Research finds material to treat sertraline in wastewater

New research describes a strategy to break down pharmaceutical pollutant sertraline in wastewater, according to a press release by the São Paulo Research Foundation.

The research article, published in Chemical Engineering, describes a strategy to produce a material based on zinc oxide (ZnO) capable of degrading sertraline, an antidepressant that has been detected, like other drugs, in groundwater worldwide and is considered an emerging pollutant. This kind of substance has certain physicochemical properties that hinder removal by conventional wastewater treatment methods.

The strategy described in the article involved experimental design and microwave-assisted solvothermal synthesis (MASS) to produce hierarchical 3D ZnO photocatalysts capable of degrading sertraline with a high level of efficiency in only ten minutes.

In the study, the 3D ZnO absorbed light energy (ultraviolet A and C) to promote efficient water photo-oxidation, producing oxidizing species that degrade organic contaminants.

Degradation performance remained high in up to five cycles of application, conserving crystal structure, morphology and other properties, while phytotoxicity assays showed that by-products formed in the sertraline degradation process were not toxic to the organisms tested, confirming the safety of the photocatalyst for wastewater treatment.

According to Ailton Moreira, a corresponding author of the article, improper disposal of pharmaceuticals is causing widespread contamination, noting the current relevance of the topic in light of the risks to human health and the environment. The choice of sertraline was significant, he explained, because the number of studies involving the application of heterogeneous photocatalysis for sertraline degradation is very limited, and the researchers’ review of the literature found none on the use of ZnO for this purpose.

Next steps include analyzing the performance of the photocatalyst in real wastewater treatment systems to see if it breaks down sertraline and other emerging pollutants individually or in more complex mixtures such as hospital or domestic wastewater processed by sewage treatment plants. These and other researchers plan to focus on a treatment plant in Gavião Peixoto, São Paulo state.