A solar-powered system for the photocatalytic detoxification of industrial dyes using green synthesized copper oxide nanoparticles

Abstract

A system for the synthesis and characterization of luminescent copper oxide nanoparticles, comprising: a) an extract preparation plant configured to produce an extract from white garland leaves by boiling cut leaves in double distilled water and subsequently filtering the mixture; b) a synthesis unit configured to mix a copper sulfate solution with the extract from white garland leaves and to obtain a black colored solid under stirring conditions; c) a centrifuge configured to separate the black-colored solid from the mixture; d) a combustion unit configured to subject the separated solid to heat treatment in a muffle furnace to obtain copper oxide nanoparticles; e) a characterization unit for the analysis of the copper oxide nanoparticles, wherein the characterization unit includes: UV-Vis spectrophotometer, X-ray diffractometer, photoluminescence spectrometer, etc. f) a photocatalytic degradation unit configured to enable the complete removal of industrial dyes (methylene blue) and g) an antimicrobial test unit for evaluating the antibacterial and antifungal activity of the copper oxide nanoparticles.

Description

AREA OF INVENTION

[0001] The present disclosure relates to a solar-powered photocatalytic detoxification system for removing industrial dyes from aqueous media. In particular, the invention discloses a reusable system based on green-synthesized copper oxide nanoparticles that enables the solar-activated photocatalytic degradation of toxic industrial dyes and thus ensures efficient detoxification of contaminated water resources. BACKGROUND OF THE INVENTION

[0002] The rapid expansion of the textile, leather, paper, and chemical industries has led to a massive discharge of synthetic dyes into natural waters. These industrial dyes are highly stable, toxic, and resistant to conventional treatment methods, resulting in serious environmental pollution and hazards to humans and aquatic life. Existing wastewater treatment processes such as adsorption, chemical oxidation, and biodegradation often have limitations, including incomplete dye removal, the formation of secondary pollutants, high operating costs, and high energy consumption.

[0003] In recent years, nanotechnology has established itself as a promising approach for environmental remediation, particularly in the development of photocatalytic systems for water purification. Metal oxide nanoparticles have attracted considerable interest due to their large surface area, chemical stability, and ability to generate reactive species upon exposure to light. Copper oxide nanoparticles (CuONPs) have proven to be promising photocatalysts active in visible light and are therefore suitable for solar-powered detoxification applications.

[0004] Conventional synthesis methods for copper oxide nanoparticles often require toxic chemicals, aggressive reaction conditions, and high energy consumption, limiting their environmental compatibility. In contrast, green synthesis methods using plant extracts offer an environmentally friendly and cost-effective alternative. Plant phytochemicals act as natural reducing and stabilizing agents, thus enabling controlled nanoparticle formation with minimal environmental impact.

[0005] The white garland lily (Hedychium calcium coronarium Koenig), also known as the ginger lily, is a perennial plant from the ginger family (Zingiberaceae) and is widely cultivated in India. It is rich in bioactive phytoconstituents and has been investigated to a limited extent for nanomaterial applications, primarily for the synthesis of silver nanoparticles. However, its potential for the environmentally friendly synthesis of copper oxide nanoparticles and their application in solar-powered photocatalytic detoxification systems has not yet been described.

[0006] Accordingly, there is a need for a sustainable, solar-activated photocatalytic system based on green-synthesized copper oxide nanoparticles that enables the efficient detoxification of industrial dyes from contaminated water. The present invention fulfills this need with an environmentally friendly, reusable, and energy-efficient solar-powered detoxification system. SUMMARY OF THE INVENTION

[0007] The present invention relates to a solar-powered photocatalytic system for the detoxification of industrial dyes from aqueous media using green-synthesized copper oxide nanoparticles. In particular, the invention discloses an environmentally friendly, energy-efficient, and reusable system in which copper oxide nanoparticles are produced by hedychium synthesis. The leaf extract of the white garland (Coronarium) acts as an effective, sunlight-activated photocatalyst for the degradation of toxic dye contaminants in industrial wastewater.

