Device and method for separating polymer particles from a sample

Abstract

The invention relates to a device (1) and a method for separating polymer particles, in particular micropolymer particles (2), from a sample (3). The invention addresses the problem of providing a solution that ensures polymer particles, in particular micropolymer particles (2), are reliably separated from the sample (3), thereby avoiding environmentally harmful waste products and reducing costs. This problem is solved on the device side in that the device (1) comprises: a container (4) with a container opening (5) for holding a liquid and the sample (3) containing polymer particles, preferably micropolymer particles (2); and a tubular container attachment (6) which is detachably connected to the container (4) and corresponds to the container opening (5) in such a way that a liquid rising out of the container (4) enters the tubular container attachment (6).

Description

[0001] Device and method for separating polymer particles from a sample

[0002] The invention relates to a device and a method for separating polymer particles from a sample, in particular micropolymer particles from a sediment sample.

[0003] In particular, the invention relates to a particularly simple possibility for separating or isolating polymer particles, in particular micropolymer particles, from samples or environmental samples, for example in preparation for investigations to be carried out on the quantity and composition of the polymer particles or micropolymer particles in an environmental sample.

[0004] Microplastics are solid and insoluble synthetic polymer particles smaller than five millimeters in size. Due to their small size, such particles are also referred to as microplastic particles or micropolymer particles. Micropolymer particles are usually formed in the environment through the weathering and fragmentation of larger plastic particles, also known as macropolymer particles. In addition to tire abrasion, the wear and tear of larger plastic parts such as packaging, the washing of synthetic textiles, and the use of micropolymer particles in cosmetics, the main causes are garbage dumps, from which micropolymer particles enter rivers, oceans, riverbanks, and agricultural land, for example.

[0005] Larger plastic pieces that enter the environment are broken down into smaller so-called micropolymer particles or even nanopolymer particles by UV radiation and mechanical influences, for example.

[0006] Since micropolymer particles are comparatively difficult to degrade naturally, it can be assumed that the concentration of micropolymer particles will continue to rise. The question of what effects this will have on humans, other organisms, and ecosystems cannot yet be conclusively answered. Answering this question requires considerable research.

[0007] However, it has already been demonstrated that micropolymer particles induce inflammatory reactions in marine organisms, such as mussels, and cause a reduction in growth rate in planktonic crustaceans. Another major problem is the ability of micropolymer particles to bind, for example, to persistent organic pollutants such as pesticides, which are then absorbed by marine organisms and thus enter the food chain.

[0008] It remains unclear how different micropolymer particle species distribute in the environment and how long they remain until they finally degrade. Possible interactions with environmental substances are also unknown.

[0009] Studies are needed to determine the effects of micropolymer particles on humans, other organisms and ecosystems.

[0010] Regarding the question of examining environmental samples for the distribution of micropolymer particles, for example, in sediment samples, two standardized methods can currently be distinguished: density separation and oil separation. In density separation, micropolymer particles are separated from a sediment sample based on their different densities. Salt solutions are used as the separation medium. The density of the separation medium lies between the density of the plastic, i.e., the micropolymer particles, and the sediment. Zinc chloride solutions, sodium tungsten solutions, and / or potassium iodide salt solutions are used as salt solutions. A particular disadvantage of this method is the use of the separation agent, which, as a contaminated material, must be disposed of at great expense.In addition, the high concentrations of the salt solutions used as separating agents, greater than 100 g / l, are associated with correspondingly high acquisition costs for the chemicals used.

[0011] The disadvantage of the density separation process is that the salts used in the process can be an environmental burden.

[0012] In oil separation, an oil such as olive oil, rapeseed oil, and / or castor oil is used as a buoyancy agent or separator. This process involves mixing a sediment sample containing water and oil. The particles / polymer particles contained in the sediment are wetted by the oil, causing the micropolymer particles in the suspension to become encased in the oil. Due to the lower density of the oil, the oil-wetted micropolymer particles are deposited on the water phase. In other words, due to the lower density of the oil compared to water or an aqueous phase, phase separation occurs, with the micropolymer particles collecting in the oil phase.

