Coupling Removal of P-Chloronitrobenzene and Its Reduction Products by Nano Iron Doped with Ni and FeOOH (nFe/Ni-FeOOH)

The removal of chlorinated pollutants from water by nanoparticles is a hot topic in the field of environmental engineering. In this work, a novel technique that includes the coupling effect of n-Fe/Ni and its transformation products (FeOOH) on the removal of p-chloronitrobenzene (p-CNB) and its reduction products, p-chloroaniline (p-CAN) and aniline (AN), were investigated. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to characterize the nano-iron before and after the reaction. The results show that Fe-0 is mainly oxidized into lath-like lepidocrocite (gamma-FeOOH) and needle-like goethite (alpha-FeOOH) after 8 h of reaction. The coupling removal process and the mechanism are as follows: Fe-0 provides electrons to reduce p-CNB to p-CAN and then dechlorinates p-CAN to AN under the catalysis of Ni. Meanwhile, Fe-0 is oxidized to FeOOH by the dissolved oxygen and H2O. AN is then adsorbed by FeOOH. Finally, p-CNB, p-CAN, and AN were completely removed from the water. In the pH range between 3 and 7, p-CAN can be completely dechlorinated by n-Fe/Ni within 20 min, while AN can be nearly 100% adsorbed by FeOOH within 36 h. When the temperature ranges from 15 degrees C to 35 degrees C, the dechlorination rate of p-CAN and the removal rate of AN are less affected by temperature. This study provides guidance on the thorough remediation of water bodies polluted by chlorinated organics.

Automated summary

The removal of chlorinated pollutants from water is a significant topic in environmental engineering. This study investigates a technique using nanoparticles to remove p-chloronitrobenzene and its reduction products from water. The results demonstrate the effective removal of these pollutants through the coupling effect of n-Fe/Ni and the transformation of FeOOH. The study provides guidance for the remediation of water bodies polluted by chlorinated organics.