Description:DESCRIPTION:
Field of the invention:
The present disclosure generally relates to the technical field of nanotechnology and photocatalyst, and in specific, relates to a method for preparation, characterization, and application of a copper-doped titanium dioxide and tungsten trioxide (Cu-TiO2 and WO3) nanocomposite for the degradation of amaranth dye under visible light.
Background of the invention:
Amaranth, a highly toxic azo dye, poses significant risks to the environment and human health due to its mutagenic and carcinogenic properties. It can cause severe reactions such as chronic urticaria and angioedema in both adults and children. Studies have shown that 25 percent of fetuses exposed to oral amaranth at doses ten times the Acceptable Daily Intake (ADI) exhibited skeletal abnormalities. Additionally, high doses of amaranth may impair liver function, and its consumption should be avoided during pregnancy.

Many manufacturing industries release various forms of organic wastes, including dyes and phenols. Organic dyes are extensively used in industries like textiles, paper, cosmetics, leather, plastics, food, printing, and pharmaceuticals. Developing sustainable and efficient methods to degrade these pigments is crucial. Photocatalytic has emerged as a viable technique for wastewater treatment due to its ability to harness solar energy and use photocatalysts to break down organic pollutants. Wastewater often contains colored organic dyes with complex molecular structures and stable properties. Even at trace concentrations (0.001 mg/L), these dyes can harm human health and are potential carcinogens. The complexity of biodegradation makes removing organic matter from wastewater extremely challenging and resource-intensive.

Several established methods, such as adsorption, biosorption, chemical oxidation, and membrane processes, have been used to treat wastewater containing dyes. Adsorption, a traditional method, transfers contaminants from the liquid phase to the solid phase, resulting in secondary contamination that requires further treatment. An innovative solution to this limitation is the advanced oxidation process (AOP).

TiO2 and WO3 are important low-cost functional materials known for their chemical stability, non-toxicity, semiconducting, electrochemical, and optoelectronic properties. WO3, being more acidic than TiO2, acts as an electron-accepting species and has been widely used to enhance the photo-electrochemical and photocatalyst performance of TiO2. One intriguing property of tungsten trioxide is its ability to function as a charge separator in certain situations. This property allows it to be used in binary composite systems, where ZnO or TiO2 frequently serve as electron donors, although NiO has also been applied. These composite systems aim to be utilized as sensors, photocatalysts, or both simultaneously.

TiO2 is the most commonly used photocatalyst due to its high efficiency, low cost, chemical stability, and non-toxicity. However, its use is limited by its high band gap value of approximately 3.2 eV, restricting its application to UV radiation. Combining TiO2 with a visible light-sensitive semiconductor offers an alternative. WO3, a semiconductor with a 2.8 eV band gap, can absorb visible light but also demonstrates rapid recombination of newly generated free carriers.

Many researchers are now focused on the application of WO3/TiO2 nanocomposite and their heterojunctions. The WO3-TiO2 nanocomposite acts as an energy-storing photocatalyst, capable of storing electrons generated in the presence of light and releasing them in the absence of light, similar to electron-mediated processes. Using a template technique, the light absorption band of a WO3/TiO2 composite hollow sphere was shifted from the near UV to the visible spectrum.

In existing technology, a method for preparing a copper-doped tungsten trioxide composite nanofiber material. Initially, dissolve ammonium metatungstate in water, add polyvinylpyrrolidone, and stir to obtain a precursor solution. Next, perform electrostatic spinning on the precursor solution to obtain primary spun fibers. Calcine the spun fibers and cool to obtain tungsten trioxide nanofibers. Finally, soaks the tungsten trioxide nanofibers in a copper salt solution, then calcine to obtain the copper-doped tungsten trioxide composite nanofiber material. However, the method that difficult to implement and cost expensive. Moreover, the method might affect the environment.

Therefore, there is a need for a method for preparation, characterization, and application of a copper-doped titanium dioxide and tungsten trioxide (Cu-TiO2 and WO3) nanocomposite for the degradation of amaranth dye under visible light. There is also a need for a method that utilize visible light reduces the need for high-energy UV light sources, leading to lower operational costs. Furthermore, there is also a need for a method that varies soaking times, the WO3 contributes to achieve maximum photocatalytic activity, thereby allowing for customization based on specific requirements.
Objectives of the invention:
The primary objective of the invention is to provide a method for preparation, characterization, and application of a copper-doped titanium dioxide and tungsten trioxide (Cu-TiO2 and WO3) nanocomposite for the degradation of amaranth dye under visible light.