[0008] The described system utilizes a plant-mediated, environmentally friendly synthesis in which phytochemicals contained in extracts from white garland leaves serve as natural reducing and stabilizing agents for the formation of copper oxide nanoparticles.

[0009] The synthesized nanoparticles exhibit strong photocatalytic activity under natural sunlight, enabling the formation of reactive oxygen species. These decompose dye molecules into less toxic or non-toxic products, thus achieving effective detoxification.

[0010] In one embodiment, the invention provides a solar-powered detoxification system comprising the following: a) an extract preparation unit configured to obtain an extract from leaves of the White Garland using an aqueous medium; b) a nanoparticle synthesis unit configured to react a copper precursor solution with the prepared plant extract to form copper oxide nanoparticles; c) a separation and heat treatment unit configured to produce crystalline copper oxide nanoparticles; d) a photocatalytic reaction unit containing dye-laden water and the synthesized copper oxide nanoparticles; and e) a solar irradiation unit configured to expose the reaction unit to natural sunlight and thereby activate the photocatalytic degradation of industrial dyes.

[0011] The system exhibits high photocatalytic degradation performance against industrial dyes such as methylene blue under sunlight, without the need for artificial irradiation or additional chemical oxidizing agents. Of particular note is that the copper oxide nanoparticles retain their photocatalytic activity over multiple reuse cycles, highlighting their suitability for practical and sustainable water purification applications.

[0012] Although the copper oxide nanoparticles may also possess additional antimicrobial properties, the focus of the present invention is on the solar-powered photocatalytic detoxification of industrial dyes, thus offering an environmentally friendly solution for the remediation of dye-contaminated water resources. Brief description of the image

[0013] These and other features, aspects and advantages of the present invention will be better understood when the following detailed description is read in conjunction with the accompanying drawings, in which the same reference numerals denote the same elements. Fig. Figure 1 shows a block diagram of a solar-powered photocatalytic detoxification system using green synthesized copper oxide nanoparticles according to an embodiment of the present invention; Fig. Figure 2 shows an X-ray diffraction (XRD) pattern of copper oxide nanoparticles synthesized using extract from white garland leaves, confirming the crystalline phase and the structural features relevant for efficient photocatalytic activity according to an embodiment of the present invention; Fig. Figure 3 shows a UV-Vis absorption spectrum of the synthesized copper oxide nanoparticles, which exhibits strong optical absorption in the UV-Vis range and, according to an embodiment of the present invention, indicates suitability for activation under natural sunlight for the photocatalytic detoxification of industrial dyes; Fig. Figure 4 shows a photoluminescence (PL) spectrum of the synthesized copper oxide nanoparticles and provides information about the recombination behavior of the charge carriers, which influences the photocatalytic performance under light irradiation, according to an embodiment of the present invention; and Fig. Figure 5 illustrates the performance of solar-driven photocatalytic detoxification of an industrial dye using the green synthesized copper oxide nanoparticles. The degradation rate is shown as a function of the solar irradiation time. This demonstrates the practical detoxification capability and reusability of the system according to one embodiment of the present invention.

[0014] Furthermore, those skilled in the art will recognize that the elements depicted in the drawings are illustrated for clarity and simplicity and are not to scale. In particular, the block diagram illustrates the main functional components of the solar-powered detoxification system to facilitate understanding of the present invention. Certain components can be represented by conventional symbols, and only the details necessary for understanding the inventive aspects of the disclosure have been shown, so as not to clutter the drawings with information that is already obvious to those skilled in the art. DETAILED DESCRIPTION OF THE INVENTION

[0015] To facilitate understanding of the principles of the invention, reference is made below to the embodiment illustrated in the drawings, which is described using specific terms. It is understood, however, that this does not limit the scope of protection of the invention. Rather, modifications and further developments of the illustrated system, as well as further applications of the inventive principles depicted therein, are conceivable, insofar as they would typically occur to a person skilled in the art in the field of the invention.

[0016] It will be clear to those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not to be understood as a limitation of it.

[0017] References to “an aspect”, “another aspect”, or similar phrases in this description 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, phrases such as “in one embodiment”, “in another embodiment”, and similar expressions in this description may, but do not necessarily, all refer to the same embodiment.