[0013] However, this method has its drawbacks. One problem is that a clear phase separation between an aqueous and an oil phase is often not achieved, making it difficult to separate polymer particles that accumulate at the phase boundary. Furthermore, oil separation poses problems when implementing the apparatus, as oil deposits can lead to contamination and blockage of glassware.

[0014] A state-of-the-art method and device for oil separation are known from Scopetani, Costanza; Chelazzi, David; Mikola, Juha; Leiniö, Ville; Heikkinen, Reijo; Cincinelli, Alessandra; Pellinen, Jukka (2020): Olive oil-based method for the extraction, quantification and identification of microplastics in soil and compost samples. In: Science of the Total Environment 733, 139338. DOI: 10.1016 / j.scitotenv.2020.139338 from 2020. However, the apparatus described therein is not suitable for real environmental samples, as only very small sample quantities can be used. In addition, difficulties arise in achieving a clear phase separation or demixing between the oil phase and the aqueous phase. Furthermore, common glassware wets or clogs during the oil separation process.

[0015] The process involves controlling the temperature of the phase mixture to support phase separation. However, cooling down to a temperature of -40 °C requires a comparatively high energy requirement to achieve the solidification temperature of the phases required for separation. Another problem with this process, associated with cooling at particularly low temperatures, is the use of water as the separation phase. Water expands significantly at very low temperatures below 0 °C, which places special demands on the equipment design to avoid damage to the equipment.

[0016] Thus, there is a need for an improved device and an improved method for the simple separation of polymer particles, in particular micropolymer particles, from a sample taken from the environment.

[0017] The object of the invention is therefore to provide a device and a method for separating polymer particles, in particular micropolymer particles, from a sample, such as a sediment sample, whereby a reliable separation of polymer particles, in particular micropolymer particles, from the sample is achieved, whereby environmentally harmful waste products or by-products are avoided and costs are reduced.

[0018] The object is achieved by a device having the features according to patent claim 1 and a method having the features according to patent claim 9. Further developments and embodiments are specified in the respective dependent patent claims.

[0019] For the purposes of the invention, microplastics, microplastic particles, polymer particles or micropolymer particles are understood to mean in particular insoluble plastic particles of different types of plastic with a particle size of less than 500 pm.

[0020] The device for separating polymer particles, preferably micropolymer particles, from a sample containing polymer particles, preferably micropolymer particles, comprises a container with a container opening for receiving a liquid and the sample containing polymer particles, preferably micropolymer particles. A further component of the device is a tubular container attachment detachably connected to the container, which corresponds to the container opening in such a way that a liquid rising from and exiting the container enters the tubular container attachment.

[0021] The container can have a flat base surface on which the container rests in its use position. The container opening can be located on a side of the container opposite the base surface. The container is preferably designed in the shape of a bottle. The container can be made of glass or plastic. The container is used to mix a sample containing micropolymer particles with water and, for example, oleic acid, thus producing a sample mixture in the container.

[0022] A tubular container attachment, which can be separated from the container opening and corresponds to the container opening, is arranged at the container opening. This tubular container attachment is sealingly connected to the container opening, which can be arranged on the top side of the container. The connection to the tubular container attachment forms a riser pipe for the sample mixture contained in the container, extending beyond the container opening.

[0023] The connection between the container and the tubular container attachment is preferably designed for multiple applications. A detachable and sealing connection between the tubular container attachment and the container opening can be realized, for example, with a screw connection, in which the tubular container attachment is designed to be screwed onto the container or screwed into the container. A clamp or snap closure, each in conjunction with a sealing ring, can also be provided as a detachable and sealing connection means.

[0024] The tubular container attachment corresponds to the container opening in such a way that a liquid rising from the container can pass through the container opening into the tubular container attachment.

[0025] In an advantageous variant of the invention, a stirring means is arranged on or within the container. A magnetic stirrer with a magnetic stir bar can be provided as the stirring means. According to one embodiment, the stirring means is designed as a magnetic stirrer known from the prior art with a magnetic stir bar inserted into the sample mixture. In this case, the container is placed on a base of the magnetic stirrer, and a glass- or plastic-coated magnetic stir bar is inserted into the container and set in rotation by the magnetic effect generated by the base.

