Method for preparing nano cuprous oxide by using curcumin and application thereof

Abstract

The application discloses a method for preparing nano cuprous oxide by using curcumin and application thereof, and belongs to the field of nano material development, energy and energy saving technology, environmental protection and resource comprehensive utilization. The method comprises the following steps: adding curcumin powder into ethanol to perform ultrasonic extraction, taking supernatant after standing to obtain curcumin extract; adding cupric sulfate pentahydrate, sodium citrate, sodium hydroxide and the curcumin extract into deionized water in sequence, heating and stirring until the reaction is completed, cooling to room temperature, and then washing and drying to obtain cuprous oxide solid powder. The prepared cuprous oxide solid powder is added into deionized water to catalyze water to generate hydrogen peroxide under light conditions, the obtained solution is used for neutralizing a washing powder solution, the neutralized washing powder solution is used for cultivating mung beans, and the mung bean germination and growth is observed and recorded. The curcumin extract is used to replace a traditional chemical reducing agent, green synthesis of nano cuprous oxide is realized, the washing powder solution is treated by using the photocatalytic performance of the curcumin extract, and good environmental benefits are achieved.

Description

Technical Field

[0001] This invention belongs to the fields of nanomaterial development, energy and energy-saving technology, environmental protection and comprehensive resource utilization. Background Technology

[0002] Currently, China ranks among the world's leaders in green chemistry and photocatalytic degradation, achieving remarkable results in environmental governance and resource recycling. Green chemistry eliminates pollution at its source, pursuing a product design, manufacturing, and use process that is harmless to health and the environment. This technology not only improves production efficiency but also protects the environment, promoting a win-win situation for the economy and ecology, and has a profound impact on the efficient use of resources and the harmonious coexistence of humans and nature. In the field of photocatalysis, cuprous oxide is a typical narrow-bandgap (1.9~2.2 eV) p-type semiconductor. Its narrow-bandgap structure endows it with excellent visible light response capabilities, enabling it to efficiently capture and utilize solar energy. In the photocatalytic production of hydrogen peroxide (H2O2), upon photoexcitation, the catalyst generates photogenerated electron-hole pairs, where the electrons selectively reduce dissolved oxygen with two electrons (O2 + 2e2e2). - +2H + →H2O2), while cavitation oxidation of water or hydroxyl groups replenishes protons, both synergistically driving the sustainable generation of H2O2. Cuprous oxide raw materials are abundant, inexpensive, and have low biotoxicity, aligning with green chemistry principles. Its core function lies in utilizing green light energy to continuously produce weakly acidic, high-value-added H2O2 under mild conditions. This product can be directly used in environmental remediation and disinfection, achieving a green conversion of light energy into chemical energy, combining environmental and economic benefits.

[0003] Traditional chemical reduction processes for cuprous oxide typically employ highly reducing agents, which are not only expensive but also environmentally problematic, contradicting the principles of green chemistry. To address these issues, this invention proposes a fully green synthesis route for cuprous oxide using curcumin extract as the reducing agent, with a core logic of "green reducing agent – ​​green catalyst – green application." Turmeric powder is a common condiment and natural pigment source in daily life, containing a large amount of curcumin-like compounds. Its reducing power primarily stems from its unique chemical structure; the phenolic hydroxyl group and β-diketone structure in the curcumin molecule are key active sites for its reducing properties. These active groups can donate hydrogen protons to copper ions, transforming themselves into a stable quinone resonance structure, thus achieving a gentle reduction of copper ions to cuprous oxide. The green application proposed in this invention treats alkaline domestic wastewater, exemplified by commercial laundry detergent solutions (pH≈9). The weakly acidic hydrogen peroxide generated through the photocatalytic action of cuprous oxide neutralizes the detergent solution, thereby reducing the harm of alkaline domestic wastewater to water sources, soil, and even living organisms. Typical domestic laundry wastewater is rich in anionic surfactants and various organic additives, characterized by large and dispersed daily discharges, severely impacting the normal growth of aquatic organisms and reducing the self-purification function of water bodies. Alkaline laundry wastewater seeps into the soil, damaging its physical and chemical properties, causing soil alkalization and compaction, and affecting the normal growth of crops. This invention further investigates the impact of neutralized laundry detergent solution on mung bean germination and growth by cultivating the plant. In daily washing, to achieve maximum surface activity and strongest detergency, the mass fraction of laundry detergent in water is typically controlled at 0.2%~0.5% (i.e., 200~500 g of laundry detergent per 100 kg of water). At this concentration, the foam is moderate, effectively emulsifying stains while facilitating rinsing and avoiding excessive residue. The detergent concentration in the wastewater generated after rinsing significantly decreases due to dilution. Therefore, the detergent concentration in the laundry wastewater indicator of this invention is set to one-tenth of the standard daily detergent usage for accurate simulation. This invention utilizes turmeric powder to extract curcumin as a reducing agent to prepare nano-cuprous oxide. Through rapid photocatalysis, water is converted into hydrogen peroxide for neutralizing domestic laundry wastewater and for application in the sprouting and growth of mung beans. This invention proposes a feasible green synthesis and application path for cuprous oxide nanomaterials, which meets the requirements of green development that is low-carbon, low-energy, and pollution-free. Summary of the Invention

