Arrangement of devices for the separation of foreign substances from aqueous liquids

Abstract

Arrangement (1) of devices (2, 3, 4) for separating foreign substances (5) from aqueous liquids (6), with a liquid treatment device (7) and a particle filter (8) in a line section (9) through which the aqueous liquid (6) can flow, wherein the particle filter (8) is arranged downstream of the liquid treatment device (7) in the line section (9), characterized in that a device (2) for contacting the aqueous liquid (6) with at least magnetite (10) or magnetite composite particles is arranged upstream of the liquid treatment device (7) in the line section (9).

Description

[0001] The invention relates to an arrangement of devices for separating foreign substances from aqueous liquids, comprising a liquid treatment device and a particle filter in a line through which the aqueous liquid can flow, wherein the particle filter is arranged downstream of the liquid treatment device in the line, according to the preamble of claim 1.

[0002] EP 427 241 B1 describes a liquid treatment device that can eliminate, i.e., separate, calcium carbonate molecules from drinking water. This liquid treatment device is installed in a pipe system, is essentially cylindrical on the outside and inside, and is flowed through by the liquid to be purified. Ring-shaped permanent magnets and iron pole pieces are arranged in a cylindrical section of the device. To prevent the liquid from coming into direct contact with the magnets and pole pieces, a plastic pipe is inserted between the water and the aforementioned components. In the inlet area, a screw-shaped, non-rotating element is also inserted, which sets the flowing water in rotation. The screw-shaped element and a centering device arranged in the outlet area support a magnetic, stainless steel rod for the special design of the magnetic fields.At the outlet of the fluid treatment device, small oxygen bubbles are created along the center line of the fluid treatment device or the pipeline.

[0003] EP 1 006 083 A1 describes a permanent-magnetic liquid treatment device with a tubular housing equipped with permanent magnets arranged axially one behind the other, through which a liquid to be treated flows. The permanent magnets, as well as the spacer rings forming the pole pieces arranged in sequence between them, are arranged on a central core spindle.

[0004] Furthermore, a plastic inner tube is arranged axially of the housing, through which the liquid to be treated flows. The two ends of the plastic tube are connected in a fluid-tight manner with connectors. The core spindle, which runs within the plastic tube, is provided with diameter extensions in the form of cams, which are located opposite the pole pieces and thus serve to concentrate the magnetic field generated by the ring magnets.

[0005] This improves the effect of the magnetic fields on the water flowing through the inner or plastic pipe. This improves the dissolution of limescale deposits in pipes and reduces the formation of limescale.

[0006] The same purpose is pursued by a permanent magnetic liquid treatment device disclosed in DE 39 37 349 A1.

[0007] These limescale deposits are due to the CaCO3 content of the water and are a direct result of the lack of nucleation centers in normal tap water. As soon as the CaCO3 concentration exceeds the solubility limit, the calcium carbonate precipitates and either attaches to foreign substances in the water or deposits on the pipe walls.

[0008] Under the influence of a magnetic field, vibrations occur in the water molecules, whereby the trace particles carried in the water become accessible as nuclei for the CaCO3 and the dissolved CaCO3 is deposited on the nuclei and not on the pipe walls.

[0009] The known devices for separating foreign substances from aqueous liquids are not suitable for removing metals and heavy metals such as arsenic, manganese, copper, magnesium, nickel, zinc, boron or cadmium, as well as microplastics from aqueous liquids, and are not suitable for achieving flow rates on an industrial scale that would enable effective purification of aqueous liquids.

[0010] The invention is therefore based on the object of providing a device for separating foreign substances from aqueous liquids, which is capable of removing these metals, heavy metals and also microplastics and, in doing so, enables a flow rate or a treatable volume of the aqueous liquid to be purified that reaches an industrial scale.

[0011] The object is achieved by an arrangement of devices having the features of claim 1 in its entirety.

[0012] Advantageous embodiments of the invention are disclosed in the subclaims.

[0013] By arranging a device for contacting the aqueous liquid with at least magnetite (Fe2O3, Fe3O4) or magnetite composite particles in the line upstream of the liquid treatment device, a technical measure is taken to provide binding sites for the undesirable foreign substances in the aqueous solution with the help of the magnetite coming into contact with the aqueous solution. Magnetite composite particles can consist of mineral components and magnetite.

