EP4598878A1

EP4598878A1 - Solar treatment of aqueous media with particulate photocatalyst

Info

Publication number: EP4598878A1
Application number: EP23782248.1A
Authority: EP
Inventors: Barbara Rossi; Raf DEWIL; Mohammadreza KAMALI
Original assignee: Katholieke Universiteit Leuven
Current assignee: Katholieke Universiteit Leuven
Priority date: 2022-10-05
Filing date: 2023-10-05
Publication date: 2025-08-13
Also published as: WO2024074646A1

Abstract

Present invention concerns water purifier for converting non-drinkable aqueous fluid to safe drinkable water. The water purifier comprises a reservoir for the aqueous fluid, a light transparent tube, a dosing system to provide particulate photocatalyst to the aqueous fluid, a solar light reflector to concentrate solar light to the tube, a sieve downstream the tube to withhold the particulate photocatalyst and let pass water, so to recover the particulate photocatalyst in a cartridge of the dosing system.

Description

SOLAR TREATMENT OF AQUEOUS MEDIA WITH PARTICULATE PHOTOCATALYST

FIELD OF THE INVENTION

The invention relates to photocatalysis based water purifying systems

BACKGROUND OF THE INVENTION

Solar light use to inactivate pathogens (disinfection) in water, by directly exposing water in PET bottles appears a straightforward solution.

However, it requires long exposure times and does not remove all pathogens, or it involves unsustainable elements and/or is only suitable for small volumes of water and/or it can result in secondary water pollution through substances released from unsustainable material. Chemical substance such as endocrine disrupting compounds, knowing to have extreme long-term adverse effects on living organisms even at very low concentrations, are not degraded through this technique. Practically pathogens would be deactivated or degraded within a few minutes.

A photoreactor with self-contained photocatalyst recapture is disclosed in US6,827,911. This type of reactor requires a specific configuration, photocatalyst with a specific buoyancy and specific flow rates of the water within the system to obtain the desired distribution of the photocatalyst in the device.

SUMMARY OF THE INVENTION

Present invention offers an improved system for generating safe drinking water by concentrated solar radiation on photocatalyst immobilized on harmless/inert porous supports comprised in the contaminated water.

Present invention relates to a method for decontaminating aqueous media such as water, and in particular drinking water that need a treat that is safe for human and non-human animals by irradiating concentrated light on said aqueous media and during the irradiation combined therein photocatalyst coupled with porous particles. More particularly, present invention concerns destruction or inactivation of microbial contaminants and chemical substance contaminants in an aqueous medium by transmitting harvested and concentrated solar radiation to aqueous medium comprising porous supports (e.g., chips, membranes, or spherical beads) coupled with photocatalyst. The invention relates to a drinking water having at least one sieve, cartridge and conveyor for recovering and reusing particulate photocatalyst material from the purified water and guiding it to non-drinkable water to be treated.

In particular the invention relates to such cartridges, sieves and conveyors that form part of a system for preparing safe drinking water.

An advantage such system can comprise a photovoltaic generated current source or coupled thereto so that it can be operated onfseiv remote places.

In this regard it can be advantageous when the photocata lytic material I supports (e.g., chips, membranes, or spherical beads) are automatically removed from the drinking water and easily or automatically replaced during operating in the water to be treated. Hereby associated automatically collecting by systems water flow and moving it by a conveyor into new water to be treated is further advantageous. This set up is so designed that the particulate photocata lytic material I supports will not remain I be introduced in the drinking water, which is a further advantage.

Some embodiments of the invention summarised in the following stamenents:

1. A water purifier system for converting non-drinkable aqueous fluid to drinkable water, characterised in that purifier comprises 1) a light transparent absorber reservoir with water stream input and a water stream output, 2) a particulate photocatalyst cartridge holder having an outer wall defining an interior volume and at least one exit opening defining a particulate photocatalyst outlet that guides into the particulate photocatalyst inlet of a particulate photocatalyst conveyor with particulate photocatalyst outlet for supplying particulate photocatalyst to the water guidance that connects with the water input of a light transparent absorber reservoir to deliver water with particulate photocatalyst to the absorber reservoir, 3) a solar light reflector positioned to concentrate solar light onto absorber, 4) a sieve downstream of the liquid stream output of the absorber reservoir, the sieve having a mesh size that withhold the particulate photocatalyst and let pass water, whereby the sieve descend towards a particulate photocatalyst cartridge so that when operational the particulate photocatalyst is collected therein.

