System for removing chloramine compounds from swimming pool water using a visible light-reactive photocatalyst

Abstract

A system for removing chloramine compounds from swimming pool water using a visible light-responsive photocatalyst, comprising: a) a photocatalytic reactor unit configured to contain a carbon nitride-based photocatalyst capable of degrading mono-, di- and trichloramine compounds upon irradiation with visible light; b) a water circulation unit integrated into the photocatalytic reactor unit, configured to circulate swimming pool water through the photocatalytic reactor unit; c) a visible light irradiation unit configured to provide visible light irradiation to activate the carbon nitride-based photocatalyst; and d) a by-product separation unit configured to separate degraded chloramine by-products from the treated water.

Description

AREA OF INVENTION

[0001] The present disclosure relates to a system for removing chloramine compounds from swimming pool water using a photocatalyst responsive to visible light. In particular, the present invention relates to a system that uses carbon nitride as an efficient and stable photocatalyst capable of degrading mono-, di-, and trichloramines under natural sunlight or artificial irradiation with visible light. BACKGROUND OF THE INVENTION

[0002] Swimming pools require continuous water treatment to ensure hygiene and prevent the growth of harmful microorganisms. Chlorine-based disinfectants are frequently used for this purpose. However, these react with organic and nitrogenous compounds in the water to form chloramines. Chloramines cause various problems, including skin and eye irritation, unpleasant odors, and reduced disinfection effectiveness. Furthermore, certain chloramines, such as trichloramine (NCl3), can pose respiratory risks and contribute to air pollution in enclosed swimming pools.

[0003] Conventional systems for removing chloramines include dilution, chemical treatments, and UV irradiation. However, these approaches have significant drawbacks. Dilution leads to excessive water waste, chemical treatments can release unwanted byproducts, and UV-based systems require high energy consumption, making them costly and environmentally unsustainable.

[0004] To overcome these limitations, an energy-efficient and environmentally friendly system for the degradation of chloramines without excessive chemical additives or external energy sources is required. This invention proposes a system with carbon nitride-based photocatalysts that utilize visible light—especially sunlight—to efficiently degrade chloramine compounds. Carbon nitride is a stable, non-toxic, and cost-effective material with a suitable band gap for activation by visible light and is therefore ideally suited for sustainable swimming pool water treatment. Summary of the invention

[0005] The present disclosure relates to a system for removing chloramine compounds from swimming pool water using a photocatalyst responsive to visible light. The system comprises a photocatalytic reactor unit with a carbon nitride photocatalyst, a water circulation unit for continuous water flow, a visible light irradiation unit utilizing natural sunlight or artificial visible light, and a by-product separation unit for removing decomposed compounds. The carbon nitride photocatalyst, with a band gap of approximately 2.7 eV, effectively decomposes mono-, di-, and trichloramine compounds into harmless by-products such as nitrogen gas, chloride ions, and water.The system does not require additional chemical disinfectants or energy-intensive UV lamps, thus offering a sustainable and cost-effective solution for swimming pool water treatment without endangering the health risks associated with chloramine exposure.

[0006] The present disclosure aims to provide a system for removing chloramine compounds from swimming pool water using a photocatalyst responsive to visible light. The system comprises: a) a photocatalytic reactor unit containing a carbon nitride-based photocatalyst capable of degrading mono-, di-, and trichloramine compounds upon irradiation with visible light; b) a water circulation unit integrated into the photocatalytic reactor unit, which circulates swimming pool water through the photocatalytic reactor unit; c) a visible light irradiation unit that activates the carbon nitride-based photocatalyst by irradiation with visible light; and d) a by-product separation unit that separates degraded chloramine by-products from the treated water.

[0007] One objective of the present disclosure is to provide a system for removing chloramine compounds from swimming pool water using a photocatalyst that responds to visible light.

[0008] A further objective of the present disclosure is to provide an environmentally friendly swimming pool water treatment system that utilizes natural sunlight as the primary activation source, thereby eliminating the need for energy-intensive UV lamps or excessive chemical disinfectants. This reduces operating costs and environmental impact while maintaining effective chloramine removal.

[0009] Another objective of the present disclosure is to effectively remove harmful chloramine compounds (mono-, di- and trichloramines) from swimming pool water without introducing additional chemical contaminants, thereby reducing skin, eye and respiratory irritation associated with prolonged chloramine exposure and improving the overall safety of swimmers.