[0014] Magnetite often serves as a catalyst in chemical reactions. Other metal atoms can bond to its surface in such a way that they remain separate from each other and do not coalesce into larger metal particles. This accelerates chemical reactions at its surface. The structure of the iron oxide surfaces on magnetite contributes significantly to this. See "An ancient material reveals a modern mystery," R. Bliem et al.; Science, December 5, 2014, Vol. 346.

[0015] The special surface configuration of iron(II,II) oxide—known as magnetite—is responsible for its excellent catalytic properties. It has been observed that fewer iron atoms are present on the surface of magnetite, and that these are arranged differently than in the unaltered oxygen lattice within the crystal.

[0016] This creates bonding sites for atoms and molecules adhering from the outside. This makes catalysis at the surface easily possible. Metal and heavy metal atoms and molecules can also attach to the magnetite surface and, if necessary, be washed out with magnetite particles that are freely mobile in the aqueous solution.

[0017] In a preferred embodiment of the arrangement, magnetite is added in the form of particles to the aqueous liquid, e.g. before commissioning of the arrangement or at discrete time intervals or continuously.

[0018] Magnetite can also advantageously be continuously added to the aqueous liquid in the form of small particles and moved along with it. The device for contacting the magnetite particles with the aqueous liquid is preferably designed as an injector that extends into the aqueous liquid or is flushed through or around by it.

[0019] In order to enable cost-effective cleaning of the aqueous liquid within the arrangement, a preferred embodiment of the invention provides that the addition of magnetite in its concentration is continuously adapted to the foreign matter load of the aqueous liquid.

[0020] The arrangement is suitable for separating at least the following foreign substances in the aqueous liquid: - Iron - Manganese - Calcium - Copper - Magnesium - Nickel - Zinc - Bor - Cadmium - Arsen - Microplastics Iron:

[0021] Groundwater is primarily used for drinking water supply, but raw water contains hardly any dissolved oxygen. Iron occurs in the divalent form, i.e., dissolved as Fe2O3H2O.

[0022] Iron can basically be separated from the aqueous liquid in three ways: 1) Fe(III) filtration-oxidation 2) Direct oxidation 3) Precipitation of Fe 2+ -Oxyhydrate by adding OH - -ions and subsequent oxidation.

[0023] 1) Filtration: Quartz sand with a grain size of 0.8 to 2 mm can be used as filter material.

[0024] The filters used can be backwashed with air and water. Uneven hydraulic loading on the filter due to rapidly changing flow rates is problematic. In addition to venting the filter vessel, sludge disposal is also a problem.

[0025] Biological filtration can also be achieved using bacteria.

[0026] 2) Direct oxidation: precipitation to Fe(OH)2 and oxidation.

[0027] The oxidation rate depends on the concentration of Fe 2+-ions, the oxygen content of the water and, above all, the hydrogen ion concentration.

[0028] In the presence of Fe 3+ The process can be greatly accelerated catalytically with hydrated oxide. The rates of iron removal are pH-dependent and also influenced by the action of microorganisms. The use of magnetite accelerates the direct oxidation and separation of iron from the aqueous solution.

[0029] 3) Precipitation: 4Fe 2+ + 8OH - → 4Fe(OH)2 with subsequent oxidation, this is a very rapid process. Manganese:

[0030] Like iron, manganese is a heavy metal and often occurs together with iron. This occurs mostly in reduced, oxygen-poor waters. Manganese usually only occurs as an oxide. Water with low oxygen content comes into contact with manganese, and the manganese oxide, reduced by redox processes in the soil, dissolves in the water. Oxidized manganese forms black deposits in pipes.