2. The water purifier system according to embodiments 1, whereby the particulate photocatalyst cartridge fits, for instance snap fits, into the particulate photocatalyst cartridge holder and with coupling means adapted for opening particulate photocatalyst cartridge at the inlet of a particulate photocatalyst conveyor.

3. The water purifier system according to embodiments 1, whereby the particulate photocatalyst cartridge is the particulate photocatalyst cartridge holder.

4. The water purifier system according to any one of the embodiments 1 to 3, whereby the particulate photocatalyst cartridge holder forms an hopper assembly with the conveyor.

5. The water purifier system according to embodiment 4, characterised in that, characterised in that hopper assembly comprises sealing lid, the auger element on axle member and the output funnel.

6. The system according to embodiment 5, characterised in that the output funnel is a housing with therein the auger element with on axle member that is functionally connected by a coupling member of to a motor or motor unit to delivery measured portion of particulate photocatalyst to a target.

7. The water purifier system according to any one of the embodiments 4 to 6, characterised in that hopper assembly, comprises a sealable opening on top sealable by a lit

8. The water purifier system according to any one of the embodiments 4 to 7, characterised in that hopper assembly has a back wall, a front wall, a left side wall and a right sidewall that forms a lower funnel shaped portion on the hopper assembly.

9. The water purifier system according to embodiment 8, characterised in that on the left side wall and right side wall , the lower section of the left side wall and right side wall slope inwards so that hopper assembly container funnels into the housing.

10. The water purifier system according to any one of the embodiments 4 to 9, characterised in that one end of each auger element is secured to an axle member seated for rotary motion within a bushing.

11. The water purifier system according to embodiment 10, characterised in that a bushing is positioned within an opening in end wall of housing and a coupling member attached to the end of axle member is adapted to be operatively connected to a motor.

12. The water purifier system according to any one of the embodiments 1 to 3, characterised in that conveyor is driven with push-pull solenoid to move particulate material fluid flow through the guidance of the conveyor. 13. The water purifier system according to any one of the embodiments 1 to 12, whereby the drive of said conveyor is controlled by hardware and software processor.

14. The water purifier system according to any one of the embodiments 1 to 13, characterised in that particulate photocatalyst comprises porous substrate particles coupled with a photocatalyst.

15. The water purifier system according to any one of the embodiments 1 to 13, characterised in that particulate photocatalyst comprises porous chips, membranes or beads coupled with photocatalyst.

16. The water purifier system according to any one of the embodiments 1 to 13, further comprising a pump for pumping a stream non drinkable water through the light transparent absorber reservoir into a drinkable water reservoir.

Yet further aspects and embodiments of the invention are summarized in the following statements:

17. A water purifier system for converting non-drinkable aqueous fluid to drinkable water, characterized in that purifier comprises

- a particulate photocatalyst,

- a reservoir for comprising untreated water, with an outlet, the outlet connecting to an optional first water guidance,

- an optional first water guidance with an inlet connecting to the reservoir and an outlet connecting to a light transparent tubing,

- a light transparent tubing with an input connecting to the first water guidance and an output, connecting to an optional second water guidance, wherein the reservoir, the first water guidance or the light transparent tubing, contains an additional inlet for receiving water with catalyst,

- an optional second water guidance with an inlet connecting to the light transparent tubing and an outlet, guiding water to a sieve,

- a sieve downstream of the water coming from the light transparent tubing or form the second water guidance, and physically separated thereof, wherein the sieve has a mesh size that withholds the photocatalyst and lets pass water, and wherein the sieve descend towards a cartridge so that when operational the photocatalyst is collected in said cartridge,

- a photocatalyst cartridge, optionally in a holder, with an outlet connecting to a third water guidance,

- a third water guidance with an inlet and an outlet connecting the cartridge with one of the reservoir for untreated water, the first water guidance or the light transparent tubing to deliver water with photocatalyst towards the light transparent tubing ,

-a solar light reflector positioned to concentrate solar light onto the light transparent tubing.