Another objective of the invention is to provide a method that significantly improves photocatalytic activity under visible light, making it more effective than conventional photocatalysts.

The other objective of the invention is to provide a method that is capable of completely degrading amaranth dye, a common pollutant in wastewater, within a short period, ensuring thorough purification.

The other objective of the invention is to provide a method that utilizes BET (Brunauer Emmett Teller) indicates that the CTW45 nanocomposite has a larger surface area, which provides more active sites for photocatalytic reactions, enhancing overall performance.

The other objective of the invention is to provide a method that varies soaking times, the tungsten trioxide (WO3) to achieve maximum photocatalytic activity, thereby allowing for customization based on specific requirements.

The other objective of the invention is to provide a method that utilizes sol-gel synthesis and soaking techniques, is straightforward and scalable, making it suitable for industrial production.

Yet other objective of the invention is to provide a method that utilizes visible light, reduces the need for high-energy UV light sources, leading to lower operational costs.

Further objective of the invention is to provide a method that provides an efficient solution for degrading harmful dyes in wastewater, contributing to environmental protection and sustainable water management.
Summary of the invention:
The present disclosure proposes a method for degradation of dye using copper doped titanium dioxide nanocomposite. . The following presents a simplified summary in order to provide a basic understanding of some aspects of the claimed subject matter. This summary is not an extensive overview. It is not intended to identify key/critical elements or to delineate the scope of the claimed subject matter. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is presented later.

In order to overcome the above deficiencies of the prior art, the present disclosure is to solve the technical problem to provide a method for preparation, characterization, and application of a copper-doped titanium dioxide and tungsten trioxide (Cu-TiO2 and WO3) nanocomposite for the degradation of amaranth dye under visible light.

According to one aspect, the invention provides a method for preparing a copper doped titanium dioxide and tungsten trioxide for degradation of a dye. At one step, 9 gm of sodium tungstate powder is added to 180 mL of at least 30 percent of hydrogen peroxide and stirring at a temperature of at least 30 °C for a time period of at least 2 hr to form a peroxotungstic acid solution. At another step, the peroxotungstic acid solution is filter to remove undissolved particles and add 180 mL of anhydrous ethanol to the peroxotungstic acid solution while stirring to displace excess peroxotungstic acid solution and make the peroxotungstic acid solution negatively charged.

At another step, 9 gm of a copper doped titanium dioxide is added to the peroxotungstic acid solution and mixing for a predetermined period. At another step, centrifuge the mixture of the copper doped titanium dioxide and the peroxotungstic acid solution at a speed of at least 10,000 rpm for a timer period of 10 min to obtain a solid and vacuum-drying the resultant solid of at least 70 °C. At another step, the dried solid is annealed in a muffle furnace at a temperature of 550 °C for a time period of at least 6 hr to promote crystallization and form the copper doped titanium dioxide and tungsten trioxide nanocomposite.

At another step, the copper doped titanium dioxide is soaks in the solution for varying times of 15, 30, 45, and 60 min to investigate the impact of tungsten content on the photocatalytic activity. At step 114, the prepared copper doped titanium dioxide and copper doped tungsten trioxide nanocomposite powder is characterized using multiple tests to measure ultraviolet-visible absorption spectra to evaluate the degradation of amaranth dye by the nanocomposite. Further, at another step, the carat total weight 45 nanocomposite demonstrates and soaked for at least 45 min exhibits the highest photocatalytic activity, thereby degrading the amaranth dye within the two hours.

According to another aspect, the invention provide a preparation method of the copper doped titanium dioxide photocatalyst is prepared by the method. At one step, dissolves 60 mL of butyl ortho titanate in 120 mL of ethanol to form a mixture and agitating the mixture for at least 10 min. At another step, the 9.6 mL of nitric acid is added to the mixture and stirring for at least 30 min to form a first solution, and mixes 21.6 mL of deionized water with 120 mL of ethanol in a separate container to form a second solution.

At another step, the second solution is added dropwise to the first solution while stirring vigorously and continuing to stir for at least 90 min to form a transparent gel. At another step, the transparent solution is allowed to mature in a dark at room temperature for at least 48 hr. Further, at another step, the dries the obtained gel by baking at least 72 °C, and calcines the dried gel in a muffle furnace at a temperature of at least 450 °C for at least 5 hr to obtain the copper doped titanium dioxide photocatalyst.

