Evaluation of Photocatalytic Degradation of Emerging Contaminants and Bacterial Inhibition by Silver Tungstate Synthesized by Microwave-assisted Hydrothermal Method

Abstract

In the present study, the microwave-assisted hydrothermal method was employed to synthesize silver tungstate (Ag2WO4) and assess its photocatalytic performance in the degradation of Rhodamine B (RhB), Fluoxetine (FLX), and Ofloxacin (OFX) under UV-C light. Its antimicrobial activity was also investigated for Escherichia coli and Staphylococcus aureus. XRD analysis confirmed the presence of α-Ag2WO4, with a predominant crystalline phase, in the material exhibiting the best performance. FEG-SEM images also reveal a characteristic morphology of α-Ag2WO4 for the samples obtained between 126 °C and 147 °C, which were produced in only 45 min. All samples presented bandgap energy (Eg) ≤ 3.50 eV, calculated by the TAUC equation. Using photoluminescence measurement, possible defects in the structure of the materials were confirmed by emissions between 2.81 eV to 2.87 eV. The low BET surface area (ABET) measured indicates that this characteristic does not have a considerable effect on the performance of the materials. Application studies have shown a 38% degradation of RhB in 120 min, 49% of FLX in 30 min, and 90% of OFX in just 5 min under UV-C (254 nm) light. A good antimicrobial activity was also observed for all materials, which was associated with the presence of reactive oxygen species (ROS) produced by the photocatalytic mechanism. The results achieved in this work contribute to the development of solutions focused on the problems of environmental contamination.