Estudio de degradación de glifosato en fase acuosa empleando dióxido de titanio expuesto a radiación beta

Abstract

It was carried out the degradation of glyphosate in aqueous medium by heterogeneous photocatalysis using TiO2 (commercial rutile and anatase) irradiated at 0, 10, 15, 20 and 60 kGy. Adsorption and degradation tests of 40 mg/L of glyphosate were performed with anatase and irradiated rutile with doses of 0, 10, 15, 20 and 60 kGy. The effect of TiO2 concentration (0.1, 3, 6 and 14 mg/L) on both anatase and rutile was studied with the best beta radiation dose previously obtained. The degradation was followed by Ultra High-Resolution Liquid Chromatography (HUPLC), Total Organic Carbon (TOC), Chemical Oxygen Demand (COD), nitrates and phosphates. Finally, CL50 toxicology tests were performed for 24 hours, using Artemia saline as bioindicators. Anatase irradiated at 0 kGy and with a concentration of 14 g/L reached a degradation of 99.5%, with a kinetics constant of 0,0315 min-1 and a mineralization of 86.3% with a kinetics constant of 0.0089 min-1, after 180 minutes under UV radiation. Rutile irradiated to 5 kGy and with a concentration of 14 g/L reached a degradation 76.74%, with a kinetics constant of 0.0083 min-1, after 180 minutes under UV radiation. From toxicity tests a LC50 of 14.58 mg/L for anatase, 19.86 mg/L for non-irradiated rutile, and 14.89 mg/L for irradiated rutile were obtained.