Influence on velocity of groundwater flow in nitrobenzene degradation by fenton-like oxidation based on natural iron extraction

The catalytic efficiency of iron (II, III) extracted from aquifer materials by DCB(dithionite-citrate-bicarbonate) to promote Fenton-like reaction and the influences of groundwater velocity upon the oxidation efficiency of catalytic reaction were both examined by employing Nitrobenzene (NB) as a model compound at neutral pH (8~10°C). Fine sand, as the solid catalyst, was selected and simpled as the most-represented aquifer materials in a famous nitrobenzene contaminated site of China based on hydrological analysis. The results indicated that the adsorption to the catalyst changed significantly with the pH value and the sorption isotherm was fitted using the Langmuir model, agent DCB performed the best but also has hysteresis property. The highest removal efficiency could reach 80.2% while the mole ratio of nitrobenzene to H₂O₂ was 1:200. On the basis of the findings, one-dimensiona soil column experiments further indicated that groundwater flow velocity could strongly impact the occurrence of extraction agents and aquifer materials so that the effective degradation of NB were repressed due to the lack of extraction reaction time or scavenging effect of hydroxyl radical by H₂O₂.