A photoreactor

Abstract

In accordance with the invention there is provided a photoreactor (10) having LEDs indicated by blocks for the visible light LED's (12), triangles for the IR LED's (14), and circles for the UV LED's (16), on the inner perimeter walls (18) of the casing (20) which forms the reactor, and which is for use in batch advanced oxidation processes experiments. The reactor consists of a reflective box type metal casing (20) with the LEDs fixed on four inner sides (18) of the casing (20) perimeter and directed inwardly into the casing (20). Inside the casing (20) is a reaction vessel (22) placed atop a magnetic stirrer (24) and having a conductivity probe (26) and a pH probe (28) protruding into the reaction vessel (22).

Description

[0001] A PHOTOREACTOR

[0002] Field of the Invention

[0003] The invention relates to a reactor. In particular, the invention includes a reactor for oxidation processes on a small scale.

[0004] Background to the Invention

[0005] Recent advancements in light emitting diode (LED) technology are inspiring a new generation of innovative reactor designs due to numerous advantages of LEDs over gas discharge lamps. LEDs are less fragile casings, do not contain toxic components, are small, and can rapidly warmup. Opportunities to improve the performance of heterogenous and homogenous photocatalytic water treatment may emerge through advances in materials science and reactor engineering design. Advanced Oxidation Processes (AOPs) encompasses a broad range of chemical processes in which highly oxidative hydroxyl radicals are generated at ambient temperature and atmospheric pressure. The hydroxyl radicals are generally non-selective towards the oxidative degradation of organic compounds and hence AOPs have found wide applications in environmental decontamination and water and wastewater treatment. Formation of the oxidative radicals is initiated by use of oxidants such as ozone (O3), peroxydisulfate (S20s2') and hydrogen peroxide (H2O2) and / or by use of high energy UV photons, solar light, ultrasound energy or electric current or a combination of these. Photocatalysis using semiconductor oxides and chalcogenides such as TiC>2, ZnO, Fe2C>3, CdS, GaP, ZnS etc is one of the most studied AOPs. The principle of photocatalysis lies in the absorption of photons of sufficient energy to excite an electron (e-) from the valence band to the conduction band of the semiconductor, leaving behind a hole (h+) in the valence band. In water treatment applications, photoreactors are based on suspended powdered nanoparticles (slurry) or immobilised nanoparticles. In both cases the light source for activation of the oxidants or the semiconductor nanoparticles becomes crucial.

[0006] Different kinds of light sources such as mercury / argon lamps, deuterium lamps, tungsten-filament, xenon lamps, xenon / mercury lamps, florescence lamps, light emitting diodes (LEDs), and the natural solar light have all been used as viable light sources for advanced oxidation processes.

[0007] LED’s are small light bulbs that do not have filaments and can fit easily into an electrical circuit. They consume less electricity and minimises energy loss due to heat generation. Illumination in LEDs is due to movement of electrons in a semiconductor material, and thus they last longer. The lifespan of an LED surpasses that of an incandescent bulb by thousands of hours. LEDs produce more lumens (or visible light) per watt and have a higher luminous efficacy than regular incandescent bulbs. A 60- watt incandescent bulb can generate between 750 - 900 lumens, which can be generated from a 6 - 8 watt LED. The same LED can last 25,000 hours while the 60- watt incandescent can only last up to about 1 ,200 hours.

[0008] In this specification, the term UV / Vis / IR LED means ultra violet, visible light, and / or infra red light sources.

[0009] Summary of the Invention

[0010] This invention provides for the use of LED light as a light source in the design of a batch photoreactor, typically such as that for use in laboratory experiments, but this may be upscaled in the future based on the principles set out herein.

[0011] According to a first aspect of the invention, there is provided a photoreactor having one or more of ultra violet, visible light, and infra red (UV / Vis / IR) LED light sources for use in batch advanced oxidation processes.

[0012] The batch advanced oxidation reactor may be an experimental reactor or for use in experiments.