In one embodiment, the second solution is added to the first solution at a temperature between 20 °C and 30 °C. In one embodiment, the transparent solution is matured for a time period of at least 48 hr to ensure optimal transparent gel formation.

In one embodiment, the calcination of the copper doped titanium dioxide photocatalyst is conducted at a ramp rate of 5 °C per minute to 450 °C. In one embodiment, the peroxotungstic acid solution is formed by maintaining the stirring speed at 500 rpm to ensure complete dissolution of the sodium tungstate powder.

In one embodiment, the copper doped titanium dioxide is soaked in the peroxotungstic acid solution for at least 45 min to achieve the optimal tungsten trioxide content for maximum photocatalytic activity. In one embodiment, the characterizing the photocatalytic efficiency of the copper doped titanium dioxide and tungsten trioxide nanocomposite using UV-Vis spectrophotometry to determine the degradation rate of amaranth dye.

Further, objects and advantages of the present invention will be apparent from a study of the following portion of the specification, the claims, and the attached drawings.
Detailed description of drawings:
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, explain the principles of the invention.

FIIG. 1 illustrates a flowchart of a method for preparing a copper doped titanium dioxide and tungsten trioxide for degradation of a dye, in accordance to an exemplary embodiment of the invention.

FIG. 2 illustrates a graphical representation of X-ray diffusion pattern of CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites, in accordance to an exemplary embodiment of the invention.

FIGs. 3A-3B illustrate graphical representations of BET (Brunauer Emmett Teller) Surface area of CTW45 and CTW60 nanocomposites, in accordance to an exemplary embodiment of the invention.

FIG. 4 illustrates a graphical representation of comparison of BET surface area for CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites, in accordance to an exemplary embodiment of the invention.

FIGs. 5A-5B illustrate graphical representations of a ultraviolet UV Visible spectrum of amaranth dye with CDT and CTW45 nanocomposites at different time intervals, in accordance to an exemplary embodiment of the invention.

FIG. 6 illustrates a graphical representation of photodegradation of amaranth dye with CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites, in accordance to an exemplary embodiment of the invention.

FIG. 7 illustrates a graphical representation of percentage of photodegradation of amaranth dye with CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites, in accordance to an exemplary embodiment of the invention.

FIG. 8 illustrates a graphical representation of percentage of photodegradation of amaranth dye with best CTW45 nanocomposite at different pH values, in accordance to an exemplary embodiment of the invention.

FIG. 9A illustrates a graphical representation of percentage of photodegradation of amaranth with best CTW45 nanocomposite at different composite concentrations, in accordance to an exemplary embodiment of the invention.

FIG. 9B illustrates a graphical representation of rate of degradation of amaranth for best CTW45 nanocomposite with different composite concentrations, in accordance to an exemplary embodiment of the invention.

FIG. 10 illustrates a schematic view of photocatalytic mechanism of amaranth dye with copper doped titanium dioxide and tungsten trioxide, in accordance to an exemplary embodiment of the invention.
Detailed invention disclosure:
Various embodiments of the present invention will be described in reference to the accompanying drawings. Wherever possible, same or similar reference numerals are used in the drawings and the description to refer to the same or like parts or steps.

The present disclosure has been made with a view towards solving the problem with the prior art described above, and it is an object of the present invention to provide a method for preparation, characterization, and application of a copper-doped titanium dioxide and tungsten trioxide (Cu-TiO2 and WO3) nanocomposite for the degradation of amaranth dye under visible light.

According to one exemplary embodiment of the invention, FIG. 1 refers to a flowchart 100 of a method for preparing the copper doped titanium dioxide and tungsten trioxide for degradation of the dye. At step 102, 9 gm of sodium tungstate powder is added to 180 mL of at least 30 percent of hydrogen peroxide and stirring at a temperature of at least 30 °C for a time period of at least 2 hr to form a peroxotungstic acid solution. At step 104, the peroxotungstic acid solution is filter to remove undissolved particles and add 180 mL of anhydrous ethanol to the peroxotungstic acid solution while stirring to displace excess peroxotungstic acid solution and make the peroxotungstic acid solution negatively charged.

