Water filtration assembly

Abstract

The present disclosure relates to a water filtration assembly (10) which includes a photocatalytic filter bed (26) comprising nanofibres embedded with photocatalytic nanoparticle composites arranged to degrade pollutants in water when exposed to a light, activation source (36).

Description

[0001] WATER FILTRATION ASSEMBLY

[0002] FIELD OF INVENTION

[0003] The invention relates to water filtration systems, in particular photocatalytic filtration systems and devices.

[0004] BACKGROUND OF THE INVENTION

[0005] Conventional water filtration systems typically employ filter media that physically remove suspended solids and other pollutants from water. A significant drawback of such systems is the gradual accumulation of pollutants within the filter media, leading to pore occlusion. This occlusion reduces the filtration efficiency, decreases the flow rate, and necessitates frequent cleaning, maintenance, or replacement of the filter elements. For instance, filter beds in traditional systems quickly become clogged with particulates and biological matter, requiring manual backwashing or chemical cleaning, which adds to operational costs and can interrupt the filtration process.

[0006] Further, many advanced water treatment technologies, including some photocatalytic systems, rely on specific light sources, such as ultraviolet (UV) light, which often require a continuous supply of electricity. This dependence on the power grid limits their applicability in remote or off-grid areas and contributes to higher energy consumption. For example, existing photocatalytic membrane reactors (e.g., US 2011 / 0150734 A1 , CN207659245U, CN112573635A, CN112939139A) are primarily based on UV light application, which poses energy and deployment challenges. While some visible-light enabled configurations exist (CN214570904U), they may lack inherent filtration capabilities, meaning the photocatalytic component does not contribute to the physical removal of pollutants. Other systems may perform catalysis without aiding the filtration function directly (CN210237185U).

[0007] Therefore, there is a need for an improved water filtration system that addresses the problem of filter occlusion by integrating a self-cleaning mechanism and a photocatalytic filtration mechanism that operates efficiently and sustainably, particularly in environments with limited access to continuous electrical power.

[0008] SUMMARY OF THE INVENTION

[0009] According to one aspect of the invention, there is provided a water filtration assembly comprising: a feed receptacle configured to receive and hold raw water; a filtrate tank configured to collect filtered water; a photocatalytic filter element in fluid communication between the feed receptacle and the filtrate tank, the photocatalytic filter element comprising at least one capillary tube and a spongy photocatalytic filter bed disposed within the at least one capillary tube, the filter bed comprising nanofibers embedded with photocatalytic nanoparticle composites, wherein the photocatalytic nanoparticle composites are activatable by visible light to degrade pollutants; and a light source arranged to illuminate the photocatalytic filter element with visible light, wherein the photocatalytic nanoparticle composites are arranged to degrade pollutants accumulating within the filter bed, thereby maintaining the permeability of the filter bed.

[0010] The at least one capillary tube is in a configuration of a coil having an inlet end in fluid communication with the feed receptacle and an outlet end in fluid communication with the filtrate tank.

[0011] The coil comprises single to multiple loops around a central core member. This further enhances the packing density of the filter element, maximizing the contact area for filtration and photocatalysis. The internal walls of the at least one capillary tube are coated with photocatalytic nanoparticle composites.

[0012] The photocatalytic nanoparticle composites comprise metal oxides and carbonaceous materials.

[0013] The metal oxides may be selected from a group comprising one or more of titanium dioxide, doped titanium dioxide, zinc oxide, doped zinc oxide and combinations thereof.

[0014] The carbonaceous material may be selected from a group comprising one or more of carbon nanotubes, amorphous carbon nanotubes, oxidized carbon nanotubes, doped carbon nanotubes and combinations thereof.

[0015] Therefore, the photocatalytic nanoparticle composites may be composites of titanium dioxide / amorphous carbon nanotubes, zinc oxide / amorphous carbon nanotubes, or a combination of the doped, oxidised or amorphous forms of the above.

[0016] Preferably, the photocatalytic nanoparticle composites may be titanium dioxide / amorphous carbon nanotubes nanocomposite materials, zinc oxide / amorphous carbon nanotube nanocomposite materials, or a combination of the doped, oxidised or amorphous forms.

[0017] The spongy photocatalytic filter bed may comprise electrospun polyacrylonitrile fibers.

[0018] The filter bed may comprise polymer nanofibers embedded with photocatalytic nanoparticle composites. Specifically, polyacrylonitrile nanofibers embedded with photocatalytic nanoparticle composites namely titanium dioxide / amorphous carbon nanotubes nanocomposite materials and zinc oxide / amorphous carbon nanotube nanocomposite materials. The light source comprises a plurality of illumination generating devices.

[0019] The plurality of illumination generating devices are LED light strips arranged to offer specific wavelength emission suitable for visible light activation.

