INQUISUR, Departamento de Química, Universidad Nacional del Sur, Av. Alem 1253, B8000CPB-Bahía Blanca, Argentina.
J Colloid Interface Sci. 2013 Mar 15;394:485-9. doi: 10.1016/j.jcis.2012.12.063. Epub 2013 Jan 9.
The desorption of glyphosate from goethite as induced by the adsorption of phosphate was investigated by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy in combination with adsorption isotherms. Desorption of glyphosate was very low in the absence of phosphate. Addition of phosphate promoted glyphosate desorption. At low initial surface coverages, added phosphate adsorbed on free surface sites, mainly, displacing a small amount of glyphosate. At high initial surface coverages, on the contrary, phosphate adsorption resulted in a significant glyphosate desorption. In the latter conditions, the ratio desorbed glyphosate to adsorbed phosphate was 0.60. The desorption process can be explained by assuming that phosphate adsorbs first forming a monodentate mononuclear complex, which rapidly evolves into a bidentate binuclear complex that displaces glyphosate.
采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）结合吸附等温线研究了磷酸根诱导下针铁矿对草甘膦的解吸作用。在没有磷酸根的情况下，草甘膦的解吸非常低。添加磷酸根促进了草甘膦的解吸。在低初始表面覆盖率下，添加的磷酸根主要吸附在自由表面位上，取代了少量的草甘膦。相反，在高初始表面覆盖率下，磷酸根吸附导致草甘膦的显著解吸。在后一种情况下，解吸的草甘膦与吸附的磷酸根的比值为 0.60。通过假设磷酸根首先吸附形成单齿单核络合物，该络合物迅速演变成双齿双核络合物，从而取代草甘膦，可解释解吸过程。