[0031] To remove manganese, oxygen enrichment must first be ensured. Catalytic demanganization is achieved with the aid of magnetite. Biological demanganization is also possible. The limit values ​​for drinking water are 0.2 mg / l for iron and 0.05 mg / l for manganese. Arsenic:

[0032] Arsenic poses a serious health threat to millions of people, particularly in groundwater used for drinking water. The oxidation state of the arsenic species As(III) and As(V) has a decisive influence on the toxicity and mobility of this heavy metal, with numerous sorption and redox reactions taking place between solids and dissolved arsenic species in groundwater. Manganese oxides are strong oxidizers for As(III), while iron(III) hydroxides rapidly and strongly sorb arsenic species. Sorption processes of arsenic on MnO2 and FeOOH occur rapidly, with MnO2 causing rapid oxidation of As(III) to As(V).

[0033] Arsenic is toxicologically effective in humans both through inhalation and orally via food (drinking water). Toxic doses of arsenic range from 5 to 50 mg / day.

[0034] Lethal doses range from 50 to 340 mg / day. The harmful effects of arsenic depend heavily on the compound form. Inorganic arsenic compounds are more toxic than organic ones. The oxidation state and solubility also influence the toxic effects of arsenic in the human organism.

[0035] The dissociation properties of arsenic species in groundwater depend on the pH value.

[0036] Arsenic acid H3AsO4 and arsenious acid H3AsO3 are the most important arsenic compounds in groundwater.

[0037] Below pH 6.9, H dominates s AsO4, above HAsO4 2- .

[0038] In arsenic acid, H3AsO3 dominates below pH 9.2, and H2AsO3 dominates above pH 9.2. -Arsenic can be removed from water by sorption on iron oxides and iron hydroxides, such as magnetite. The effectiveness of this removal depends heavily on groundwater properties such as pH or phosphate content. See A. Treter, dissertation "Sorption and Redox Processes of Arsenic on Oxide Surfaces," University of Heidelberg, 2002. Microplastics:

[0039] Many water sources in developing countries are contaminated by high concentrations of organic pollutants, heavy metals, or microbial contamination. Microplastic particles are also pollutants that can be introduced into the food chain through ingestion by marine organisms. Microplastics bind and concentrate persistent organic pollutants, thus increasing the health risks they pose.

[0040] Purification of aqueous liquids with magnetic particles enables the removal of microplastics. In "Water Purification and Microplastic Removal by Magnetic Polyoxometalate-Assisted Ionic Liquid Phases (magPOM-SILPs)" (Misra, Zanbrzychi et al., Wiley VCH Verlag, pp. 1618–1622, 2020), a method is proposed for binding microplastics to core-shell particles composed of superparamagnetic iron oxide cores, Fe2O3 magnetite, and a porous silicate shell, forming a microporous Fe2O3SiO2 composite. The magnetite particles, along with the attached microplastic particles, are removed from the aqueous liquid by exposure to a magnetic field.

[0041] In all processes claimed here, magnetic fields are used to mobilize the magnetite particles in the aqueous liquid and to improve the contact of the magnetite particles with the contaminants to be bound, such as heavy metals and microplastic particles in the aqueous liquid.

[0042] As mentioned, the arrangement according to the invention can be used to purify both groundwater and surface water and process it into drinking water. It goes without saying that the aqueous liquid can be subjected to a first filtration step before entering the arrangement, which removes suspended solids or organic material.

[0043] The following tables show exemplary measurement results before and after the treatment of groundwater with the arrangement according to the invention. Arrangement without filter Arrangement with filter µg / l µg / l arsenic 4,1 2,1 barium 12 5 Berylium 0,4 <0,4 boron 20 <20 cadmium 1 <1 Calcium 34,6 34 chrome <2 <2 Cobalt <2 <2 copper <2 <2 iron 1621 H <50 Lead 1,9 <0,5 magnesium 2,7 2,1 manganese 376 H 146 H molybdenum <2 <2 nickel <2 <2 potassium 1,6 2,9 selenium <2 <2 Silver <2 <2 sodium 10,6 11,9 strontium 97 93 Thallium <2 <2 tin <2 <2 titanium <2 <2 uranium 1,1 0,7 Vanadium <2 <2 zinc 10 24 CaCo3 97,4 93,5

[0044] In a preferred embodiment, a liquid treatment device is formed as part of the arrangement, essentially tubular, with the aqueous liquid flowing through it. An inner cone arranged on its inflow side serves to accelerate the aqueous liquid. A screw-shaped element is arranged on the inside of the inflow side and serves to impart a swirl to the aqueous liquid.

