纳米零价铁活化过硫酸盐降解新兴污染物咖啡因

Activation of persulfate by nano zero-valent iron for degradation of emerging pollutant caffeine

采用液相还原法制备纳米零价铁(nZVI),通过X射线衍射、扫描电镜−能谱、傅里叶红外光谱及X射线光电子能谱对其进行表征。考察了nZVI活化过硫酸盐(PS)降解咖啡因(CAF)的性能。实验结果表明,当PS为5 mmol/L、nZVI投加量为0.2 g/L时,50 mg/L的CAF可在15 min内降解97.6%;溶液初始pH和腐殖酸(HA)对nZVI/PS体系降解CAF无影响;Cl^(-)、SO_(4)^(2-)、H_(2)PO_(4)-和NO_(3)-对CAF的降解呈抑制效果;自由基抑制实验表明体系中存在·OH与SO_(4)^(•-),且SO_(4)^(•-)占主导,nZVI/PS体系可有效降解多种污染物。

Nano zero⁃valent iron(nZVI),prepared by liquid phase reduction method,was characterized by X−ray diffraction,scanning electron microscope⁃energy dispersive spectrometer,Fourier transform infrared spectroscopy and X−ray photoelectron spectroscopy.Degradation efficiency of caffeine(CAF)by nZVI activated PS was investigated.The results showed that 97.6%of CAF was degraded within 15 minutes when PS concentration was 5 mmol/L and nZVI dosage was 0.2 g/L.The initial pH and HA had no effect on the degradation of caffeine in the nZVI/PS system.Cl^(-),SO_(4)^(2-),H_(2)PO_(4)^(-),and NO_(3)-had a negative effect on the degra⁃dation of caffeine.The result of free radical suppression experiment showed that·OH and SO_(4)^(•-)coexisted in the system,but SO_(4)^(•-)dominated,nZVI/PS system can effectively degrade a variety of pollutants.