Speaker
Description
Losartan (LOS) is among the most widely prescribed antihypertensive drugs worldwide, and methocarbamol (MET) is a commonly utilized analgesic in recent years. These pharmaceuticals are considered emerging contaminants, posing risks to the environment and aquatic ecosystems. Traditional wastewater treatment technologies currently face challenges in adequately eliminating these substances. In this study, we describe the successful degradation and mineralization of both losartan and methocarbamol in aqueous solution using Electron beam irradiation. Aqueous solutions of MET and LOS were subjected to irradiation at doses ranging from 1 to 4 kGy. The results obtained demonstrated a removal efficiency of 98%. Investigations into the changes in absorption spectra, pH impact, Chemical Oxygen Demand (COD), and Total Organic Carbon (TOC) were conducted. The findings revealed a decrease in all absorption bands with an increase in irradiation dose, eventually disappearing entirely after a 4 kGy dose. The radiolytic degradation of MET and LOS under three different pH conditions (pH = 10, 6.2, and 3) highlighted that the highest removal efficiency was achieved at a neutral pH. Remarkably, % TOC removal reached 98% at 4 kGy for both compounds, indicating quasi-total mineralization. Furthermore, the results of spectrophotometric analyses provided evidence in favor of a pseudo-first-order degradation kinetic for LOS and MET. Finally, by identifying by-products through liquid chromatography–mass spectrometry (LC/MS), proposed degradation mechanistic pathways for LOS and MET were elucidated, indicating that the irradiation process initiates with the fragmentation of the starting molecule involving hydroxyl radicals generated by water radiolysis.
