Micro and nanoparticle sampling device in aquatic ecosystems and collection system associated

The present invention has as its object a capture system for obtaining micro and nano particle samples in aquatic ecosystems. This device is a passive sampler in situ, capable of filtering large volumes of water, recording the water flow during the sampling period, and providing greater efficiency in the filtering process by using the water stream to force water filtration, or the own weight of the particles. Currently, the methodologies developed for the sampling of micro and nano plastics in seawater are limited, for micro plastics, to plankton nets with a single determined pore size, and, for size <1 µm (nano plastics) to sophisticated expensive pumping systems associated to specific high-cost filters. In all cases, a sample collection is limited to a single fraction of specific size, either micro or nanoparticles, depending on the network, filter or sieve used. In other words, capture devices and / or capture systems that allow the simultaneous obtaining of samples separated by fractions of different sizes of micro and nanoparticles, coming from the same volume of water, is not available in the market. On the other hand, the pumping procedure uses a lot of energy, and require complicated extraction procedures in the laboratory. The present invention solves the aforementioned problems by means of a selective, passive and inexpensive collection device for obtaining micro and nanoparticle samples from aquatic ecosystems in fractions separated according to their size. Said device also has a construction configuration specially designed to facilitate the extraction of samples of different sizes, in addition to being made up of inert, non-polluting, light and resistant materials. The device is configured to filter large volumes of water and obtain maximum use of water currents, in order to force their filtration.

Specifications

Figure 1 shows an exploded view of the sampling device (1) of the present invention, according to a first preferred embodiment.

As can be seen, the sampling device (1) for micro and nanoparticles in aquatic ecosystems of the present invention comprises a body (2) that defines an inlet end (3e) and an outlet end (3s), configured to allow the filtering the water (A) of an aquatic ecosystem that circulates between the inlet end (3e) and the outlet end (3s). Said device (1) comprises a plurality of filters (4M, 4N) arranged sequentially between the inlet end (3e) and the outlet end (3s), configured to obtain samples of micro and nanoparticles in fractions separated according to their size.

The filters (4M, 4N) are arranged sequentially between the input end (3e) and the output end (3s) ordered from largest to smallest filter size, that is, in descending order of their filter size between the end of inlet (3e) and the outlet end (3s).

The body (2) has a funnel or conical shape, in which the inlet end (3e) has a larger diameter than the outlet end (3s).

The device (1) comprises a plurality of micro filters (4M) configured to obtain samples of microparticles equal to or greater than 1 µm in size, and up to 5 mm in size.

According to the present example, the device (1) comprises a selection of micro (4M) filters of 5 mm, 1 mm, 500 µm, 250 µm, 100 µm, 50 µm, 20 µm, and 1 µm filter size. In this case, separate fractions of microparticles are obtained, whose microparticle sizes are between the following ranges: from 5 mm to 1 mm, from 1 mm to 500 µm, from 500 µm to 250 µm, from 250 µm to 100 µm, 100 µm to 50 µm, 50 µm to 20 µm, and 20 µm to 1 µm.

Micro (4M) filters are washable and reusable stainless steel sieves.

The device (1) comprises a plurality of nano filters (4N) configured to obtain nanoparticle samples smaller than 1 µm in size.

According to the present example, the device (1) comprises a selection of nano (4N) filters of 0.45 µm or 0.2 µm, and of less than 0.1 µm in filter size.

The 0.45 µm or 0.2 µm nano (4N) filters are disposable filters made of polytetrafluoroethylene (PTFE), better known as Teflon. Nano (4N) filters with filter size less than 0.1 µm are disposable Polyethersulfone (PES) filters.

According to the present example, the body (2) is made up of the filters themselves (4M, 4N), where each of said filters (4M, 4N) forms a separable segment of said body (2). For this, the filters (4M, 4N) are joined sequentially in the appropriate order by means of facing holes (12) enabled in the adjacent filters (4M, 4N), which work in collaboration with screws (13) to allow their assembly and disassembly. repeatedly. Likewise, each filter (4M, 4N) can have its own extraction or removal elements, such as handles or handles (11).

As can be seen in Figure 2, the device (1) comprises a plurality of rudder blades (5) arranged around the body (2), configured to orient the device (1) according to the direction of the water current. In this case, four rudder blades (5) arranged equidistant around the body (2), that is to say at 90º to each other. Said rudder blades (5) ensure the correct positioning of the device (1) in the countercurrent position, in order to increase the water pressure against the filters (4M, 4N), favoring the passage of particles through them.

