Glyphosate Photodegradation. Stoichiometry, Kinetic and Catalytic Effects.

MARÍA MAR ARECO; MARÍA ALCIRA TRINELLI; MARIA DOS SANTOS AFONSO; CECILIA G. CANTERA

International Journal of Environment and Health

Inderscience Enterprises Ltd.

Año: 2019 vol. 9 p. 306 - 326

1743-4955

In the present study the photodegradation of glyphosate (PMG) in aqueous polution by the action of UV-light and the catalytic effect of copper and copper-alga Ulva lactuca is described. The photodegradation kinetic reaction of PMG can be explained using a firstorder kinetic model, with a mean rate constant of k = (0.04 ± 0.01) h-1 48 and a mean half-life () = (17 ± 4) h. The photolytic process seems to be the main responsible for the herbicide degradation; the quantum yield () obtained for the photochemical decomposition of PMG was (4.8 ± 0.1) 10-4 mol Einstein-1. The resulting photodegradation by-products obtained were acetate, aminomethylphosphonic acid (AMPA), phosphate, sarcosine and to a lesser extent nitrate. The rate of PMG degradation is greatly increased around 30 times by the presence of copper and to a lesser extent (≈ 855 times) by the presence of Cu-alga Ulva Lactuca in the reaction media. The present work represents a new understanding on the photodegradation of the herbicide glyphosate and the results obtained may contribute to the development of new remediation technologies.