Journal
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Volume 623, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.colsurfa.2021.126691
Keywords
Carbon tetrachloride (CT); Bimetallic nanocomposites Ni-4/Fe@Fe3O4; Removal efficiency; Reusability; Degradation mechanism
Categories
Funding
- Open Project of Key Laboratory of Ground water Circulation and Environmental Evolution (China University of Geosciences (Beijing)), Ministry of Education, China
- National Natural Science Foundation of China [50578151]
- National Science and Technology Major Project of China [2015ZX07406-005, 2016YFC0209205]
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The bimetallic nanocomposite Ni-4/Fe@Fe3O4 showed excellent performance in the reductive dechlorination of carbon tetrachloride (CT), with high removal efficiency achieved within a short time. It displayed good reusability and stability, and can degrade CT through various pathways, following pseudo first-order kinetics. This nanocomposite has great potential for applications in CT degradation from aqueous solutions.
A bimetallic nanocomposite, named as Ni-4/Fe@Fe3O4, which was prepared via loading Fe/Ni bimetallic onto magnetite (Fe3O4), was applied to the reductive dechlorination of carbon tetrachloride (CT) for the first time and was identified by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) to explore its structure and properties. The effects of the Ni loading (weight ratio of Fe/Ni), CT concentration, initial solution pH, temperature and Ni-4/Fe@Fe3O4 dosage on the reaction system were studied. The experimental results showed that the nanoscale Ni/Fe@Fe3O4 bimetallic particles with a mass ratio of 4% of Ni/Fe exhibited excellent performance for CT degradation. The removal efficiency of CT can reach 96.3% within 35 min with only 0.2 g/L of Ni-4/Fe@Fe3O4. The degradation kinetics of CT by Ni-4/Fe@Fe3O4 nanocomposites was conformed to the pseudo first-order kinetics and the activation energies (Ea) was 25.87 kJ/mol. Moreover, Ni-4/Fe@Fe3O4 presented good reusability and stability after four cycles. Based on the detection results of CT degradation products by gas chromatography (GC), a possible degradation mechanism was discussed, which can be divided into the following ways: (1) Migration and adsorption of CT molecules. (2) Direct reductive dechlorination of CT molecules by nano zero-valent iron (nZVI). (3) Reduction dechlorination of CT by Fe2+ released by Ni-4/Fe@Fe3O4. (4) Ni-0 might induce the conversion of H-2 to active atomic hydrogen (.H) to degrade chloromethane. These results exhibited that Ni-4/Fe@Fe3O4 will be a nanocomposite with great application potential for CT degradation from aqueous solutions.
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