Natural titanomagnetite, a potential catalyst, was used as a peroxydisulfate (PDS) activator for the removal of atrazine (ATZ) in water for the first time. The surface ≡Fe(Ⅱ) and ≡Fe(III) of titanomagnetite was certified as the active components by XRD and XPS analyses. ATZ removal showed a strong dependence on the titanomagnetite concentration (0-10 g/L), PDS concentration (0-10 mM) and the initial pH (3.0-11.0) under experimental conditions. Quite different from the traditional heterogeneous PDS-activated processes, titanomagnetite/PDS system could remove ATZ via both radical and nonradical pathways. Here, both free radicals (SO₄^•- and HO^•) and high-valent iron-oxo species were proved to be the main reactive oxygen species (ROS) by quenching experiments, EPR tests and UPLC/ESI−MS/MS analysis. The high-valent iron-oxo species, ≡Fe^Ⅳ=O and ≡Fe^Ⅴ=O, could be generated from the ≡Fe(Ⅱ) and ≡Fe(III) of the titanomagnetite via a nonradical pathway. In addition, the generated passivation layer after reaction was found via XPS analysis, which could block the function of ≡Fe(Ⅱ) and ≡Fe(III), hindering the generation of ROS. However, the catalytic activity of titanomagnetite could recover if passivation layer was removed by ultrasonic cleaning. Finally, ten intermediates of ATZ were measured by UPLC-QTOF-MS/MS and the degradation pathways of ATZ in titanomagnetite/PDS system were proposed with the Gaussian 09 results. This work helps to better understand the generation of high-valent iron-oxo species and re-evaluate the effect of high-valent iron-oxo species in the heterogeneous iron-based PDS-activated processes.

天然钛磁铁矿（一种潜在的催化剂）被用作过氧二硫酸盐（PDS）活化剂，首次用于去除水中的at去津（ATZ）。通过XRD和XPS分析证明钛磁铁矿的表面≡Fe（Ⅱ）和≡Fe（III）为有效成分。在实验条件下，去除ATZ表现出对钛磁铁矿浓度（0-10 g / L），PDS浓度（0-10 mM）和初始pH（3.0-11.0）的强烈依赖性。钛磁铁矿/ PDS系统与传统的异质PDS活化过程完全不同，它可以通过自由基和非自由基途径去除ATZ。在这里，两个自由基（SO ₄ ^•-和HO ^•），淬灭实验，EPR试验和UPLC / ESI-MS / MS分析证明高价铁氧是主要的活性氧（ROS）。高价铁氧物种，≡Fe ^Ⅳ = O和≡Fe ^Ⅴ钛磁铁矿的≡Fe（Ⅱ）和≡Fe（III）可以通过非自由基途径生成= O。另外，通过XPS分析发现反应后产生的钝化层可能阻碍≡Fe（Ⅱ）和≡Fe（III）的功能，阻碍了ROS的生成。但是，如果通过超声清洗除去钝化层，则钛磁铁矿的催化活性可以恢复。最后，通过UPLC-QTOF-MS / MS测定了十种ATZ中间体，并用高斯09结果提出了ATZ在钛磁铁矿/ PDS系统中的降解途径。这项工作有助于更好地了解高价铁氧代物种的产生，并重新评估高价铁氧代物种在异质铁基PDS活化过程中的作用。