[0018] The terms "includes," "comprehensive," or similar expressions denote non-exclusive inclusion. Thus, a procedure or method containing a list of steps does not only include those steps but may also include further steps not explicitly listed or inherent in the procedure or method. Likewise, the statement "includes..." for one or more devices, subsystems, elements, structures, or components, without further limitations, does not preclude the existence of other devices, subsystems, elements, structures, or components.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meanings generally known to those skilled in the art in the field to which this invention belongs. The systems, methods, and examples described herein serve only for illustration and are not to be understood as limiting.

[0020] Embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. System architecture:

[0021] with reference to Fig. 1 a solar-powered photocatalytic detoxification system (100) configured to decompose toxic industrial dyes from aqueous media using green synthesized copper oxide nanoparticles.

[0022] In one embodiment, the system comprises (100): • an extract preparation unit (102) configured to produce an aqueous extract of Hedychium leaves of the white garland lily (Coronarium); • A phytochemical screening unit (116) configured to determine the plant metabolites present in aqueous leaf extract. • a nanoparticle synthesis unit (104) configured for the synthesis of copper oxide nanoparticles using the prepared plant extract; • a separation and heat treatment unit (106, 108) configured to produce crystalline copper oxide nanoparticles; • a photocatalytic detoxification unit (114) designed for the decomposition of industrial dyes under natural sunlight; and • Optionally, a characterization unit (110) can be used to verify physicochemical properties relevant to photocatalytic performance. • An antimicrobial test unit (112) for assessing the antimicrobial efficacy of manufactured luminescent copper oxide nanoparticles

[0023] Additional units such as units for phytochemical analysis or antimicrobial testing may be included in certain embodiments, but are not essential to the primary invention concept of solar-powered detoxification.

[0024] The present invention relates to a system and a process for the environmentally friendly synthesis of luminescent copper oxide nanoparticles using a bioactive extract from the white garland lily (Hedychium). The described system is configured to produce copper oxide nanoparticles with improved luminescence properties, photocatalytic activity, and antimicrobial efficacy.

[0025] The synthesized copper oxide nanoparticles exhibit, in particular, effective photocatalytic decomposition of toxic industrial dyes in aqueous media, as well as antimicrobial activity against selected strains of bacteria and fungi. The system comprises several interconnected functional units to perform the controlled extraction, nanoparticle synthesis, purification, characterization, and application-oriented evaluation of the synthesized nanoparticles for the detoxification of industrial dyes and for antimicrobial treatment.

[0026] The extract preparation unit is used to obtain a bioactive extract from White Garland leaves. Fresh leaves weighing approximately 20 g are first washed with tap water and then with double-distilled water to remove surface impurities. The cleaned leaves are finely crushed and placed in a vessel containing approximately 200 ml of double-distilled water. The mixture is heated on a hot plate and kept at a simmer for about one hour to promote the extraction of the phytoconstituents. The mixture then undergoes sequential filtration, first with conventional filter paper and then with Whatman No. 1 filter paper, to obtain a clear White Garland Leaf Extract (WGLLE). The extract preparation unit also includes a cooling module for storing the produced extract under controlled conditions until further processing.

[0027] The synthesis unit is configured to produce copper oxide nanoparticles using the manufactured WGLLE. The unit contains an aqueous copper precursor solution consisting of freshly prepared 0.1 M copper sulfate. Copper(II) oxide pentahydrate (CuSO₄·5H₂O) is adjusted to a pH of approximately 4.6. The copper precursor solution is mixed with WGLLE in an optimized volume ratio of 1:4. During mixing, a visible color change from green to dark green is observed, indicating the onset of nanoparticle formation. The synthesis unit includes a magnetic stirrer configured to stir the reaction mixture at approximately 500 rpm for about 50 minutes. During this time, the reaction mixture continues to change color to black, indicating the formation of copper oxide nanoparticles.

[0028] A centrifuge is coupled to the synthesis unit and serves to separate the formed nanoparticulate solid from the reaction mixture. The centrifuge operates at a speed of approximately 3500 rpm for about 45 minutes to ensure effective separation of the solid phase.