[0045] Downstream of the inner cone there is a cylindrical section, which in turn is followed downstream by a second inner cone.

[0046] A support element is arranged in the inner cone, which is formed as a screw-shaped element and increases the swirl of the aqueous liquid as it flows through.

[0047] The screw-shaped element of the inflow side and the support element of the outflow side are connected to each other via a rod or cross member, whereby the rod can be made of a ferrous material.

[0048] Alternating circular disk-shaped permanent magnets with pole pieces are mounted on an inner, thin-walled tube. These are surrounded by an outer protective tube.

[0049] The arrangement imposes a magnetic field on the aqueous liquid flowing in the inner, thin-walled tube and imposes the field on the magnetite particles flowing in the aqueous liquid and improves the movement of the magnetite particles in the aqueous liquid, with the result that contact with foreign substances can be significantly increased.

[0050] Downstream of the liquid treatment device, the aqueous liquid flows in a meandering or spiral-shaped pipe section to the filter, whereby this pipe section should be at least 1.5 m long in order to ensure further, intensive contact of the magnetite particles with the foreign substances in the aqueous liquid.

[0051] In the filter, which can also be designed as a backwash filter, the magnetite particles and their adhering foreign matter are filtered out and separated. The backwash filter can be made of a mineral, metal, or plastic material and can also contain a mineral particle bed.

[0052] Depending on the volume flows to be handled, further such arrangements according to the invention can also be connected in series or parallel. List of reference symbols 1 arrangement 2 Contacting device, injector 3 Device, liquid treatment device 4 Device, filter 5 Foreign substance 6 Liquid, watery 7 Fluid treatment device 8 particle filters 9 Cable harness 10 Magnetite 11 Inlet side 12 inner cone 13 Element, helical 14 Section, cylindrical 15 Inner cone, second 16 Support element 17 Outlet side 18 bars 19 Pipe, thin-walled 20 permanent magnets 21 Pole piece 22 Protective tube, outer 23 Source d 14 inner diameter s flow direction

[0053] The invention is described below using an exemplary embodiment and shown in the figures. They show: Fig. 1 a schematic view of an arrangement according to the invention, Fig.2 a longitudinal section through a liquid treatment device of the arrangement in Fig. 1, Fig. 3 a detail III in Fig. 1

[0054] In Fig. 1 shows a schematic, not to scale view of an arrangement of devices 2, 3, 4 for separating foreign substances 5 from aqueous liquids 6.

[0055] The aqueous liquid 6 is, for example, water originating from a source 23, such as groundwater or surface water. The water or aqueous liquid 6 may be contaminated in a variety of ways with heavy metals and / or biotic foreign substances 5 that are hazardous to human health. The source 23 may also be fed by surface water that contains, for example, microplastics.

[0056] In a line 9, which leads from the source 23 to a device 4 shown as a filter for separating foreign substances 5, in the direction of view of the Fig. 1, from left to right, a device 2, designed as an injector 1, a device 3, designed as a liquid treatment device 7, and the aforementioned filter 4, with all devices 2, 3, 4 being in constant fluid communication with one another. The filter 4 can be designed as a particle filter 8, which is backwashable, or as a bed of mineral particles or activated carbon, or as synthetic particles.

[0057] The injector I can be formed in a manner known per se by the negative pressure prevailing at its outlet, caused by the flow of the aqueous liquid 6, and serves for the metered supply of iron (II, II) oxide, known as “magnetite” in particle form.

[0058] Magnetite can be continuously added here and constantly loaded with foreign substances 5 and then separated at the particle filter 8.

[0059] In Fig. Figure 2 shows a schematic longitudinal section through the device 3, referred to here as the liquid treatment device 7. This device serves to separate impurities 5 from the aqueous liquid 6, which is already doped with magnetite particles upon entering the device 7. As mentioned above, magnetite, due to its defects in the atomic lattice, forms deposit sites on its surface, particularly for heavy metals, and also serves as a catalyst for redox reactions on deposited heavy metals, which were already mentioned above.

