天然黄铁矿活化过硫酸盐降解阿特拉津性能及影响因素

The Performance and Influencing Factors of Degradation of Atrazine with Pyrite-activated Persulfate

阿特拉津(atrazine,ATZ)作为一种常见的除草剂被广泛应用于农业生产中,但因其毒性强、易残留等,现已成为水体中检测率极高的污染物之一,给生态环境以及人类健康带来了巨大的危害。选用环境友好、来源广泛的天然黄铁矿(pyrite,FeS_(2))来活化过硫酸盐(persulfate,PS)降解水中ATZ并探讨了天然水体中常见的8种无机离子:NH_(4)^(+)、Cu^(2+)、Mn^(2+)、HCO_(3)^(-)、CO_(3)^(2-)、H_(2)PO_(4)^(-)、NO_(3)^(-)、Cl^(-)和腐殖酸(humic acid,HA)对该体系降解ATZ的影响。电子顺磁共振波谱仪(electron paramagnetic resonance,EPR)检测发现黄铁矿活化PS产生的强氧化性自由基·OH和SO_(4)^(-)·是氧化去除ATZ的主要原因。此外,8种无机离子对pyrite/PS体系降解ATZ均具有不同程度的抑制作用且抑制效果最强的3种无机离子从大到小依次为CO_(3)^(2-)、HCO_(3)^(-)、H_(2)PO_(4)^(-)。HA对ATZ的降解具有轻微抑制作用。常见的金属螯合剂如EDTA、柠檬酸钠和草酸因易与黄铁矿产生的Fe^(2+)络合,降低了黄铁矿活化PS的性能,从而显著抑制ATZ的降解。利用黄铁矿活化PS可实现尾矿资源的再利用,研究结果可为pyrite/PS降解ATZ的实际应用提供一定的理论依据。

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(FeS_(2)),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:NH_(4)^(+),Cu^(2+),Mn^(2+),HCO_(3)^(-),CO_(3)^(2-),H_(2)PO_(4)^(-),NO_(3)^(-),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 SO_(4)^(-)·,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 CO_(3)^(2-),HCO_(3)^(-)and H_(2)PO_(4)^(-)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 Fe^(2+)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.