Emergency remediation of simulated chromium (VI)-polluted river by nanoscale zero-valent iron: Laboratory study and numerical simulation

The remediation effectiveness and negative effect on ecotoxicity are needed to be considered in a suitable emergency remedial action for polluted river. In this work, the stabilized nanoscale zero-valent iron (nZVI) was applied in the remediation of a simulated Cr(VI)-polluted river, and a mathematical model was developed based on a reaction network to describe the process. The results showed that the remediation effectiveness was improved with the increasing nZVI dose, decreasing initial concentration of pollution source and water flow rate. Water analysis was conducted to investigate the effects of the nZVI to the process. Toxicity evaluation indicated that almost no toxicity was detected in 36 days’ exposure of reaction products in the water. Model parameters including mass-loss coefficient (K1) and reaction coefficient (K2) were obtained in laboratorial experiment, and a statistical comparison method was employed to assess the simulated results. Thus, the obtained mathematical modeling and physical modeling could be exploratory researches for practical remediation of polluted river.

► Stabilized-nZVI was competent for the simulated remediation.
► The fate of Cr(VI) was described by a developed mathematical model.
► Remediation effect was impacted by dose, concentration and water flow rate.
► Almost no toxicity was detected in the treated solution even after 36 days.