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Wang X.,Northwest Normal University | Wang X.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Lu M.,Northwest Normal University | Wang H.,Northwest Normal University | And 5 more authors.
New Journal of Chemistry | Year: 2016

Graphene aerogel-mesoporous carbon (GA-MC) composites with three-dimensional (3D) hierarchical nanostructures were synthesized using a nanocasting technique. The honeycomb-like GA-MC composites exhibited very high surface areas (728.3 m2 g-1), and ultra large pore sizes (48 nm) and pore volumes (0.96 cm3 g-1) due to the synergistic combination of the advantages of both macro-porous graphene aerogels and the meso-pores of mesoporous carbon. These wonderful features made GA-MC a promising enrichment material for SPME fiber coating. Under the optimum conditions, the home-made fiber (GA-MC) was successfully applied to extract BFRs in real wastewater samples and ideal results were obtained with recoveries of 74.6-96.2%. The new fibers demonstrated excellent enrichment capabilities compared to commercial polydimethylsiloxane (PDMS) and polyacrylate (PA) fibers for six brominated flame retardants (BFRs). The ideal extraction performance of the novel graphene aerogel-mesoporous composites creates new opportunities for SPME applied in environmental analysis. © 2016 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. Source


Wang X.,Northwest Normal University | Wang X.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Lu M.,Northwest Normal University | Pei Y.,Northwest Normal University | And 4 more authors.
Journal of Porous Materials | Year: 2014

Two novel mesoporous cellular foams (MCFs) materials with well-defined large and aerogel-like mesostructure were successfully synthesized using tetraethyl orthosilicate as silica source, cyclohexane (CHE) as a swelling agent and triblock copolymer Pluronic P123 and F68 as a template, respectively. The effect of CHE on the expansion of the framework were characterized in detailed by small-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption–desorption. The results showed that CHE was an effective swelling agent on the pore size of MCFs. All as-prepared materials were employed as the adsorbent to brominated flame retardants (BFRs) from environmental water samples. The adsorption study indicated the new materials exhibited superior adsorption capacity, the removal efficiencies of MCF-1-1.5 for seven BFRs reached 81.4–95.2 % in industrial wastewater. The recoveries of method were in the range of 86.3–105.7 % for Xiaoqing River sample and 74.6–114.6 % for chemical plant wastewater sample. © 2014, Springer Science+Business Media New York. Source


Wang X.,Northwest Normal University | Wang X.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Wang H.,Northwest Normal University | Lu M.,Northwest Normal University | And 6 more authors.
Journal of Separation Science | Year: 2016

Three-dimensional graphene-supported mesoporous silica@Fe3O4 composites (mSiO2@Fe3O4-G) were prepared by modifying mesoporous SiO2-coated Fe3O4 onto hydrophobic graphene nanosheets through a simple adsorption co-condensation method. The obtained composites possess unique properties of large surface area (332.9 m2/g), pore volume (0.68 cm3/g), highly open pore structure with uniform pore size (31.1 nm), as well as good magnetic separation properties. The adsorbent (mSiO2@Fe3O4-G) was used for the magnetic solid-phase extraction of seven pesticides with benzene rings in different aqueous samples before high-performance liquid chromatography. The main parameters affecting the extraction such as adsorbent amount, volume of elution solvent, time of extraction and desorption, salt effect, oscillation rate were investigated. Under the optimal conditions, this method provided low limits of detection (S/N = 3, 0.525-3.30 μg/L) and good linearity (5.0-1000 μg/L, R2 > 0.9954). Method validation proved the feasibility of the developed adsorbent, which has a high extraction efficiency and excellent enhancement performance for pesticides in this study. The proposed method was successfully applied to real aqueous samples, and satisfactory recoveries ranging from 77.5 to 113.6% with relative standard deviations within 9.7% were obtained. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Wang X.,Northwest Normal University | Wang X.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Lu M.,Northwest Normal University | Wang H.,Northwest Normal University | And 4 more authors.
Separation and Purification Technology | Year: 2015

Three-dimensional (3D) graphene aerogels-mesoporous silica (GAs-MS) frameworks were successfully fabricated. The interconnected macropores were obtained from hydrothermally assembled 3D GAs, while the mesopores were generated by the silica uniformly grown on the surface of graphene. The resulting GAs-MS exhibited narrow mesopore size distribution (1.87 nm), high surface area (1000.80 m2 g-1), and hierarchical macro- and mesoporous structures. These wonderful features made GAs-MS as a promising adsorbent for the removal of hazardous phenols from wastewater. The adsorption study implied that the novel materials exhibited superior adsorption capacity of phenols to such as phenol, catechol, resorcinol and hydroquinone, with removal efficiencies of 68.6%, 86.6%, 91.1% and 94.7%, respectively. © 2015 Elsevier B.V. All rights reserved. Source


Peng B.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Wan J.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Li X.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | Zhang Z.,Key Laboratory of Bioelectrochemistry and Environmental Analysis of Gansu Province | And 2 more authors.
Separation Science and Technology (Philadelphia) | Year: 2012

Separation and recovery of cadmium from sulphate leach liquors of spent Ni-Cd batteries using TBP, HDEHP (D2EHPA), EHEHPA (PC 88A or Ionquest 801 or P507) have been investigated in a laboratory scale. Cadmium can be extracted into paraffin waxes from acidic solutions in the temperature range of 55-75°C using different extractants. The influence of various parameters on extraction and stripping were studied in detail. The feasibility of separation of cadmium from nickel using these extractants and their combination was studied. The mixture extractant of EHEHPA and TBP was found to be the best for the separation of Cd and Ni. A three-stage counter-current extraction simulation test for cadmium extraction was carried out at an A/O phase ratio of 4:1 and pH 2.5. More than 99.97% Cd 2+ was extracted with the organic phase containing 0.7 mol L -1 EHEHPA and 0.5 mol L -1 TBP, while more than 99.97% nickel was left in the raffinate. The cadmium loaded organic phase was stripped with 2 mol L -1 hydrochloric acid in the stripping stage. The present method can be applied to the separation and recovery of cadmium from acidic leach liquor of spent Ni-Cd batteries or related waste liquor. © 2012 Copyright Taylor and Francis Group, LLC. Source

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