Researchers in Brazil conducted experiments on a zinc oxide-based photocatalyst, discovering its effectiveness in degrading sertraline, an emerging pollutant.
The sertraline molecule is not degraded by conventional water treatment methods. Image Credit: Arek Socha/Pixabay
An article published in the Chemical Engineering Journal outlines a strategy for developing a material based on zinc oxide (ZnO) capable of efficiently degrading sertraline.
This antidepressant, detected globally in groundwater along with other drugs, poses a challenge for conventional wastewater treatment methods due to its specific physicochemical properties.
The study, supported by FAPESP, was carried out by scientists from the Center for Development of Functional Materials (CDMF), the Brazilian Agricultural Research Corporation (EMBRAPA), the Federal University of Alfenas (UNIFAL), and the Federal University of Paraíba (UFPB). CDMF, a Research, Innovation, and Dissemination Center (RIDC) funded by FAPESP, is hosted by the Federal University of São Carlos (UFSCar).
The described strategy involved experimental design and microwave-assisted solvothermal synthesis (MASS) to create hierarchical 3D ZnO photocatalysts. These demonstrated high efficiency in degrading sertraline within just 10 minutes.
The researchers utilized principal component analysis (PCA), an underutilized approach in materials synthesis, to correlate the physicochemical and photocatalytic properties with the synthetic conditions investigated. Results indicated that chemometric tools excel in studying synthetic systems with extensive experimental data.
Identified were samples with significant potential for environmental remediation. The 3D ZnO photocatalysts efficiently degraded both an organic dye and the emerging pollutant sertraline in natural water. The study confirmed that 3D ZnO absorbs light energy (ultraviolet A and C), promoting efficient water photo-oxidation and generating oxidizing species that degrade organic contaminants.
The photocatalyst's degradation performance remained consistently high over five application cycles, preserving crystal structure, morphology, and other properties. Phytotoxicity assays affirmed that byproducts from the sertraline degradation process were non-toxic to tested organisms, ensuring the safety of the photocatalyst for wastewater treatment.
Comparative analysis with other materials reported in the literature revealed the competitive performance of the study’s results. The article concludes that materials obtained under advantageous synthetic conditions offer a promising avenue for developing novel technologies to address emerging pollutants in natural water.
Ailton Moreira, a researcher at CDMF and the article's corresponding author, emphasized the widespread contamination caused by improper pharmaceutical disposal. He underscored the topic's current relevance in light of risks to human health and the environment.
The choice of sertraline was significant due to the limited studies on the application of heterogeneous photocatalysis for its degradation, with none found on the use of ZnO for this purpose in the literature.
Future steps involve evaluating the photocatalyst's performance in real wastewater treatment systems, and assessing its ability to break down sertraline and other emerging pollutants in various mixtures, including those found in hospital or domestic wastewater processed by sewage treatment plants. These investigations, along with others, will focus on a treatment plant in Gavião Peixoto, São Paulo state.
Journal Reference
Silva, T. E. M., et al. (2023). Hierarchical structure of 3D ZnO experimentally designed to achieve high performance in the sertraline photocatalysis in natural waters. Chemical Engineering Journal. doi.org/10.1016/j.cej.2023.146235.