[0029] The separated solid is transferred to a combustion unit, which includes a muffle furnace for heat treatment of the solid at a temperature of approximately 450 °C. This combustion process causes the complete conversion and crystallization of the material, yielding the final copper oxide nanoparticles. The system also includes storage containers or sample tubes for preserving the synthesized nanoparticles for subsequent characterization and application.

[0030] The phytochemical screening unit analyzes extracts from White Garland leaves (WGLLE) and identifies bioactive phytometabolites involved in nanoparticle synthesis. The unit performs qualitative and / or quantitative analyses according to standard phytochemical protocols. It detects various classes of phytochemicals, including alkaloids, flavonoids, phenols, terpenoids, glycosides, saponins, tannins, proteins, and reducing sugars. The identified phytochemicals act as reducing, protective, and stabilizing agents in the formation of copper oxide nanoparticles. The screening unit also elucidates the role of the phytometabolites in controlling the nucleation, growth, and stability of the nanoparticles. The data obtained ensure the reproducibility and consistency of the synthesis process.The results correlate the phytochemical composition with the luminescence, antimicrobial and photocatalytic properties of the synthesized nanoparticles.

[0031] The phytoconstituents contained in WGLLE, including flavonoids, terpenoids, phenols, steroids, glycosides, etc., presumably act as natural stabilizers and reducing agents in the phytofabrication of CuONPs. The possible growth mechanism of CuONPs involves an initial binding in which the active site of WGLLE binds to Cu 2+ binds, which then forms Cu 0 is reduced. This Cu 0 Oxidation leads to the formation of CuONPs.

[0032] Fig. Figure 2 shows that X-ray diffraction analysis confirms the crystalline monoclinic phase of the copper oxide nanoparticles. The crystal structure is crucial for efficient charge transport and photocatalytic activity. An X-ray diffractometer (XRD, Bruker, D8-Advanced Diffractometer) using Cu-Ka radiation (λ = 0.154 nm) at 40 kV and 40 mA was configured to record XRD spectra in the range of 10–80°.

[0033] The phytostructured CuONPs were glossy black. The structure and crystallinity of the CuONPs prepared using WGLLE were investigated by X-ray diffraction (XRD) (see Fig. 2) Powder XRD measurements were performed using monochromatic CuKα radiation (wavelength 1.5406 Å) in the angular range 20 from 20° to 80° at a voltage of 40 kV and a current of 40 mA. XRD profile analysis revealed a series of prominent diffraction peaks at 32.48°, 35.54°, 38.72°, 48.8°, 53.48°, 58.32°, 61.58°, 68.6°, 72.38°, and 75.16°, corresponding to lattice planes (110), (002), (111), (20-2), (020), (202), (11-3), (220), (311), and (004), respectively. Additionally, some unidentifiable peaks appeared, which are attributed to organic components or amorphous impurities. The observed network planes were indexed based on the monoclinic structure of CuO by comparison with the data from JCPDS map No. 48-1548. Due to the monoclinic structure of CuO, the XRD profile analysis clearly showed that the phytogenically synthesized CuONPs exhibit good crystallinity and high purity. The mean particle size of the phytogenically synthesized CuONPs was 40 ± 0.5 nm (calculated using the Debye-Scherrer formula).

[0034] Fig. Figure 3 shows that UV-Vis spectroscopy confirms strong absorption of the synthesized copper oxide nanoparticles in the ultraviolet-visible range. This indicates effective activation under natural sunlight according to the present invention. The UV-Vis spectra were recorded in a wavelength range of approximately 200–800 nm. A characteristic absorption band at about 300 nm confirms the formation of copper oxide nanoparticles. This absorption is attributed to the electronic charge transfer from the valence band to the conduction band and corresponds to O 2- -to-Cu 2+ -transitions within the copper oxide lattice.