[0010] Another objective of this disclosure is to integrate the water treatment system into the existing filtration infrastructure of swimming pools. Several configuration options are available, including suspended photocatalyst chambers, fixed-bed reactors, and coated filter systems, thus enabling continuous operation during normal swimming pool maintenance cycles.

[0011] To further clarify the advantages and features of the present disclosure, the invention is explained in more detail with reference to specific embodiments illustrated in the accompanying drawings. These drawings merely show typical embodiments of the invention and are therefore not to be understood as limiting its scope. The invention is described and explained more precisely and in greater detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE FIGURES

[0012] These and other features, aspects, and advantages of the present disclosure will be better understood if the following detailed description is read with reference to the accompanying drawings, in which identical symbols consistently represent identical parts. The following applies: Fig. Figure 1 shows a block diagram of a system for removing chloramine compounds from swimming pool water using a photocatalyst that reacts to visible light according to an embodiment of the present disclosure. Fig. Figure 2 shows a schematic diagram illustrating the mechanism of water treatment carried out by the proposed system according to an embodiment of the present disclosure; and Fig. Figure 3 shows a graphical representation of the photolysis of chloramine under different light sources according to an embodiment of the present disclosure.

[0013] Experts will also recognize that the elements in the drawings are presented for the sake of simplicity and are not necessarily to scale. For example, the flowcharts illustrate the process by highlighting the main steps to enhance understanding of the aspects of this disclosure. Furthermore, with regard to the design of the device, one or more components of the device may be represented in the drawings by conventional symbols, and the drawings may show only the specific details relevant to understanding the embodiments of this disclosure, so as not to clutter the drawings with details that are readily apparent to those skilled in the art after reading this description. DETAILED DESCRIPTION:

[0014] For a better understanding of the inventive principles, reference is made below to the embodiment shown in the drawings, which is described in specific language. However, this does not limit the scope of the invention. Changes and further modifications of the illustrated system, as well as further applications of the inventive principles, are possible, as would normally occur to a person skilled in the art in this field.

[0015] It is clear to the person skilled in the art that the preceding general description and the following detailed description are exemplary and explanatory of the invention and are not intended as a limitation of it.

[0016] References in this specification to “an aspect”, “another aspect”, or similar expressions mean that a particular feature, structure, or property described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, occurrences of the expressions “in one embodiment”, “in another embodiment”, and similar expressions in this specification may all refer to the same embodiment, but need not.

[0017] The terms "includes," "include," or other variations thereof are intended to cover non-exclusive inclusion, such that a process or method that includes a list of steps may not only contain those steps but may also include other steps not expressly listed or inherent in such process or method. Likewise, the statement "includes..." in the case of one or more devices, subsystems, elements, structures, or components does not, without further limitations, preclude the existence of other devices, subsystems, elements, structures, components, or additional devices, subsystems, elements, structures, or components.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by a person skilled in the art in the field of the invention. The system, methods, and examples provided here serve only for illustration and are not to be construed as a limitation.

[0019] Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0020] Fig. Figure 1 shows a block diagram of a system (100) for removing chloramine compounds from swimming pool water using a photocatalyst that responds to visible light according to an embodiment of the present disclosure.

[0021] Referring to Fig. 1 The system (100) comprises: a) a photocatalytic reactor unit (102) containing a carbon nitride-based photocatalyst capable of degrading mono-, di-, and trichloramine compounds upon irradiation with visible light; b) a water circulation unit (104) integrated into the photocatalytic reactor unit (102) that circulates swimming pool water through the photocatalytic reactor unit (102); c) a visible light irradiation unit (106) that provides visible light irradiation to activate the carbon nitride-based photocatalyst; and d) a by-product separation unit (108) that separates degraded chloramine by-products from the treated water.

[0022] In one embodiment, the carbon nitride-based photocatalyst is selected from the group consisting of solid carbon nitride, nanolayer carbon nitride, mesoporous carbon nitride structures and carbon nitride composites.

[0023] In one embodiment, the carbon nitride-based photocatalyst is modified with dopants selected from the group consisting of transition metals, comprising Ni, Fe, Cu and Pt, and non-metals, comprising S, P and B, to improve charge separation and the absorption of visible light.

[0024] In one embodiment, the photocatalytic reactor unit (102) is configured in a form selected from the group consisting of a suspended photocatalyst chamber, a fixed-bed reactor, a coated filter system and a reactor with an immobilized surface.

[0025] In one embodiment, the photocatalytic reactor unit (102) comprises a coating of the carbon nitride-based photocatalyst applied to surfaces selected from the group consisting of filtration membranes, quartz tubes, ceramic supports and glass tubes.