[0026] The purpose of this stirring agent is to ensure thorough mixing of the liquids introduced into or present in the container.

[0027] According to a preferred embodiment of the device, the container can have a gassing agent with which a gas can be introduced into the interior of the container and in particular into a sample mixture contained in the container.

[0028] Such a fumigant can be temporarily arranged on the container and causes a gas to be introduced into the container. In the simplest case, air is used for fumigation. Alternatively, nitrogen or argon can also be used. The fumigant can have a pipe which is introduced into the interior of the container via the container opening. In one embodiment, the pipe is arranged inserted in a wall of the tubular container attachment. This pipe is arranged in the wall of the tubular container attachment in such a way that it projects into the container on one side via the container opening and projects beyond the second side of the tubular container attachment remote from the container opening in order to connect, for example, a means for generating a gas at a predetermined pressure to this end.According to an alternative embodiment of the container, the introduction of a gas can also be achieved through a second opening formed in the container. The second opening for gas introduction can be formed in a jacket surface of the container close to the bottom or directly in the bottom of the container. For the embodiment in which the second opening for gas introduction is formed directly in the bottom of the container, a holder for the container can be provided in order to enable access for the gas introduction from below, namely from the bottom of the container. According to a further advantageous embodiment of the invention, the device further comprises a temperature control device with which at least the tubular container attachment connected to the container can be cooled at least in some regions.The temperature control device is designed such that a region of the tubular container attachment to be temperature controlled can be temperature controlled in a temperature range preferably between 17 °C and 0 °C.

[0029] The temperature control device can have Peltier elements or fluid-carrying lines, which are arranged on the tubular container attachment for temperature control of the tubular container attachment. For example, fluid-carrying lines can be arranged on the outer circumference of the tubular container attachment. Also conceivable is a design in which a spiral arrangement of the fluid-carrying line or lines forms the tubular container attachment. This means that the tubular container attachment is formed solely by the spiral arrangement of the fluid-carrying line. In this case, the fluid-carrying line designed as a tubular container attachment can have line connections for detachable connection to the temperature control device in order to be able to separate the fluid-carrying line from the temperature control device.

[0030] According to a further embodiment of the device according to the invention, the temperature control device can be designed to control the temperature of the entire container. A design of the temperature control device that allows temperature control in different zones is also conceivable. Thus, the temperature control device can be designed to heat the container, with the tubular container attachment being able to be cooled and heated at different times.

[0031] According to one embodiment of the invention, the tubular container attachment is made of plastic, for example, polytetrafluoroethylene (PTFE). Due to its fluid-repellent properties, PTFE is particularly suitable as a material for the tubular container attachment. Transparent materials are also advantageous, allowing for easy reading of the fill level in the tubular container attachment.

[0032] The tubular container attachment is preferably designed as a straight hollow cylinder. A straight hollow cylinder is easy to manufacture and can be easily connected to the circular container opening in a sealing and matching manner. Other tubular container attachment shapes, for example, with a curved section, can be provided if the design requires it.

[0033] In an alternative embodiment of the invention, the container has a variable volume. Such a container can be made of an elastic material, preferably a plastic. By compressing the elastic container, the internal volume is reduced, so that any liquid present in the container is forced out of the container through the container opening into the tubular container attachment.

[0034] In order to reduce the volume in the container, a design with a piston guided in the cylindrical container can also be provided, which is movable in a direction towards the container opening in such a way that a liquid present in the container passes through the container opening into the tubular container attachment in the direction of the container opening.

