Construction And Properties Investigation Of Chemical Oxidation System With Underground Transport Ability

Heterogeneous Fenton-like reaction offers significant advantages over homogeneous Fenton reaction because it overcomes the shortcomings associated with initial acidification.However,previous studies have mainly centered on its application in wastewater treatment while overlooked its potential for subsurface remediation.The primary purpose of this paper is to prepare a novel heterogeneous Fenton-like reaction catalyst（γ-Fe₂O₃/C）which could freely move through the model sediments and easily seize the pollutants in addition to efficiently catalyze H₂O₂,well suitable for soil and groundwater remediation.Moreover,Fe/C obtained by further carbonizing theγ-Fe₂O₃/C can effectively activate persulfate and be suitable for the field of in-situ chemical oxidation.In this experiment,submicronγ-Fe₂O₃/C was prepared using ultrasonic spray pyrolysis（USP）without expensive and cumbersome precursors,and Fe/C could be obtained by further carbonization.The properties ofγ-Fe₂O₃/C were characterized by XRD,XPS,SEM and TEM.In a series of column tests,these spheres exhibit better transport ability due to their optimal size,conforming to the prediction by the Tufenkji–Elimelech filtration theory.Meanwhile,γ-Fe₂O₃/C spheres could act as a strong adsorbent for organic pollutants owing to the presence of carbon,thereby providing a driving force to gather contaminants into their vicinity and facilitating the reaction.In addition,immobilization ofγ-Fe₂O₃ nanoparticles into carbon spheres protects iron oxides from aggregation,and thus retains the number of active sites for catalytic decomposition of H₂O₂.Hence,the system containing the as-preparedγ-Fe₂O₃/C spheres and H₂O₂ shows the high removal efficiency and degradation efficiency in the remediation of recalcitrant organic contaminants such as methylene blue and sulfamethoxazole.Finally,Fe/C obtained by further carbonizing theγ-Fe₂O₃/C was used as an activator to construct an activated persulfate system to degrade sulfamethoxazole,and the types of free radicals generated during the reaction were detected,which proved the good persulfate activation effect.The column tests was also carried out to further verify the prediction of T-E model.The results of the present work suggest that the obtained submicronγ-Fe₂O₃/C spheres possess multi-functions including transport,adsorption and catalysis,holding the great potential to be an effective heterogeneous Fenton-like catalyst,and the Fe/C obtained after carbonization of the material can also activate persulfate,which has broad prospects in the field of soil and groundwater remediation.