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Hu X.,Inner Mongolia Normal University | Zhang D.,Inner Mongolia Normal University | Zhao S.,Inner Mongolia Normal University | Zhao S.,Key Laboratory of Physics and Chemistry of Functional Materials | And 2 more authors.
MATEC Web of Conferences | Year: 2016

Highly water-dispersible and very small TiO2 nanoparticles (∼3 nm anatase) with large specific surface area have been synthesized by hydrolysis and hydrothermal reactions of titanium butoxide and used for the removal of three azo dyes (Congo red, orange II, and methyl orange) with different molecular structure from simulated wastewaters. The synthesized TiO2 nanoparticles are well dispersed in water with large specific surface area up to 417 m2 g-1. Adsorption experiments demonstrated that the water-dispersible TiO2 nanoparticles possess excellent adsorption capacities for Congo red, orange II, and methyl orange, which could be attributed to their good water-dispersibility and large specific surface area. © The Authors, published by EDP Sciences, 2016.


Gao W.,Inner Mongolia Normal University | Zhao S.,Inner Mongolia Normal University | Zhao S.,Key Laboratory of Physics and Chemistry of Functional Materials | Wu H.,Inner Mongolia Normal University | And 3 more authors.
Applied Clay Science | Year: 2016

Coal-bearing kaolinite was directly treated with concentrated sulfuric acid to improve its surface properties and adsorption ability. Acid treatment was carried out at various temperatures (i.e., room temperature -250 °C), by varying time of treatment from 0 to 120 min. The samples were characterized by X-ray diffraction analysis, elemental analyses, thermogravimetric analysis, N2 adsorption-desorption analysis, high-resolution transmission electron microscopy, and Fourier transformed infrared spectroscopy. The activation of kaolinite strongly depended on the acid treatment including treatment temperature and time. Acid treatment at room temperature did not cause significant alterations either in the chemical composition or in the structure of the kaolinite. On the other hand, treatment at increased temperature led to the removal of Al3+ ions and thus increased the porosity of the material. The surface area and the pore volume of original kaolinite could be greatly changed as a function of treatment temperature and time of treatment, and they increased from 13.6 to 257.8 m2 g-1 and from 0.045 to 0.25 cm3 g-1, respectively, when the kaolinite was treated at 200 °C for 30 min. The adsorption ability of acid-activated kaolinite (AAK) was investigated using methylene blue (MB) as a typical pollutant. For this, the effects of contact time, pH, initial MB concentration and temperature were studied in batch mode. Gibb's free energy (δG0), entropy (δS0) and enthalpy (δH0) changes for MB adsorption were calculated. Owing to its high surface area, the AAK showed higher removal efficiency for MB than for original kaolinite, with a maximum adsorption capacity of 101.5 mg g-1. © 2016 Elsevier B.V.


Gao Z.,Inner Mongolia Normal University | Li X.,Inner Mongolia Normal University | Wu H.,Inner Mongolia Normal University | Zhao S.,Inner Mongolia Normal University | And 4 more authors.
Microporous and Mesoporous Materials | Year: 2015

Maghemite (γ-Fe2O3) nanoparticles were synthesized onto the surface of acid-activated kaolin (AAK), prepared by calcination and acid activation of a coal bearing kaolin, by immobilizing an Fe-urea complex ([Fe(NH2CONH2)6](NO3)3) and subsequent calcination. The obtained samples were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), vibrating sample magnetic measurements, and transmission electron microscopy (TEM). The results confirm the formation of ferromagnetic γ-Fe2O3 nanoparticles, approximately 18 nm in size, onto the AAK surface. The obtained γ-Fe2O3/AAK nanocomposite has a high Brunauer-Emmett-Teller (BET) surface area of 99.4 m2/g and possesses ferromagnetic characteristics with a maximum magnetization of 26.5 emu/g. The adsorption ability of γ-Fe2O3/AAK nanocomposite was investigated using methylene blue (MB) as a typical pollutant. Owing to its high surface area, the γ-Fe2O3/AAK nanocomposite showed higher removal efficiency for MB than for parent kaolin, with a maximum adsorption capacity of 50.2 mg/g. The adsorption kinetics of MB fit well with the pseudo-second-order kinetic model, and the equilibrium data can be well described by the Langmuir adsorption model. © 2014 Elsevier Inc.


Wang S.,CAS Beijing National Laboratory for Molecular | Wang S.,Inner Mongolia Normal University | Wang S.,Key Laboratory of Physics and Chemistry of Functional Materials | Zhang W.,CAS Beijing National Laboratory for Molecular | And 5 more authors.
Journal of Organometallic Chemistry | Year: 2015

Propyl substituted 4-arylimino-1,2,3-trihydroacridylnickel dihalide complexes were designed and prepared by metal-induced template reaction with NiCl2·6H2O or (DME)NiBr2. They were characterized by infrared spectroscopy and elemental analysis. Single crystal X-ray crystallography of representative complex Ni3 revealed a distorted trigonal bipyramidal geometry around nickel. The catalytic activities of the title nickel complexes were negatively affected by propyl substituent on their backbone when comparing with the results by unsubstituted ones. With the activation of diethylaluminium chloride, all nickel complexes exhibited moderate activity (up to 5.10×105gmol-1(Ni)h-1) for ethylene oligomerization and oligomeric products ranged from C4 to C16. © 2015 Elsevier B.V.


Hai Y.,Inner Mongolia Normal University | Li X.,Inner Mongolia Normal University | Wu H.,Inner Mongolia Normal University | Zhao S.,Inner Mongolia Normal University | And 4 more authors.
Applied Clay Science | Year: 2015

Acid-activated kaolinite (AAK), prepared by the calcination and acid activation of coal-bearing kaolinite, was modified with TiO2 to improve its ability to adsorb and hence remove azo dyes. X-ray diffraction analysis, N2 adsorption-desorption analysis, and high-resolution transmission electron microscopy were used to characterize the synthesized samples and confirm the formation of anatase TiO2 nanoparticles on the surface of the AAK bulk. The obtained AAK/TiO2 nanocomposites retained the porous structure of AAK and exhibited a Brunauer-Emmett-Teller surface area as high as 358.6m2g-1. The dye-adsorption abilities of the synthesized samples were investigated using anionic dyes such as Congo red (CR), Direct Fast Scarlet 4BS (4BS), and weak acid dark blue 5R (5R), which are common pollutants. The dye-removal efficiency increased from 25 to 95%, 11 to 90%, and 13 to 97% for CR, 4BS, and 5R, respectively, under the same adsorption conditions, when the TiO2 content in the nanocomposite was increased from 0 to 30mass%, indicating the anionic-dye-removal ability of AAK improved significantly after modification with TiO2. The dye-adsorption kinetics fit well the pseudo-second-order rate equation, while the adsorption isotherm data could best be described by the Langmuir adsorption model. © 2015 Elsevier B.V.

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