[0013] The reactor may include a reflective casing having a permitter wall and an inner chamber defined by the perimeter, with fixed LED’s directed inwardly from several locations along the perimeter of the casing. In the instance of the casing being box shaped in profile, the LED’s are located on each of the four sides of the casing.

[0014] The casing may be made of metal.

[0015] The inner chamber may accommodate reactor vessels of up to 2000mL and include a magnetic stirrer of dimensions that permit the stirrer to fit into the reactor. The reactor vessels may be of standard volumes selected from 50mL, 100mL, 150mL, up to 2000mL and preferably made from quartz glass.

[0016] The inner chamber may include a flow through reactor system.

[0017] An electronic controller may be attached to the reactor for controlling power supply to the LED and has inputs for pH and conductivity probes.

[0018] The photoreactor may include or be used together with:

[0019] (a) pH and conductivity control system

[0020] (b) Turbidity measurement sensor

[0021] (c) Irradiance measuring device

[0022] (d) Auto switch system

[0023] (e) Autosampler capability - to handle up to 50 samples (f) Use of a cylindrical chamber with many LEDs up to a total maximum power of 500 watts

[0024] (g) Flow through reactor vessel with a separate flow and pressure control system and a feed tank

[0025] (h) Electronic control software.

[0026] Thus, this versatile reactor may be used for experiments in which UV / Vis / IR light may be required.

[0027] Description of embodiments of the Invention

[0028] The invention will now be described, by way of non-limiting example only, with reference to the accompanying diagrammatic drawings and representations.

[0029] In the drawings and representations,

[0030] Fig 1 shows a photograph representation of a prototype photoreactor generally in accordance with the invention;

[0031] Fig 2 shows a sketch of a magnetic stirrer for use with the photoreactor; Fig 3 shows a flow reactor arrangement for use with the photoreactor; and

[0032] Fig 4 shows a schematic arrangement of a photoreactor broadly in accordance with the invention.

[0033] In an example of the invention as shown in Figures 1 and 4, there is provided a photoreactor 10 having LEDs indicated by blocks for the visible light LED’s 12, triangles for the IR LED’s 14, and circles for the UV LED’s 16, on the inner perimeter walls 18 of the casing 20 which forms the reactor, and which is for use in batch advanced oxidation processes experiments.

[0034] In the embodiment of the example of the invention illustrated in the Figures 1 and 4, the reactor consists of a reflective box type metal casing 20 (in this example 22 cm x 22 cm x 30 cm) with LEDs shown in Figure 4 indicated by blocks for the visible light LED’s 12, triangles for the IR LED’s 14, and circles for the UV LED’s 16, fixed on four inner sides 18 of the casing 20 perimeter and directed inwardly into the casing 20. Inside the casing 20 is a reaction vessel 22 placed atop a magnetic stirrer 24 and having a conductivity probe 26 and a pH probe 28 protruding into the reaction vessel 22. The magnetic stirrer 24 is shown separately in Figure 2.

[0035] An electronic controller 30 with an LED display 32, is located outside the casing 20 but operatively connected to the casing 20 and its contents so as to control the LED’s 12, 14, 16, the probes 26 and 28, and the stirrer 24 and to record data being collected from an experiment conducted therein.

[0036] The inner chamber 19 can accommodate reactor vessels 22 of up to 2000 mL sitting on the magnetic stirrer 24 of dimensions 11 cm x 11 cm footprint and 14.5 cm in height that can allow it to fit into the reactor 10. A flow through reactor system 40 having a spiral tube 42 connected to a peristaltic pump for reactants to be pumped therethrough as shown in Fig 3 can also be accommodated in the inner chamber 19 instead of the reaction vessel 22 of Fig 4.

[0037] Thus, this versatile reactor shown in the Figures can be used for all experiments in which UV / Vis / IR light may be required.