At step 106, the 9 gm of a copper doped titanium dioxide is added to the peroxotungstic acid solution and mixing for a predetermined period. At step 108, centrifuge the mixture of the copper doped titanium dioxide and the peroxotungstic acid solution at a speed of at least 10,000 rpm for a timer period of 10 min to obtain a solid and vacuum-drying the resultant solid of at least 70 °C. At step 110, the dried solid is annealed in a muffle furnace at a temperature of 550 °C for a time period of at least 6 hr to promote crystallization and form the copper doped titanium dioxide and tungsten trioxide nanocomposite.

At step 112, the copper doped titanium dioxide is soaks in the solution for varying times of 15, 30, 45, and 60 min to investigate the impact of tungsten content on the photocatalytic activity. At step 114, the prepared copper doped titanium dioxide and copper doped tungsten trioxide nanocomposite powder is characterized using multiple tests to measure ultraviolet-visible absorption spectra to evaluate the degradation of amaranth dye by the nanocomposite. Further, at step 116, the carat total weight 45 nanocomposite demonstrates and soaked for at least 45 min exhibits the highest photocatalytic activity, thereby degrading the amaranth dye within the two hours.

In one embodiment herein, the preparation method of the copper doped titanium dioxide photocatalyst is prepared by the method. At one step, dissolves 60 mL of butyl ortho titanate in 120 mL of ethanol to form a mixture and agitating the mixture for at least 10 min. At another step, the 9.6 mL of nitric acid is added to the mixture and stirring for at least 30 min to form a first solution, and mixes 21.6 mL of deionized water with 120 mL of ethanol in a separate container to form a second solution.

At another step, the second solution is added dropwise to the first solution while stirring vigorously and continuing to stir for at least 90 min to form a transparent gel. At another step, the transparent solution is allowed to mature in a dark at room temperature for at least 48 hr. Further, at another step, the dries the obtained gel by baking at least 72 °C, and calcines the dried gel in a muffle furnace at a temperature of at least 450 °C for at least 5 hr to obtain the copper doped titanium dioxide photocatalyst.

In one embodiment, the second solution is added to the first solution at a temperature between 20 °C and 30 °C. In one embodiment, the transparent solution is matured for a time period of at least 48 hr to ensure optimal transparent gel formation.

In one embodiment, the calcination of the copper doped titanium dioxide photocatalyst is conducted at a ramp rate of 5 °C per minute to 450 °C. In one embodiment, the peroxotungstic acid solution is formed by maintaining the stirring speed at 500 rpm to ensure complete dissolution of the sodium tungstate powder.

In one embodiment, the copper doped titanium dioxide is soaked in the peroxotungstic acid solution for at least 45 min to achieve the optimal tungsten trioxide content for maximum photocatalytic activity. In one embodiment, the characterizing the photocatalytic efficiency of the copper doped titanium dioxide and tungsten trioxide nanocomposite using UV-Vis spectrophotometry to determine the degradation rate of amaranth dye.

According to another exemplary embodiment of the invention, FIG. 2 refers to a graphical representation 200 of X-ray diffusion pattern of CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites. In one embodiment herein, the X-ray diffraction recorded in the 2? range between 20-80 degrees, the crystalline phase structure of CDT nanoparticle and Cu- TiO2 and WO3 nanocomposite with increased soaking over different time intervals (CTW15, CTW30, CTW45, and CTW60) were identified. The Cu- TiO2 and WO3 nanocomposites showed peaks that were well indexed. The XRD peaks at 2? values of 25.29°, 37.78°, 48.02°, 53.93°, 55.28°, 62.64°, 69.68°, and 75.04° are indexed as (101), (004), (200), (105), (211), (204), (220), and (215). Since the anatase phase is more active than the rutile and brookite phases, the CDT will exhibit greater photoactivity as a result of all these peaks revealing a tetragonal anatase phase.