[0020] The LED light strips may be fitted around the central core member and arranged to face an inner radius / side of the loops of the coil.

[0021] The assembly may further comprise a power generating and storage assembly comprising a photovoltaic sheet and a rechargeable battery, wherein the power generating and storage assembly is configured to provide electrical power to the light source.

[0022] The power generating and storage assembly may further comprise circuitry configured to activate the light source at lower ambient light intensity.

[0023] The assembly may further comprise a tap connected to the filtrate tank.

[0024] The assembly may further comprise an upper manifold connecting the at least one capillary tube to the feed receptacle and a lower manifold connecting the at least one capillary tube to the filtrate tank.

[0025] The feed receptacle may comprise a sieve configured to filter large suspended solids. The filtrate tank comprises a service outlet configured for flushing the assembly.

[0026] According to a second aspect of the invention, there is provided a photocatalytic filter element for a water filtration assembly, the photocatalytic filter element comprising at least one capillary tube; and a spongy photocatalytic filter bed disposed within the at least one capillary tube, the filter bed comprising nanofibers embedded with photocatalytic nanoparticle composites, wherein the photocatalytic nanoparticle composites are activatable by visible light to degrade pollutants; and wherein the photocatalytic nanoparticle composites are arranged to degrade pollutants accumulating within the filter bed, thereby maintaining the permeability of the filter bed.

[0027] The at least one capillary tube is in a configuration of a coil having an inlet end configured for fluid communication with a feed receptacle and an outlet end configured for fluid communication with a filtrate tank.

[0028] The coil comprises single to multiple loops around a central core member.

[0029] The spongy photocatalytic filter bed comprises electrospun polyacrylonitrile fibers.

[0030] The internal walls of the at least one capillary tube may be coated with photocatalytic nanoparticle composites or the nanoparticles may be incorporated in the fibers.

[0031] The photocatalytic nanoparticle composites comprise metal oxides and carbonaceous materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

[0033] Figure 1 - shows a perspective view of a water filtration assembly in accordance with the invention;

[0034] Figure 2 - shows a front view of the water filtration assembly in accordance with the invention;

[0035] Figure 3 - shows an exploded view of the water filtration assembly in accordance with the invention; and

[0036] Figure 4 - shows a cross-sectional view of a photocatalytic filter element of the water filtration assembly in accordance with the invention.

[0037] DESCRIPTION OF THE INVENTION

[0038] As can be seen in the drawings, there is provided a water filtration assembly 10. The water filtration assembly 10 comprises a feed receptacle 12 configured for holding raw, unfiltered water. The feed receptacle 12 is generally cylindrical and defines an internal chamber (not shown) for holding raw, unfiltered water. A threaded neck 14 protrudes upwardly from a flat upper portion of the feed receptacle 12 and defines a channel (not shown) that is in fluid communication with the internal chamber (not shown). An inlet opening 16 is defined by the neck 14, providing access to the channel (not shown). A threaded lid 17 is configured to be locatable on the neck 14 and can be threadably displaced relative to the neck 14. This threaded engagement allows for manual adjustment of the flowrate of liquid that is discharged from an outlet (not explicitly numbered but implied by the flow path) of the feed receptacle 12. A first filter member, in the form of a sieve (not shown), is fitted to the inlet opening 16 to retain and prevent large suspended solids from entering the internal chamber (not shown) of the feed receptacle 12. This initial filtration step protects downstream components from gross contamination.

[0039] A photovoltaic module, specifically a photovoltaic sheet 18, is provided in the form of a disc. The photovoltaic sheet 18 defines a central opening 20. The discshaped photovoltaic sheet 18 is arranged to be positioned on an upper flat portion of the feed receptacle 12, with the neck 14 extending through the central opening 20 of the disc 18. The photovoltaic sheet 18 is configured to capture incident light, such as solar radiation, and convert this light energy into electrical energy. This electrical energy is subsequently stored in energy storage devices, such as rechargeable batteries (not shown). The rechargeable batteries (not shown) are housed within a central bore 32 of the assembly 10 and are supported by a lower perforated plate 40 of a filtrate tank 38. Electrical wires (not shown) connect the photovoltaic sheet 18 to the rechargeable batteries (not shown) and further to other electrical components. These electrical wires (not shown) are isolated from the water filtration pathway and other parts of the water filtration assembly 10 by being routed through a hollow conduit (not shown) situated either on the side of or through the feed receptacle 12, ensuring electrical safety and preventing water ingress.

[0040] An upper perforated plate 22 forms part of the feed receptacle 12. This upper perforated plate 22 is circular and comprises a plurality of spaced apart openings 24. These openings 24 are configured to establish fluid communication with an arrangement of photocatalytic filter capillary tubes 26.