As can be seen in Figures 2, the filters (4M, 4N) of smaller filtering size are configured as a cartridge (22) to allow the bulk extraction of a set of filters (4M, 4N). Specifically, said cartridge (22) comprises a selection of filters (4M, 4N) of 10 µm, 1 µm, and 0.1 µm filter size. For this, the body (2) comprises a housing (23) configured to house said cartridge (22) and allow its extraction. The housing (23) has the necessary closing and / or fitting means (21) to allow access to the cartridge (22) for its handling and extraction.

The body device (2) may comprise other micro filters (4M) of a larger filtering size ahead of the cartridge (22), that is, close to the inlet end (3e).

As can be seen in Figures 2 and 3, the device (1) comprises a plurality of rudder blades (5) arranged around the body (2), configured to orient the device (1) according to the direction of the water current. In this case, two rudder blades (5) arranged around the body (2) equidistant, that is to say at 180º between them. Said rudder blades (5) ensure the correct positioning of the device (1) in the countercurrent position, in order to increase the water pressure against the filters (4M, 4N), favoring the passage of particles through them.

As can be seen in Figure 2, the filters (4M, 4N) of smaller filtering size are configured as a cartridge (22) to allow the bulk extraction of a set of filters (4M, 4N). Specifically, said cartridge (22) comprises a selection of filters (4M, 4N) of 100 µm, 50 µm, 20 µm, and 0.45 or 0.2 µm filter size. For this, the body (2) comprises a housing (23) configured to house said cartridge (22) and allow its extraction. The housing (23) has the necessary closing and / or fitting means (21) to allow access to the cartridge (22) for its handling and extraction.

The body device (2) may comprise other micro filters (4M) of a larger filtering size ahead of the cartridge (22), that is, close to the inlet end (3e).

Figure 3 shows a schematic view of the capture system (300) for obtaining samples of micro and nano particles in aquatic ecosystems of the present invention, with two sampling devices (1) of the present invention, one of them arranged horizontally and the other arranged vertically. This system (300) can be used with any of the previously described embodiments of the sampling device (1) of the present invention.

As can be seen, the capture system (300) for obtaining micro and nano particle samples in aquatic ecosystems comprises:

- a flotation element (101) configured to float on the surface (S) of the water (A) of an aquatic ecosystem; and

- a first sampling device (1) configured to be immersed in the water (A) of said aquatic ecosystem, between the surface (S) and the bottom (F) thereof;

where said first device (1) is arranged horizontally (1H), attached to the flotation element (101) and to the bottom (F);

- a second sampling device (1) configured to be immersed in the water (A) of an aquatic ecosystem, at the bottom (F) thereof;

where said second device (1) is arranged vertically (1V), subject to the bottom (F).

Advantages and detailed description

The micro and nanoparticle sampling device in aquatic ecosystems of the present invention comprises a body that defines an inlet end and an outlet end, configured to allow the filtering of water from an aquatic ecosystem that circulates between the inlet end and the outlet end. output. The device is characterized by a plurality of filters arranged sequentially between the inlet end and the outlet (Fig. 1) end, configured to obtain samples of micro and nanoparticles in fractions separated according to their size.

The filters are arranged sequentially between the inlet end and the outlet end ordered from largest to smallest filtering size.

Preferably, the body is funnel-shaped, or conical, with the inlet end having a larger diameter than the outlet end. This makes it possible to increase the speed of the water flow as it advances through the body, due to the reduction of the passage section, reaching the maximum speed at the outlet end. The intersection of the water passage due to filters of different pore diameters favors the retention of the particles in the filters according to size distribution. According to other realizations (Fig. 2), the body can have tubular shapes, with circular, square, rectangular passage sections, or combinations thereof, which can also be adopted at its inlet and outlet ends. The body can have other constructive and / or mounting configurations, with the main purpose of preventing certain materials and large particles from clogging the sampler or filter device. One of them contemplates the use of a body with a conical shape inverse to the direction of the current. That is, with an inlet end having a smaller diameter than the outlet end. In this way, the current itself moves the particles and macro materials out of the sampling device. Another embodiment contemplates the use of a ring-shaped body, so that the macro materials and particles can pass through a central hole arranged therein.

Preferably, the body is made of carbon fiber or fiberglass, since they are harmless, malleable and light materials, which favor the manufacture of the device, as well as its transport and assembly, in addition to presenting a great resistance capable of resisting the strong tides and / or ocean currents often frequent in the aquatic ecosystems for which the use of the micro and nanoparticle sampling device is intended. The body can be manufactured using other materials with similar characteristics and / or performance, although less light, such as stainless steel.

