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Zhang X.,Fujian Normal University | Lin S.,Fujian Normal University | Chen Z.,Fujian Normal University | Chen Z.,University of South Australia | And 5 more authors.
Water Research | Year: 2011

The use of nanoscale zero-valent iron (nZVI) to remediate contaminated groundwater is limited due to its lack of durability and mechanical strength. To address this issue, 20% (w/w) nZVI was loaded onto kaolinite as a support material (K-nZVI). More than 96% of Pb2+ was removed from aqueous solution using K-nZVI at an initial condition of 500 mg/L Pb2+ within 30 min under the conditions of 10 g/L of K-nZVI, pH 5.10 and a temperature of 30 °C. To understand the mechanism of removal of Pb2+, various techniques were implemented to characterize K-nZVI. Scanning electron microscopy (SEM) indicated that K-nZVI had a suitable dispersive state with a lower aggregation, where the mean specific surface area and average particle size as determined by the BET-N2 method and X-ray diffraction (XRD), were 26.11 m2/g and 44.3 nm, respectively. The results obtained from XRD, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) indicated that a small number of iron oxides formed on the surface of K-nZVI, suggesting that free Pb2+ was adsorbed onto K-nZVI and subsequently reduced to Pb0. © 2011 Elsevier Ltd. Source


Su J.,Fujian Normal University | Lin S.,Fujian Normal University | Chen Z.,Fujian Normal University | Chen Z.,University of South Australia | And 5 more authors.
Desalination | Year: 2011

To increase the dispersion of nanoparticles and enhance their reactivity, bentonite-supported Fe/Pd nanoparticles (B/Fe/Pd) were synthesized and used for the dechlorination of P-chlorophenol (p-CP) from aqueous solution. The B/Fe/Pd was characterized with a scanning electron microscope (SEM), X-ray energy-dispersive spectrometer (EDS), X-ray diffraction (XRD), and specific surface area (BET). The results showed that the presence of bentonite led to a decrease in aggregation of Fe/Pd nanoparticles and enhanced their reactivity. More specifically, B/Fe/Pd indicated the highest p-CP dechlorination of 100%, while only 25.0% and 15.0% were obtained using B/Fe and bentonite (the conditions: C0=5.0mg/L and dose: 10.0g/L), respectively. In addition, kinetic studies show that the dechlorination rate of p-CP was described by pseudo first-order reaction kinetics, and the dechlorination rate increased with rising temperature and Pd loading. The apparent activation energy for dechlorination p-CP using B/Fe/Pd was 40.1kJ/mol, which is characteristic of a chemically surface-controlled reaction. Finally, a potential mechanism for degradation of p-CP is proposed, which is based on Fe acting as the reducing agent, while Pd acts as a catalyst with hydrogen generated from water and bentonite as a support. © 2011 Elsevier B.V. Source


Huang L.,Fujian Normal University | Weng X.,Fujian Normal University | Chen Z.,Fujian Normal University | Chen Z.,University of South Australia | And 5 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Iron nanoparticles (Fe NPs) are often synthesized using sodium borohydride with aggregation, which is a high cost process and environmentally toxic. To address these issues, Fe NPs were synthesized using green methods based on tea extracts, including green, oolong and black teas. The best method for degrading malachite green (MG) was Fe NPs synthesized by green tea extracts because it contains a high concentration of caffeine/polyphenols which act as both reducing and capping agents in the synthesis of Fe NPs. These characteristics were confirmed by a scanning electron microscope (SEM), UV-visible (UV-vis) and specific surface area (BET). To understand the formation of Fe NPs using various tea extracts, the synthesized Fe NPs were characterized by SEM, X-ray energy-dispersive spectrometer (EDS), and X-ray diffraction (XRD). What emerged were different sizes and concentrations of Fe NPs being synthesized by tea extracts, leading to various degradations of MG. Furthermore, kinetics for the degradation of MG using these Fe NPs fitted well to the pseudo first-order reaction kinetics model with more than 20 kJ/mol activation energy, suggesting a chemically diffusion-controlled reaction. The degradation mechanism using these Fe NPs included adsorption of MG to Fe NPs, oxidation of iron, and cleaving the bond that was connected to the benzene ring. © 2014 Elsevier B.V. All rights reserved. Source


Huang L.,Fujian Normal University | Weng X.,Fujian Normal University | Chen Z.,Fujian Normal University | Chen Z.,University of South Australia | And 5 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2014

Iron-based nanoparticles (OT-FeNP) were synthesized using oolong tea extracts. Their morphology, structure and size were confirmed by scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), UV-visible (UV-vis) and Fourier Transform Infrared spectroscopy (FTIR). Formation of FeNP results in mostly spherical particles with diameters ranging from 40 to 50 nm. Degradation of malachite green (MG) using OT-FeNP demonstrated that kinetics fitted well to the pseudo first-order reaction by removing 75.5% of MG (50 mg/L). This indicated that OT-FeNP has the potential to serve as a green nanomaterial for environmental remediation. © 2013 Elsevier B.V. All rights reserved. Source


Wang Z.,University of South Australia | Wang Z.,Cooperative Research Center for Contamination Assessment and Remediation of Environments | Fang C.,University of South Australia | Fang C.,Cooperative Research Center for Contamination Assessment and Remediation of Environments | And 2 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2014

In this paper, iron-polyphenol nanoparticles (Fe-P NPs) were synthesized using the extracts obtained from Australian native plant leaves, these being Eucalyptus tereticornis, Melaleuca nesophila, and Rosemarinus officinalis. The Fe-P NPs synthesized from the extracts were characterized using scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The results show that the reaction between iron ions and polyphenols can form complex nanoparticles with sizes ranging from 50 to 80 nm, the surface of which presents organic characters. The synthesized nanoparticles were then utilized as a Fenton-like catalyst for decolorization of acid black 194 in solution. The batch experiments showed that 100% of acid black was decolorized, and over 87% total organic carbon (TOC) was removed. In addition, removal of acid black 194 fitted well to the pseudo-first-order model. Compared with the conventional Fenton reaction, the Fenton-like reaction with Fe-P NPs takes place more sustained and carefully within 200 min. Furthermore, it does not need to adjust pH for the reaction. © 2014 American Chemical Society. Source

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