[0004] This invention uses edible turmeric powder as a green reducing agent to extract curcumin, which has reducing properties, to replace the toxic and harmful chemical reducing agents in traditional synthesis processes. This invention aims to establish a green, sustainable, and environmentally friendly pathway for the preparation and green circular application of nano-cuprous oxide. The method for preparing nano-cuprous oxide using curcumin and its application, as described in this invention, are achieved through the following steps.

[0005] Step 1: Disperse turmeric powder in ethanol using ultrasound, let it stand and retain the clear liquid to obtain curcumin extract.

[0006] Step 2: Add copper sulfate pentahydrate, sodium citrate, sodium hydroxide, and curcumin extract to deionized water in sequence, heat and stir until the reaction is complete, cool to room temperature, wash and dry to obtain cuprous oxide solid powder.

[0007] Step 3: Place the cuprous oxide solid powder into deionized water, stir and disperse it rapidly under light source, then centrifuge to collect the supernatant solution for neutralization titration of commercial laundry detergent solution.

[0008] Step 4: Take equal amounts of mung beans and place them into equal volumes of deionized water, laundry detergent solution, and neutralized laundry detergent solution, respectively. Observe and record the sprouting and growth of the mung beans.

[0009] Further specify that in step one, 10-30 g of turmeric powder is added to 80-120 mL of ethanol, and the sonication time is 60-100 min.

[0010] Further specifying, in step two, 350-400 mg of copper sulfate pentahydrate, 135-155 mg of sodium citrate, 0.8-1.2 g of sodium hydroxide, and 30-80 mL of curcumin extract are added sequentially to 80-100 mL of deionized water.

[0011] Further specifying, the heating temperature in step two is 40~60 ℃, and the heating time is 20~40 min.

[0012] Further specifying, in step two, the vacuum drying oven is kept at 60 ℃ for 12 h.

[0013] Further specifying, in step three, 5-15 mg of cuprous oxide powder is placed in 30-70 mL of deionized water, and after rapid stirring for 5-15 min under 300W xenon lamp irradiation, 20-60 mL of the centrifuged liquid is taken to neutralize and titrate 30-70 mL of a commercial laundry detergent solution with a concentration of 100-300 μg / mL.

[0014] To further refine the process, in step four, three groups of mung beans of similar size, each containing 10-30 beans, were placed in 5-15 mL of equal amounts of deionized water, laundry detergent solution, and neutralized laundry detergent solution for comparison. The sprouting status of the mung beans was observed and recorded every 12-36 hours.