Preferably, the device comprises one or more micro filters configured to obtain samples of microparticles equal to or greater than 1 µm in size, and preferably, up to 5 mm in size.

Preferably, the device comprises a plurality of micro filters configured to obtain microparticle samples of different sizes, selectable between 5 mm, 2 mm, 1 mm, 500 µm, 250 µm, 100 µm, 50 µm, 20 µm, and 1 µm of filter size, among other possible sizes. You can select all of them at the same time, or only some, to form the desired combinations. The greater the number of filters selected, the greater the number of microparticle samples in fractions separated according to their size. In turn, depending on the selected micro filters, different particle size ranges are obtained for each fraction.

Preferably, the micro filters are washable and reusable stainless steel sieves.

Preferably, the device comprises one or more nano filters configured to obtain nanoparticle samples smaller than 1 µm in size.

Preferably, the device comprises a plurality of nano filters configured to obtain nanoparticle samples of different sizes, selectable between 0.45 µm, 0.2 µm and from 150 to 800 Da (Daltons) of filter size, among other possible sizes. You can select all of them at the same time, or some of them, to form the desired combinations. The greater the number of filters selected, the greater the number of nanoparticle samples in fractions separated according to their size. In turn, depending on the nano filters selected, different particle size ranges are obtained for each fraction.

Preferably, the nano filters are made of polytetrafluoroethylene (PTFE), better known as Teflon, or membranes of polymeric material, or combinations thereof.

For example, for 0.45 µm and 0.2 µm filtration, Teflon nano filters can be used, which are characterized by being very resistant and comfortable to work with; such as Whatman® PTFE filters. For filtration less than 0.1 µm, or 150 to 800 Da (Daltons), Microdyn Nadir® Flat Sheet Membrane filters, NP010, PES, NF, 297x210mm, made of different polymeric materials (Polyamide-Thin Film Composite, Cellulose acetate, Polyethersulfone (PES), Polypiperazine amide). Some of these filters then allow to go to electron microscope, and IR or RAMAN spectroscopies to determine shapes and composition of the polymers.

Micro filters and nano filters can adopt different constructive configurations in the device, mainly aimed at guaranteeing its functionality and robustness, facilitating the handling and removal of filters, etc.

According to a first case of constructive embodiment (Fig 1), the body is made up of the filters themselves, where each of said filters forms a separable segment of said body. This constructive configuration has multiple advantages. In the first place, it facilitates the manufacture, transport and assembly of the device, being able to be assembled at the place of use thereof. Second, it facilitates the removal of the filters after the filtering process, for the subsequent analysis of the samples. For this, the filters themselves are joined sequentially in the appropriate order by means of screws, bolts, pins or other non-permanent joining elements, configured to allow their assembly and disassembly repeatedly. Likewise, each filter can have its own extraction or removal elements, such as handles, handles, etc.

According to a second constructive realizations (Fig 2), the filters are configured as cartridges to allow bulk extraction of a set of filters, preferably those with the smallest filtering size. For this, the body comprises a housing configured to house said cartridge and allow its extraction. The housing has the necessary closing and / or fitting means to allow the cartridge to be attached to the device and access to it during its subsequent extraction.

Both constructive realizations allow each fraction of different size to be easily extracted, preventing the samples from being accidentally mixed, and using inert materials that prevent their contamination.

Preferably, the device comprises one or more rudder blades arranged around the body, configured to orient the device according to the direction of the water flow. Said rudder blades ensure the correct positioning of the device in the countercurrent position, in order to increase the water pressure against the filters, favoring the passage of the particles through them.

The monitoring system associated to the sampling device has three realizations (Fig 3), which are related with the horizontal positioning, vertical positioning, or both at the same time, of the sampling device during its operation.

In the first case (horizontal positioning), the monitoring system for obtaining micro and nano particle samples in aquatic ecosystems is characterized by comprising:

- a buoyancy element, for example a marker buoy, configured to float on the water surface of an aquatic ecosystem; and

- a sampling device according to specifications below configured to be immersed in the water of the chosen aquatic ecosystem, between the surface and the bottom;

where the device is arranged horizontally, attached to the flotation element and to the bottom.

In this way, the sampling device, also called in this case horizontal collector, makes it possible to obtain samples of micro and nanoparticles, especially micro and nano plastics, representative at a given depth. The horizontal collector is therefore located in the water column and in a countercurrent position, for the differential capture of particles, taking advantage of the force of the tides and surface currents of aquatic ecosystems.

Preferably, this monitoring system include a current meter, or flow meter, configured to record the flow of water during the sampling period.

