Ultrasound key to battle against water polluting painkillers

An international team of scientists has developed a novel method for eliminating pharmaceutical products from water using ultrasound treatment.

Keeping our waterways pollutant free could be made easier with ultrasound

Designed for use in water purification plants, the method could reduce the emission of pharmaceutical pollutants into rivers, lakes, seas and other surface waters. The team of scientists chose ibuprofen for the study as it is one of the drugs that appears with the most frequency in waste waters due to its high consumption as an anti-inflammatory and analgesic.

“Pharmaceutical compounds are pollutant substances from the moment in which they maintain their pharmacological activity outside the environment for which they were designed”, said Fabiola Méndez-Arriaga - co-author of the study and a researcher at the Department of Chemical Engineering in the University of Barcelona.

The technique consists of subjecting water polluted with ibuprofen to ultrasonic waves that are generated by a piezoelectric generator, which converts electrical energy into mechanical energy and is located at the bottom of the reaction tank. During the application of ultrasonic waves to the polluted liquid a physical and chemical reaction is generated known as "sonolysis", in which water is disassociated into highly oxidant radicals such as hydroxyl. This radical facilitates the oxidation and breaking down of ibuprofen into other low-molecular mass compounds.

“Ultrasonic waves are applied for half an hour and this enables up to 98% of ibuprofen to be broken down and after two hours of irradiation the drug is eliminated completely and transformed into biodegradable substances which can be removed or eliminated in a conventional purification plant”, said Méndez-Arriaga.

Méndez-Arriaga points out that the final objective of these techniques is to eliminate pharmaceutical compounds from the environment, where they end up after consumption, thanks precisely to the chemical properties they were created with, namely their biological resistance and high solubility.