Glyphosate (PMG) has been demonstrated to be strongly adsorbed on iron oxides, but few studies have been made on the subsequent degradation process. As the mechanism and process of PMG degradation plays a crucial role on its existence in the environment, this study aims to investigate the comparative adsorption and photo-degradation of PMG on goethite and magnetite. The results show that the Langmuir adsorption capacity of goethite (7.9 mg/g) was higher than that of magnetite (6.7 mg/g) at pH = 7. Further clarifying of Zeta potential and attenuated total reflectance Fourier-transform infrared spectroscopy measurements revealed that PMG was absorbed through the coordination of phosphonate moiety. In contrast, PMG degradation due to the photo-catalysis effectiveness of magnetite (k_app = 1.2 h⁻¹) was significantly higher than that of goethite (k_app = 0.4 h⁻¹) at pH = 7. This phenomenon was primarily due to the greater release of the dissolved iron in magnetite which led to the promotion of reactive oxygen species generation in the magnetite/UV system. DFT results show that the formation of FeOP bonds in the presence of iron oxide would change the electron density distribution around the phosphorus center of PMG, and potentially made the CP bond more assailable to ROS. Furthermore, electron spin resonance results identified the existence of OH and O₂⁻, and further tests by adding radical captures proved the domination of OH in degrading PMG. In addition, intermediate identification of PMG revealed that amino acid, carboxyl acid and other inorganic ions were the main products in the process of photo-degradation. Therefore, it is concluded that the comparative exploration of goethite and magnetite on PMG degradation provides an integrated insight into the similar fate of PMG heterogeneous photo-degradation in the environment.

草甘膦（PMG）已被证明能强烈吸附在氧化铁上，但对随后的降解过程却鲜有研究。由于PMG降解的机理和过程对其在环境中的存在起着至关重要的作用，因此本研究旨在研究PMG在针铁矿和磁铁矿上的相对吸附和光降解作用。结果表明，在pH = 7时，针铁矿（7.9 mg / g）的Langmuir吸附能力高于磁铁矿（6.7 mg / g）的Langmuir吸附能力。进一步阐明Zeta电位和衰减的全反射率傅里叶变换红外光谱测量表明： PMG通过膦酸酯部分的配位被吸收。相反，由于磁铁矿的光催化作用，PMG降解（k _app  = 1.2 h^-1）在pH = 7时显着高于针铁矿（k _app  = 0.4 h ^-1）。这种现象主要是由于磁铁矿中溶解的铁释放更多，导致促进了活性氧的生成。磁铁矿/紫外线系统。DFT结果表明，在存在氧化铁的情况下形成Fe O P键会改变PMG磷中心周围的电子密度分布，并可能使C P键更容易被ROS吸收。此外，电子自旋共振结果鉴定的存在OH和O ₂ ^-通过添加自由基捕捉，和进一步试验证明的支配OH降解PMG。另外，PMG的中间鉴定表明，氨基酸，羧酸和其他无机离子是光降解过程中的主要产物。因此，可以得出结论，针铁矿和磁铁矿对PMG降解的比较研究为环境中PMG异质光降解的相似命运提供了综合见解。