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Preparation of titanium dioxide/attapulgite composites and their application in treating Reactive Black KN-B wastewater

Xie A., Luo S., Chaoyao Y.

Environment Protection Engineering

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2014

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Vol. 40, nr 1

45--56

EN

Removal of water soluble Reactive Black KN-B from aqueous media by means of titanium dioxide/attapulgite (TiO2/ATP) composites was studied in a batch system. The composites were investigated using X-ray diffraction and surface area analysis. Under UV irradiation, the photocatalytic effect of TiO2/ATP composites, pH and reaction temperature on the decolorization rate of Reactive Black KN-B were investigated in detail. The adsorption experiments of TiO2/ATP composites showed that the isotherms and adsorption kinetics were well followed by the Langmuir model and the zero order equation, respectively. The maximum adsorption capacity of TiO2/ATP composites for Reactive Black KN-B calculated by the Langmuir model was 20.08 mg g-1. It can be concluded that the TiO2/ATP composites could be good photocatalysts/adsorbents for treating Reactive Black KN-B wastewater.

2

Investigation of the effect of heat treatment process on characteristics and photocatalytic activity of TiO2-UV100 nanoparticles

Behnajady M. A., Alamdari M. E., Modirshahla N.

Environment Protection Engineering

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2013

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Vol. 39, nr 1

33--46

EN

The effect of heat treatment process on crystallite size, phase content, surface area, band gap energy and photocatalytic activity of TiO 2-UV100 nanoparticles were investigated. Heat treated TiO2 nanoparticles were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) isotherm and diffuse reflectance spectroscopy (DRS) techniques, and its photocatalytic activity was investigated in the removal of C.I. Acid Red 88 (AR88), an anionic monoazo dye of acid class, as a model contaminant. Heat treatment process at 600 °C causes an increase in crystallite size and band gap energy of TiO2-UV100 nanoparticles. The results indicate that the nanoparticles treated for 1 h at 600 °C show the highest photocatalytic activity which can effectively degrade AR88 under UV-irradiation. Increasing heat treatment temperature above 600 °C led to reduction in TiO2 photoactivity which may be related to the anatase-rutile phase transformation, increasing particle size and decreasing specific surface area. Removal efficiency of AR88 with heat treated TiO 2-UV100 nanoparticles was sensitive to the operational parameters such as catalyst dosage, pollutant concentration and light intensity.

3

Catalytic decomposition of toluene over La1-xSr xMnO3/palygorskite synthesized catalysts

Song L., Chen T., Chen D., Chen Y., Xie J., Liu H.

Environment Protection Engineering

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2013

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Vol. 39, nr 3

31--42

EN

Palygorskite (PG) supported La1-xSrxMnO3 catalysts were fabricated by copreripitation. The catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), specific surface area (SSA) and H2 temperature programmed reduction (H 2-TPR). Catalytic activity for VOCs was examined by using toluene as a model compound. The results show that the surface area as well as mechanical strength of catalysts increase substantially after catalysts loaded in PG. XRD patterns show that after calcination at 700 0C, PG as a support in 9% LaMn03/PG and 9% La0.7Sr0.3MnO3/PG was transformed into amorphous phase and the morphology was not destroyed. It was well established that the main reductive components are factually Mn(III) or Mn(IV) oxides in catalysts based on the results of TPR. It was also found that Mn(IV) increases while Mn(III) reduces responding with the increasing amount of Sr. Toluene conversion rate of as-preparedμ% La1-xSr xMnO3/PG increases with the increasing values of x and μ when x=0-0.3 and μ = 3-9%. Toluene can be converted completely at 285 0C by 9% La0.7Sr0.3MnO3/PG catalyst while no significant change was observed after addition on the doping and loading amount of Sr. During a 100 h stability experiment of 9% La 0.7Sr0.3MnO3/PG catalyst, toluene removal was found to be above 95%.