[0041] The arrangement of photocatalytic capillary tubes 26 operably connects the feed receptacle 12 to the filtrate tank 38, which is positioned at the bottom of the water filtration assembly 10. The arrangement of photocatalytic filter capillary tubes 26 comprises several individual capillary tubes, each in fluid communication with the feed receptacle 12 via the upper perforated plate 22. As depicted in the figures, the arrangement of photocatalytic capillary tubes includes at least a first photocatalytic capillary tube 28 and a second photocatalytic capillary tube 30 both defining a channel / bore 32 and each having a plurality of coils. A support / core member 34, in the form of a transparent hollow tube, is provided centrally within the bore 32, and extends centrally between a lower surface of the feed receptacle 12 and upper surface of the filter tank 38. A series of LED light strips 36 (visible in Figure 4) are fitted externally on the support / core member 34 and may be arranged in an array on the external surface of the core member. These LED light strips 36 are specifically arranged to emit light radially outwards, facing an inner side or inner radius of the arrangement of coiled photocatalytic capillary tubes 26.

[0042] The transparent hollow tube, or support / core member 34, serves multiple structural and functional roles. It is arranged to maintain a defined physical separation between the feed receptacle 12 and the filtrate tank 38. Furthermore, the support / core member 34 provides a structural support for the entire capillary tube arrangement 26. A photocatalytic filter element, in the form of a filter bed, is fitted within the lumen of each of the capillary tubes 28, 30. The filter bed comprises a spongy polymer material that is embedded with photocatalytic nanomaterials. This spongy polymer material is fitted inside the capillary tubes 28, 30 and may also coat an internal wall 48 of each of the capillary tubes 28, 30. The photocatalytic nanomaterials are configured as nanofibers, in particular electrospun fibers, which are further embedded with photocatalytic nanoparticle composites. These nanoparticle composites are constituted of metal oxides and carbonaceous materials, selected for their ability to be activated by visible light. The packing density of the electrospun nanofibers within the filter bed is precisely controlled to balance optimal filtration efficiency with the desired water flow rate. The photocatalytic filter element is designed to not only physically filter pollutants but also to actively degrade them when exposed to light, providing a selfcleaning mechanism.

[0043] The upper perforated plate 22 and its corresponding lower perforated plate 40 act as terminal points for the arrangement of photocatalytic capillaries 26. The lower perforated plate 40 opens into the filtrate tank 38. Both the upper perforated plate 22 and the lower perforated plate 40 are each fitted with a porous filter material (not shown). The porous filter material fitted in the upper plate 22 acts as an additional prefilter, providing a secondary stage of coarse filtration before water enters the capillaries. The porous filter material (not shown) fitted to the lower plate 40 acts as a retention sieve 41 , primarily to prevent the photocatalytic filter bed material from extruding out of the capillaries and into the filtrate tank 38.

[0044] The water filtration assembly 10 further comprises a power generating and storage assembly. This assembly integrates the photovoltaic sheet 18, which functions as a solar panel, and the rechargeable batteries (not shown), which serve as a power storage device. The power generating and storage assembly is configured to supply electrical power to the LED light strips 36 as required. The power generating and storage assembly also includes suitable circuitry (not shown) that is specifically arranged to activate the LED light strips 36 when the ambient light intensity, such as from the sun, falls below a predetermined threshold. This ensures continuous illumination of the photocatalytic filter elements, maintaining the self-cleaning and purification process regardless of external light conditions.

[0045] The water filtration assembly 10 comprises the filtrate tank 38 for collecting and holding filtered water. This filtered water is obtained from the outlet ends (not individually numbered) of the capillary tubes 28, 30, which discharge into the filtrate tank 38 via one or more perforated openings 42 defined on the lower plate 40 of the filtrate tank 38.

[0046] A tap 44 is fitted to an outlet 45 defined on a sidewall of the filtrate tank 38, providing a controlled dispensing point for the purified water. Although not explicitly shown in the provided figures, emergency flush valves may be integrated into the feed receptacle 12 and the filtrate tank 38. The valves would allow for rapid draining and flushing of the receptacles 12, 38 for maintenance or in emergency situations.

[0047] In use, raw, unfiltered water is introduced into the feed receptacle 12. From the feed receptacle 12, the water flows into the first and second capillary tubes 28, 30, which house the photocatalytic filter beds. The LED light strips 36 are illuminated, either directly by incident light captured by the photovoltaic sheet 18 from the sun or by the rechargeable batteries (not shown) when solar radiation is insufficient. The illumination from the LED light strips 36 activates the photocatalytic nanomaterials within the filter beds and on the internal walls of the capillary tubes 28, 30. This activation initiates a photocatalytic degradation process which degrades the pollutants present in the raw water, breaking them down into harmless molecules. Typically, the process removes over 99% of organic pollutants in the water. Concurrently, the physical structure of the filter beds removes suspended particles. The continuous photocatalytic action on the accumulated pollutants within the filter bed prevents pore clogging, ensuring the self-cleaning property and sustained filtration efficiency. Filtered and purified water is then discharged from the ends of the first and second capillary tubes 28, 30 and collected in the filtrate tank 38. The purified water can then be accessed from the filtrate tank 38 via the tap 44. This integrated system provides efficient, sustainable, and low-maintenance water purification.