The WO3 peaks in CTW45 and CTW60 are indicated by the symbol, indicating that the nanocomposites show minor monoclinic tungsten peaks and a major tetragonal anatase phase after 45 and 60 min of soaking time, respectively. The slight WO3 peaks result from an extension of the reaction time for WO3 doping in Cu-TiO2 nanocomposites beyond 45 min. It was also noted that the addition of WO3 to Cu-TiO2 caused all of the peaks of the Cu- TiO2 and WO3 nanocomposites to slightly shift towards a higher diffraction angle. The average crystallite size of CDT, CTW15, CTW30, CTW45, and CTW60 nanocomposites is determined using Scherrer's relation.
(1)
Where k = 0.94 is the shape factor, ß1 is the full width at half maximum (FWHM) of the most intense diffraction peak, ? is Bragg's angle, and ? is the wavelength of copper, Ka source radiation is 1.54. In the tetragonal anatase phase, the average crystallite sizes of CDT, CTW15, CTW30, CTW45, and CTW60 Nanocomposites are 4.979, 5.163, 5.137, 4.427, and 6.025 nm, respectively. As the Cu-TiO2/WO3 nanocomposites soak time (reaction time) increases, so does the average crystallite size of CDT nanoparticles. However, in the minor monoclinic tungsten phases, the average crystallite sizes of CTW45 and CTW60 are 71.84 and 81.20 nm, respectively.

According to another exemplary embodiment of the invention, FIGs. 3A-3B refer to graphical representations (300, 302) of BET Surface area of CTW45 and CTW60 nanocomposites. In one embodiment herein, the BET analyses the surface area and porosity of materials. The surface area made available by pores for the adsorption of gas molecules. The surface area and porosity of CDT, CTW15, CTW30, CTW45, and CTW60 nanocomposites. The nanocomposites show a type IV pattern with H3 hysteresis, suggesting that they are all mesoporous, according to IUPAC and the BDDT organisation. The CDT nanoparticle exhibits a hysteresis loop between relative pressures of 0.45 and 0.96, suggesting the existence of a small number of micropores and mesopores similar to those previously reported.

The adsorption and desorption isotherms of CDT nanoparticles range from 89 to 82 and exhibit random fluctuations in response to an increase in the soaking time (reaction time) of Cu-TiO2 and WO3 nanocomposites. However, the CTW45 nanocomposite has more adsorption and desorption isotherms than other nanocomposites. A few of the composites exhibit a slightly enlarged hysteresis loop, and the CDT and Cu-TiO2 and WO3 nanocomposites adsorption and desorption isotherms are almost the same. The CTW45 nanocomposite has a wider hysteresis loop than other composites, which suggests that at a relative pressure range of 0.48 to 0.95, the nanocatalyst has more mesopores than other nanocomposites.

According to another exemplary embodiment of the invention, FIG. 4 refers to a graphical representation 400 of comparison of BET surface area for CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites. In one embodiment herein, the BET surface areas of the nanocomposites CDT, CTW15, CTW30, CTW45, and CTW60 are contrasted. Compared to Cu-TiO2 and WO3 and CDT nanoparticles, the CTW45 nanocomposite which is coloured light blue on the nanocomposites bar graph has a larger surface area. The average size of the pores in the CDT was 8.66 nm, and these varied erratically as the Cu-TiO2 and WO3 nanocomposites were soaked for longer periods of time. Compared to CDT nanoparticles, the pores in the CTW45 nanocomposite are 7.365 nm smaller.

Table. 1
Nano composites Surface area (m2/g) Total Pore Volume (cm3/g) Mean Pore Diameter (nm)
CDT 62.38 0.133 8.661
CTW15 61.75 0.077 9.454
CTW30 89.48 0.096 9.968
CTW45 130.67 0.072 7.361
CTW60 99.68 0.087 9.375

The Cu-TiO2 and WO3 nanocomposite pore volume, which was measured at 0.1308 cm3/g, randomly decreases as the soaking duration is increases. The CTW45 nanocomposite has a lower pore volume than the CDT nanoparticle, measuring of 0.0858 cm3/g. After 45 min of immersion, the Cu-TiO2 and WO3 nanocomposite revealed reduced porosity and volume of CTW45 nanocomposite, demonstrating the crystalline nature of the nanocomposite.
According to another exemplary embodiment of the invention, FIGs. 5A-5B illustrate graphical representations (500, 502) of a ultraviolet UV Visible spectrum of amaranth dye with CDT and CTW45 nanocomposites at different time intervals. In one embodiment herein, the UV-visible spectroscopy is utilized to evaluate the chemical properties of different nanocomposites. The UV-Visible spectroscopy is used to determine the absorbance of light for amaranth dye degradation with CDT and CTW45 nanocomposites at various time intervals. The UV-visible absorption spectra of amaranth dye with CDT and CTW45 nanocomposites, which are measured in the 200 nm–800 nm range. The majority of the light absorbed in CDT with amaranth dye is due to the high light absorbance of amaranth dye.

