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Wu Z.,South China University of Technology | Zhang L.,Guangdong Polytechnic | Guan Q.,Kunming University of Science and Technology | Ning P.,Kunming University of Science and Technology | And 3 more authors.
Chemical Engineering Journal | Year: 2014

In order to prevent the reunion of reduced graphene oxide (rGO) during storage, α-zirconium phosphate (ZrP) was used as the modifier, and a peculiar adsorbent of ZrP-pillared rGO (rGO-ZrP) was prepared. The features of rGO-ZrP were characterized by using Fourier transform infrared (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersion X-ray (EDX) spectrometer, atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements. Then, rGO-ZrP was employed as the adsorbent and the adsorption characteristics of rGO-ZrP toward methylene blue (MB) were evaluated under laboratory conditions. The results showed that rGO-ZrP possessed a higher BET specific surface area relative to rGO. The maximum adsorption quantity of MB onto the new prepared rGO-ZrP was ~1.38. g/g at 30. °C. With the increase of storage day, the BET specific surface area and the maximum adsorption capacity of rGO-ZrP approximately remained unchanged. Under the maximum adsorption capacity, the adsorption quantity of MB onto rGO-ZrP was dependent on the initial concentration of MB, and higher temperature could facilitate the adsorption process. The efficiency of rGO-ZrP almost remained constant during the first six cycles of adsorption-desorption process. In addition, the fluorescence spectra implied that the adsorption of MB onto rGO-ZrP was a π-π stacking adsorption process, and the pillared structure of rGO-ZrP greatly enhanced the noncovalent adhesion. In conclusion, rGO-ZrP could serve as a promising adsorbent for the removal of MB in waste water. © 2014.

Liao Y.,South China University of Technology | Liao Y.,Xinjiang University | He L.,South China University of Technology | Man C.,Stevens Institute of Technology | And 10 more authors.
Chemical Engineering Journal | Year: 2014

Ceria nanorods with various aspect ratios were successfully synthesized by a convenient hydrothermal method without any templates or surfactants. The samples were characterized by TEM, HRTEM, XRD, N2 adsorption/desorption, XPS, Raman and H2-TPR. The results showed that the diameter and length of the ceria nanorods were determined by the concentration of NaOH solution and the hydrothermal reaction time, respectively. In addition, the diameter-dependent catalytic activity for abatement of toluene had been found over the nanorods with various aspect ratios. The thinner nanorods presented higher catalytic activity owing to the existence of more Ce3+ ions and more oxygen vacancy sites on the surface. Over the thinnest nanorods, the most active catalyst, three consecutive runs in toluene oxidation and a longstanding oxidation test running at 380°C for 100h were also carried out. © 2014 Elsevier B.V.

Wu Z.,Guangdong Polytechnic | Wu Z.,South China University of Technology | Zhang L.,Guangdong Polytechnic | Guan Q.,Kunming University of Science and Technology | And 7 more authors.
Materials Research Bulletin | Year: 2015

Abstract Au-Co supported on mesoporous silica materials SBA-15 was prepared with about 15 wt.% cobalt then deposition-precipitation with 2 wt.% Au. The results showed that while SBA-15 provided the long ordered arrangement of the channels for support, mixtures of cobalt oxides and gold nanoparticles are dispersed in the mesoporous channels. The sample exhibited excellent catalytic activity for toluene combustion, a complete decomposition (about 100%) of toluene had been achieved at the reaction temperature over 573 K and space velocity 30,000 h-1. The kinetics showed that the activation energy of the sample was 96.06 kJ/mol (22.96 kcal/mol) and frequency factor was 1.05 × 1010 s-1, respectively. All these results indicate that while mesoporous materials give a high surface area support for metals, cobalt offers active supports for gold particles, which might be a combined way to overcome the shortcomings of low specific area for reducible transition metal oxides and low activity for inert oxides. Crown Copyright © 2015 Published by Elsevier Ltd.

Wang K.,South China University of Technology | Wang K.,Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control SCUT | Zhao J.,South China University of Technology | Fu M.,South China University of Technology | And 4 more authors.
Aerosol and Air Quality Research | Year: 2013

In recent years a number of mechanisms for the preparation of ordered mesoporous carbons (OMCs) have been proposed for different systems. However, the exact preparation mechanism for the soft template method remains unclear, which seriously inhibits the further design and development of OMC materials on the molecular level, as well as better understanding of the related structure-activity relationship and their wider application. To clarify the mechanisms involved in the preparation of OMCs via the soft-template method, experimental and molecular simulation studies were performed in this work. First, OMCs were prepared using a triblock copolymer Pluronic F127 as the template and phenolic resin as the carbon source. These OMCs were characterized using X-ray diffraction (XRD), N2 adsorption-desorption and transmission electron microscopy (TEM), and the results show that the OMCs have well-ordered 2D-hexagonal structures and narrow pore size distributions. Additionally, the dissipative particle dynamics (DPD) method was carried out to investigate the phase behavior and self-assembly process of the F127/phenolic resin/ethanol system. The simulation results show that F127 could self-assemble a series of stable micellar structures at different concentrations, such as spherical, cylindrical, lamellar, body-centered cubic and cubic perforative ones. These micellar structures, similar to the template used in the experiment, controlled the structure of phenolic resin in ethanol solution, while the introduction of phenolic resin did not affect the selfassembled structure of F127. An investigation of the dynamic formation process involved in production of the cylindrical micelles indicates that the system transformed from a homogeneous state into the typical stable micellar structures due to their amphiphilic properties, which explains why cylindrical and uniform mesopores of OMCs were experimentally obtained. This work deepens our understanding of the mechanisms involved in the preparation of OMCs on a mesoscopic level. It also demonstrates that the DPD method is effective for studying the self-assembly of polymer systems, and provides useful guidance for the fabrication of novel materials. © Taiwan Association for Aerosol Research.

Lu M.,South China University of Technology | Huang R.,South China University of Technology | Wu J.,South China University of Technology | Wu J.,Guangdong Provincial Key Laboratory of Atmospheric Environment and Pollution Control SCUT | And 6 more authors.
Catalysis Today | Year: 2015

FeOx/SBA-15 catalysts were prepared via impregnation and utilized for toluene removal in dielectric barrier discharge (DBD) plasma at atmospheric pressure and room temperature. Toluene removal was investigated in the environment of various mixed N2/O2 plasmas, showing that toluene removal efficiency and COx selectivity were greatly increased by FeOx/SBA-15 and that the organic intermediates were greatly reduced by catalysts. In pure N2 plasma, the bulk oxygen in the catalyst was involved in the toluene oxidation, and the 3%FeOx/SBA-15 catalyst showed the optimal toluene oxidation activity. The catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and O2 temperature-programmed desorption (O2-TPD), showing that toluene oxidation was closely related to the highly dispersed nature of iron on the SBA-15 surface, the reduction temperature of Fe2+ and the oxygen adsorption ability of the catalyst. The pathways of toluene decomposition in the combination of FeOx/SBA-15 with a non-thermal plasma (NTP) system were proposed based on the identified intermediates. © 2014 Elsevier B.V. All rights reserved.

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