蒙脱石搭载纳米Ni-Fe超声降解十溴二苯醚

Ultrasound enhanced degradation of decabromodiphenyl ether by montmorillonite supported Ni-Fe nanoparticles

为解决传统纳米零价铁(nZVI)降解污染物时易氧化团聚、反应活性低的问题,通过改性手段制备并表征了蒙脱石搭载纳米Ni-Fe(Ni-Fe/蒙脱石)等复合材料,考察污染物和纳米材料质量浓度、温度、溶液初始pH、超声辅助等对其降解十溴二苯醚(BDE-209)的影响,比较nZVI改性前后的降解效果,分析其机理并建立了反应动力学方程。结果表明:最佳反应条件为5mg/L的BDE-209、2g/L的nZVI、温度35℃、pH=3。超声处理10min时BDE-209基本降解完,其表观速率常数(kobs,0.519min^(–1))是震荡处理(0.013min^(–1))的40倍、静置处理(0.004min^(–1))的130倍。几种材料在10min时对BDE-209的降解率为:Ni-Fe/蒙脱石(99.5%)>nZVI/蒙脱石(85.1%)>纳米Ni-Fe(64.8%)>nZVI(48.1%)>蒙脱石(4.1%)>纳米Ni(1.1%),120min时kobs为:Ni-Fe/蒙脱石(0.519min^(–1))>nZVI/蒙脱石(0.209min^(–1))>纳米Ni-Fe(0.050min^(–1))>nZVI(0.024min^(–1))。蒙脱石、纳米Ni及超声本身基本不降解BDE-209。

In order to resolve the problem of traditional nanoscale zero valent iron（nZVI）in the degradation of pollutants,which include easily oxidization,accumulation and low reactivity,montmorillonite supported nanoscale Ni-Fe（Ni-Fe/mont） etc.were prepared and characterized.Influencing factors in the degradation of decabromodiphenyl ether（BDE-209） were investigated,which include the concentration of BDE-209 or nZVI,temperature,initial pH of solution,and ultrasounic assistance.The BDE-209 degradation efficiencies of nZVI and modified nZVI were compared.The reaction mechanisms were discussed and reaction kinetic equations were calculated.Results showed that the optimum conditions were 5.0 mg/L BDE-209,2.0 g/L catalyst,temperature=35℃ and pH=3.The degradation of BDE-209 was completed within 10 min for the ultrasounic treatment,and its observed rate constant（kobs,0.519 min–1）was 40 times faster than the shaking treatment（0.013 min–1）,and 130 times faster than the static treatment（0.004 min–1）.At 10 min,the BDE-209 degradation rate was followed the order of Ni-Fe/mont（99.5%）〉 nZVI/mont（85.1%）〉nanoscale Ni-Fe（64.8%）〉nZVI（48.1%）〉mont（4.1%）〉nanoscale Ni（1.1%）.At 120 min,the kobs was followed the order of Ni-Fe/mont（0.519 min–1）〉nZVI/mont（0.209 min–1）〉nanoscale Ni-Fe（0.050 min–1）〉nZVI（0.024 min–1）.No significant degradation of BDE-209 was found for montmorillonite,nanoscale nickel,or ultrasound in itself.