Degradation And Mechanism Of Dimethyl Phthalate By Fenton Reagent Assisted With Microwave Irradiation

Dimethyl Phthalate is widly used to improve plasticity and strength of plastic products, and can diffuse to the environment to pollute water environment,atmospheric environment and soil environment. Further studies have shown that DMP is an important endocrine disruptor which can cause body’s reproductive system anomalies, decrease of immune function, cancer and other environmental diseases.Based on these, we carry out the research of degradation and mechanism of DMP by microwave irradiation assisted with Fenton Reagent.First, microwave is carried out to degrade DMP.Then, investigation on DMP degraded by Fenton reagent was carried out in this paper, The effects of Fe2+and DMP concentration, dosage ratio of Fe2+: H2O2, initial p H value of DMP aqueous solution and dosage of Fenton reagent on the degradation efficiency of DMP were investigated and optimized. The influence of UV light on Fenton and Fenton-like reaction,respectively, was studied. Finally, degradation apparent rate for DMP is established based on the first-order kinetics model.Finally, Microwave-Fenton reagent combined process is carried out to degrade DMP.The effects of Fe2+and H2O2 initial concentration, p H value of DMP aqueous solution and microwave power are investigated and optimized. Fenton-like system and some heavy metal ions like Fe2+, Cu2+ are introduced to analysis the effect of Fenton reagent and MW/Fenton on the degradation of DMP comparatively. Concerted mechanism of DMP degraded by Microwave-Fenton is studied through the change of Fe2+, H2O2 concentration and p H value. Exploratory study has been made on the degradation process of DMP based on DMP chromatogram, too.Experimental results displayed that the degradation efficiency of DMP was96.08% after 30 min when the initial concentration of DMP and Fe2+ was 2 mg/L and2.5 mg/L, respectively, the dosage ratio of Fe2+: H2O2 was 1:10 and the initial p H value was 3. The degradation efficiency of DMP was more than 30% under UV irradiation in Fenton or Fenton-like system, compared that without UV irradiation.Apparentkinetic equation for DMP was lnc0/c=f(c0,n, p H)=2.068c0-0.7928n-1.4157(p H)0.6336.Experimental results also displayed that the degradation efficiency of DMP is 96.21%after 30 min when the initial concentration of Fe2+ and H2O2 is 2 mg/L and 20 mg/L,respectively, the Microwave Power is 385 W, initial p H value is 3 and concentration of DMP is 2mg/L. Degradation reaction of DMP follows one order reaction kinetics equation well. Rapid circulation between Fe2+and Fe3+ in microwave field is the main cause that lead DMP to degrade by microwave-assisted Fenton.