Abstract

General Background: Nanotechnology has gained significant attention for its potential applications in environmental remediation, particularly in the degradation of organic pollutants. Specific Background: Green synthesis of nanoparticles using plant extracts is a sustainable approach that reduces the need for hazardous chemicals. Knowledge Gap: However, the role of Laurus nobilis (bay laurel) in synthesizing cadmium nanoparticles (CdNPs) and their effectiveness in dye degradation remains underexplored. Aims: This study investigates the feasibility of synthesizing CdNPs using Laurus nobilis leaf extract as a natural reducing and stabilizing agent and evaluates their potential in methylene blue (MB) dye degradation. Results: The formation of CdNPs was confirmed by UV-visible spectroscopy, exhibiting a surface plasmon resonance peak at 435 nm, and SEM-EDX analysis revealed spherical nanoparticles with an average size of 61.36 nm and a cadmium composition of 87.57%. The synthesized CdNPs achieved a 60% degradation efficiency for MB dye under visible light exposure. Novelty: This work presents an eco-friendly, rapid, and simple method for synthesizing CdNPs using Laurus nobilis, highlighting the phytochemical-mediated nanoparticle stabilization. Implications: The findings demonstrate the potential of plant-based CdNPs for wastewater treatment applications, contributing to sustainable and green chemistry solutions for environmental pollution.

Highlights:

1. Green synthesis of cadmium nanoparticles using Laurus nobilis extract.
2. Spherical CdNPs (61.36 nm) achieved 60% methylene blue degradation.
3. Eco-friendly nanotechnology for wastewater treatment and environmental remediation.

Keywords: cadmium nanoparticles, degradation, green synthesis, Laurus nobilis Leaves extract.

Introduction

Nanotechnology has revolutionized several sectors by enabling the development of materials with unique properties that distinguish them from their bulk counterparts [1]. Due to their small size and large surface area, nanoparticles in particular have been the focus of a lot of research because of their unique optical, electrical, and catalytic properties [2]. One of these cadmium nanoparticles was used for a different purpose. Among the various types of nanoparticles, cadmium nanoparticles (Cd nanoparticles) have attracted a lot of interest due to their potential uses in bioimaging, photovoltaics, catalysis, and antimicrobial therapeutics [3, 4].

Conventional chemical and physical synthesis methods for Cd nanoparticles often use high temperatures, toxic chemicals, and other energy-intensive processes that can be detrimental to human health and the environment [5, 6]. Therefore, the development of sustainable nanotechnology depends on the discovery of various, eco-friendly synthesis techniques. Green synthesis techniques have become more popular in response to these worries since they employ natural materials and function in mild environments, which lessens their negative environmental effects [7, 8]. Utilizing biological materials as natural reducing and stabilizing agents in the production of NANOPARTICLES, such as plant extracts, microbes, and algae, is an efficient strategy within this paradigm [9]. This method efficiently stabilizes metal ions while reducing them to their nanoparticle form by utilizing the bioactive chemicals found in plants, which can function as natural antioxidants [10]. Specifically, plant-mediated production of Cd nanoparticles has been studied using a variety of plants, such as Azadirachta indica (neem), Ocimum sanctum, Moringa oleifera, and Aloe vera [11,12,13].

Phytochemicals like polyphenols, flavonoids, and alkaloids are abundant in these plants. Polyphenols, flavonoids, and alkaloids are among the many phytochemicals found in these plants that aid in the stabilization and reduction processes [14,15]. The benefits of this environmentally benign method are confirmed by numerous research that have effectively produced Cd nanoparticles using different plant extracts. For example, scientists produced well-dispersed Cd nanoparticles with strong antibacterial activity using Moringa oleifera leaf extract [16]. Aloe vera extract was used in another study to create Cd nanoparticles with possible photocatalytic properties [17]. The stability and biocompatibility of Cd nanoparticles were also found to be enhanced by Azadirachta indica extracts, making them suitable for use in biomedical applications [18]. There are benefits to using plant extracts beyond their environmental safety. These green-synthesized nanoparticles have been shown to have improved biocompatibility, which is essential for applications in drug delivery, tissue engineering, and biosensing [19,20].

Additionally, the natural capping agents that plant compounds provide improve the stability and longevity of the nanoparticles, both of which are essential for industrial and medical applications [21]. Systematic research is still needed to assess long-term stability, optimize synthesis conditions, and investigate toxicity repercussions in biological systems, notwithstanding the progress made in the production of environmentally acceptable Cd nanoparticles [22]. comprehensive study addressing.

