化工专业英语口语演讲

1、会计学1化工专业英语口语演讲化工专业英语口语演讲第1页/共15页IntroductionExperimentalResultsContents第2页/共15页 Chlorinated phenols (CPs) constitute an important class of pollutants because of their wide use in the production of woodpreservers, pesticides and biocides. Due to their reactive nature,CPs are highly toxic, mutagenic a

2、nd possibly carcinogenic. Furthermore, they are biorefractory and tend to accumulate in animal tissues. Once released into the environment, CPs will accumulate in the surrounding areas and pose a great health threat to humans and ecosystems over a long period of time, hence their fate in the environ

3、ment is of great importance in waste treatment.第3页/共15页 Some physical and chemical methods have also been used for the removal of CPs and their derivatives fromwastewater. However the high cost and low efficiency of these processes limit their applicability. The use of NZVI and bimetallic Pd/Fe nano

4、particles have shown to be an effective technology for the remediation of contaminated groundwaters.第4页/共15页 2,4-Dichlorophenol2,4-DCP was selected as a model compound due to its abundance in the contaminated groundwater.We systematically discuss NZVI and nanoscale Pd/Fe bimetal reductive dechlorina

5、tion of 2,4-DCP.第5页/共15页 How to get NZVI? FeSO47H2O+2BH4Fe+2B（OH）3+7H2How to get bimetallic Pd/Fe nanoparticles ?PdCl62-+2Fe2Fe2+Pd+6Cl-第6页/共15页 The batch experiments for 2,4-DCP dechlorination were performed in the same three-necked flask into which NZVI or Pd/Fe nanoparticles were added. 2,4-DCP s

6、tock solutions and a certain amount of deoxygenated deionized water were added into the flask containing freshly prepared NZVI or Pd/Fe nanoparticles. The reactionsolution was stirred under nitrogen flow. Aliquots of samples were periodically collected with glass syringes and the reaction was quench

7、ed by passing through 0.45 m membrane filters. The reductive dechlorination of 2,4-DCP.第7页/共15页 TEM images of NZVI particles第8页/共15页 TEM images of nanoscale Pd/Fe particles第9页/共15页 SEM images of NZVI particles第10页/共15页 SEM images of nanoscale Pd/Fe particles第11页/共15页 （1）The size of NZVI and nanoscal

8、e Pd/Fe particles were less than 100nm; （2）The nanoscale Pd/Fe particles exhibited high reactivity. It was observed that there was an obvious enhanced 2,4-DCP degradation reaction rate by using nanoscale Pd/Fe particles as catalysis and the Pd/Fe particles was prepared by solution phase reduction un

9、der ultrasonic irradiation;（3）The experimental results showed that the mass fraction of Pd （Pd）, the mass concentration of nanoscale Pd/Fe particles （Pd/Fe）, reaction temperature, initial pH value alter noticeably the reaction rates and kinetics, with preferable operation condition at high （Pd）0.2%,

10、 room temperature, weak acid condition and high （Pd/Fe）.The results are showed as following:第12页/共15页第13页/共15页IntroductionExperimentalResultsContents第14页/共15页 Some physical and chemical methods have also been used for the removal of CPs and their derivatives fromwastewater. However the high cost and low efficiency of these processes limit their appli