[0015] This invention uses turmeric powder as a natural raw material, utilizing its curcumin-like components as a natural antioxidant and reducing agent for the green and rapid synthesis of nano-cuprous oxide. Furthermore, this nanocatalyst's ability to rapidly photocatalyze water to produce weakly acidic hydrogen peroxide neutralizes laundry wastewater. The neutralized solution is then better suited for mung bean germination and growth. This preparation method avoids the use of high-cost, high-polluting chemical reducing agents in traditional processes, effectively reducing the environmental impact and energy consumption of the preparation process. The production of high-value-added hydrogen peroxide and its green, low-energy applications in domestic laundry wastewater treatment and plant growth provide a new technical solution and practical prospect for enhancing the environmentally friendly usability of this nanocatalyst. Attached Figure Description

[0016] Figure 1 This is the XRD pattern of nano-cuprous oxide; Figure 2 This is a scanning electron microscope image of nano-cuprous oxide; Figure 3 It shows the ultraviolet-visible absorption spectrum and optical band gap of nano-cuprous oxide; Figure 4 These are the Mott-Schottky test lines for nano-cuprous oxide; Figure 5 The curve of H2O2 concentration versus time during photocatalytic synthesis of nano-cuprous oxide and the standard curve of H2O2 concentration determined by iodometric titration; Figure 6 These are the curcumin spectral scanning curve and the curcumin concentration standard curve; Figure 7 This is a comparison of the results of cultivating mung bean sprouts using the neutralized laundry wastewater used in this embodiment and two control groups (deionized water and unneutralized laundry wastewater). Detailed Implementation

[0017] Example 1: This example provides a method for preparing nano-cuprous oxide using curcumin and its application, which is carried out according to the following steps.

[0018] (I) Preparation of curcumin extract

[0019] Take 15 g of turmeric powder, add 100 mL of ethanol, sonicate for 60 min, let stand and retain the clear liquid to obtain curcumin extract.

[0020] (II) Preparation of nano-cuprous oxide

[0021] 375 mg copper sulfate pentahydrate, 147 mg sodium citrate, 1 g sodium hydroxide, and 50 mL curcumin extract were sequentially added to 100 mL of deionized water and heated and stirred at 60 °C for 30 min. After the reaction was completed, the mixture was cooled to room temperature and washed three times with ethanol. The mixture was then dried under vacuum at 60 °C for 12 h to obtain cuprous oxide solid powder.

[0022] (III) Photocatalytic synthesis of hydrogen peroxide from nano-cuprous oxide and its application in the neutralization treatment of laundry wastewater and bean sprout growth

[0023] 10 mg of cuprous oxide powder was added to 50 mL of deionized water, and a photocatalytic reaction to produce hydrogen peroxide was carried out under irradiation with a 300 W xenon lamp. The supernatant was collected every 5 min, and the hydrogen peroxide yield was measured using a photometer. Figure 5 As shown. Figure 5 It is evident that the nano-cuprous oxide catalyst can continuously produce hydrogen peroxide in deionized water, and can rapidly and linearly increase to a high concentration within 10 minutes. Therefore, the green application of hydrogen peroxide production based on the nano-cuprous oxide catalyst in this invention is evaluated using the centrifuged reaction liquid after 10 minutes of photoreaction.

[0024] 40 mL of the reaction solution was used to neutralize 40 mL of a commercial laundry detergent solution with a concentration of 200 μg / mL (pH≈9), resulting in a neutralized laundry detergent solution (pH≈7). As a comparison, 40 mL of deionized water was added to the above laundry detergent solution to obtain a diluted laundry detergent solution (pH≈8). This demonstrates that the complete neutralization of the alkaline laundry detergent solution to neutral is due to the production of hydrogen peroxide by the photoreaction of the catalyst in this invention. Figure 7 As shown.

[0025] Equal volumes of neutralized solution (pH≈7), deionized water (pH≈7), and laundry detergent solution (pH≈9) were used as culture media for equal volumes of mung beans. The growth of the bean sprouts was observed and compared every 24 hours, and the results were recorded as Application Example, Control Example 1, and Control Example 2, respectively. To avoid interference with photosynthesis, all three comparative experiments were conducted under dark conditions at a temperature of 25±2 ℃. Figure 7 As shown, the specific operation is as follows.

[0026] Application example: Take 20 mung beans and place them in a measuring cup. Add 10 mL of neutralized laundry detergent solution (pH≈7) to cover the mung beans. Incubate in the dark and observe and record the germination status of the mung beans every 24 hours. At 24 hours, the germination rate reached 50%; at 48 hours, all beans had sprouted and grown; at 72 hours, the average sprout length was 3 cm; at 96 hours, the average sprout length was 4 cm, which was second only to control example 1 but better than control example 2; at 120 hours, the average sprout length was 8 cm, which was the best among the three groups.