These components will be crucial for the practical application of plant-mediated Cd nanoparticles in domains such as environmental remediation and nanomedicine [23, 24, 25]. Given these considerations, the aim of this work is to synthesize Cd nanoparticles using a specific plant extract, characterize the resulting nanoparticles, and evaluate their potential applications. The findings of this study contribute to the growing body of knowledge on sustainable nanoparticle synthesis and explore the potential of plant-mediated Cd nanoparticles as versatile agents in a range of industries [26].

Methods

Experimental

We obtained leaves (Laurus nobilis) from local markets. The leaves were then washed well with water several times. Then the leaves were left to dry for 10 days at 25 °C. After that, an electric grinder was used to crush the dried leaves into a very fine powder. 0.1 g of the ground and sieved powder with a size of 150 micrometers was taken and dissolved with 100 ml of deionized water. Then the extract was placed on a magnetic stirrer for an hour at a temperature of 90 °C. Finally, the extract was filtered.

2. Preparation of cadmiumnanoparticles by wet chemical method

25 ml of laurel extract was taken with 25 ml of cadmium nitrate solution (1000 ppm was prepared by dissolving (0.1 g) of cadmium nitrate in 100 ml deionized water) and placed on a magnetic stirrer at 80 °C for 5 minutes until the colour changed to brown due to the form of cadmium nanoparticles. Figure 1, shows cadmium nanoparticles and laser beam pass through the solution shows Tyndall effect [27].

Figure 1. shows cadmium nano particles and laser beam pass through the solution shows Tyndall effect.

3. preparation of a methylene blue solution

A methylene blue solution with a concentration of 1000 ppm has been prepared by adding 0.1 g of methylene blue to 100 ml of deionized water, and the other solution was prepared by dilution.

4.Study of the maximum wavelength (λ_max) of methylene blue

The absorbance of the dye solution, which is a ketogenic dye and whose chemical formula symbol is (C₁₆H₁₈ClN₃S), was measured using a single-beam UV-visible spectrometer of the type (Spectrophotometers 303-PD). The maximum measured wavelength (663 nm) was determined as shown in figure (2).

Figure 2. represents the UV-Vi z spectrum of methylene blue dye.

Results and Discussion

Investigation of surface plasmon resonance (SPR)

UV-Vis Spectroscopy, which uses the detection of the distinctive SPR peak to track the synthesis of cadmium nanoparticles.

Figure 3. shows plasmon spectra for cadmium nanoparticles.

The solution obtained from a solution of cadmium nanoparticles prepared at a concentration of 1000 ppm showed a clearer surface plasmon resonance peak at (435 nm) using a UV-Vis spectrometer and scanning at wavelengths from 380 to 500nm). This agrees with what others found [28], and the plasmon spectrum appeared as shown in Figure 3.

Characterization by SEM

The morphology of cadmium nanoparticles was examined using a scanning electron microscopy, as shown in Figure 4.

Figure 4. Scanning electron microscope (SEM) images of the prepared cadmium nanoparticles .

SEM was used to study the outer surface, morphology, and size of the nanoparticles. The agglomerated particles appear in the image in the form of a small size due to the existing agglomeration, and the exact measurement for them cannot be calculated due to their morphological size. A clear image of the prepared cadmium nanoparticles appears, and they appear in spherical oval shapes. When EDX was done, it appeared at a size of 61.3 nm) as shown in Figure 5.

EDX is a method used in science to measure the energy of X-rays emitted by a material in order to determine its chemical composition. The produced cadmium nanoparticle’s composition was determined by an Energy Dispersive X-ray Spectroscopy (EDX) analysis.

The presence of cadmium, oxygen, carbon, atoms was shown through spectroscopy used for dispersed energy X-rays (EDX) to determine the components of the elements in the sample, as shown in figures 5. The main output obtained shows the highest volume of cadmium (87.57%). As shown in figure 5, oxygen has a peak of 9.29%, carbon has a peak of 3.13%.

Figure 5. Energy dispersive X -ray spectroscopy of cadmium nanoparticles .

Dynamic light scattering of cadmium nanoparticles

Figure (6) shows the range of sizes of cadmium nanoparticles. which prepared at a concentration of 1000 ppm, represents the size distribution of particles reached to (67.47nm) which is agreement with the SEM results.

Figure 6. shows the size distribution of cadmium nanoparticles

Application of cadmium nanoparticles

The rate of the photocatalytic degradation process was affected by different parameters such as the concentration of dye, effect of volume of nanoparticles, and the effect of intensity of light.

