Influence of ZnO on the structural, optical, ligand field and antibacterial characteristics of sodium borosilicate glasses containing minor Cr₂O₃ additions

Abstract

In this work, the structural, optical, ligand field and antibacterial properties of Cr2O3, ZnO and Na2O borosilicate glasses were studied. A glass system of the compositions 70B2O3-14.8 SiO2-(15-x)Na2O-0.2Cr2O3-xZnO, where x = 0, 3, 5 and 7 mol% were prepared via melt-quenching technique. In this study, X-ray diffraction (XRD) spectra were used to check the amorphous state of the prepared glass specimens. Infrared (IR) spectra were used to study the internal structure of the formed units and groups within the glass matrix. Moreover, the optical absorbance spectra were used to study the optical parameters such as optical band gap (Eg), Urbach energies (EU) and ligand field parameters (10Dq, B, Dq/B and β). Furthermore, the antibacterial activities of the glass samples were investigated against different antibiofilm activities for example, Staphylococcus aureus and Escherichia coli. However, the fixed Cr2O3 concentrations, IR results showed the gradual conversion of Cr3+ cations’ coordination from octahedral (CrO6; glass modifier) to tetrahedral (CrO4; glass former) with more replacement of Na2O by ZnO. This result confirms the significant influence of the environment on Cr cations’ coordination. While the optical studies showed that, Eg values increased from 3.06 to 3.62 with further ZnO doping. Furthermore, 10Dq values increased and B values decreased with the increase in ZnO content. These 10Dq increased values reflect the increased interactions between the Cr3+ cations and their environments, such as oxygen anions. Further, the decreased values of B refer to the tendency of the bonds of Cr3+ cations and their environments toward the covalent nature. On the other hand, the results showed that the investigated glasses are promising materials owing to high antibacterial activity on a large scale (food covering, wound curing, and surface coatings), especially the glass sample that contains the highest concentrations of ZnO. 

Comparative Study of Callistemon citrinus (Bottlebrush) and Punica granatum (Pomegranate) Extracts for Sustainable Synthesis of Silver Nanoparticles and Their Oral Antimicrobial Efficacy

“…To sum up, both extracts are applicable for the green synthesis of Ag NPs, while the BBE is likely to be more efficient in producing an increased number. The monodispersed distributed size of the bandgap can be extracted from the UV-Vis absorbance curve, commonly known as the Tauc plot [ 68 , 69 , 70 ]. The equation is mathematically expressed as in [ 70 ]: the silver nanoparticles exhibit a faster approach.…”