[0027] Control Example 1: Take 20 mung beans and place them in a measuring cup. Add 10 mL of deionized water (pH≈7) to cover the mung beans and incubate in the dark. Observe and record the germination status of the mung beans every 24 hours. At 24 hours, the germination rate reached 85%; at 48 hours, all beans had sprouted and grown; at 72 hours, the average sprout length was 3 cm; at 96 hours, the average sprout length was 5 cm, the longest among the three groups; at 120 hours, the average sprout length was 7 cm, which was second only to the application example but better than Control Example 2.

[0028] Comparative Example 2: Take 20 mung beans and place them in a measuring cup. Add 10 mL of laundry detergent solution (pH≈9) to cover the mung beans and incubate them in the dark. Observe and record the germination status of the mung beans every 24 hours. At 24 hours, the germination rate was nearly 50%; at 48 hours, all of them had sprouted and grown; at 72 hours, the average sprout length was 2.5 cm, the worst among the three groups; at 96 hours, the average sprout length was 3 cm, the worst among the three groups; at 120 hours, the average sprout length was 4 cm, the worst among the three groups.

[0029] The above comparative results show that the nano-cuprous oxide prepared by the present invention can generate weakly acidic hydrogen peroxide through rapid photocatalytic water reaction. The reaction solution can be effectively used for the neutralization treatment of domestic sewage, represented by alkaline laundry detergent solution. Moreover, the neutralized laundry detergent solution not only has no inhibitory effect on the growth of mung bean sprouts, but also performs better than deionized water, far exceeding untreated laundry sewage.

Claims

1. A method for preparing nano-cuprous oxide using curcumin and its application, characterized in that... The preparation method and its application are accomplished through the following steps: Step 1: Turmeric powder is extracted with ultrasound in ethanol, and the clear liquid is retained after standing to obtain curcumin extract; Step 2: Copper sulfate pentahydrate, sodium citrate, sodium hydroxide, and curcumin extract are added sequentially to deionized water, heated and stirred until the reaction is complete, cooled to room temperature, washed, and dried to obtain cuprous oxide solid powder; Step 3: Cuprous oxide solid powder is placed in deionized water, rapidly stirred and dispersed under light source irradiation, and the supernatant after centrifugation is used for neutralization titration with commercial laundry detergent solution; Step 4: Three groups of mung beans of similar size are taken, each group in equal amounts, and placed in equal amounts of deionized water, laundry detergent solution, and neutralized laundry detergent solution, respectively. The changes in mung bean sprouting and growth are observed and recorded.

2. The method according to claim 1, characterized in that... In step one, add 10-30 g of turmeric powder to 80-120 mL of ethanol and sonicate for 60-100 min.

3. The method according to claim 1, characterized in that... In step two, 350-400 mg of copper sulfate pentahydrate, 135-155 mg of sodium citrate, 0.8-1.2 g of sodium hydroxide, and 30-80 mL of curcumin extract are added sequentially to 80-100 mL of deionized water.

4. The method according to claim 1, characterized in that... In step two, the heating temperature is 40~60 ℃, the heating time is 20~40 min, and the temperature is kept at 60 ℃ for 12 h in a vacuum drying oven.

5. The method according to claim 1, characterized in that... In step three, 5-15 mg of cuprous oxide powder is placed in 30-70 mL of deionized water and stirred rapidly for 5-15 min under 300 W xenon lamp irradiation. Then, 20-60 mL of the supernatant after centrifugation is taken and neutralized and titrated with 30-70 mL of a commercial laundry detergent solution with a concentration of 100-300 μg / mL.

6. The method according to claim 1, characterized in that... In step four, 10-30 mung beans from each of three groups of similar size were placed in 5-15 mL of deionized water, laundry detergent solution, and neutralized laundry detergent solution for comparison. The sprouting status of the mung beans was observed every 12-36 hours.

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