At a wavelength of 615 nm, the dye amaranth displays an absorbance peak. The fastest rate of degradation of the amaranth dye in the UV-visible spectra of CDT and CTW45 nanocomposites, at wavelengths of 614 nm and 617 nm, respectively. Because of WO3 smaller band gap, the CTW45 nanocomposite absorption edges were slightly moved into the visible light region. The Amaranth dye-containing CDT and CTW45 nanocomposites show a large absorption peak in the wavelength range of 293–418 nm.

Every 15 min, the absorbance of the CTW45 nanocomposite with amaranth dye decreases and become less than that of the CDT with the same dye. The complete reduction of the absorbance peak of the CTW45 nanocomposite with amaranth dye after two hr indicates that both the amaranth dye and CTW45 nanocomposite underwent complete degraded. The CTW45 absorbs significantly less amaranth dye than the remaining CDT, which could be attributed to the high surface area listed in Table 1 and the smaller crystallite size described in XRD.

According to another exemplary embodiment of the invention, FIG. 6 refers to a graphical representation 600 of photodegradation of amaranth dye with CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites. In one embodiment herein, the degradation of amaranth dye using CDT, CTW15, CTW30, CTW45, and CTW60 nanocomposites. It was found that amaranth dye did not entirely degrade with CDT, and that the degradation of Cu-TiO2 and WO3 nanocomposites containing amaranth dye increased with increasing soaking time. At two hour, CTW45 with amaranth dye degradation was more advanced than that of CDT, CTW15, CTW30, and CTW60 nanocomposites.

Because of its increased surface area and smaller crystallite size, the CTW45 composite with amaranth dye shows significant photocatalytic activity. The amaranth dye degradation rate (C/C0) with CDT, CTW15, CTW30, CTW45, and CTW60 nanocomposites. The longer the Cu-TiO2 and WO3 nanocomposites are immersed, the more quickly the amaranth dye degrades with CDT. However, because of its high photocatalytic activity, the rate of amaranth dye degradation with the CTW45 nanocomposite was higher than that of the CDT, CTW15, CTW30, and CTW60 nanocomposites.

According to another exemplary embodiment of the invention, FIG. 7 refers to a graphical representation 700 of percentage of photodegradation of amaranth dye with CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites. In one embodiment herein, the amaranth dye with Cu-TiO2 and WO3 nanocomposites at various soaking times during photodegradation acquired the UV spectrum using the Beer-Lambert relation. The Beer-Lambert equation is used to determine the proportion of photocatalytic degradation of amaranth dye using CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites.
Percentage of degradation =((C_0-C)/C_0 )*100 (2)
The amaranth dye is exposed to visible light with Co representing the initial dye solution absorbance, and C representing the dye solution absorbance at time t. The photodegradation rate of amaranth dye in CDT, CTW15, CTW30, CTW45 and CTW60 nanocomposites. It was discovered that the photodegradation of amaranth dye with CDT was low and rises when the soaking time of Cu-TiO2 and WO3 nanocomposite increased up to 45 min, after which degradation decreased for at least 1 hour soaking time. The percentage of degradation of amaranth dye with CTW45 nanocomposite was more than CDT, CTW15, CTW30 and CTW60 nanocomposites due to high surface area and low crystallite size. The percentage of photodegradation of amaranth dye with CTW45 nanocomposite was 94.89 at 2 hr.

According to another exemplary embodiment of the invention, FIG. 8 refers to a graphical representation 800 of percentage of photodegradation of amaranth dye with best CTW45 nanocomposite at different pH values. In one embodiment herein, the percentage of degradation of amaranth dye using CTW45 nanocomposite at different pH values. The pH values other than pH4 cause the percentage of IC dye in CTW45 nanocomposite to drop. The reason pH4 has a higher proportion of amaranth dye with CTW45 than pH2, pH3, pH8, and pH10 is that when surface titanyl groups (Ti-OH) are protonated in acidic conditions, Cu-TiO2 and WO3 develop a positive surface charge. The positive surface charge is easier for the negatively charged (anionic dye) amaranth dye to adhere electrostatically to the catalyst surface.

The adsorption of colour molecules therefore steadily decreases except for pH4. The rate of amaranth dye degradation decreases. Due to the formation of negative surfaces, the positivity of the surface gradually decreases at the basic pH, or pH8, and the degradation efficiency is found to be rather low. Furthermore, under extremely basic circumstances, the negatively charged dye would be rejected by the negatively charged Cu-TiO2 and WO3 surface, thereby lowering the dye's rate of adsorption and minimizing degradation.