[0060] In order to enable an increase in the mixing of the aqueous liquid 6 with magnetite particles and thus to significantly increase the volume of the aqueous liquid contacted by magnetite particles, the liquid treatment device 7 is provided.

[0061] The aqueous liquid 6 to be decontaminated flows in the direction of the Fig. 2 enters a tapered inner cone 12 from the left at an inlet side 11. A screw-shaped element 13 is arranged in the inner cone 12 in a rotationally secure manner. In the inner cone 12, the liquid 6, together with the magnetite particles 10 contained therein, is accelerated and imparted with a swirl. The swirl is maintained up to the axial region of the line 9 between the device 3 and the filter 4.

[0062] Downstream of the inner cone 12 is a cylindrical section 14. This section 14 has a thin-walled plastic tube 19, onto the outside of which permanent magnets 20 and pole pieces 21 are alternately pushed. These permanent magnets 20, formed as ring magnets, are axially magnetized and arranged in pairs with opposite poles. The pole sequence is NS and SN. Each pair of consecutive permanent magnets 20 is separated from each other by a pole piece 21 formed as a ring.

[0063] The fields generated by the magnets are aligned at right angles to the spiral flow direction of the water flowing through the thin-walled tube 19.

[0064] On the downstream side 17 of the device 3, downstream of the thin-walled tube 19, there is a second inner cone 15 that widens and contains a support element 16. The support element 16 is designed to impart a further swirl to the flow.

[0065] A rod 18 is arranged between the inner cone 12 and the inner cone 15, which secures and connects a swirl element arranged in the respective inner cone 12 or 15. The rod 18 has the smallest possible diameter so as not to disrupt the swirling flow inside the liquid treatment device 7. It is preferably made of a stainless, non-magnetic material.

[0066] The inner diameter d 14 of the cylindrical section 14 is equal to the inner diameter of the respective cone 12, 15 at its respective coupling point with the cylindrical section 14.

[0067] An outer protective tube 22 surrounds the permanent magnets 10 / 20 and the pole pieces 21.

[0068] With the Fig.Figure 1 shows an embodiment of the arrangement 1 according to the invention. Tests have surprisingly shown that for a significant separation of the foreign substances 5, it is important to arrange the filter 4 or particle filter 8 downstream of the liquid treatment device 7, as viewed in the flow direction s, and not to arrange a filter, as is customary in the prior art, for example, upstream of the injector 1.

[0069] Furthermore, the length of the flow path to be covered from the downstream side 17 of the liquid treatment device 7 to the filter 4 is important for the cleaning success of the entire assembly 1. This length should not be less than 1.5 m. The relevant line section can be designed in a meandering or helical manner to further support the mixing of the aqueous liquid 6 with magnetite 10.

[0070] The tables shown above in the general description section show achievable concentrations of foreign substances, such as heavy metals, when using devices 2 and 3 of arrangement 1 on the left and when using devices 2, 3 and 4 on the right, wherein the filter 4 has an activated carbon component.

[0071] It may be advantageous to arrange several arrangements 1 in series or in parallel in order to enable a further, improved cleaning effect and / or larger volume flows of aqueous liquid 6 to be cleaned.

[0072] The fluid treatment device can make an important contribution to the purification of the aqueous fluid, but is not fundamentally necessary for its success. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 427 241 B1

[0002] EP 1 006 083 A1

[0003] DE 39 37 349 A1

[0006] Cited non-patent literature

[0000] “A modern puzzle is revealed from a well-known material”, R. Bliem et al.; Science, 5.12.2014, Vol. 346

[0014] A. Treter, Dissertation “Sorption and redox processes of arsenic on oxide surfaces”, University of Heidelberg, 2002

[0038] Water purification and microplastic removal by magnetic polyoxometalate-supported ionic liquid phases (magPOM-SILPs)"; Misra, Zanbrzychi et al. Wiley VCH Verlag, pp. 1618–1622, 2020

[0040]

