| The extensive use and discharge of halogenated organic matter has led to the increasing pollution of halogenated materials in soil groundwater,threatening ecological safety and human health.sulfurizced nZVI(Fe/FeS)is the latest nano-iron technology in recent years and has been widely used in the degradation of halogenated hydrocarbons.However,sulfurized nZVI greatly reduces its dispersibility,stability,migration and degradability of pollutants in soil groundwater due to agglomeration and passivation.In this study,we used a"ship-in-a-bottle" method to synthesize Fe/FeS@SiO2 yolk-shell particles.The results show that the Fe/FeS@SiO2 material possess distinctive structures,including active cores,mesoporous network,shells and hollow cavities,which not only prevents the agglomeration of Fe/FeS,but also provides a large surface area(85 m2/g V.S 8 m2/g)compared to Fe/FeS.Good dispersibility,stability and low electronegativity under neutral pH conditions make Fe/FeS@SiO2 materials have good migration ability in porous media.The HMSS package reduces the agglomeration of the particles,while the open pores and larger specific surface area allow more contaminants to be adsorbed and reacted with the central core,thereby reducing the efficiency of the Fe/FeS@SiO2 material for removing TBBPA and TCE.Both are significantly improved,and the reactions follow the first-order reaction kinetics.Studying the degradation pathway of TBBPA found that the degradation of halogenated organics by Fe/FeS@SiO2 is a continuous dehalogenation reaction.And after 6 cycles of degradation of TCE,the removal rate can still reach 80%,showing good recyclability.This study proves that Fe/FeS@SiO2 has good prospects as an agent for in situ repair of halogenated organic matter in soil groundwater. |
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