2016_03_21_CIE_dia_agua

Nerea Rioja, a researcher at the University of Navarra, has developed in her doctoral thesis a prototype reactor that could be used in industry, or as tertiary treatment in a wastewater treatment plant, for fill in cleaning emerging pollutants, such as drugs, which currently cannot be removed.

On the occasion of World Water Day, which is celebrated on March 22, the new doctor at Chemistry explains that wastewater treatment plants are unable to eliminate these pollutants, which are increasingly reaching the water, especially rivers: "In our work we used several references, including the values detected in a wastewater treatment plant in Seville over the course of a year. There they observed that the Degree of elimination of these compounds depends on the drug subject and the season of the year. Ibuprofen is eliminated up to 87.5% and carbamazepine (a drug for epileptic seizures and bipolar disorder), on the other hand, is only eliminated at 8.1%", explains the researcher.

In total, they considered the presence of five drugs: sulfamethoxazole, cabamazepine, clofibric acid, diclofenac and ibuprofen, the mixture of which was taken as a target pollutant. From here, the scientist set out to find out why it was not possible to eliminate these substances with current purification systems. "We discovered that the inorganic salts were the ones that deactivated the catalysts the most. internship After this, we added different substances to the base decontaminant, including powdered activated carbon, which gave the greatest combined effect of adsorption and photocatalysis, and managed to eliminate the entire target mixture of the five drugs," she stresses.

Fish and algae affected in rivers and seas

In addition, due to the size of some of the particles used to purify water, they observed that there were large leaks when passing through the purification systems: "So we thought of developing a new material that would contain integrated in its composition the decontaminating substances in the necessary proportion to combine absorption and photocatalysis. We then manufactured a photocatalytic reactor on the scale of laboratory that maintains the contact between the pollutant and the catalyst inside the reactor, so that no leaks are generated into the environment," explains the researcher from the University of Navarra.

After conducting several experiments with the mixture of the five drugs, they confirmed that the reactor effectively treated flows of entrance and relatively high contaminant concentrations in both river and seawater.

Although the reactor is currently under development at test, its use could mitigate the consequences of the presence of drugs for the fauna and flora of rivers and seas: "It has been observed that certain hormonal compounds can cause serious estrogenic effects in fish, even in low concentrations. In the case of algae, moreover, the effects can be very serious, since sulfamethoxazole or diclofenac affect the function of their chloroplasts, responsible for photosynthesis", warns the scientist.