[0035] In addition to the device, the invention also relates to a method for separating polymer particles, preferably micropolymer particles, from a sample containing polymer particles, in particular a sediment sample. For the sake of simplicity, a sample containing polymer particles, in particular a sediment sample, is referred to below as a sample. The method proceeds in such a way that a sample is mixed with a water-oil mixture, preferably with a water-oleic acid mixture, in a container. The water-oil mixture, preferably water-oleic acid mixture, can be initially introduced into the container, with the sample being subsequently added to the container. Furthermore, it can be provided that the sample is first introduced into the container and then the water-oil mixture, preferably water-oleic acid mixture, or water and oil or water and oleic acid are subsequently added separately to the container.

[0036] Good mixing promotes good wetting of the surfaces of micropolymer particles contained in the sediment sample with the oil or oleic acid used, thereby achieving better separation of the micropolymer particles from the sample.

[0037] Following mixing, for which a duration can be specified, the prepared sample mixture separates into an aqueous phase and an oily phase floating on the aqueous phase, in which the micropolymer particles contained in the sample collect. After mixing, a specified rest period can be observed for phase formation or phase separation to occur. The oily phase, which separates out and floats on the aqueous phase after mixing, is transferred, along with the polymer particles it contains, from the container into a tubular container attachment that is detachably connected to the container by a rise in the aqueous phase.Once the oily phase is transferred into the tubular container attachment, the level of the liquid level of the aqueous phase is no longer changed in order to keep the oily phase in its position in the tubular container attachment.

[0038] The increase in the aqueous phase in or out of the container can be achieved by increasing the volume of the aqueous phase in the container, for example by introducing water or a liquid that has a greater density than the oil used into the container without disturbing the formation of the oily phase. The introduction of the water or the liquid that has a greater density than the oil used can, for example, occur through a gassing tube or through a designated opening in the container. It is also possible to achieve an increase in the aqueous phase by reducing the container volume. When using an elastic container, the volume reduction can be achieved by compressing the container.Alternatively, a reciprocating piston device can be used, as described above, to reduce the container volume and displace the aqueous phase with the floating oily phase through the container opening into the tubular container attachment. It should be noted that the transfer of the floating oily phase into the tubular container attachment should be carried out carefully and at an appropriate speed so as not to impair phase separation.

[0039] After the oily phase has been transferred to the tubular container attachment, the temperature is lowered until the oily phase solidifies, and the oily phase, which has solidified in the tubular container attachment, is separated from the container in its solid state, along with the micropolymer particles it contains. During the separation process, the aqueous phase can flow out of the tubular container attachment.

[0040] The separated solidified oily phase is then heated, releasing the separated polymer particles and micropolymer particles.

[0041] According to one embodiment of the method, it can be provided that the sample mixture formed from the water-oil mixture, preferably water-oleic acid mixture, and the sample is gassed with a gas during or after mixing.

[0042] To do this, a hose or tube can be inserted into the sample mixture through the container opening, and a gas, such as air, can be introduced into the sample mixture. Nitrogen or argon can be used as the gas, although ambient air is preferred for cost reasons. Introducing a gas into the sample mixture promotes phase separation of the sample mixture.

[0043] It has proven advantageous to temper the sample mixture formed from the water-oil mixture, preferably a water-oleic acid mixture, and the sample during or after mixing. It has been shown that tempering the sample mixture in the container contributes to better mixing and improved wetting of polymer particles, which can increase separation efficiency. The temperature is preferably controlled above the solidification temperature of the oily phase.

[0044] The method according to the invention is based on the natural process of phase separation between an aqueous phase and an oily phase and the possibility of converting the oily phase into a solid or at least pasty form by lowering the temperature in order to achieve separation from the still liquid aqueous phase. The temperatures for tempering the resulting sample mixture are selected according to the method such that the oil or oleic acid used can solidify in the oily phase once the oily phase has been transferred into the tubular container attachment, while the aqueous phase remains liquid. The aqueous phase can contain a dissolved salt to prevent solidification of the aqueous phase below 0 °C. This can be advantageous for some applications. The exact temperatures depend on the oils or oleic acid used and the composition of the aqueous component.

