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Kang J.,CAS Research Center for Eco Environmental Sciences | Kang J.,Hubei Provincial Research Institute of Environmental Science | Liu H.,CAS Research Center for Eco Environmental Sciences | Zheng Y.-M.,National University of Singapore | And 2 more authors.
Journal of Colloid and Interface Science | Year: 2011

Extensive usage of tetracycline has resulted in its contamination in surface water and groundwater. The adsorption of tetracycline on zeolite beta was systematically investigated for the decontamination of the antibiotic polluted water in this study. Ninety percent of uptake by the zeolite beta occured in 0.25. h, and the adsorption equilibrium was obtained within 3. h, which was well described by an intraparticle diffusion model. The adsorption generally increased when pH was increased from 4.0 to 5.0, and then decreased significantly as the pH was further increased, which was caused by the pH-dependent speciation of tetracycline and surface charge of zeolite beta. Both Freundlich and Langmuir equations well described the adsorption isotherm. A thermodynamic analysis showed that the sorption process was spontaneous and endothermic. Aluminum atoms in the zeolite played a crucial role in the uptake; the adsorption increased with the increasing aluminum content in zeolite. The UV-Visible spectroscopy study showed that the spectra of tetracycline changed upon the interaction with zeolite beta, which could be ascribed to the formation of complexes of tetracycline and aluminum atoms in the zeolite surface. Nuclear magnetic resonance spectroscopy study further confirmed the participation of Al in the tetracycline adsorption. Fourier transform infrared spectroscopy studies showed that the amino functional groups in tetracycline were involved in the complexation with the zeolite surface. © 2010 Elsevier Inc.


Nirmala R.,Chonbuk National University | Kim H.Y.,Chonbuk National University | Navamathavan R.,Chonbuk National University | Yi C.,Hubei Provincial Research Institute of Environmental Science | And 5 more authors.
Ceramics International | Year: 2012

SnO 2 doped TiO 2 electropsun nanofiber photocatalysts were successfully prepared by means of electrospinning process. The surface morphology, structure and optical properties of the resultant products were characterized by field-emission electron microscopy (FE-SEM), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), UV-vis spectroscopy, photoluminescence (PL) and cathodoluminescence (CL) techniques. The utilized physiochemical analyses indicated that the introduced SnO 2 doped TiO 2 nanofibers have a smooth surface and uniform diameters along their lengths. The photocatalytic performance of the composite nanofibers was tested for degradation of methylene blue (MB) and methyl orange (MO) dye solution under ultraviolet (UV) irradiation. Under the UV irradiation, the photocatalytic reaction rate in case of utilizing SnO 2-doped TiO 2 nanofibers was rapidly increased than that of the pristine TiO 2 nanofibers. Overall, this study demonstrates cheap, stable and effective material for photocatalytic degradation at room temperature. © 2012 Elsevier Ltd and Techna Group S.r.l. All rights reserved.


Nirmala R.,Chonbuk National University | Won J.J.,Chonbuk National University | Kim H.Y.,Chonbuk National University | Navamathavan R.,Chonbuk National University | And 3 more authors.
Journal of the Korean Physical Society | Year: 2012

We report on the preparation and the characterization of TiO 2 nanoparticles incorporated with nylon-6 composite nanofibers by using electrospinning technique. Two different composite nanofiber mats with TiO 2 nanoparticles sizes of 20 and 300 nm were prepared. The resultant nanofibers exhibited good incorporation of TiO 2 nanoparticles. The doping of TiO 2 nanoparticles into the nylon-6 nanofibers was confirmed by using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) spectroscopy. The measurement of the electrical conductivity of the TiO 2 nanoparticles incorporated with nylon-6 nanofibers were carried out. Current-voltage (I-V) characteristics revealed that the current was enhanced for the sample with 300 nm TiO 2 nanoparticles compared to that with 20-nm TiO 2 nanoparticles. © 2012 The Korean Physical Society.


Nirmala R.,Chonbuk National University | Kim H.Y.,Chonbuk National University | Yi C.,Hubei Provincial Research Institute of Environmental Science | Barakat N.A.M.,Chonbuk National University | And 2 more authors.
International Journal of Hydrogen Energy | Year: 2012

In this study, Ni-doped titanium dioxide (TiO 2) electrospun nanofibers are introduced as novel material for dehydrogenation of ammonia borane (AB) complex. Hydrolysis experiments with introduced catalytic nanofibers are prevailed to rapidly release hydrogen from AB complex. Typically, Ni nanoparticles (NPs) behave as a catalyst, meanwhile the incorporation of nickel NPs lead to decrease in the electrons/holes recombination rate in TiO 2 which resulted in the increase of active ions in the solution to a rapid evolution of hydrogen gas at room temperature. The utilized physiochemical analyses indicate that the introduced Ni-doped TiO 2 nanofibers have a smooth surface and uniform diameters along their lengths. Under sunlight irradiation, the hydrogen production rate in case of utilizing Ni-doped TiO 2 nanofibers is rapidly increased compared to the pristine TiO 2 nanofibers, the maximum hydrogen equivalent in case of the doped nanofibers is 2.6 while the pristine one is 1.4. Both formulations exhibit almost equal low activity in daylight as the observed hydrogen equivalent is 0.4. Overall, this study proposes cheap, stable and effective material for AB dehydrogenation at room temperature. Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Peng T.,CAS Research Center for Eco Environmental Sciences | Peng T.,Hubei Provincial Research Institute of Environmental Science | Tu J.,CAS Research Center for Eco Environmental Sciences | Hu C.,CAS Research Center for Eco Environmental Sciences | And 2 more authors.
Journal of Chemical Technology and Biotechnology | Year: 2014

BACKGROUND: The plasmon-induced photocatalytic reduction of bromate (BrO3 -) was investigated in visible-light irradiated Au-Ag-AgI/Al2O3 suspension. The BrO3 - reduction process was studied in detail. RESULTS: The catalyst was found to be highly effective for the reduction of BrO3 - from pH 3 to 6. An enhancement of the electrical interaction between BrO3 - and the positively charged surface of the photocatalyst favored adsorption and reduction of BrO3 -. Organic compounds such as ethanol could react as sacrificial electron donors with excited holes (h+) on the metal nanoparticles (NPs) to accelerate electron transfer, inhibiting the release of metal ions and the recombination of h+ and electrons, hence promoting photocatalytic reduction of BrO3 -. Electron quenching and cyclic voltammetry studies under a variety of experimental conditions verified that BrO3 - trapped conduction band electrons of AgI from the excited metal NPs were reduced, competing with O2. CONCLUSION: The photocatalyst Au-Ag-AgI/Al2O3 exhibited particularly good reduction of BrO3 - under visible-light irradiation. The BrO3 - reduction was highly favored at acidic condition due to the greater adsorption of BrO3 - onto the catalyst. This finding indicates that this visible-light-driven catalyst could be applied to the reduction of some oxidative pollutants or even simultaneous removal of both oxidative and reductive pollutants. © 2013 Society of Chemical Industry.

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