Introduction

Metal oxide NPs (MO – NPs) have proved to be particularly effective in inhibiting bacterial growth [1-3] and antibacterial resistance, treatment to remove multiple heavy metal ions from waste water by using Fe₃O₄NPs, gas sensor, and catalyst [4-6]. Manufacture oxide nanoparticles with specified sizes and shapes, green synthesis is a challenge [7, 8]. Because of their ease of use, abundant biodiversity and eco- friendly processes, biosynthesis technologies offer a distinct advantage over other traditional synthesis approaches. [9, 10]. Mentha Puegium (pennyroyal) leaf extract was used to make silver nanoparticles for antibacterial use [11, 12]. Bi₂O₃ NPs was synthesized via green synthesis using Mentha Pulegium aqueous extract and it showed antibacterial activities [7]. Researchers have synthesized Bi₂O₃ NPs by using Jotopha multifidi leaf extract. The Bi₂O₃ NPs that were generated contain a monoclinic structure, a 3.34 eV optical band gap, agglomeration morphology and a particle size of 17.26 nm [13]. At room temperature, the researchers biosynthesized Bi₂O₃ NPs in a size range of 5-8 nm by fungus – fusarium oxysporum with Bi(NO₃)₃.5H₂O [14]. In the present study, we have developed a facile green synthesis method for preparation of Bi₂O₃ NPs using beta vulgaris extract. The objective of this research was to achieve the goals of green synthesis for potential application and antibacterial activity used as adsorbent to metal ions.     

Materials and Methods

Sample collection

Beta vulgaris was taken from a nearby source and marked. Bismuth nitrate. penta hydrate Bi (NO₃)₃.5H₂O and Bismuth sulfate, Bi₂(SO₄)₃ were purchased from Germany/ Merck, NaOH form Alpha India/ Alpha Chemica, Ethanol from Spain/ RBL, also Cobalt sulfate CoSO₄, Copper sulfate. Penta hydrate CuSO₄. 5H₂O and Nickel sulfate. Hepta hydrate NiSO₄.7H₂O. All chemicals employed without additional purification.

Various spectroscopic and microscopic approaches were used to synthesize and identify Bi₂O₃NPs as follows: A Sensitive Electronic Balance type RADWAG, model / As 220 /C / 1, Magnetic stirrer, Centrifuge type PLC, (4000 – 4500 rpm) [(66–90 w) power: 110 L 60 Hz, 230 L 50 Hz], Electric oven type (FAITHFUL) model – WHL. 25 AB, Shaking water bath type (SCL FINETEDI), Tape measure of PH, (UV-vis) kind, (160/ Uv) Shimadzu spectroscopy, FT-IR (8500S) type Shimadzu at university of Baghdad / Collage of science and (XRD) X-ray diffraction type (Phillips/ Holland) were examined in the laboratories of the (center of examinations) at Baghdad. SEM with Field Emission (FE) type (Hv 300/ Ziess sigma -Germany) and X-ray energy dispersion device (EDX) were applied. Transmission electron microscope (TEM) (kind/ EM10C-100Kv Germany) was put to test at Kashan University in Iran. The antimicrobial activity of the synthetic Bi₂O₃ NPs was tested against two reference bacterial strains, (G⁺) Staphylococcus aureus, and (G^-), Escherichia coli and, as well as Candida albicans fungal, using the disc diffusion method in a nutrient medium (jellose medium) type Muller Hinton agar, and the same method was used for antifungal activity using the nutrient medium (agar) potato dextrose PDA.