[0045] In principle, numerous unsaturated and saturated oils are conceivable as components of the water-oil mixture. Furthermore, the use of a silicone oil as a component of the water-oil mixture is also possible. However, the use of oleic acid (9-octadecenoic acid) as a component in a mixture with water makes handling in the laboratory particularly practical. The proportion of oil or oleic acid is selected such that the solid oil or oleic acid can be easily removed – i.e., it does not exceed the volume of the tubular container attachment. If necessary, the size or capacity of the tubular container attachment can be adjusted. Furthermore, the amount or proportion of the aqueous phase can be increased if the sample contains a lot of sediment with relatively few micropolymer particles. This could then also affect the detection limit and thus make the method according to the invention more sensitive.

[0046] It has proven particularly advantageous to maintain the oily phase transferred into the tubular container attachment at a temperature in the range between 17 °C and 0 °C, preferably between 10 °C and 2 °C. This is especially true when a water-oleic acid mixture is used.

[0047] This tempering of the oily phase can be achieved by means of a tempering device which cools at least part of the tubular container attachment arranged on the container.

[0048] Alternatively, the tempering of the oily phase can be achieved by placing the entire container, together with the container attachment arranged on the container, in which the still liquid oily phase is located, in a cooling device such as a refrigerator.

[0049] In both cases, the transition of the oily phase from its liquid state to a solid state occurs in a temperature range below approximately 17 °C. To prevent destruction of the container, cooling is stopped at a temperature of approximately 0 °C at the latest, so that the aqueous phase in the container cannot transition to a solid state, in which the volume of the aqueous phase would increase.

[0050] The optimal temperature for such cooling or tempering of the oily phase when using a water-oleic acid mixture is between 17 °C and 0 °C, particularly between 10 °C and 2 °C. This temperature range advantageously prevents the container from being destroyed by a frozen sample mixture, as the aqueous phase remains liquid and can flow out of the tubular container attachment. Alternatively, the aqueous phase can have a predetermined salt concentration, which inhibits the solidification of the aqueous phase at temperatures below 0 °C. However, the use of salts is associated with additional costs.

[0051] According to a further embodiment of the method, the solidified oily phase with the polymer particles contained therein is removed from the container attachment and heated over a filter, whereby the oily phase melts and the polymer particles are retained in the filter.

[0052] For selection or further processing of the polymer particles separated from the sample according to the method, which are still contained in the solidified oily phase, the solidified oily phase with the micropolymer particles is removed from the tubular container attachment, which can be done using a pestle, for example. The solidified oily phase, which has the shape of a plug, for example, is deposited in a filter. This plug of oily phase is heated above the filter, whereby the polymer particles are separated by the filter, since the oil or oleic acid of the liquefied oily phase can penetrate the filter. When using oil or oleic acid, only a temperature of 17 °C or more is necessary to convert the oily phase from a solid to a liquid state. This process can therefore take place at room temperature and does not require an additional heat source.The oil or oleic acid passes through the filter mesh, leaving behind the polymer particles that originate from the sample, such as a sediment sample. The mesh or pore size of the filter is selected so that polymer particles of the desired size can be retained. Such filters also retain larger polymer particles. Therefore, several filters with successively smaller mesh or pore sizes can be arranged to achieve size separation of the polymer particles.

[0053] The present process takes into account three essential aspects, which include a simple process design, a simple and inexpensive device and the improvement of the ecological balance.

[0054] The first aspect can be achieved through the use of oleic acid. The targeted solidification of the oily phase and the associated simple liquid-solid phase separation enables analytical work without the need for additional resources, such as labor and equipment. Oleic acid has a unique selling point in this context. It occurs naturally in various vegetable oils and, with a melting point of approximately 17 °C, ensures processing in the liquid state at room temperature while simultaneously maintaining a solid-liquid phase boundary during solidification, for example, in a refrigerator on a liquid aqueous phase.

[0055] The use of the device according to the invention is necessary for sample preparation for analytical testing. The tubular container attachment in the form of a PTFE hollow cylinder used in the described device reduces losses due to the adhesion of the oil phase to device surfaces. The low interaction between oleic acid and PTFE also enables complete transfer of the solidified oily phase or oil phase from the PTFE hollow cylinder for further processing. The third aspect of cost-neutral ecological improvement through an alternative to density separation can be achieved by eliminating the salt solution. Small amounts of oleic acid also have an impact on the economic balance. The invention enables reproducible enrichment of micropolymer particles with a particle size < 500 pm from, for example, sandy sediment.Accordingly, a constant separation performance can be assumed compared to density separation.

