纳米TiO_2-UV联合(类)Fenton试剂光催化降解乐果

Photocatalytic degradation of the pesticide dimethoate by the nano TiO_2-UV/Fenton or Fenton-like process

以悬浮态纳米TiO2-UV光催化降解乐果体系为基础,首先研究了单纯添加H2O2、Fe2+、Fe3+或Cu2+对降解过程影响,进而探讨添加Fenton或类Fenton试剂对降解过程的作用。结果表明,与单纯Fe2+或Fe3+对乐果光催化降解过程的抑制作用相比,单独添加H2O22 mmol/L或Cu2+1 mmol/L有利于反应初期(0～20 min)内乐果纳米TiO2-UV光催化降解效果的提高;与类Fenton试剂相比,纳米TiO2-UV联合Fenton试剂能够有效促进乐果的降解;当在纳米TiO2-UV光催化降解乐果体系中添加由Fe2+1 mmol/L和H2O22 mmol/L组成的Fenton试剂,并调节反应液初始pH为1时,可使20 mg/L的乐果溶液在20 min内完全降解,具有相对较高的降解效率。

The effects of H2O2、Fe2＋、Fe3＋,Cu2＋ , Fenton and Fenton-like reagents on the photodegrada- tion efficiency of dimethoate, an organophosphorous pesticide, in a nano TiO2-UV system have been exam- ined. The results indicated that the addition of H2O2 2 mmol/L or Cu2＋ 1 mmol/L would be favorable for the degradation of dimethoate within the first 20min, while the addition of Fe2＋ or Fe3＋ would hinder the process. Compared with Fenton-like reagents, the combination of nanometer TiO2-UV process with Fenton reagent would be more efficient for the degradation. When the Fenton reagent was composed of Fe2＋ 1 mmol/L and H2O2 2 mmol/L and the initial pH value was 1 ,the dimethoate （20 mg/L） could be completely degraded by the nano TiO2-UV/Fenton process within 20 min, and the degradation efficiency was relatively high.