[0026] In one embodiment, the photocatalytic reactor unit (102) is integrated into the existing filter system and water circulation unit (104) of a swimming pool and is configured to operate continuously during the normal circulation cycles of the pool water.

[0027] In one embodiment, the carbon nitride-based photocatalyst has a band gap of approximately 2.7 eV and is configured to generate reactive oxygen species, including superoxide radicals and hydroxyl radicals, when activated with visible light.

[0028] In one embodiment, the exposure unit (106) for visible light is configured to use natural sunlight as the primary activation source, without requiring external electrical energy to activate the photocatalyst.

[0029] In one embodiment, the system (100) also includes a monitoring unit (110) configured to measure the chloramine concentration levels and water quality parameters in the treated swimming pool water.

[0030] In one embodiment, the system is configured to enable the degradation of chloramine compounds into harmless byproducts such as nitrogen gas, chloride ions and water, without the need for additional chemical disinfectants.

[0031] The present invention relates to a chloramine removal system consisting of four primary functional units that operate in a coordinated manner: The photocatalytic reactor unit contains a carbon nitride-based photocatalyst in various forms, including solid carbon nitride, nanolayers, or doped variants, wherein the reactor can be configured as a suspended chamber, fixed-bed system, or coating on existing filter components. The water circulation unit ensures a continuous flow of pool water through the photocatalytic reactor and maintains contact between the contaminated water and the photocatalyst for effective treatment. The visible light irradiation unit provides the necessary irradiation with visible light to activate the photocatalyst.The system primarily utilizes natural sunlight, but artificial visible light sources are also compatible for indoor applications. The by-product separation unit separates and removes degraded chloramine by-products from the treated water, ensuring the return of clean water to the swimming pool. When the pool water circulates through the reactor under the influence of visible light, the carbon nitride photocatalyst generates reactive oxygen species (superoxide and hydroxyl radicals) that break down chloramine compounds into harmless products, thus continuously improving water quality without the need for chemical additives.

[0032] Fig. Figure 2 shows a schematic diagram illustrating the mechanism of water treatment carried out by the proposed system according to one embodiment of the present disclosure.

[0033] In one embodiment, graphitic carbon nitride nanopowder is applied to a glass tube near the swimming pool. The swimming pool water circulates continuously through the circulating glass tube, which is located in a chamber exposed to sunlight (see Fig. 2) During circulation, chloramine compounds in the water are photocatalytically broken down into harmless byproducts, resulting in improved water quality without additional chemical treatment.

[0034] The present invention provides a system for removing chloramine compounds from swimming pool water using a carbon nitride-based photocatalyst activated by visible light, particularly sunlight. The invention utilizes the photocatalytic properties of carbon nitride to efficiently degrade and remove chloramines without the need for excessive chemical treatments or energy-intensive UV irradiation.

[0035] In one embodiment, the invention utilizes a modified carbon nitride material with enhanced photocatalytic activity under visible light. The photocatalyst can be introduced into the swimming pool water in various forms, for example, as suspended nanoparticles, as a coated filter system, or as a fixed-bed reactor. Upon exposure to sunlight, the photocatalyst generates reactive species that decompose chloramine compounds into harmless byproducts. This improves water quality and minimizes the health risks associated with prolonged chloramine exposure. The invention offers a sustainable, cost-effective, and energy-efficient alternative to conventional methods of chloramine removal.By harnessing the power of visible light, especially natural sunlight, the system operates with minimal external energy input, thus providing an environmentally friendly solution for continuous swimming pool water treatment.

[0036] In one embodiment, the photocatalyst consists of carbon nitride (C3N4), a metal-free semiconductor with a band gap of approximately 2.7 eV, which makes it reactive to visible light. The material can be produced in various forms, including solid carbon nitride, nanolayers, mesoporous structures, or composites. In certain embodiments, the photocatalyst can be modified by doping with transition metals (e.g., Ni, Fe, Cu, Pt) or nonmetals (e.g., S, P, B) to improve charge separation and increase the absorption of visible light. Additionally, coupling carbon nitride with co-catalysts or carbon-based supports can further enhance the photocatalytic efficiency.

[0037] In one implementation, the carbon nitride photocatalyst can be used in several configurations, including: suspended powder form, where the photocatalyst is distributed directly in the pool water; immobilized coating, applied to the surface of filter membranes, quartz tubes, ceramic supports, or pool liners; fixed-bed or cartridge system, where water circulates through a reactor filled with the photocatalyst; and hybrid filtration-photocatalysis units, which allow simultaneous physical filtration and chemical decomposition of chloramines.