Filters containing micro and nanoparticles can be removed and analyzed. The amount of micro and nanoparticles refers to the filtered volume, calculated with the flow (through the membranes of different porosity) and the sampling surface.

Preferably, this monitoring system include a solar panel to supply the necessary electrical energy to the current meter, and / or to other electrical control and / or monitoring equipment.

Preferably, the attachment of the device to the floating element and to the bottom is carried out through rotating anchors to allow the device to be oriented according to the direction of the water flow.

In the second case (vertical arrangement), the capture system for obtaining micro and nano particle samples in aquatic ecosystems is characterized by comprising:

- a sampling device according to any of claims 1 to 13 configured to be immersed in an aquatic ecosystem, at the bottom thereof;

where said device is arranged vertically, subject to the bottom.

In this way, the sampling device, also called in this case vertical collector, makes it possible to obtain samples of micro and nanoparticles, especially micro and nano plastics, of greater weight, which settle from the water column to the bottom of the sea.

In the third case (horizontal and vertical arrangement), the capture system for obtaining micro and nano particle samples in aquatic ecosystems is characterized by comprising:

- a buoyancy element configured to float on the water surface of an aquatic ecosystem; and

- a first sampling device configured to be immersed in the water of said aquatic ecosystem, between the surface and the bottom thereof;

where said first device is arranged horizontally, attached to the flotation element and to the bottom;

- a second sampling device configured to be immersed in said aquatic ecosystem, at the bottom thereof;

where said second device is arranged vertically, attached to the bottom.

The joint use of both horizontal and vertical arrangements of the sampling device offers beneficial complementary information for the analysis of the samples obtained.

The sampler device of the present invention can be used according to the above-described systems, especially passive systems, as well as through other active capture systems, such as hooking and dragging by boats, pressure pumping, etc. For example, an active catchment system in which the sampling device is fixed under a ship.Currently, the methodologies developed for the sampling of microplastics larger than 80 µm in seawater are limited to plankton nets with a single determined pore size, without the possibility of distinguishing between different sizes. Plankton nets are equipment used to collect samples of plankton in large lakes and seas. A plankton net generally consists of a tow line and zip ties, a nylon mesh net or polypropylene fiber tarp with a pick-up end.

On the other hand, the sampling of microplastics of size between 80 and 20 µm can be obtained by pumping large volumes of water into sieves with a single determined pore dimension. The main disadvantage is that this procedure uses a lot of energy, and require sophisticated pumping systems.

For sizes between 1 and 0.1 µm considered as nanoplastics, it can be obtained with the suction of large amounts of water with high-pressure pumps, the use of specific high-cost filters and complicated extraction procedures in the laboratory. Among these procedures is the application of chemical compounds, which can damage and / or deteriorate the nanoparticles, reducing the efficiency of the sample collection process, in addition to being more polluting.

In all cases, a sample collection is limited to a single fraction of specific size, either micro or nanoparticles, depending on the network, filter or sieve used. In other words, capture devices and / or capture systems that allow the simultaneous obtaining of samples separated by fractions of different sizes of micro and nanoparticles, coming from the same volume of water, is not available in the market.

The biggest drawback of this is the long work time required to separate the fractions according to their size by the technical-scientific staff. It is also more difficult to determine the origin of these samples, specifically, to determine if they come from the decomposition of larger particles from the same area, or if they have been carried by the current from other areas.

The present invention solves the aforementioned problems by means of a selective, passive and inexpensive collection device for obtaining micro and nanoparticle samples from aquatic ecosystems in fractions separated according to their size. Said device also has a construction configuration specially designed to facilitate the extraction of samples of different sizes, in addition to being made up of inert, non-polluting, light and resistant materials.

The present invention also solves the aforementioned problems by means of a passive in situ capture system associated with said device, configured to filter large volumes of water and obtain maximum use of water currents, in order to force their filtration.

Applications:

The present invention is especially applicable in the field of environmental management, and more specifically, to verify water quality and detect the presence of micro and nano plastics in water management systems.

The device is of particular interest to water manager and industries to check water quality and assess the presence of micro and nano plastics.

The device is particularly indicated in case of application in sea water or river water, also it is possible to apply both as passive sampler or active e.g. attached to a boat.

Users of the technology will be environmental and laboratory technicians related with water quality control and researcher in the environmental protection field (WWTPs, sea, river monitoring).

Beneficiaries of the technology will be the same clients, for saving money in water monitoring, and for gaining in efficiency and citizens for the improvement in water safety. In addition, the use of the device can have a considerable impact on public opinion and a positive feedback in terms of public approval.