Synthesis and Characterization of ZnBi2O4 Nanoparticles: Photocatalytic Performance for Antibiotic Removal under Different Light Sources

Abstract

This work aims to synthesize a photocatalyst with high photocatalytic performances and explore the possibility of using it for antibiotic removal from wastewater. For that, the spinel ZnBi2O4 (ZBO) was produced with the co-precipitation method and its optical, dielectric, and electrochemical characteristics were studied. The phase has been determined and characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). For the ZBO morphology, a Scanning Electron Microscopy (SEM) has been used. Then, the optical and dielectric properties of ZBO have been evaluated by calculating refractive index n (λ), extinction coefficient (k), dissipation factor (tan δ), relaxation time (τ), and optical conductivity (σopt) using the spectral distribution of T(λ) and R(λ). An optical gap band of 2.8 eV was determined and confirmed. The electrochemical performance of ZBO was investigated and an n-type semiconductor with a flat band potential of 0.54 V_SCE was found. The photocatalytic efficiency of ZBO was investigated in order to degrade the antibiotic Cefixime (CFX) under different light source irradiations to exploit the optical properties. A high CFX degradation of approximately 89% was obtained under solar light (98 mW cm−2) only after 30 min, while 88% of CFX degradation efficiency has been reached after 2 h under UV irradiation (20 mW cm−2); this is in line with the finding of the optical characterizations. According to the obtained data, solar light assisted nanoparticle ZBO can be used successfully in wastewater to remove pharmaceutical products.

Application of Bi12ZnO20 Sillenite as an Efficient Photocatalyst for Wastewater Treatment: Removal of Both Organic and Inorganic Compounds

“…As can be seen, the achieved rate of CFX degradation was 94.34% within 3 h, which demonstrated that CFX was successfully removed using BZO crystals as a photocatalyst. This degradation rate was higher than that obtained using others catalysts during our previous studies [13,14]. As BZO crystals have shown great degradation for CFX, it can be concluded that they can be effective catalysts for the removal of organic pollutants.…”

“…Starting with antibiotics, which are a topical example of organic pollutants and are extremely dangerous due to their wide use in both human and veterinary drugs [11], an analysis of antibiotic use has shown that global antibiotic use was recorded at approximately 200,000 tons and has grown by 65% over only 15 years from 2000 and will double by around 2030 [12,13]. This widespread use assures the presence of these antibiotics in different water supplies, in quantities extending from ng/L to µg/L [14]. Taking cefixime (CFX) as an example, it has been detected in various water environments with quantities ranging from 278 to 422 ng/L [15,16].…”

Structural and Optical Properties of Bi12NiO19 Sillenite Crystals: Application for the Removal of Basic Blue 41 from Wastewater

“…As can be observed, the degradation efficiency of BB41 achieved 98% within just 180 min at pH ~9 and 25 °C. This result can be explained by the gap energy of the catalyst (2.1 eV), which offers a higher absorption in both UV and visible areas from 200 to 800 mm [42]. It was already demonstrated in our previous works [13,14] that the degradation of the dye as an organic compound in the photocatalytic process is mainly due to the reactive oxidative species (ROS) such as superoxide radicals (O2  − ) and hydroxyl radicals ( • OH), where the electrons of Bi12NiO19 conduction band are degraded the Basic Blue 41 by reducing the absorbed O2 to the super-radical anion O2  − .…”

A Review of the Use of Semiconductors as Catalysts in the Photocatalytic Inactivation of Microorganisms

“…This process lasts for a few femtoseconds and is then followed by recombination of the excited negative electrons in the conduction band (CB) with the previously generated positive holes at the valence band (VB) either on the surface or in the bulk of the particle releasing heat energy [29][30][31]. Otherwise, these produced charge carriers (e − and h + ) can migrate to the surface of the photocatalyst and initiate further redox or oxidation reactions with adsorbed or reactant molecules on the surface if they have sufficient time or energy, as illustrated in Figure 1, which is inspired from a previous article [16].…”