[0038] In one implementation, the carbon nitride photocatalyst is photoexcited by visible light, generating electron-hole pairs. These charge carriers trigger redox reactions at the surface of the photocatalyst: Photoexcited electrons reduce dissolved oxygen and generate superoxide radicals (·O₂). - ); and photogenerated holes oxidize water or hydroxide ions, generating hydroxyl radicals (·OH). These reactive oxygen species attack chloramine compounds such as monochloramine (NH₂Cl), dichloramine (NHCl₂), and trichloramine (NCl₃), decomposing them into harmless products such as nitrogen gas (N₂) and chloride ions (Cl₂). -) and water (H₂O). The carbon nitride can operate efficiently under visible light, especially natural sunlight, thus eliminating the need for expensive artificial UV light sources. This allows for continuous operation in outdoor swimming pools and significant energy savings. In indoor swimming pools, visible light LED sources can be used to activate the photocatalyst.

[0039] Fig. Figure 3 shows a graphical representation of the photolysis of chloramine under different light sources according to an embodiment of the present disclosure.

[0040] In Fig. Figure 3 shows the photolysis of chloramine under dark conditions, under UV illumination and after illumination with visible light compared to photocatalysis via carbon nitride.

[0041] In one embodiment, the massive graphitic carbon nitride (g-C3N4) was synthesized by thermal polymerization of melamine. Ten grams of melamine were placed in a covered aluminum crucible and heated in air at a rate of 5 °C / min to 550 °C for four hours. The resulting yellow powder was milled and collected as massive g-C3N4. To enhance performance, exfoliated g-C3N4 nanosheets were produced by ultrasonic treatment of the massive material in ethanol and subsequently dried at 80 °C. The resulting nanosheets exhibited a larger surface area and improved photocatalytic activity.

[0042] In another embodiment, a 100 mg / l suspension of g-C3N4 nanosheets was placed in simulated swimming pool water containing 2 mg / l chloramine compounds (NH₃ × Cl₂). yThe suspension was prepared. It was irradiated with a visible light halogen lamp (λ > 420 nm) to simulate visible sunlight. The results showed that more than 95% of the monochloramine was degraded within 60 minutes of irradiation, whereas without a photocatalyst or in the dark, only negligible degradation occurred (see [reference]). Fig. ).

[0043] In another embodiment, a prototype fixed-bed reactor was constructed by depositing g-C3N4 nanosheets onto a porous ceramic substrate. The reactor was integrated into the circulation system of a 200-liter swimming pool model. The system was operated outdoors under natural sunlight (average intensity ~50,000 lux). After four hours of circulation, the total chloramine concentration decreased by ~80%, compared to only a 10% reduction in a control pool without a photocatalyst. Water clarity and odor improved significantly.

[0044] In another example, a comparative study was conducted between g-C3N4 photocatalysis (sunlight-powered) and conventional UV treatment. With the same treatment duration (3 hours), the photocatalyst under sunlight achieved a chloramine removal rate of 75%, while the UV lamp achieved a removal rate of 70%, but consumed 450 Wh of electrical energy. The photocatalyst process required no external energy input and thus demonstrated greater sustainability.

[0045] The results confirm that carbon nitride photocatalysts degrade chloramines with high efficiency under visible light, including natural sunlight. The invention offers a sustainable, chemical-free, and energy-saving method for swimming pool water treatment compared to conventional UV or chemical-based methods.

[0046] The present invention is used in the field of water treatment, particularly in the management and purification of swimming pool water. The carbon nitride-based photocatalyst can be produced on a large scale using inexpensive raw materials such as melamine or urea, making the technology practical and economical for commercial use. The invention can be integrated into existing swimming pool circulation and filtration systems without significant modifications, thus enabling easy application in both private and public swimming pools. Thanks to its ability to operate efficiently under visible light, especially natural sunlight, the system significantly reduces energy consumption compared to conventional UV treatment methods and is therefore suitable for large outdoor pools and energy-conscious facilities.Beyond swimming pools, the invention can also be applied in related industries where the removal of chloramine or the control of disinfection byproducts is required, such as in spa and leisure water treatment systems, aquaculture facilities, industrial water recycling systems, and municipal water treatment plants (for the degradation of residual chloramine). Thus, the invention offers a scalable, sustainable, and environmentally friendly solution for the water treatment industry.

