Adsorption and desorption kinetics of glyphosate on Mn oxide and BSA-Mn oxide interfaces were estimated using the integral phosphonate frequency region (1200 to 910 cm -1 ; ν(PO)). As mentioned before, the IR signal of other PO-containing species (i.e., AMPA and orthophosphate) in in-situ ATR-FTIR experiments were negligible, and the evolution of ν(PO) vibrational modes were assumed to originate from adsorption and desorption of glyphosate only. All surfaceassociated reactions were well described by the modified pseudo-first-order model 14 , using Eq.