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Chen R.,Hebei Normal University | Chen R.,Key Laboratory of Inorganic Nanomaterial of Hebei Province | Zhang X.,Hebei Normal University | Liu H.,Hebei Normal University | And 2 more authors.
RSC Advances | Year: 2015

High- and low-crystalline goethite (α-FeOOH) were obtained via air oxidation of Fe(OH)2. Rhodamine B (RhB) was selected as a model pollutant, and the photocatalytic activity of the α-FeOOH/oxalate system under light irradiation was evaluated. The crystal structure, morphology, and specific surface area of the prepared α-FeOOH samples were determined by X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET), respectively. The adsorption behavior of α-FeOOH was determined using the Langmuir model. The effects of initial pH value, initial concentration of oxalic acid, and light intensity on RhB photodegradation were investigated in the α-FeOOH/oxalate suspension. In contrast to high-crystalline α-FeOOH, low-crystalline α-FeOOH with a high specific surface shows higher adsorption and photocatalytic activity toward RhB photodegradation by a photo-Fenton-like reaction. A possible mechanism for RhB degradation was also suggested. © 2015 Royal Society of Chemistry. Source


Zhang X.,Shanxi Institute of Coal CAS Chemistry | Zhang X.,University of Chinese Academy of Sciences | Zhang X.,Hebei Normal University | Chen Y.,Hebei Normal University | And 5 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2014

In this paper, a simple and efficient route had been developed for the synthesis of hierarchical α-Fe2O3hollow microspheres with open pores on the shells. All chemicals used were low-cost compounds and environmentally benign. The as-prepared samples were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) gas sorptometry. The results showed that the chelating ligand SSA and the initial pH value of the solution played important roles in the morphological control of the α-Fe2O3nanostructures. A possible formation mechanism was described based on the experimental results. The obtained α-Fe2O3hollow spheres exhibited an excellent adsorption capacity for Cr(VI) ions because of their high surface area and a good ability to preserve the accessible surface. Copyright © 2014 American Scientific Publishers All rights reserved. Source


Zhang X.,Hebei Normal University | Zhang X.,Shanxi Institute of Coal CAS Chemistry | Chen Y.,Hebei Normal University | Zhao N.,Shanxi Institute of Coal CAS Chemistry | And 4 more authors.
RSC Advances | Year: 2014

Hierarchical citrate modified ferrihydrite microstructures (Fh1) with flower-like morphologies were successfully synthesized via a simple aqueous solution route without the addition of any organic solvent or surfactant. The obtained products were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), BET analyses, Fourier-transform IR spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The prepared citrate modified ferrihydrite microstructures (Fh1) exhibited superior adsorption abilities for removal of methylene blue (MB) and Cr(vi) ions from aqueous solution. In addition, these citrate modified ferrihydrite microstructures also exhibited high activity to produce hydroxyl radicals through catalytic decomposition of H2O2 and could degrade highly concentrated MB solution at neutral pH. The results indicate that citrate modified ferrihydrite microstructures are very promising adsorbents and (photo-) Fenton-like catalysts for the treatment of pollutants. This journal is © the Partner Organisations 2014. Source


Zhang X.,Shanxi Institute of Coal CAS Chemistry | Zhang X.,University of Chinese Academy of Sciences | Zhang X.,Hebei Normal University | Chen Y.,Hebei Normal University | And 5 more authors.
Journal of Alloys and Compounds | Year: 2013

In this paper, a simple and efficient route had been developed for morphology-controlled synthesis of hierarchical α-Fe2O 3 superstructures assembled by nanocrystallites. All chemicals used were low-cost compounds and environmentally benign. The morphologies and structures of the α-Fe2O3 crystals were characterized by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and Fourier-transform IR spectroscopy (FTIR). The results showed that different shapes of hierarchical α-Fe2O3 nanostructures such as peanuts-like, capsule-like, cantaloupe-like and almond-shaped could be prepared by simply varying the concentration of silicate anions and other inorganic reagents. The as-prepared α-Fe 2O3 architectures were composed of nanorods or nanosheets at different synthesis temperature. The possible formation mechanism was described based on the experimental results. Magnetic hysteresis measurements revealed the as-prepared superstructures displayed ferromagnetic behavior with higher remanence and coercivity at room temperature, which was attributed to the superstructure or the shape anisotropy of the samples. © 2012 Elsevier B.V. All rights reserved. Source


Zhao L.,Hebei Normal University | Lu B.,Hebei Normal University | Liu H.,Hebei Normal University | Liu H.,Key Laboratory of Inorganic Nanomaterial of Hebei Province | And 2 more authors.
Huagong Xuebao/CIESC Journal | Year: 2011

Uniform pseudocube nano-iron oxide red (hematite)particles was prepared in the liquid phase by using δ-FeOOH as seed and iron as raw material at low temperature. The effects of such factors as initial pH of reaction, concentration of catalyst, reaction time on the preparation of these hematite particles were investigated. The product was characterized by XRD, IR, FESEM. The results showed that pure pseudocube hematite particles could be prepared under the experimental conditions of solution initial pH 7, β=0.09(β=[Fe 2+]/[δ-FeOOH]), air oxidation temperature and time of 100°C and 48 h respectively. The product crystallized integrally with particle diameter 90-100 nm, and its color was brightly red. This is a new method to prepare high-purity nano-iron oxide red with the characteristics of simple operation, non-pollution and low cost. © All Rights Reserved. Source

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