18. The water purifier system according to statement 17, wherein the first water guidance and the second water guidance are present.

19. The water purifier system according to statement 17 or 18, wherein the first water guidance contains the additional inlet for receiving water with catalyst.

20. The water purifier system according to any one of statements 17 to 19, wherein the third water guidance is driven with a push-pull solenoid to move a material fluid flow through the guidance.

21. The water purifier system according to any one of the statements 17 to 20, wherein the third water guidance and the light transparent tubing do not form an assembly of an inner third water guidance cylinder within an outer light transparent tubing cylinder.

22. The water purifier system according to any one of the statements 17 to 21, wherein the photocatalyst comprises porous substrate particles coupled with a photocatalyst.

23. The water purifier system according to any one of the statements 17 to 22, wherein the photocatalyst comprises porous chips, membranes, or beads coupled with photocatalyst.

24. The water purifier system according to any one of the statements 17 to 23, wherein the photocatalyst is not a buoyant photocatalyst.

25. The water purifier system according to any one of the statements 17 to 24, whereby the photocatalyst cartridge holder forms an hopper assembly with the third water guidance.

26. The water purifier system according to statement 25, wherein the hopper assembly comprises a sealing lid, an auger element on axle member and an output funnel.

27. The system according to statement 1 to 26, wherein the output funnel is a housing with therein the auger element with on axle member that is functionally connected by a coupling member of to a motor or motor unit to delivery measured portion of photocatalyst to a target.

28. The water purifier system according to any one of the statements 25 to 27, wherein the hopper assembly comprises a sealable opening on top sealable by a lid. 29. The water purifier system according to any one of the statements 25 to 28, wherein the hopper assembly has a back wall, a front wall, a left side wall and a right sidewall that forms a lower funnel shaped portion on the hopper assembly.

30. The water purifier system according to statement 29, wherein on the left side wall and right side wall , the lower section of the left side wall and right side wall slope inwards so that hopper assembly container funnels into the housing.

31. The water purifier system according to any one of the statements 26 to 30, wherein one end of each auger element is secured to an axle member seated for rotary motion within a bushing.

32. The water purifier system according to statement 31, wherein a bushing is positioned within an opening in end wall of housing and a coupling member attached to the end of axle member is adapted to be operatively connected to a motor.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Detailed Description

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is a photographic showing that untreated water is pumped through the light transparent tubing from the contaminated water unit (I) where porous chips or beads coupled with photocatalyst (in this set up chips) enter rom the photocata lytic substrate holding container, compartment (C) into the water flow guidance through connection (b) into the water flow guidance. The chips coupled with photocatalyst were held in compartment (C) displayed in the top left of the unit which is photographically shown in the Fig. 1 b panel. A guidance that comprises a push-pull solenoid guided the chips into the water stream. In this set up it was controlled via an Arduino. The water and chip mix travelled through the light transparent tubing located in the focus of the parabolic trough (II) (also displayed in the Fig 1 B panel) where the photocatalysis occurs with concentrated sunlight light from the parabolic trough (II). Treated water is pumped through the tubing into a filtering unit (III) with sieve (shown on photographic of Fig.l c panel (in top view of the filtering unit without sealing roof) where the chips were filtered out of the mix of water and chips. The sieve compartment is easy to remove to refill compartment (C). The Fig. 1 (B) panel is a photographic of the chips with photocatalyst.

FIG. 2 is a schematic graphic showing the experimental set up of examples 1 and 2 The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and equivalents thereof.

The following detailed description of the invention refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and equivalents thereof.

Several documents are cited throughout the text of this specification. Each of the documents herein (including any manufacturer's specifications, instructions etc.) are hereby incorporated by reference; however, there is no admission that any document cited is indeed prior art of the present invention.