The efficiency of material was calculated by using following Equation (1) [29].

Efficiency%= A_o− A_t/A_{o ٭} 100………(1)

where, A₀ is initial absorbance, and A_t is absorbance after t time reaction.

1. Study the effect of utilising varying c admium nanoparticle sizes in a solution on the methylene blue dye's degradation.

Using three different sizes of cadmium nanoparticles solutions (0.5 ml, 1 ml, and 1.5 ml), the degradation of methylene blue dye was investigated. (20) ml of the methylene blue dye was mixed with these various sizes. Using visible light at a strength of 15 W, the dye's degradation was observed for one hour. Using a UV-Vis equipment, the absorbance was measured at the maximum wavelength of methylene blue dye (663 nm) at predetermined intervals (every 15 minutes). Over time, we observe a decline in the absorbance value and a progressive fading of the solution's kind. Table 2 and figure 7 displays the results.

Figure 7. shows the degradation of methylene blue dye, using different volumes of cadmium nanoparticles solution, and using a light source with a power of (15W)

From the table, we note that the highest degradation of methylene blue dye is when using a volume of 0.1 ml of cadmium nanoparticles solution, where the percentage was 33%, followed by using a volume of 1 ml of cadmium nanoparticles solution, where the degradation was 23.6%. However, for using (1.5 ml) of cadmium nanoparticles solution presented the degradation percentage about (22.8%).

2. Study the effect of the varying amounts of cadmium nanoparticles affects the methylene blue dye's breakdown

Using three different concentrations of a wet-prepared solution of cadmium nanoparticles (250 ppm, 500 ppm, and 1000 ppm), the degradation of methylene blue dye was investigated. These concentrations were taken in fixed volumes of 1 ml each, then applied to 20 ml of methylene blue dye. Visible light was used to study the degradation. The outcomes at a 15W power were displayed in Table 3 and Figure 8.

Figure 8. shows the degradation of methylene blue dye using different concentrations of cadmium nanoparticles solution and a light source with a power of 15 W.

From table (3), we note that the highest degradation of methylene blue dye is using a cadmium nanoparticles solution with a concentration of 250 ppm, where 57% of the dye was broken after an hour and using light, followed by the degradation of methylene blue dye using a cadmium nanoparticles solution with a concentration of 500 ppm, where 51.8% was broken. The percentage of dye for the same time, followed by breaking the methylene blue dye using a cadmium nanoparticles solution at a concentration of 1000 ppm, which broke 47.1% of the dye. (The higher the concentration, the greater the absorption, and thus the less degradation).

3. Study the effect of degradation of methylene blue dye in the occurrence of different power light sources (15W and 30W) and prepared cadmium nanoparticles.

In this study, a fixed size (1 ml) of prepared cadmium nanoparticles with a concentration of 250 ppm, which acts as a catalyst, methylene blue dye prepared with a size of 20 ml and a concentration of 1 ppm, and a different light source with a power of 15 and 30 watts were used, and the results appeared as shown in the table (4) and figure (9).

Figure 9. shows the degradation of methylene blue dye in the presence of different light sources using prepared c admium nanoparticles that act as catalysts.

Table 4 shows that the percentage of degradation of the methylene blue dye without using the prepared cadmium nanoparticles is very low, the percentage of degradation was low when using a 15-watt source, and the percentage of degradation of the organic dye methylene blue dye with the prepared cadmium nanoparticles was higher when using a light source (30-watt). The percentage of degradation was 60.1% higher than the percentage of degradation of methylene blue dye with cadmium nanoparticles prepared when using a light source with a power of 15 W, whose percentage of degradation was 57%. That is, the greater the intensity of the source, the greater the crushing.

Conclusion

The studies clearly demonstrated the feasibility of synthesizing cadmium nanoparticles and revealed the presence of several phytochemical compounds in the plant extract, which act as encapsulating and stabilizing agents for the resulting nanoparticles. By analyzing the results, it is clear that the starting materials played a vital role in the surface morphology and structure of cadmium nanoparticles. Our results confirm the potential of bay leaves (Laurus nobilis) in synthesizing cadmium nanoparticles in a simple, rapid and environmentally friendly manner. Cadmium nanoparticles can be used in the degradation of methylene blue dye in polluted water using visible light (tungsten lamp) for one hour. Percentage of degradation of methylene blue dye achieved with synthesized cadmium nanoparticles was 60%.

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