Cancer cells are more susceptible to H2O2 induced cell death than normal cells. H2O2-activatable and O2-evolving nanoparticles could be used as photodynamic therapy agents in hypoxic environments. In this report, a photo-active Mn(II) complex of boradiazaindacene derivatives (Mn1) was used as a dioxygen generator under irradiation with LED light in water. Moreover, the in vitro biological evaluation for Mn1 and its loaded graphene oxide (herein called Mn1@GO) on HepG-2 cells in normal and hypoxic conditions has been performed. In particular, Mn1@GO can react with H2O2 resulting active anticancer species, which show high inhibition on both HepG-2 cells and CoCl2-treated HepG-2 cells (hypoxic cancer cells). The mechanism of LED light enhanced anticancer activity for Mn1@GO on HepG-2 cells was discussed. Our results show that Mn(II) complexes of boradiazaindacene (BODIPY) derivatives loaded GO can be both LED light and H2O2-activated anticancer agents in hypoxic environments.
The separation performance of Hg2+ in desulfurization wastewater by a graphene oxide (GO) polyethersulfone (PES) membrane was investigated in this article. The GO membrane was assembled on a PES microfiltration membrane by the vacuum filtration method and characterized by scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The characterization results showed that the GO-PES membrane used in this experiment was compactly assembled and highly oxidized and contained a large number of oxygen-containing functional groups. Besides, the Hg2+ removal performances of the GO-PES membrane under different conditions, such as GO loading, initial Hg2+ concentration, temperature, pH value, and ion component of wastewater, were investigated. The results indicated that the Hg2+ retention rate of 80.33% and the flux of 26.3 L·m–2·h–1 could be achieved under typical conditions. A higher GO loading, lower initial Hg2+ concentration, and higher wastewater temperature was beneficial for the improvement of Hg2+ removal efficiency; the optimum separation performance of Hg2+ could be obtained at a wastewater pH value of 9. The influence of Ca2+, Mg2+, and K+ on Hg2+ removal was unobvious, whereas Na+ had an inhibitory effect. Furthermore, the recyclability of the GO-PES membrane was also investigated. The results showed that after three circulations, the retention rate of 60.63% could still be obtained.
The MnOx-CeO2/t-ZrO2 catalyst was prepared by impregnation with nano t-ZrO2 as the support. The influence of active component and reaction temperature on denitration performance of catalyst was investigated. The results showed that denitration efficiency improved as active component increased and reaction temperature rose. The denitration efficiency of 2.5% MnOx-CeO2/t-ZrO2 at 100°C was 68.1% while 15% MnOx-CeO2/t-ZrO2 was 97.4%. The results of XRD, BET and H2-TPR showed that surface structure of loaded catalyst was good for oxidation-reduction and denigration. NH3-TPD test demonstrated that NH3 was mainly adsorbed at Lewis acid sites on the surface of catalysts and became coordination NH3. Intermediate product NH2NO generated from reactions between coordination NH3 and NO which finally changed into N2 and H2O.NOx are potentially harmful to humans as a kind of primary pollutants. And NOx are the main cause of many environment problems, such as acid rain, surface ozone pollution and Particulate Matter 2.5[1]. The emission of NOx was 2337.8 tons in China in 2011 and that was 2275.4 tons[2]. The environmental situation is grim although the emission of NOx had begun decreasing. Emission standard of air pollutants for thermal power plants which came into effect on January 1, 2012 require the emission concentration of NOx under 100mg·m-3. The task is arduous.Selective catalytic reduction (SCR) of NOx with NH3 is the most promising method to remove NOx and catalysts with high activity play a decisive part in low temperature SCR technology. Many researches about metal oxide as SCR catalyst support have been reported recently, such as TiO2[3], Al2O3[4], activated carbon[5] and molecular sieve[6]. Zirconium oxide has attracted considerable attention recently as a catalyst support because of its special characteristics. Takahashi et al.[7] investigated the influence of the various compositions of TiO2 and ZrO2 on the NOx removal ability over a sulfur-treated NSR catalyst and came to a conclusion that ZrO2 support suppressed the solid phase reaction with potassium. Reddy et al.[8, 9] investigated structural characteristics of nanosized ceria-silica, ceria-titania, and ceria-zirconia mixed oxide catalysts and found these mixed oxides exhibit better redox properties than pure CeO2. YAN Zhi-yong et al.[10] reported that the existence of ZrO2 in catalysts can raise its specific area and enhance the dispersion of CeO2 on catalysts which results in high activity of the catalysts. CeO2/TiO2-ZrO2 catalyst has strong tolerance to water vapor and sulfur dioxide.It is well known that ZrO2 exists mainly in three polymorphs with monoclinic (m-ZrO2), tetragonal (t-ZrO2) and (c-ZrO2) cubic structures[11]. ZrO2 polymorphs have different amphoteric character of its surface hydroxyl groups. The crystalline phase of ZrO2 has a great effect on the structure, activity and selectivity of catalysts. Therefore, it is valuable to investigate the effects of nanocrystalline zirconia polymorphs on catalytic properties of MnOx-CeO2/t-ZrO2 Catalysts which few researchers have concerned about. In this study, we try to investigate catalytic activity and microstructure of SCR catalysts with manganese oxide and cerium oxide supported on t-ZrO2.
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