[0047] The proposed system is energy-efficient, utilizing visible light, primarily sunlight, thus reducing operating costs. It offers safety by avoiding or minimizing chemical additives and preventing secondary contamination. The proposed system is sustainable because carbon nitride is inexpensive, stable, metal-free, and environmentally friendly. Furthermore, it offers health benefits, such as a reduction in skin, eye, and respiratory irritation caused by chloramine exposure. The proposed system offers flexibility in integration, as the photocatalyst can be incorporated into existing pool filtration and circulation systems with minimal modifications.

[0048] The drawings and the preceding description show examples of embodiments. Those skilled in the art will recognize that one or more of the described elements can be combined to form a single functional element. Alternatively, certain elements can be divided into several functional elements. Elements of one embodiment can be added to another embodiment. For example, the sequence of the processes described here can be changed and is not limited to the manner described here. Furthermore, the actions of a flowchart need not be implemented in the sequence shown; nor does it necessarily have to be performed by all actions. Actions that are not dependent on other actions can also be performed in parallel with the other actions. The scope of the embodiments is in no way limited by these specific examples.Numerous variations are possible, whether explicitly stated in the specification or not, such as differences in structure, dimensions, and material use. The range of embodiments is at least as broad as specified in the following claims.

[0049] Advantages, further benefits, and problem solutions have been described above with reference to specific embodiments. However, the advantages, benefits, problem solutions, and all components that can lead to an advantage, benefit, or solution occurring or becoming more apparent are not to be construed as critical, necessary, or essential features or components of individual or all claims. REFERENCES 100 A system for the removal of chloramine compounds from swimming pool water using a photocatalyst that reacts to visible light. 102 A photocatalytic reactor unit 104 Water circulation unit 106 exposure units for 108 By-product separation unit 110 monitoring unit 202 Swimming pool 204 Water circulation 206 Glass tube, internally coated with carbon nitride 302 Chloramine (%) 304 Time (min) 306 Photolysis UV 308 Photolysis Vis 310 CN Photocatalysis 312 Dark

Claims

[1] A system for removing chloramine compounds from swimming pool water using a photocatalyst that responds to visible light, comprising: a) a photocatalytic reactor unit configured to contain a carbon nitride-based photocatalyst capable of degrading mono-, di- and trichloramine compounds upon irradiation with visible light; b) a water circulation unit integrated into the photocatalytic reactor unit, configured to circulate swimming pool water through the photocatalytic reactor unit; c) a visible light irradiation unit configured to provide visible light irradiation to activate the carbon nitride-based photocatalyst; and d) a by-product separation unit configured to separate degraded chloramine by-products from the treated water. [2] System according to claim 1, wherein the carbon nitride-based photocatalyst is selected from the group consisting of solid carbon nitride, nano-layer carbon nitride, mesoporous carbon nitride structures and carbon nitride composites. [3] System according to claim 1, wherein the carbon nitride-based photocatalyst is modified with dopants selected from the group consisting of transition metals comprising Ni, Fe, Cu and Pt, and non-metals comprising S, P and B, to improve charge separation and the absorption of visible light. [4] System according to claim 1, wherein the photocatalytic reactor unit is configured in a form selected from the group consisting of a suspended photocatalyst chamber, a fixed-bed reactor, a coated filtration system and a reactor with an immobilized surface. [5] System according to claim 1, wherein the photocatalytic reactor unit comprises a coating of the carbon nitride-based photocatalyst applied to surfaces selected from the group consisting of filtration membranes, quartz tubes, ceramic supports and glass tubes. [6] System according to claim 1, wherein the photocatalytic reactor unit is integrated into the existing filter system and water circulation unit of the swimming pool and is configured to operate continuously during the normal circulation cycles of the pool water. [7] System according to claim 1, wherein the carbon nitride-based photocatalyst has a band gap of approximately 2.7 eV and is configured to generate reactive oxygen species, including superoxide radicals and hydroxyl radicals, upon activation with visible light. [8] System according to claim 1, wherein the exposure unit for visible light is configured to use natural sunlight as the primary activation source without requiring external electrical energy to activate the photocatalyst. [9] System according to claim 1, further comprising a monitoring unit configured to measure the chloramine concentration levels and water quality parameters in the treated swimming pool water. [10] System according to claim 1, wherein the system is configured to achieve the degradation of chloramine compounds into harmless by-products consisting of nitrogen gas, chloride ions and water, without the need for additional chemical disinfectants.

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