal of impurities from a liquid by coagulation according to claim 1. The method for removal of impurities from a liquid, comprises the step of; adding a composition of chitosan and zirconium salt to the liquid, followed by particle removal. The coagulation composition comprises chitosan and zirconium salt.The present invention relates to a simple and robust method for purification of water. A coagulant composition consisting of chitosan and zirconium salt in a specific ratio is added to the water to be treated in a specific concentration and under specific pH conditions to coagulate and precipitate impurities.The object of the present invention is to remove particles and dissolved matter from water, producing a safe drinking water, reducing negative environmental impact from release of polluted waste water or to produce a water quality suitable for industrial processes.The coagulant composition comprises of chitosan (a natural organic cationic polymer) (C6H12O4N)n, dissolved together with zirconium salt (zirconium oxychloride octahydrate ZrOCl2·8H2O). The concentration weight ratio of chitosan to zirconium metal in the composition should be between 1:1 and 1:10. The pH of the water after adding the composition should be between 4 and 11.The present invention is especially effective for purification of color-rich waters, which would meet all European standards for color, THM, TOC or other water treatment demands, with significant reduction in residual waste compared to traditionally used coagulants. Effect could be explained by a synergetic effect between the components.Additional synergic effect of application of the present method includes the possibility to avoid using concentrated acid to dissolve chitosan prior to use, as addition of zirconium oxychloride substitutes the acid when dissolving chitosan.Detailed description of the invention The composition comprises a natural, cationic polymer chitosan and zirconium oxychloride coagulant. Both Chitosan and zirconium salts can be used for water treatment alone (US Patent 3.533.940, US patent 5.543.056 and US Patent 3.997.439).Used together in a specific ratio and under specific conditions, four synergetic effects are obtained:1) The water purifying effect of zirconium salts is obtained at a wider range of concentrations, making the use of zirconium salts more robust and practical for real life use.2) The purifying efficiency of dissolved matter is increased for chitosan, without interrupting the low waste production associated with using chitosan alone.3) Using concentrated acid in dissolving of chitosan is not needed.4) Residual Zr in the treated water is low, and proportional with treated water colour.Chitosan needs to be dissolved in an acidic solution prior to addition to the water to be treated. This requires the preparation of a chitosan solution by mixing chitosan and water with concentrated acid, normally hydrochloric acid. Hydrochloric acid is corrosive, and generally undesired in a water treatment environment. However, when mixed together with ZrOCl2·8H2O, chitosan will dissolve without the need for any separate acid addition. Hence, the following method is recommended for the composition preparation. At a water treatment plant the coagulant composition can be prepared in a tank by:1) dispersion of necessary amount of chitosan in 2/3 of the water volume needed for the solution preparation2) the rest 1/3 of the water volume is used for preparation of the concentrate ZrOCl2·8H2O solution, which is pumped to the tank with chitosan;3) ZrOCl2·8H2O solution is added under constant stirring until the chitosan is dissolved 4) a preferred concentration weight ratio of chitosan to zirconium metal in the composition should be between 1:2 and 1:2,5.The coagulation composition is added in an amount effective to form a floc in the drinking water. Purifying water composition can be dosed right after the preparation. Dosing of the composition may be conducted with or without pH adjustment of the water to be purified. In the former case, raw water should be adjusted to pH value around 4.5 by dosing concentrated HCl into the line before the coagulant feed. It should be taking into consideration that without pH adjustment the coagulant consumption will increase. In each case, the consumption is better to determine by preliminary jar-tests.At the next water treatment step separation of the coagulated mass, containing particles that cause turbidity and color, and treated water may be performed by means of filtration, flotation or sedimentation.Example 1These tests were run to determine effect of ingredients alone and in various mixtures on a series of parameters routinely controlled in water treatment. The tests were performed with and without pH adjustment of the water to be cleaned. The trials were run on a Norwegian pilot plant, where the water source is located 12 meter above the sea level, and can be characterized as oligotrophic, humic and color rich. Table 1. Characteristics of the raw and treated water. Treatment comprised coagulation and sand filtration, where the coagulation was performed with chitosan alone or in a mixture with zirconium oxychloride, with or without pH adjustment before the coagulation.1.92 mgL-1 Zr, 3.10 mgL-1 Zr, 2 mgL-1Raw 0.92 mgL-1 1.40 mgL-1 Parameter chitosan, pHwater chitosan, pH chitosan, no4.54.5 pH adjustment pH 6.3 7.08 ND 7.70 True color, mgPtL-1 31 12 4 4Turbidity, FNU 0.23 <0,10 <0,15 <0,15 Total organiccarbon, mgL-1 3.56 ND 1.32 1.22Dissolved organiccarbon, mgL-1 3.09 ND 1.27 1.13UV-transmission(non-filtered 68.4 38 91.6 92.4 sample), %5cm-1Residual Zr, µg L-1 ND ND <10 <10ND stands for “not detected”.The tests showed considerable improvement of the water characteristics when the coagulation was performed with the mixture of chitosan and zirconium, compared with treatment by chitosan alone. The difference was especially significant for the water color and organic carbon content, indicating high efficiency of zirconium to remove NOM. In both cases, where zirconium was included the national standard for color of less than 5 mg Ptl-1 after the treatment was complied. The coagulant consumption was doubled after a drop off the pH adjustment, however, was still relatively low, while the water quality was high in both cases. Important, that residual Zr was extremely low in the treated water. Example 2Raw water is in a jar test treated with 3 different coagulant mixtures:a) Chitosan onlyb) Zirconium onlyc) Chitosan and Zirconium mixture (according to this application)The result is plotted as a function of treated water colour against the mixture dose used. The X-legend is the mixture ratio between chitosan and zirconium, showing increasing amounts of Zr in the mixture.When using Zr alone, a low treated water colour is achieved, but the operational window is narrow, and only slight overdosing causes the water colour to increase again. When using chitosan alone, the minimum treated water colour is not as low as when using Zr, but the operational window is wide and a range of other benefits from using chitosan is obtained.When using the Chitosan/Zr mixture, both low water colour and a wide operational window is achieved, both to a greater extent than when using either alone. The preparation of chitosan has also been achieved without the use of hydrochloric acid otherwise required.While the invention has been described with reference to specific examples and embodiments, the scope of the invention is determined by the accompanying claims.
Claims
CLAIMS1. A method for removal of impurities from a liquid by coagulation characterised in using a composition of dissolved chitosan and zirconium salt as a coagulant to be added to the liquid, followed by particle removal of the liquid, wherein preparation of the coagulant comprises adding chitosan and zirconium salt to water under stirring before the preparation is dosed into the liquid to be purified.2. A method of claim 1 wherein the liquid is water and the zirconium salt added is zirconium oxychloride.3. A method of any of the preceding claims wherein the weight ratio of chitosan to zirconium metal in the composition is between 1:1 and 1:10, preferably between 1:2 and 1:2,5.4. A method of any of the preceding claims wherein the separation of particles is done by use of a filter, a membrane or by sedimentation.5. A method of any of the preceding claims wherein the pH in the liquid is adjusted in the range of 4.0-6.5.6. A method of any of the preceding claims wherein the impurities in the liquid is suspended and/or dissolved impurities.7. A method of any of the preceding claims wherein a coagulant composition is prepared by dissolving of chitosan in zirconium oxychloride solution.8. A method of any of the preceding claims wherein there is no other chemical used for preparation of the coagulant than water, chitosan and a zirconium salt.9. A method of any of the preceding claims wherein the coagulant forms a floc.KRAVENE1. En fremgangsmåte for fjerning av urenheter fra en væske ved koagulasjon, karakterisert ved anvendelse av en sammensetning av oppløst kitosan og zirkoniumsalt, som koagulant som skal tilsettes væsken, etterfulgt av fjerning av partikler fra væsken, hvori fremstilling av koagulanten omfatter tilsetning av kitosan og zirkoniumsalt til vann under omrøring før preparatet doseres inn i væsken som skal renses.2. En fremgangsmåte i henhold til krav 1, hvori væsken er vann og zirkoniumsaltet som tilsettes er zirkonium oksyklorid.3. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori vektforholdet av kitosan til zirkoniummetall i sammensetningen er mellom 1:1 og 1:10, fortrinnsvis mellom 1:2 og 1:2,5.4. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori separasjonen av partikler gjøres ved bruk av et filter, en membran eller ved sedimentering.5. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori pH i væsken er justert i området 4.0-6.5.6. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori urenhetene i væsken er suspenderte og/ eller oppløste urenheter.7. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori en koagulant sammensetning fremstilles ved oppløsning av kitosan i zirkonium oksyklorid løsning.8. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori intet annet kjemikalium er brukt for fremstillingen av koagulanten enn vann, kitosan og et zirkoniumsalt.9. En fremgangsmåte i henhold til hvilke som helst av de foregående krav, hvori koagulanten danner en flokk.

