Prepartion Of Al-Mg-Zn Composite Iron Powdrs And Their Degradation Property To Halogenated Organic Compound In Water

The present dissertation is designed to prepare Al-Mg-Zn/Fe composite powder by reducing iron on the surface of Al-Mg-Zn alloy. The reaction time, concentration and pH value are investigated and the prepared powders were characterized by means of XRD,XPS and SEM. We has investigated the degradation of to CT, PCE and 4-CDP by composite powder, and effect of the temperature, initial concentration and amount of powder on the degradation reaction were studied. Electrochemical method was used to explore the degradation mechanism of CT and PCE. The results show that good powder can be prepared under the following condition: iron salt concentration 0.3mol/L, ratio of Na2S2O4 to NaOH =1:4 and reaction time 2 hours. The characterization result shows that particle size distribution of the composite powders is 20～60um, iron settling on the surface is amorphous and coverage ratio of iron on the alloy powder surface is approximately 70%. The composite iron powders and the Fe/Ni system have good degradation efficiency to CT and PCE, especially to alkane. The doped nickel has excellent catalytic effect on degradation, especially on the degradation of alkene. Result of electrochemical test demonstrates that the dechlorination of alkene mainly perform through the reduction by atomic hydrogen, while the dechlorination of carbon tetrachloride is controlled by direct electron transfer.