Claims

[1] Arrangement (1) of devices (2, 3, 4) for separating foreign substances (5) from aqueous liquids (6), with a liquid treatment device (7) and a particle filter (8) in a line (9) through which the aqueous liquid (6) can flow, wherein the particle filter (8) is arranged downstream of the liquid treatment device (7) in the line (9), characterized by that upstream of the liquid treatment device (7) a device (2) for contacting the aqueous liquid (6) with at least magnetite (10) or magnetite composite particles is arranged in the line string (9). [2] Arrangement according to claim 1, characterized by that magnetite (10) is added to the contacting device (2) in the form of particles of the aqueous liquid (6). [3] Arrangement according to claim 2, characterized by that magnetite (10) is continuously added to the aqueous liquid (6) during operation of the arrangement (1). [4] Arrangement according to claims 1 to 3, characterized by that the contacting device (2) is designed in the manner of an injector (I). [5] Arrangement according to one of claims 1 to 4, characterized by that the addition of magnetite (10) is adapted in its concentration to the foreign matter load of the aqueous liquid (6). [6] Arrangement according to one of claims 1 to 5, characterized by that the arrangement (1) is suitable for separating iron and / or manganese and / or calcium and / or copper and / or magnesium and / or nickel and / or zinc and / or boron and / or cadmium and / or arsenic and / or microplastics from the aqueous liquid (6), so that the aqueous liquid (6) can be used as drinking water after passing through the arrangement (1). [7] Arrangement according to one of claims 1 to 6, characterized by that the aqueous liquid (6) is groundwater or surface water. [8] Arrangement according to one of claims 1 to 7, characterized bythat the liquid treatment device (7) has at least the following features: a) the liquid treatment device (7) is essentially tubular and is flowed through by the aqueous liquid (6) in its interior, b) an inner cone (12) is arranged on the inflow side (11) of the liquid treatment device (7), c) which tapers in the direction of flow (s), thereby accelerating the liquid flow, d) a screw-shaped element (13) is arranged in a rotationally fixed manner in the inner cone (12) of the inflow side (11), whereby the aqueous liquid (6) flowing through is set in rotation, e) viewed in the flow direction (s) of the aqueous liquid (6) there follows a cylindrical section (14), f) its inner diameter (d 14 ) corresponds to the smaller diameter of the inner cone (12). [9] Arrangement according to claim 8, characterized bythat a second inner cone (15) is arranged after the cylindrical section (14) of the inflow side (11) of the liquid treatment device (7). [10] Arrangement according to claim 9, characterized by that the second inner cone (15) viewed in the flow direction (s) of the aqueous liquid (6) has the inner diameter (d 14 ) of the cylindrical section (14) and then widens. [11] Arrangement according to one of claims 8 to 10, characterized by that a support element (16) is arranged in the second inner cone (15), which can be designed as a screw-shaped element. [12] Arrangement according to one of claims 8 to 11, characterized by that the screw-shaped element in the inner cone (15) of the inflow side (11) of the aqueous liquid (6) imposes the same direction of rotation as the screw-shaped element in the second inner cone (15). [13] Arrangement according to one of claims 8 to 12, characterized bythat the screw-shaped element of the inflow side (11) and the support element (16) of the outflow side (17) are connected to one another via a rod (18). [14] Arrangement according to one of claims 8 to 13, characterized by that the rod (18) is made of iron or steel. [15] Arrangement according to one of claims 1 to 14, characterized by that the cylindrical section (14) of the liquid treatment device (7) is formed by an inner, thin-walled tube (19) surrounded by concentric, but axially offset, permanent magnets (20) and pole shoes (21). [16] Arrangement according to claim 15, characterized by that the annular permanent magnets (20) and pole shoes (21) are surrounded by an outer protective tube (22). [17] Arrangement according to one of claims 15 or 16, characterized by that the pole shoes (21) are made of iron or steel. [18] Arrangement according to one of claims 1 to 17, characterized bythat the devices (2, 3, 4) for separating foreign substances form a coherent delivery unit. [19] Arrangement according to one of claims 1 to 18, characterized by that a meander line is arranged between the liquid treatment device (7) and the particle filter (8). [20] Arrangement according to one of claims 1 to 18, characterized by that a spiral line is arranged between the liquid treatment device (7) and the particle filter (8), [21] Arrangement according to one of claims 1 to 20, characterized by that several arrangements (1) are arranged one behind the other or in parallel in the cable harness (9).

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