Abstract
Passivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly. In this study, Cu/Fe bimetallic nanoparticles were prepared by liquid-phase chemical reduction for removal of hexavalent chromium (Cr(VI)) from wastewater. Synthesized bimetallic nanoparticles were characterized by transmission electron microscopy, Brunauer–Emmet–Teller isotherm, and X-ray diffraction. The results showed that Cu loading can significantly enhance the removal efficiency of Cr(VI) by 29.3% to 84.0%, and the optimal Cu loading rate was 3% (wt%). The removal efficiency decreased with increasing initial pH and Cr(VI) concentration. The removal of Cr(VI) was better fitted by pseudo-second-order model than pseudo-first-order model. Thermodynamic analysis revealed that the Cr(VI) removal was spontaneous and endothermic, and the increase of reaction temperature facilitated the process. X-ray photoelectron spectroscopy (XPS) analysis indicated that Cr(VI) was completely reduced to Cr(III) and precipitated on the particle surface as hydroxylated Cr(OH)3 and CrxFe1−x(OH)3 coprecipitation. Our work could be beneficial for the application of iron-based nanomaterials in remediation of wastewater.
Highlights
Passivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly
Recent studies have pointed out that (1) catalytic metals can enhance the oxidation of Nanoscale zerovalent iron (nZVI) during the interaction with pollutants through the formation of galvanic cells; (2) catalytic metals can facilitate the generation of activated atomic hydrogens which lead to the enhancement of reduction of pollutants and corrosion of n ZVI29–31
Cu/Fe bimetallic nanoparticles were prepared by chemical reduction in aqueous solutions and their reactivity towards Cr(VI) in wastewater was examined
Summary
Passivation of nanoscale zerovalent iron hinders its efficiency in water treatment, and loading another catalytic metal has been found to improve the efficiency significantly. Cu/Fe bimetallic nanoparticles were prepared by liquid-phase chemical reduction for removal of hexavalent chromium (Cr(VI)) from wastewater. In recent years, loading another catalytic metal onto the surface of nZVI has been found to effectively alleviate the passivation of nZVI16,18,19. The catalytic metal, such as Pd20,21, Ni22,23, and Cu18,24, can provide more reactivity sites and promote electron transfer on nanoparticles’ surface. Cu/Fe bimetallic nanoparticles were prepared by chemical reduction in aqueous solutions and their reactivity towards Cr(VI) in wastewater was examined. Results of this study could provide a theoretical basis for the application of iron-based nanomaterials in environmental remediation
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