[0056] Further details, features, and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. They show:

[0057] Fig. 1: a schematic representation of an embodiment of a device according to the invention for implementing the method for separating micropolymer particles from a sample,

[0058] Fig. 2a to 2d: schematic representations of selected process steps to explain the process according to the invention for the separation of micropolymer particles,

[0059] Fig. 3: a schematic representation of a solidified oil phase formed according to the method in the device according to the invention for separating micropolymer particles from a sample in a three-dimensional representation and

[0060] Fig. 4a and 4b: schematic representations of a process step in which micropolymer particles are released from the solidified oil phase produced in the separation process.

[0061] Figure 1 shows a schematic representation of an embodiment of a device 1 according to the invention for implementing the method for separating polymer particles, in particular micropolymer particles 2, from a sample 3. The sample 3 is not shown in Figure 1. The device 1 comprises a container 4 having a container opening 5. The container 4 is designed in the form of a glass bottle, but is not limited to this embodiment. The container 4 has a base surface on which it is placed in its position of use. The container opening 5 is arranged opposite the base surface.

[0062] A tubular container attachment 6 is arranged at the container opening 5 of the container 4 and is sealingly connected to the container opening 5. The connection can be designed as a screw connection so that the tubular container attachment 6 can be removed from the container 4. The tubular container attachment 6 forms a riser tube on the container 4 for a liquid located in the container 4, which in the example is a sample mixture 12 containing a sample 3 with micropolymer particles 2 to be separated and a water-oleic acid mixture.

[0063] In the embodiment of Figure 1, a tube 7 is arranged in the tubular container attachment 6 or in the wall of the tubular container attachment 6. A first end 8 of this tube 7 extends from the tubular container attachment 6 via the container opening 5 of the container 4 into an area near the bottom surface of the container 4. A second end 9 of this tube 7 protrudes from the tubular container attachment 6 at an end of the tubular container attachment 6 remote from the container opening 5 of the container 4 and enables, for example, a connection to a fumigant (not shown) for introducing a gas into the container 4.

[0064] Figures 2a to 2d show schematic representations of selected process steps to explain the process according to the invention for separating micropolymer particles 2 from a sample 3.

[0065] Figures 2a to 2d each show the device 1 with the container 4 and the tubular container attachment 6 which is arranged sealingly at the container opening 5 and which is only partially shown, as well as the tube 7, the second end 9 of which projects into the container 4.

[0066] In Figure 2a, a sample 3, for example a sediment sample containing micropolymer particles 2, is introduced into the container 4. Additionally, the container 4 contains a mixture comprising water 10 and oleic acid 11. The water 10 and the oleic acid 11 can be presented as a water-oleic acid mixture.

[0067] Figure 2b illustrates the process step in which sample 3 is thoroughly mixed with the water-oleic acid mixture in container 4. This produces the sample mixture 12 shown in container 4 in Figure 2b. This sample mixture 12 thus contains sample 3 with the micropolymer particles 2 as well as a portion of water 10 and a portion of oleic acid 11.

[0068] Figure 2b illustrates components of an exemplary stirring means using a dashed line. This stirring means comprises a stationary part of a magnetic stirrer 13, on which the container 4 of the device 1 is placed with its bottom surface, as well as a magnetic stirrer bar 14 contained in the container 4. This magnetic stirrer bar 14 is set in rotation by a magnetic effect emanating from the stationary part of the magnetic stirrer 13, which is represented by an arrow in Figure 2b. The rotational movement brings about the desired mixing.

[0069] Optionally, the sample mixture 12 can be gassed. The gas required for this is introduced into the sample mixture 12 via the tube 7. For this purpose, the first end 8 of the tube 7 (not shown) is connected to a gassing agent that provides a gas in a predetermined quantity and at a predetermined pressure.