[0038] Photoreactors have found applications in a wide range of fields that include wastewater treatment, food production, material science, electronics, chemistry, air pollution, dye sensitised solar cells, medicine, and biotechnology. In most of these applications, photoreactors are used to monitor the effect of irradiance on a chemical reaction or the device response to light irradiation. In antimicrobial studies, the effect of visible light on pathogen inactivation is studied. Photochemistry studies include reactions on activation of oxidants, synthesis of new chemicals, toxic gas oxidation, and photochemical response monitoring studies. In the example above:

[0039] 1 . UVA / is / IR LED photoreactor specifications

[0040] (a) Casing material - steel

[0041] (b) L x W x H = 22 cm 22 cm x 30 cm

[0042] (c) Four panel LED array

[0043] (d) Number of LEDS on the side panel = 12

[0044] (e) Power rating of each LED = 4.167 Watts

[0045] (f) Wavelength range of each UV LED = 365 - 385 nm

[0046] (g) Wavelength range of each Vis LED = 450 to 700 nm (Amax = 600nm)

[0047] (h) Wavelength range of each IR LED = 800 to 900 nm (Amax = 850nm)

[0048] 2. Magnetic stirrer specifications

[0049] (a) AC / DC input - 230 VAC

[0050] (b) Material - ceramic plate

[0051] (c) Stirrer speed - 100 -1500 rpm

[0052] (d) W x D x H = 200 mm x 200 mm x 100 mm

[0053] (e) Platform size = 200 mm x 200 mm

[0054] (f) Stirrer volume Up to 2 L Benefits of the Invention as Illustrated

[0055] The inventor believes that benefits of this invention include simplicity of the design and low cost of the photoreactor. Flexibility in operation of the photoreactor means small to large volume experiments can be accommodated. The irradiance power from the LEDs can be controlled between 50% and 100% depending on the experimental requirements.

[0056] Another believed benefit is that the system can accommodate attachment of other convenient electronic systems such as turbidity measurement, auto switch system, autosampler and data logging component. Another benefit is safety of using LEDs compared to existing systems is being able to control the radiation flux electronically. The UV, Vis and IR LEDs can be used separately or combined by selecting the proper combination from the electronics controller.

Claims

Claims1. A photoreactor having one or more perimeter walls forming a chamber, wherein the chamber has one or more reflective inner wall portions, one or more of ultra violet, visible light, and infra red LED light sources located within the chamber and directed inwardly for use in illuminating a reactor in which batch advanced oxidation processes are carried out.

2. A photoreactor as claimed in claim 1 , wherein one or more of the perimeter walls is metallic.

3. The photoreactor as claimed in claim 1 or claim 2, wherein the LED light sources are fixed LEDs directed inwardly from several locations along the perimeter of the casing.

4. The photoreactor as claimed in claim 3, wherein in the instance of the casing being box shaped in profile, the LEDs are located on each of the four sides of the casing.

5. The photoreactor as claimed in any one of the preceding claims, wherein the inner chamber is sized and dimensioned to accommodate a reactor vessel ofup to 2000 mL and a magnetic stirrer of dimensions that permit the stirrer to fit into the reactor.

6. The photoreactor as claimed in claim 5, wherein the reactor vessel is of standard volumes selected from 50 mL, 100 mL, 150 mL, up to 2000 mL made from quartz glass.

7. The photoreactor as claimed in any one of the preceding claims, wherein the chamber includes a flow through reactor system.

8. The photoreactor as claimed in any one of the preceding claims, wherein an electronic controller is attached to the reactor for controlling power supply to the LED’s and has inputs for pH and conductivity probes.

9. The photoreactor as claimed in any one of the preceding claims, which includes one or more of:(a) pH and conductivity control system;(b) Turbidity measurement sensor;(c) Irradiance measuring device;(d) Auto switch system;(e) Autosampler;(f) LEDs up to a total maximum power of 500 watts;(g) flow through reactor vessel with a separate flow and pressure control system and a feed tank; and(h) Electronic control software.

10. A photoreactor as claimed in claim 1, substantially as herein described and illustrated.

11. A new photoreactor substantially as herein described.

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