[0035] Fig. Figure 4 shows the photoluminescence analysis used to investigate the charge carrier recombination behavior of the synthesized copper oxide nanoparticles, which directly influences their photocatalytic performance under light irradiation. The photoluminescence spectrum was recorded in a wavelength range of approximately 280–601 nm. It exhibits emission bands at about 295 nm and 590 nm, indicating greenish-yellow luminescence properties of the WGLLE-mediated copper oxide nanoparticles. The emission near 295 nm is attributed to band edge recombination, while the emission around 590 nm is associated with defect- or surface-related transitions. A Stokes shift was observed, as the emission wavelength is approximately twice that of the excitation wavelength. This confirms the luminescence properties, which are advantageous for photocatalytic applications.

[0036] These analyses confirm overall that the synthesized copper oxide nanoparticles possess properties suitable for solar-powered photocatalytic detoxification.

[0037] Fig. Figure 5 shows the photocatalytic detoxification unit (114), which is used to investigate the degradation of industrial dyes such as methylene blue under natural sunlight. In one embodiment, copper oxide nanoparticles are dispersed in dye-contaminated aqueous media. The resulting suspension is initially kept in the dark to establish an adsorption-desorption equilibrium between the dye molecules and the photocatalyst surface.

[0038] When exposed to sunlight, the copper oxide nanoparticles are photoactivated, generating electron-hole pairs and producing reactive oxygen species, including hydroxyl and superoxide radicals. These reactive species oxidatively decompose the dye molecules into less toxic or non-toxic products, thus enabling effective detoxification.

[0039] The photocatalytic activity of copper oxide nanoparticles was investigated using methylene blue as a model dye under sunlight irradiation. Control experiments without a photocatalyst showed negligible dye degradation, confirming minimal photolysis. In contrast, the presence of the photocatalyst led to a progressive decrease in dye concentration with increasing irradiation time, with complete degradation achieved within approximately 70 minutes under optimized conditions.

[0040] Optimization of photocatalyst loading in the range of 0.1 to 1.0 g / dm³ 3 This resulted in an optimal concentration that enabled complete dye degradation within the defined irradiation time. Further increasing the catalyst concentration beyond the optimal value led to reduced degradation performance due to nanoparticle aggregation and light scattering effects.

[0041] Experimental observations further demonstrate that the photocatalyst maintains high detoxification efficiency over multiple reuse cycles, indicating good reusability and operational stability of the photocatalytic detoxification unit. The observed performance confirms the suitability of WGLLE-mediated copper oxide nanoparticles for solar-driven detoxification of industrial dye impurities.

[0042] In certain embodiments, the copper oxide nanoparticles can exhibit additional antibacterial or antifungal properties due to their nanosize and surface chemistry. While these properties are advantageous, they are not central to the concept according to the invention, which primarily aims at the solar-powered detoxification of industrial dyes.

[0043] In addition to their primary function in photocatalytic dye degradation, the copper oxide nanoparticles produced using WGLLE exhibit antimicrobial properties. The nanoparticles demonstrate effective antibacterial activity against Escherichia coli and Streptococcus pyogenes, as well as moderate activity against Staphylococcus aureus and Pseudomonas aeruginosa. Furthermore, the nanoparticles exhibit antifungal activity against Aspergillus niger and Aspergillus clavatus. These additional antimicrobial properties enhance the functional applicability of the nanoparticles without limiting their primary role in industrial dye detoxification.

[0044] The present invention describes a solar-powered system for the photocatalytic detoxification of industrial dyes using green-synthesized copper oxide nanoparticles. The nanoparticles are produced according to the principles of green chemistry using an environmentally friendly and sustainable process based on extract from White Garland leaves (WGLLE). The synthesis method offers a simple, environmentally sound, and scalable route to the production of functionally active copper oxide nanoparticles.

[0045] The synthesized copper oxide nanoparticles were characterized using analytical techniques such as UV-Vis spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, field emission scanning electron microscopy with energy-dispersive X-ray analysis, high-resolution transmission electron microscopy, and photoluminescence spectroscopy to confirm their structural, optical, and morphological properties. The nanoparticles are optimized for solar-driven dye degradation and also exhibit luminescence as well as antimicrobial activity against selected bacterial and fungal pathogens.

