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Updated: Oct 22, 2025
Reverse Microemulsion-mediated Synthesis of Monometallic and Bimetallic Early Transition Metal Carbide and Nitride Nanoparticles
Published on: November 27, 2015
A collaborative strategy for elevated reduction and immobilization of Cr(VI) using nano zero valent iron assisted by
Yingying Xie1, Guining Lu2, Xueqin Tao3
1School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou 521041, China.
Abstract:
A novel collaborative strategy for enhanced removal of Cr(VI) using nano zero valent iron (nZVI) assisted by schwertmannite (Sch) with two synthesis methods was designed. Batch experiments demonstrated that nZVI/Sch-AP (synthesized by abiotic precipitation of Fe3+ species) exhibited excellent removal performance for Cr(VI) than nZVI/Sch-CO (synthesized by chemical oxidation of Fe2+ species). The results indicated that the removal efficiencies of Cr(VI) by nZVI/Sch-AP and nZVI/Sch-CO were highly pH-dependent and achieved to be 99.99% and 98.01% under the optimal conditions of 10 mg L-1 Cr(VI) concentration, a pH of 6.3 and a Fe(0)/Cr(VI) molar ratio of 12. But nZVI/Sch-AP emerged greater k of 0.1097 min-1 than that of nZVI/Sch-CO (0.0485 min-1). Humic acid exhibited promotion effect on the Cr(VI) removal in low concentration of 1 mg L-1. Results of XRD and XPS demonstrated that α-FeOOH was the dominant products in both incubations of nZVI/Sch-AP and nZVI/Sch-CO, accompanied with FeCr2O4 and CrFe mixed (oxy)hydroxides, and γ-FeOOH was found alone in the incubations of nZVI/Sch-CO. We proposed a consecutive and simultaneous process involving surface absorption-reduction and co-precipitation/immobilization for the removal. This study provides new insights into the elimination of Cr(VI) from wastewater by nZVI/Sch, especially in acid mine drainage.