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn to scale for illustrative purposes. The dimensions and the relative dimensions do not correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. Moreover, the terms top, bottom, over, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to the devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination. In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only. Each and every claim is incorporated into the specification as an embodiment of the present invention. Thus, the claims are part of the description and are a further description and are in addition to the preferred embodiments of the present invention.

Each of the claims set out a particular embodiment of the invention.

The following terms are provided solely to aid in the understanding of the invention.

Definitions

Reservoirs containing contaminant water and receiving pure water are for example, buckets, barrels or flexible bags.

In the most simple configuration the transparent tubing is immediately place at the outlet of the reservoir, whereby the water exiting the transparent may flow directly on the sieve. Typically, in order to have an optimal positioning towards the solar reflector, the light transparent tubing has a water guidance at both ends for respectively connecting with the reservoir and direction the water to sieve.

First and second water guidance may be rigid as well as flexible. Depending on the place of entry of the particulate catalyst, the diameter should be large enough to allow the passage of particulate catalyst.

The light transparent tubing may of glass or plastic as long as it transparent or at least translucent to the wavelength of light used for photocatalysis.

The particulate catalyst is introduced via the third guidance in the system prior to where the reaction takes place in the light transparent tubing. The particulate catalyst can be introduced in the reservoir with contaminated water, or at any place in the first water guidance or near the inlet of the light transparent tubing before the part of the guidance where the photocatalysis takes place. Generally a non-return valve is placed at the place of entry of the particulate catalyst, to prevent contaminated water entering the third guidance

The flow of the water through the system can be gravity driven, optionally with flow restrictor to reduce the water flow. Alternatively a pump transports the water through the system.

The system only requires one sieve to retain and collect the particulate catalyst. No additional sieves or needed between the reservoir and the outlet of the third guidance to restrict the movement of the particulate catalyst within a section of the system. This avoids a pressure built-up when catalyst or other solid particles would clog filters in a system.

Present invention relates to a method for decontaminating aqueous media such as water, and in particular drinking water that need a treat that is safe for human and non-human animals by irradiating concentrated light on said aqueous media and during the irradiation combined therein photocatalyst coupled with porous particles. More particularly, present invention concerns destruction or inactivation of microbial contaminants and chemical substance contaminants in an aqueous medium by transmitting harvested and concentrated solar radiation to aqueous medium comprising porous supports (e.g., chips, membranes, or spherical beads) coupled with photocatalyst.

The invention provides a way to decontaminate an aqueous fluid of microbial and/or chemical contaminants, in particular drinking water, while guaranteeing safety for the consumer. Particularly suitable to achieve this solution an embodiment of present invention provides 1) at least one solar light harvester that concentrates and transmits the harvested concentrated light (1) 2) porous substrate/support, for instance microporous and/or macroporous particles, the substrate being coupled with a photocatalyst (2) and 3) a light transparent container to contain said the aqueous fluid with the substrate (3). The object of the present invention of decontaminating is achieved by means of having the aqueous fluid with photocatalyst substrate (2) contained in the container (3) being functionally connected with the at least one light concentrator and concentrated light emitter (1).

Photocatalyst coupling to substrate can be achieved through covalent coupling to reactive groups on substrate surface on the outer surface and the interior pore surfaces or through functional groups connecting substrate and photocatalyst. Compared to devices such as disclosed in US6827911 the devices of the present invention have numerous advantages.

The devices of the present invention can be built with simple materials and broken parts can be easily replaced.

Apart from the positioning of the sieve in order to collect the photocatalyst there is a large versatility in dimensions and positioning of the different elements in the device. No precautions need to be taken for selecting catalyst particles with a specific buoyance and determining flow rates of the water flow in the different parts of the device.

