Remediation of phenanthrene contaminated soil by g-C3N4/Fe3O4 composites and its phytotoxicity evaluation.

This work is a premier demonstrating the technical feasibility of remediation of PAHs-contaminated soil by g-C3N4/Fe3O4. g-C3N4/Fe3O4 has been synthesized by typical two steps involved the synthesis of g-C3N4 and the subsequent in situ co-precipitation of Fe3O4 nanoparticles. g-C3N4/Fe3O4 exhibits excellent visible-light-driven photocatalytic activity for the degradation of phenanthrene in soil at circumneutral pH. The enhanced photocatalytic activity of g-C3N4/Fe3O4 should be attributed to the hybrid of Fe3O4 and g-C3N4 and appropriate Fe3O4 loading amount can improve not only the visible light absorption ability but also the separation of the photo-induced electron-hole pairs. The phytotoxicity evaluation, a preliminary ecological risk assess, was conducted on lettuce cultivation experiments. Base on the data of growth indexes including seeds germination percentage, root length, leaf length, and fresh weight of lettuce, it can be conclude that photocatalytic oxidation based on g-C3N4/Fe3O4 provide a mild oxidation process to degrade the phenanthrene from contaminated soil and there is no negative impact on the growth of lettuce. This work definitely demonstrates that this soil remediation method based on g-C3N4/Fe3O4 is technologically feasible and has immense potential in the application of remediation of organic pollutant contaminated soils.