Electrochemical removal of pharmaceuticals from water streams: Reactivity elucidation by mass spectrometry

• Electrochemical advanced oxidation processes remediating pharmaceutical wastewater.
• Solar photoelectro-Fenton and electrochemical oxidation with boron-doped diamond.
• Reactivity of pharmaceuticals with oxidizing agents elucidated.
• Complementary analysis by HPLC and IC shows evolution of reaction products.
• Toxicity and biodegradability tests for environmental assessment.

Electrochemical technology has attracted increasing interest in recent years as an environment-friendly solution to many industrial problems and challenges. First, we give an overview on the fundamentals of electrochemical processes for the removal of pharmaceuticals from water, particularly electrochemical oxidation and Fenton-based processes, such as electro-Fenton and ultraviolet (UV) and solar photoelectro-Fenton, that have improved performance. We also mention other less studied methods, although the main focus is on reactivity elucidation by chromatography with UV or conductivity detection, especially by mass spectrometry techniques (e.g. coupled to gas chromatography or liquid chromatography), in order to discuss the degradation pathways of pharmaceuticals on the basis of the reactive species electrogenerated in each technology. In some cases, simultaneous assessment of toxicity adds crucial information for the future integration of these technologies in water-treatment facilities where pharmaceuticals and their byproducts can occur.