Claims

CLAIMS1 . A water filtration assembly comprising: a feed receptacle configured to receive and hold raw water; a filtrate tank configured to collect filtered water; a photocatalytic filter element in fluid communication between the feed receptacle and the filtrate tank, the photocatalytic filter element (26) comprising: at least one capillary tube; and a photocatalytic filter bed disposed within the at least one capillary tube, the filter bed comprising nanofibers embedded with photocatalytic nanoparticle composites, wherein the photocatalytic filter bed is activatable by visible light; and a light, activation source arranged to illuminate the photocatalytic filter bed, wherein the photocatalytic filter bed, once illuminated, is arranged to degrade pollutants accumulating within the filter bed, thereby maintaining the permeability of the filter bed.

2. The water filtration assembly according to claim 1 , wherein the at least one capillary tube is in a configuration of a coil having an inlet end in fluid communication with the feed receptacle and an outlet end in fluid communication with the filtrate tank.

3. The water filtration assembly according to claim 2, wherein the coil comprises a single or multiple loops located around a central core member.

4. The water filtration assembly according to any preceding claim, wherein the photocatalytic filter bed comprises electrospun polyacrylonitrile fibers.

5. The water filtration assembly according to any preceding claim, wherein internal walls of the at least one capillary tube are coated with photocatalytic nanoparticle composites.

6. The water filtration assembly according to any preceding claim, wherein the photocatalytic nanoparticle composites comprise metal oxides and carbonaceous materials, wherein the metal oxides are selected from a group comprising one or more of titanium dioxide, doped titanium dioxide, zinc oxide, doped zinc oxide and combinations thereof, and wherein the carbonaceous materials are selected from a group comprising one or more of carbon nanotubes, amorphous carbon nanotubes, oxidized carbon nanotubes, doped carbon nanotubes and combinations thereof.

7. The water filtration assembly according to any preceding claim, wherein the light, activation source comprises a plurality of illumination generating devices.

8. The water filtration assembly according to claim 7, wherein the plurality of illumination generating devices are LED light strips.

9. The water filtration assembly according to claim 7, when dependent on claim 3, wherein the illumination generating devices are fitted around the central core member and arranged to face an inner side of the single or multiple loops of the coil.

10. The water filtration assembly according to any preceding claim, further comprising a power generating and storage assembly comprising a photovoltaic sheet and a rechargeable battery, wherein the power generating and storage assembly is configured to provide electrical power to the light, activation source.

11. The water filtration assembly according to claim 10, wherein the power generating and storage assembly further comprises circuitry configured to activate the light, activation source at lower ambient light intensity.

12. The water filtration assembly according to any preceding claim, further comprising a tap connected to the filtrate tank.

13. The water filtration assembly according to any preceding claim, wherein the feed receptacle comprises a sieve configured to filter large, suspended solids.

14. The water filtration assembly according to any preceding claim, wherein the filtrate tank comprises a service outlet configured for flushing the assembly.

15. A photocatalytic filter element for a water filtration assembly, the photocatalytic filter element comprising: at least one capillary tube; and a photocatalytic filter bed disposed within the at least one capillary tube, the filter bed comprising nanofibers embedded with photocatalytic nanoparticle composites, wherein the photocatalytic filter bed is activatable by visible light to degrade pollutants, in use.

16. The photocatalytic filter element according to claim 15, wherein the at least one capillary tube is in a configuration of a coil having an inlet end configured for fluid communication with a feed receptacle and an outlet end configured for fluid communication with a filtrate tank.

17. The photocatalytic filter element according to claim 16, wherein the coil comprises a single or multiple loops operably located around a central core member of a water filtration assembly.

18. The photocatalytic filter element according to any of claims 15 to 17, wherein the nanofibres are electrospun polyacrylonitrile fibers.

19. The photocatalytic filter element according to any of claims 15 to 18, wherein internal walls of the at least one capillary tube are coated with the photocatalytic nanoparticle composites.

20. The photocatalytic filter element according to any of claims 15 to 19, wherein the photocatalytic nanoparticle composites comprise metal oxides and carbonaceous materials, wherein the metal oxides are selected from a group comprising one or more of titanium dioxide, doped titanium dioxide, zinc oxide, doped zinc oxide and combinations thereof, and wherein the carbonaceous materials are selected from a group comprising one or more of carbon nanotubes, amorphous carbon nanotubes, oxidized carbon nanotubes, doped carbon nanotubes and combinations thereof.

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