Bi₂O₃NPs preparation by (Beta vulgaris extract) with Bi₂(SO₄)₃ and Bi(NO₃)₃. 5H₂O (D₁ and D₂)

Fresh Beta vulgaris must be first prepared. Beta vulgaris was rinsed with tap water to eliminate any contaminants and dried at 37 °C for one day. About 20 g of beta vulgaris was poured in a 500 mL beaker with 200 mL deionized water, mixed thoroughly and heated at 90 °C for 30 minutes. The extracted solution's hue changed from maroon to red-purple when it was allowed to cool to ambient temperature. Whatman filter paper No. 1 was used to filter the mixture. The resultant solution was centrifuged for 15 minutes at 4000 rpm in a 1.5 mL tube. Beta vulgaris extract stock solution was obtained. (7.06 g) of Bi₂(SO₄)₃ or Bi(NO₃)₃.5H₂O was dissolved in 30 mL deionized water, then 100 mL Beta-vulgaris extract was added as dispersant, with stirring and heating at a temperature 90 Celsius, then a solution of (1 M) NaOH was gradually added to it drop by drop by dissolving 2 g of NaOH in 500 mL of deionized distilled water until the pH value turned 12. The mixture was left for 48 hours in order to precipitate, forming a pale green precipitate. Next, separating was done by using a centrifuge, washing the precipitate with hot distilled water and hot EtOH, and getting it dried at a temperature of 300 Celsius by using an electric oven for 10 hours, leaving a pale brown powder of D₁ and yellow powder of D₂.

Results and Discussion  

The two samples (D₁ and D₂) were analyzed using FT-IR spectrum. Figure 1 shows absorption bands at 600 cm^-1, both of which were due to the stretching mode of Bi-O while the peak of stretching vibration of O-H appeared at 3429 cm^-1. Peaks at 2900 cm^-1, 2800 cm^-1 and 1113 cm^-1, 1046 cm^-1 are attributed to vibrations of CH₂ aliphatic and C-O bond respectively of beta vulgaris precursor [7, 15].

Spectra for both D₁, D₂ confirmed the presence of Bi₂O₃NPs. As shown in Figure 2 at 326 nm, an absorption peak was seen, attributed to Bi₂O₃NPs. The energy gap was calculated by using equation Eg = 1239.83 / λ. Eg is the bulk band expressed in eV. λ = lambada is peak absorbsotion, Eg = 1239.83 / 326 = 3.80 eV [7].

Figure 1: FT – IR spectrum of Bi₂O₃NP for (D₁, D₂ samples)

Figure 2: UV-Vis spectrum of Bi₂O₃ Nps

Pattern of Bi₂O₃ Np was synthesized from Bi₂(SO₄)₃ (D₁) of beta vulgaris. Figure 3 gives peaks indicating that the Bi₂O₃ Np are amorphous. The peaks are associated with the monoclinic crystal phase of Bi₂O₃ (COD: No-96-152-6459) at the 2θ value of 28.56, 34.35, 42.52, 46.50 and 58.58 [13].

Figure 3: XRD of Bi₂O₃ Nps for (D₁ sample)

The Bi₂O₃ NPs was synthesized from Bi(NO₃)₃.5H₂O (D₂) of beta vulgaris. Figure 4 showed rhombohedral phase of Bi₂O₃ suitable with JCPDS file - 27- 50 (Bi₂O₃) at the 2θ value of 27.66, 31.39, 32.501, 45.89, 55.34, and 74.45. The Debye Scherres equation was used to compute the average crystallite size of both samples, and the average crystal size of D₁ and D₂ was found to be 30.284 nm and 34.896 nm, respectively [16].

The morphology studies of both Bi₂O₃ samples (D₁ and D₂) are shown in Figure 5. The image shows that spherical particles tend to aggregate with average size of the particles by 30.28 nm and 34.89 nm [17].

The elemental and compositional properties of both sample of Bi₂O₃NPs were studied by EDX. The EDX spectra of Bi₂O₃NPs were synthesized by beta vulgaris extracts. Figure 6 depicts the discovery of strong bismuth (Bi) peaks at 2.5 and a medium peak of oxygen (O) at 0.5. [13].

Figure 4: XRD of Bi₂O₃ Nps for (D₂ sample)

Figure 5: Image of SEM Characterized for D₁ and D₂

Figure 6: EDX of Bi₂O₃ Nps for (D₁, D₂)

The morphology of Bi₂O₃Nps was studied using a transmission electron microscope (Figure 7). TEM image reveals an aggregation of thin sheet clusters [18].

