Hydrothermal Synthesis Of Iron-Carbon Composites With Their Remediation Of Chlorinated Pollutants In Groundwater

In recent years,in-situ reaction zone(IRZ)technology is an effective processing technology of groundwater pollution.The key of IRZ technology is choosing an appropriate reaction reagent to removal of the pollutants efficiently.At present,as a typical reaction reagent,nanoscale zero-valent iron(nZVI)has strong reactivity and larger specific surface area,therefore n ZVI has been utilized in the IRZ technology.The use of n ZVI in the environment leads to little environmental threat.So,it is desirable to be able to treatment the pollution of TCE using n ZVI.But the n ZVI particles with poor mobility causes because of they are easily rapid agglomeration,and they are easily lost their high surface reactivity because of oxidized by air.The characteristics of the nZVI particles have become serious drawbacks in the groundwater treatment.Therefore,the objective of this study is to design and prepare the n ZVI coated with sucrose through a simple green technology,and assess its potential of the TCE removal in the groundwater.In the article,sucrose and ferric chloride as the starting materials,the iron-carbon composites by hydrothermal method.The physical and chemical properties were analyzed by SEM,XRD,BET and TGA.The results are as follows.Firstly,the iron-carbon composites can reach the submicron level by ball milling process,and the dispersibility is well without agglomeration.Secondly,the specific surface area of the particles is 369 cm2 / g,which is 2.5 larger than that of the ordinary commercial activated carbon,indicating that iron-carbon composites have excellent adsorption potential.Thirdly,the content of iron in the iron-carbon composites can be changed by changing the pH value of the starting materials.The order of the iron content is: Fe/C(pH=2)<Fe/C(pH=4)<Fe/C(pH=6)<Fe/C(pH=8)<Fe/C(pH=10).Fourthly,by changing the pH value of the starting material,it is possible to control the size of the nZVI particles in the produced iron-carbon composites.The order of average particle size is: Fe/C(pH=2)<Fe/C(pH=4)<Fe/C(pH=6)<Fe/C(pH=8)<Fe/C(pH=10).In the study of degradation of pollutants,according to the research data,the removal rate of TCE can reach 100%.This is because the iron-carbon compositer combine the advantages of the high adsorption property of carbon material and the high reduction activity of zero valent iron.TCE removal rate is as follows: Fe/C(pH=2)>Fe/C(pH=4)>Fe/C(pH=6)>Fe/C(pH=8)>Fe/C(pH=10).By detecting the generating of chloride ion,the reduction rate of nZVI is as follows:Fe/C(pH=2)<Fe/C(pH=4)<Fe/C(pH=6)<Fe/C(pH=8)<Fe/C(pH=10).In the study of underground transmission,iron-carbon composite materials and commercially available zero-price iron were all employed to do sand column transmission experiments,the comparison results show that the iron-carbon composites have better transmission performance.