According to another exemplary embodiment of the invention, FIG. 9A refers to a graphical representation 900 of percentage of photodegradation of amaranth with best CTW45 nanocomposite at different composite concentrations. In one embodiment herein, the percentage of the photodegradation of amaranth dye with best CTW45 nanocomposite at different composite concentration of 25 mg/L, 50 mg/L, 100 mg/L, and 150mg/L. The percentage of degradation of amaranth dye with CTW45 decreases with increased composite concentration except for 100 mg/L. The percentage of photodegradation of amaranth dye was more with the concentration of CTW45 with 100 mg/L. The amaranth with CTW45 nanocomposite compared to the higher degradations than other concentrations. The percentage of amaranth dye degradation is more with the CTW45 concentration of 100 mg/L and the dye concentration of 5 mg/L at pH4.

According to another exemplary embodiment of the invention, FIG. 9B refers to a graphical representation 902 of rate of degradation of amaranth for best CTW45 nanocomposite with different composite concentrations. In one embodiment herein, the rate of degradation Amaranth dye with different concentrations of CTW45 nanocomposite. The rate of degradation randomly changes with different concentration of CTW45 nanocomposite. The rate of degradation of amaranth dye is more for 100 mg/L concentration of CTW45 nanocomposite. The rate degradation show a maximum at 100 mg/L among other concentration of CTW45 nanocomposite.

According to another exemplary embodiment of the invention, FIG. 10 refers to a schematic view 1000 of photocatalytic mechanism of amaranth dye with copper doped titanium dioxide and tungsten trioxide. In one embodiment herein, the process initiates with the absorption of visible light (h?) by the Cu-TiO2 and WO3 nanocomposite. The energy of the absorbed proton (h?) must be equal to or greater than the band gap energy (Eg) of the material. The electron-hole pair are generated in both the Cu-TiO2 and WO3 nanocomposite. The electrons (e-) are excited from the valence band (VB) to the conduction band (CB), thereby abandoning holes (h+) in the valence band.

In one embodiment herein, the charge separation and transfer the electrons in the CB in Cu-TiO2 are transferred to the CB of WO3, thereby separating the electron-hole pairs, and reducing the recombination rate and enhancing the photocatalytic efficiency. In another embodiment herein, the photocatalytic reactions is configured to reduction reaction (WO3) and oxidation reaction (Cu-TiO2). The reduction reaction (WO3) is react with oxygen (O2) to form superoxide radicals (O2•-). The superoxide radical further react to form other reactive oxygen species (ROS), which can degrade organic pollutants. The oxidation reaction (Cu-TiO2) oxidize water (H2O) or hydroxide ions (OH-) to generate hydroxyl radicals (•OH), which is highly reactive and degrade organic pollutants as amaranth dye.

In one embodiment herein, the reactive oxygen species attack the amaranth dye molecules, thereby bond dissociation into less harmful substances such as carbon dioxide (CO2) and water (H2O). The path for electron-hole recombination within the Cu-TiO2 component, which is an undesirable process as it reduces the photocatalytic efficiency. However, the presence of WO3 assist in reducing the recombination by facilitating charge separation. The photocatalytic degradation process involves the conversion of amaranth dye into CO2 and H2O, facilitated by the Cu-TiO2 and WO3 nanocomposite under visible light irradiation.

Numerous advantages of the present disclosure may be apparent from the discussion above. In accordance with the present disclosure, the method for preparing the copper doped titanium dioxide and tungsten trioxide for degradation of the amaranth dye. The proposed method significantly improves photocatalytic activity under visible light, making it more effective than conventional photocatalysts. The proposed method is capable of completely degrading amaranth dye, a common pollutant in wastewater, within a short period, ensuring thorough purification. The proposed method utilizes BET (Brunauer Emmett Teller) indicates that the CTW45 nanocomposite has a larger surface area, which provides more active sites for photocatalytic reactions, enhancing overall performance.

The proposed method varies soaking times, the WO3 to achieve maximum photocatalytic activity, thereby allowing for customization based on specific requirements. The proposed method utilizes sol-gel synthesis and soaking techniques, is straightforward and scalable, making it suitable for industrial production. The proposed method utilizes visible light, reduces the need for high-energy UV light sources, leading to lower operational costs. The proposed method provides an efficient solution for degrading harmful dyes in wastewater, contributing to environmental protection and sustainable water management.