Adsorption activity of Bi₂O₃NPs 

The use of nanomaterials to remove various metal ions present in water simultaneously opens up a new path that is free of secondary contamination and is very affordable. Bi₂O₃ NPs has a large specific surf ace area, surface area per unit mass, porous material and the structure and surface shape of Bi₂O₃ NPs, as seen in Figures 6 and 7 (SEM TEM), making it a strong adsorption candidate. At room temperature and pH = 6, three metal ions, namely Co⁺², Ni⁺², and Cu⁺², were effectively removed from water concurrently using Bi₂O₃NPs. The removal of these metal ions from water is shown in this research to have a quick adsorption of Co⁺², Ni⁺² and Cu⁺², with more than 90% adsorption in less than a minute for Ni⁺². As seen in Figure 8, the rate of metal ions uptake steadily declined and did not appear to grow any more throughout this time. These findings may be explained by the fact that there were more active sites available on the Bi₂O₃ NPs, adsorbent, at the start of the adsorption process, and as time passed, these sites gradually became saturated [19, 20]. For the D₁ sample, the removal efficiencies of Co(II), Ni(II) and Cu(II) ions were 89.68%, 85.56%, and 94.56%, respectively and for sample D₂, the removal efficiencies of Co(II), Ni(II) and Cu(II) ions were 93.3%, 87.7 % and 88.54 %, respectively.

Figure 7: Image of TEM characterized for D₁ and D₂

Figure 8: The removal efficiencies of Co(II), Ni(II), and Cu(II) ions for D₁and D₂ sample

Antibacterial activity of Bi₂O₃ NPs

Bismuth is found as [Bi₂O₃, Bi₂ (CO₃)₃, Bi₂S₃] in medicine. Bismuth has been employed as an antidiarrheal to treat vomiting, stomach, and pain nauseas. Bi₂O₃NPs porous Nano spheres demonstrated inactivation of (G^–) and (G⁺) bacteria [21, 22]. To perform a qualitative antimicrobial screening, agar well diffusion and minimum inhibitory concentration experiments are carried out. The zones of inhibition at diluted concentration of HCl (0.02g / mL) for D₁ are obtained as E. Coli and S. aures is (31 and 29 mm) for D₁ is (30 and 30 mm), candida albicans (43 and 45 mm) of D₁ and D₂ for Bi₂O₃NPs preparation. After this compressive analysis, we concluded that both Staphylococcus aureus and E. Coli have the highest inhibitory values with sample D₁ and D₂ and also a very high inhibition with Candida albicans fungal for the same samples as shown in Figure 9 [23, 24].

Figure 9: Types of bacteria and fungi tested and inhibition diameters in units (mm) of prepared Bi₂O₃NPs for D₁ and D₂ samples

Conclusion

Bi₂O₃NPs were successfully synthesized by a simple cost-effective biosynthesis method of Bi₂O₃ monoclinic phase with diameter of 30. 284 nm produced by using Bi₂(SO₄)₃. Bi₂O₃ rhombohedral phase with diameter (34.896) nm was obtained by using Bi(NO₃)₃.5H₂O. The morphology of Bi₂O₃NPs was as aggregation of thin sheet cluster. They have antimicrobial activity inhibiting the growth of S. aures, E. Coli and a very high inhibition with Candida albicans fungal. Bi₂O₃NPs were successfully removed simultineously with three metal ions (M⁺² = Co, Ni and Cu) from water contaminated with them.

Funding

This research did not receive any specific grant from fundig agencies in the public, commercial, or not-for-profit sectors.

Authors' contributions

All authors contributed toward data analysis, drafting and revising the paper and agreed to responsible for all the aspects of this work.

Conflict of Interest

We have no conflicts of interest to disclose.

HOW TO CITE THIS ARTICLE

Aqeel O. Flayyih, Waleed K. Mahdi, Yousif. I. M. Abu Zaid, Falih H. Musa. Biosynthesis, Characterization, and Applications of Bismuth Oxide Nanoparticles Using Aqueous Extract of Beta Vulgaris. Chem. Methodol., 2022, 6(8) 620-628

https://doi.org/10.22034/CHEMM.2022.342124.1522

URL: http://www.chemmethod.com/article_151251.html