EXAMPLES

Example 1

The present invention is predicated on the discovery by the inventors that when microbial and chemical contaminated water is pumped into a clear solid pipe with photocatalyst coupled to porous supports and is irradiated by highly concentrated solar light this leads to the total degradation or mineralization of pharmaceuticals through photocatalysis. Surprisingly this process was completed within minutes to produce safe drinkable water that is clean from pharmaceuticals. After porous supports are filtered out the water-support mix treated as such the treated water is drinkable. The filtered out supports are reusable. Typically a solar light concentrator concerns a set of concave reflectors (parabolic trough) that concentrate solar rays on a receiver container that is located in the focus. In this example such receiver container was a light transparent tubing where through the to be treated water was pumped and the photocatalyst porous beads were introduced. The photocatalyst porous beads enter the water flow from a reservoir and the beads travelled through a software controlled push-pull solenoid. The bead-water mix travelled through a transparent reactor where photocatalysis occurred. The treated water was then pumped into another reservoir where the beads were filtered out of the mix, collected in a removable compartment to easily be reused by refilling the bead compartment.

Suitable for present invention are also comprises dish-shaped light collector or paraboloidal light collector and paraboloidal reflector with a concave reflective surface to concentrate collected light and optionally device for transmitting such high-density or concentrated light as the collected sunlight to the target, in present invention the target being a light transparent water container for photocata lytic treating of contaminated water.

Example 2

Contaminated water with the compounds Carbamazepine (CBZ) and 17-o- Ethynylestradiol (EE2) is provided with ZnO photocatalyst coupled on porous chip form substrates is guided into a light transparent pipe and illuminated or irradiated with concentrated solar light. The presence of the photocatalyst and concentrated solar light lead to degradation of contaminants within a few minutes to produce clean drinkable water. To concentrate the light, a solar trough is used.

Example 3

Contaminated water with the Carbamazepine (CBZ) and 17-o-Ethynylestradiol is provided with graphitic carbon nitride (g-C3N4) coupled porous chip form substrates and guided into a light transparent that is radiated by concentrated solar light from a sunlight illuminated solar trough. The presence of a catalyst and concentrated solar light in the contaminated water lead to degradation of these pharmaceuticals contaminants within a few minutes to produce clean drinkable water.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Claims

1. A water purifier system for converting non-drinkable aqueous fluid to drinkable water, characterised in that purifier comprises

- a particulate photocatalyst,

2. The water purifier system according to claim 1, wherein the first water guidance and the second water guidance are present.

3. The water purifier system according to claim 1 or 2, wherein the first water guidance contains the additional inlet for receiving water with catalyst. The water purifier system according to any one of claims 1 to 3, wherein the third water guidance is driven with a push-pull solenoid to move a material fluid flow through the guidance. The water purifier system according to any one of the claims 1 to 4, wherein the third water guidance and the light transparent tubing do not form an assembly of an inner third water guidance cylinder within an outer light transparent tubing cylinder. The water purifier system according to any one of the claims 1 to 5, wherein the photocatalyst comprises porous substrate particles coupled with a photocatalyst. The water purifier system according to any one of the claims 1 to 6, wherein the photocatalyst comprises porous chips, membranes, or beads coupled with photocatalyst. The water purifier system according to any one of the claims 1 to 7, wherein the photocatalyst is not a buoyant photocatalyst. The water purifier system according to any one of the claims 1 to 8, whereby the photocatalyst cartridge holder forms an hopper assembly with the third water guidance. The water purifier system according to claim 9, wherein the hopper assembly comprises a sealing lid, an auger element on axle member and an output funnel. The system according to claim 10, wherein the output funnel is a housing with therein the auger element with on axle member that is functionally connected by a coupling member of to a motor or motor unit to delivery measured portion of photocatalyst to a target. The water purifier system according to any one of the claims 9 to 11, wherein the hopper assembly comprises a sealable opening on top sealable by a lid. The water purifier system according to any one of the claims 9 to 12, wherein the hopper assembly has a back wall, a front wall, a left side wall and a right sidewall that forms a lower funnel shaped portion on the hopper assembly. The water purifier system according to claim 13, wherein on the left side wall and right side wall , the lower section of the left side wall and right side wall slope inwards so that hopper assembly container funnels into the housing. The water purifier system according to any one of the claims 10 to 14, wherein one end of each auger element is secured to an axle member seated for rotary motion within a bushing. The water purifier system according to claim 15, wherein a bushing is positioned within an opening in end wall of housing and a coupling member attached to the end of axle member is adapted to be operatively connected to a motor.