Priority

No priority

Patent classes

IPC classesC02F 1/52C02F 1/56CPC classesC02F 1/5263C02F 1/56

Citations

Liu Qian et al, ”Removal of fluoride from aqueous solution using Zr(IV) immobilized cross-linked chitosan”, International journal of biological macromolecules, 77 (2015), 15-23, ISSN 1879-0003. ()Dong-Wan Cho et al, “Synthesis of hydrous zirconium oxide-impregnated chitosan beads and their application for removal of fluoride and lead”, Applied Surface Science, 372 (2016), 13-18, ISSN 0169-4332. ()Zhang Lingfane et al, “Preparation and characterization of chitosan-zirconium(IV) composite for adsorption of vanadium(V)”, International journal of biological macromolecules, 64 (2014), 155-161, ISSN 1879-0003. ()CN 103894159 A (A)CN 105964230 A (A)

Applicants, owners and inventors

Owners
TETA VANNRENSING AS
Aspertunet 1 A 2040 KLØFTA NO (ULLENSAKER Municipality, Akershus county)Org. number: 913521072Inventors
Tor Håkonsen
Bakkevegen 13 2040 KLØFTA NO (ULLENSAKER Municipality, Akershus county)
Ekaterina Christensen
Olaf Schous vei 3 0572 OSLO NO (OSLO Municipality, Oslo county)

Agent

DEHNS NORDIC AS
DEHNS NORDIC AS

Org. number: 925704261

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