Abstract: Atrazine (ATZ) is one kind of common herbicide,which is widely used in agricultural.However,ATZ pose a threat to the ecological environment as well as human beings,due to its high toxicity and easy residue.It has become one of the highly detected pollutants in water.Natural pyrite (FeS₂),which is environmentally friendly and widely available,was selected for the activation of sodium persulfate (PS) to degrade ATZ in water.The effects of eight common inorganic ions in natural water: NH₄⁺,Cu²⁺,Mn²⁺,HCO₃^-,CO₃^2-,H₂PO₄^-,NO₃^-,Cl^- and humic acid (HA) on the degradation of ATZ were investigated.Electron paramagnetic resonance (EPR) detection revealed that the activation of PS by pyrite was found to produce strong oxidizing radicals ·OH and SO₄^-·,which are the main cause of oxidative removal of ATZ.In addition,all eight inorganic ions had different degrees of inhibition and the three inorganic ions with the strongest inhibitory effect were CO₃^2-,HCO₃^- and H₂PO₄^- in descending order.The degradation rate of ATZ was slightly inhibited by HA.Common metal chelating agents such as EDTA,sodium citrate and oxalic acid significantly inhibited the degradation of ATZ due to their tendency to complex with Fe²⁺ produced by pyrite,which reduced the performance of pyrite activated PS,thus significantly inhibiting the degradation of ATZ.The use of pyrite to activate PS can realize the reuse of tailings,and the results of the study also can provide certain theoretical basis for the practical application of pyrite/PS to degrade ATZ.

Key words: pyrite, persulfate, atrazine, advanced oxidation