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Abstract In order to study the remediation effeciency for nitrobenzene pollution, in-situ reactive zone of modified nanosale zero valent iron was created in one-dimensional simulation columns using prepared slurry, and the persistence of its function was also assessed through the calculation of permeability change. The results of simulated experiments show that the removal efficiency of nitrobenzene was 45%~80%, and the changing process of the permeability of the reactive zone could be divided into thress stages: rapid decline in 0~10d, slow decline in 10~30 d and stable stage in 30~60d with average decrease of 53.2%. Still, the reactive zone kept favourable operation without blocking in different aquifer conditions, which proved that the zone of SM-NZVI could continue to remediate availably. Larger particle size of aquifer medium and suspension concentration resulted in higher degradation efficiency of nitrobenzene which increased by 23.7% and 13.7%, respectively. However, higher flow velocity of underground water and pollutant concentration were adverse to the removal of nitrobenzene which both decreased by 46.8% or so. The ratio of iron to nitrobenzene participating in the reaction actually in each zone was 11.2, 17.9, 12.6, 3.3 and 25.7, respectively, it means that the utilization percentage of SM-NZVI particles was relatively low and thus excess suspension should be injected to the underground for ideal remediation results.
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Received: 16 April 2015
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