[0046] Most importantly, the copper oxide nanoparticles exhibit excellent photocatalytic activity under natural sunlight, completely degrading the dye methylene blue within approximately 70 minutes. This performance establishes the green-synthesized copper oxide nanoparticles as an effective and sustainable photocatalyst for the solar-powered detoxification of industrially contaminated dye wastewater.

[0047] The present invention relates to: i. offers a solar-powered and energy-efficient photocatalytic detoxification system, eliminating the need for external power sources; ii. utilizes an environmentally friendly, plant-mediated synthesis pathway using phytochemicals as reducing and stabilizing agents and avoids toxic reagents; iii. achieves the complete degradation of industrial dyes without the formation of secondary or hazardous by-products; iv. exhibits high photocatalytic stability and reusability over multiple operating cycles with minimal loss of efficiency; and v. demonstrates practical applicability for industrial wastewater treatment and environmental remediation, especially for dye-contaminated aqueous systems.

[0048] The drawings and the preceding description illustrate 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. For example, the process flows described here can be modified and are not limited to the manner described herein. Furthermore, the actions of a flowchart need not be performed in the sequence shown; nor do all actions necessarily need to be carried out. Actions that do not depend on other actions can be performed in parallel with the other actions. The scope of protection of the embodiments is in no way limited by these specific examples. Numerous variations, whether explicitly stated in the description or not, such as...Differences in structure, dimensions, and materials are possible. The scope of protection of the embodiments is at least as comprehensive as described by the following claims.

[0049] The advantages, other benefits, and problem solutions have been described above with reference to specific embodiments. However, the advantages, benefits, problem solutions, and any components that can effect or enhance an advantage, benefit, or solution are not to be construed as critical, necessary, or essential features or components of the claims. REFERENCES 100 A solar-powered photocatalytic detoxification system using green synthesized copper oxide nanoparticles. 102 Extract processing unit 104 synthesis unit 106 Centrifuge 108 combustion unit 110 Characterization Unit 112 Antimicrobial test unit 114 Photocatalytic degradation unit 116 Phytochemical Screening Unit

Claims

[1] A system for the synthesis and characterization of luminescent copper oxide nanoparticles, comprising: a) an extract preparation plant configured to produce an extract from white garland leaves by boiling cut leaves in double distilled water and subsequently filtering the mixture; b) a synthesis unit configured to mix a copper sulfate solution with the extract from white garland leaves and to obtain a black colored solid under stirring conditions; c) a centrifuge configured to separate the black-colored solid from the mixture; d) a combustion unit configured to subject the separated solid to heat treatment in a muffle furnace to obtain copper oxide nanoparticles; e) a characterization unit for the analysis of the copper oxide nanoparticles, wherein the characterization unit includes: UV-Vis spectrophotometer, X-ray diffractometer, photoluminescence spectrometer, etc. f) a photocatalytic degradation unit configured to enable the complete removal of industrial dyes (methylene blue) and g) an antimicrobial test unit for evaluating the antibacterial and antifungal activity of the copper oxide nanoparticles. [2] System according to claim 1, wherein the synthesis unit is configured to mix a 0.1 M copper sulfate solution with the extract from white garland leaves in a ratio of 1:

4. [3] System according to claim 1, wherein the synthesis unit is configured to maintain a stirring speed of 500 rpm for 50 minutes. [4] System according to claim 1, wherein the centrifugation unit is designed for operation at 3500 rpm for 45 minutes. [5] System according to claim 1, wherein the combustion unit is configured to maintain a temperature of 450°C. [6] The system according to claim 1 comprises a photocatalytic degradation unit configured to test the photocatalytic degradation performance of the copper oxide nanoparticles against the dye methylene blue. [7] System according to claim 6, wherein the photocatalytic degradation unit is configured to disperse the copper oxide nanoparticles in the dye solution and expose the solution to solar radiation. [8] System according to claim 1, wherein the antimicrobial test unit is configured to perform the broth dilution technique for antibacterial evaluation and the agar dilution protocol for antifungal evaluation. [9] System according to claim 1, further comprising a phytochemical screening unit for determining active phytometabolites in the extract of the leaves of the White Garland.

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