Fe(Ⅵ)/Na2SO3体系降解阿特拉津效能

利用高铁酸钾活化亚硫酸钠(Fe(Ⅵ)/Na₂SO₃体系),探究其对阿特拉津(ATZ)的降解效能;鉴别了反应体系主要活性组分,并考察了Na₂SO₃投加量、反应溶液pH值和水质背景成分对ATZ降解效能的影响.结果表明:当Fe(VI)和Na₂SO₃的投加量分别为50和200μmol/L时,反应10s后Fe(Ⅵ)/Na₂SO₃体系对ATZ的降解效能达到74.4%,单独Fe(VI)(50μmol/L)和单独Na₂SO₃(200μmol/L)对ATZ的去除率仅为10.2%和7.5%.探针化合物和溶解氧作用等实验证实体系中主要的活性基团为SO₄^·-.在pH=8,Fe(VI)投加量为50μmol/L时,随着Na₂SO₃投加量的增大,Fe(Ⅵ)/Na₂SO₃体系对ATZ的去除效率先增大后减小,其中最佳Na₂SO₃投加量为150~200μmol/L.Fe(Ⅵ)/Na₂SO₃体系在pH 7~10的范围内,均可以快速降解ATZ.在天然水体中,Fe(Ⅵ)/Na₂SO₃体系也可以高效降解ATZ,但是水质背景成分会竞争消耗SO₄^·-,导致Fe(Ⅵ)/Na₂SO₃体系对ATZ的降解效能降低.

Degradation efficiency of atrazine by Fe(VI)/Na2SO3 system

The degradation efficiency of atrazine (ATZ) by Na₂SO₃ activated with potassium ferrate (K₂FeO₄) was studied. The primary reactive species formed in Fe(VI)/sulfite system were identified. In addition, the influences of dosages of sulfite, solution pH as well as water background matrices including humic acid (HA), Cl^-, and CO₃^2- on the transformation efficiency of ATZ in Fe(VI)/sulfite process were evaluated. The results showed that 74.4% of ATZ was transformed by the combination of 50μmol/L Fe(VI) and 200μmol/L Na₂SO₃ at 10s, while only 10.2% and 7.5% of ATZ was removed at 60s by individual Fe(VI) and Na₂SO₃, respectively, under similar conditions. Sulfate radicals (SO₄^·-) was responsible for the degradation of ATZ based on the results of radical probe compound and dissolved oxygen experiments. In the presence of 50μmol/L Fe(VI) and at pH=8, the degradation efficacy of ATZ firstly increased, then decreased with increasing the dosage of Na₂SO₃, in which the optimal concentration of Na₂SO₃ was 150~200μmol/L. The enhanced degradation of ATZ by Fe(Ⅵ)/Na₂SO₃ system was observed in the pH range of 7~10. The removal of ATZ in natural water by Fe(VI)/sulfite process was also confirmed, but with lower efficiency compared to synthetic water, mainly resulting from the competition of SO₄^·- by water background matrix.