[0070] Figure 2c shows a further process step in which the mixing and gassing are terminated, resulting in a separation of the sample mixture 12 into an oily phase 15, which contains the micropolymer particles 2, and an aqueous phase 16. To enable the process of independent phase separation, a period of time can be specified during which the sample mixture 12 remains at rest—i.e., is not moved.

[0071] As schematically shown in Figure 2c, the oily phase 15 forms above the aqueous phase 16 due to its lower density.

[0072] The subsequent process step, in which additional water 10 is introduced into the container 4 after separation has taken place, whereby a fill level in the container 4 rises, is not shown in the figures. In this process step, water 10 is introduced into the container 4 via the pipe 7. The level of the aqueous phase 16 rises, so that the oily phase 15 located on top of the aqueous phase 16 in the container 4 is lifted or moved in the direction of the tubular container attachment 6. The water is introduced as gently as possible and at a low speed so that the oily phase 15 formed is not destroyed during transfer to the tubular container attachment 6.

[0073] Figure 2d shows the subsequent process step, in which the introduction of water 10 into the aqueous phase 16 was terminated after the oily phase 15 was raised by the rising fill level in the container 4 into the area of ​​the tubular container attachment 6 arranged at the container opening 5. The tubular container attachment 6 is dimensioned in its length and diameter such that it can accommodate the entire volume of the oily phase 15.

[0074] In the subsequent process step, which is not shown in the figures, at least the region of the tubular container attachment 6 in which the oily phase 15 is located is cooled until the oily phase 15 solidifies in the tubular container attachment 6. For cooling, the temperature is kept in the range below 17°C to 0°C, whereby the temperature is prevented from falling below 0°C in order to prevent damage from frozen water. After the oily phase has solidified, the tubular container attachment 6 is separated from the container 4 and the solidified oily phase 15 is removed from the tubular container attachment 6 with a spatula. The removed solidified oily phase 15 is heated over a filter, whereby the oily phase 15 melts. The micropolymer particles 2 contained in the oily phase 15 remain in the filter. These steps are explained in more detail in Figures 3 and 4.

[0075] Figure 3 shows a schematic representation of a solidified oil phase formed according to the method in the device 1 according to the invention for separating micropolymer particles 2 in a three-dimensional representation.

[0076] The device 1 comprises the container 4, the tubular container attachment 6 arranged at the container opening 5, the tube 7 with the first end 8 and the second end 9 located in the container 4, and the aqueous phase 16, which is at least largely located in the container 4.

[0077] As shown schematically in Figure 3, after cooling, a solidified oily phase 15, which contains the micropolymer particles 2, has formed in the form of a cylinder or plug in the region of the tubular container attachment 6 according to the method.

[0078] Figures 4a and 4b show schematic representations of a process step in which micropolymer particles are released from the solidified oil phase 15 produced in the separation process. Specifically, Figures 4a and 4b show a separation of micropolymer particles 2 from the solidified oily phase 15 produced in the process for separating polymer particles, in particular micropolymer particles 2, from a sample 3.

[0079] For further processing of the micropolymer particles 2 separated from the sample 3 according to the method, which are still contained in the solidified oily phase 15, the solidified oily phase 15 with the micropolymer particles 2 is removed from the tubular container attachment 6 by means of a spatula and deposited in a filter 17 shown in Figures 4a and 4b, which is arranged in a collecting tray 18 by way of example in Figures 4a and 4b.

[0080] The material of the oily phase 15 is heated above the filter 17, whereby the micropolymer particles 2 are separated in the filter 17, since the oil or oleic acid of the liquefied oily phase 15 can penetrate the filter 17. When using oleic acid 11, a temperature of only 17 °C is necessary to convert the oily phase 15 from a solid to a liquid state. Since the oil or oleic acid 11 passes through or penetrates the structure of the filter 17, the micropolymer particles 2 separated from the sample 3 remain in the filter 17, which is schematically illustrated in Figure 4b.