It will readily be apparent that numerous modifications and alterations can be made to the processes described in the foregoing examples without departing from the principles underlying the invention, and all such modifications and alterations are intended to be embraced by this application.
, Claims:CLAIMS:
I / We Claim:
1. A method for preparing a copper doped titanium dioxide and tungsten trioxide for degradation of a dye, comprising:
adding 9 gm of sodium tungstate powder to 180 mL of at least 30 percent of hydrogen peroxide and stirring at a temperature of at least 30 °C for a time period of at least 2 hr to form a peroxotungstic acid solution;
filtering the peroxotungstic acid solution to remove undissolved particles, and adding 180 mL of anhydrous ethanol to the peroxotungstic acid solution while stirring to displace excess peroxotungstic acid solution and make the peroxotungstic acid solution negatively charged;
adding 9 gm of a copper doped titanium dioxide to the peroxotungstic acid solution and mixing for a predetermined period;
centrifuging the mixture of the copper doped titanium dioxide and the peroxotungstic acid solution at a speed of at least 10,000 rpm for a time period of at least 10 min to obtain a solid and vacuum-drying the resultant solid at a temperature of at least 70 °C;
annealing the dried solid in a muffle furnace at a temperature of at least 550 °C for a time period of at least 6 hr to promote crystallization and form the copper doped titanium dioxide and tungsten trioxide nanocomposite;
soaking the copper doped titanium dioxide in the solution for varying times of 15, 30, 45, and 60 min to investigate the impact of tungsten content on the photocatalytic activity;
characterizing the prepared copper doped titanium dioxide and copper doped tungsten trioxide nanocomposite powder using multiple tests to measure ultraviolet-visible absorption spectra to evaluate the degradation of amaranth dye by the nanocomposite; and
demonstrating the carat total weight 45 nanocomposite, soaked for at least 45 min exhibits the highest photocatalytic activity, thereby degrading the amaranth dye within the two hr.
2. The method as claimed in claim 1, wherein the multiple tests include brunauer Emmett teller (BET) surface area analysis, X-ray diffraction (XRD) measurements, and ultraviolet-visible spectroscopy to measure ultraviolet-visible absorption spectra to evaluate the degradation of the amaranth dye.
3. The method as claimed in claim 1, wherein the copper doped titanium dioxide photocatalyst is prepared by a method, comprises:
dissolving 60 mL of butyl ortho titanate in 120 mL of ethanol to form a mixture and agitating the mixture for at least 10 min;
adding 9.6 mL of nitric acid to the mixture and stirring for at least 30 min to form a first solution, and mixing 21.6 mL of deionized water with 120 mL of ethanol in a separate container to form a second solution;
adding the second solution dropwise to the first solution while stirring vigorously and continuing to stir for at least 90 min to form a transparent gel;
allowing the transparent solution to mature in a dark at a room temperature for at least 48 hr, thereby obtaining a gel; and
drying the obtained gel by baking at a temperature of at least 72 °C, and calcining the dried gel in a muffle furnace at a temperature of at least 450 °C for at least 5 hr to obtain the copper doped titanium dioxide photocatalyst.
4. The method as claimed in claim 3, wherein the second solution is added to the first solution at a temperature varies between 20 °C and 30 °C.
5. The method as claimed in claim 3, wherein the transparent solution is matured for a time period of at least 48 hr to ensure optimal transparent gel formation.
6. The method as claimed in claim 1, wherein the calcination of the copper doped titanium dioxide photocatalyst is conducted at a ramp rate of 5 °C per minute to 450 °C.
7. The method as claimed in claim 1, wherein the peroxotungstic acid solution is formed by maintaining the stirring speed of at least 500 rpm to ensure complete dissolution of the sodium tungstate powder.
8. The method as claimed in claim 1, wherein the copper doped titanium dioxide is soaked in the peroxotungstic acid solution for at least 45 min to achieve the optimal tungsten trioxide content for maximum photocatalytic activity.
9. The method as claimed in claim 1, wherein the characterizing the efficiency of the copper doped titanium dioxide photocatalytic and tungsten trioxide nanocomposite using UV-Vis spectrophotometry to determine the degradation rate of amaranth dye.