[0081] List of reference symbols

[0082] 1 device

[0083] 2 micropolymer particles

[0084] 3 Sample

[0085] 4 containers

[0086] 5 Container opening

[0087] 6 tubular container attachment

[0088] 7 pipe

[0089] 8 first end

[0090] 9 second end

[0091] 10 Water

[0092] 11 Oleic acid

[0093] 12 sample mixture

[0094] 13 stationary part of magnetic stirrer

[0095] 14 magnetic stirring bar

[0096] 15 oily phase

[0097] 16 aqueous phase

[0098] 17 filters

[0099] 18 drip tray

Claims

Patent claims 1. Device (1) for separating polymer particles, preferably micropolymer particles (2) from a sample (3) containing polymer particles, preferably micropolymer particles (2), comprising a container (4) with a container opening (5) for receiving a liquid and the sample (3) containing polymer particles, preferably micropolymer particles (2), and a tubular container attachment (6) which is detachably connected to the container (4) and corresponds to the container opening (5) in such a way that a liquid rising from and emerging from the container (4) reaches the tubular container attachment (6).

2. Device (1) according to claim 1, characterized in that a stirring means is arranged on or in the container (4).

3. Device (1) according to claim 1 or 2, characterized in that the stirring means is a magnetic stirrer (13) with a magnetic stirring bar (14).

4. Device (1) according to one of the preceding claims, characterized in that the container (4) has a gassing agent with which a gas can be introduced into the interior of the container (4).

5. Device (1) according to one of the preceding claims, further comprising a temperature control device with which at least the tubular container attachment (6) connected to the container (4) can be temperature controlled at least in some areas.

6. Device (1) according to one of the preceding claims, characterized in that the tubular container attachment (6) is made of plastic, preferably of polytetrafluoroethylene (PTFE).

7. Device (1) according to one of the preceding claims, characterized in that the tubular container attachment (6) is designed as a straight hollow cylinder.

8. Device (1) according to one of the preceding claims, characterized in that the container (4) is made of an elastic plastic.

9. A method for separating polymer particles, preferably micropolymer particles (2) from a sample (3) containing polymer particles, in particular a sediment sample, in which a sample (3) containing polymer particles, in particular a sediment sample containing micropolymer particles (2), is mixed with a water-oil mixture, preferably with a water-oleic acid mixture, in a container (4), and after the mixing has ended, polymer particles collected in an oily phase (15) separating floating on an aqueous phase (16) are transferred with the oily phase (15) from the container (4) into a tubular container attachment (6) detachably connected to the container (4) by a rise in the aqueous phase (16),subsequently, the temperature is reduced until the oily phase (15) solidifies, and the oily phase (15) solidified in the tubular container attachment (6) is separated from the container (4) in the solid state together with the polymer particles contained therein, finally, the separated solidified oily phase (15) is heated, whereby the separated polymer particles are released.

10. The method according to claim 9, characterized in that the sample mixture (12) formed from the water-oil mixture, preferably water-oleic acid mixture, and the sample (3) containing polymer particles is gassed with a gas during or after the mixing. 11 . Method according to one of the preceding claims, characterized characterized in that the sample mixture (12) formed from the water-oil mixture, preferably water-oleic acid mixture, and the sample (3) containing polymer particles is tempered during or after mixing.

12. Method according to one of the preceding claims, characterized in that for the rise of the aqueous phase (16) a liquid is introduced into the container (4) which has a greater density than the oily phase (15).

13. Method according to one of the preceding claims 9 to 11, characterized in that the volume of the container (4) is reduced for the increase of the aqueous phase (16).

14. Method according to one of the preceding claims, characterized in that the oily phase (15) transferred into the tubular container attachment (6) is tempered at a temperature in the range between 17 °C and 0 °C, preferably in the range between 10 °C and 2 °C.

15. Method according to one of the preceding claims, characterized in that the solidified oily phase (15) with the polymer particles contained therein is removed from the tubular container attachment (6) and heated over a filter (17), whereby the oily phase (15) melts and the polymer particles are retained in the filter (17).

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