Pd/La 0.8 Ce 0.2 MnO 3 catalysts supported on various kinds of zeolites (ZSM-5, MOR, NaY, and b) were prepared by incipient wetness impregnation method, and these catalysts were investigated by Brunauer-Emmett-Teller, X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy, and H 2 -temperature programmed reduction. The catalytic activity of these catalysts was tested for toluene catalytic combustion, and the support effect was investigated. It was found that the ZSM-5 is the best support than other zeolites (MOR, NaY, and b), because it processes the higher acidity and reducibility, although its specific surface area is smaller than the others. Result of XRD indicates that Pd species are highly dispersed on the surface of the catalysts, and the doping of Pd could greatly improve the activity of La 0.8 Ce 0.2 MnO 3 , the light-off and complete conversion temperature of Pd/La 0.8 Ce 0.2 MnO 3 / ZSM-5 are only 112 and 2278C, respectively. V C 2017 American Institute of Chemical Engineers Environ Prog, 37: 215-220, 2018
Rational design and construction of Z-scheme photocatalysts have received much attention in the fields of organic pollutants degradation and H2 evolution because of their potentials to solve the current environmental and energy crises. Herein, a novel nitrogen defects-rich 0D/2D [Formula: see text]-Fe2O3/g-C3N4 Z-scheme photocatalyst was fabricated via a one-pot co-pyrolysis method. Quantum-sized [Formula: see text]-Fe2O3 dots with a diameter of approximately 5[Formula: see text]nm were uniformly distributed on the surface of 2D g-C3N4. Besides, the prepared 0D/2D [Formula: see text]-Fe2O3/g-C3N4 composites exhibited excellent RhB degradation ability and simultaneous H2 evolution efficiency. In comparison with 2D g-C3N4, the RhB degradation rate and H2 evolution catalyzed by 0D/2D [Formula: see text]-Fe2O3/g-C3N4 were enhanced 3.9 and 1.8 times, respectively. The improved photoredox activity was predominantly attributed to the formation of the nitrogen defects and a Z-scheme heterojunction. This study provides novel insights into the design and fabrication of nitrogen defects-rich g-C3N4-based Z-scheme photocatalysts for the simultaneous environmental purification and H2 evolution.
Understanding the influence of nutrient levels on biofouling control is an important requirement for management strategies in a recirculating cooling water system. Nutrient limitation may be one way to control biofouling development without increasing biocide dosing. Therefore, this study was carried out to investigate the effects of nutrient levels on biofouling characteristics and to identify the preponderant bacteria in the batch tests with a simulated cooling water system. The biofouling characteristics were assessed by varying the biofoulant mass and the bacteria respiratory activity, which was estimated by measuring oxygen uptake rates. According to the results obtained in nutrient factor experiments, the biofouling could be better controlled at carbon, nitrogen and phosphorus concentrations of 30 mg N/L, 8 mg N/L and 1.0 mg P/L, respectively. Increasing carbon concentrations shortened the biofouling initial growth period and resulted in higher biofoulant mass. The preponderant bacteria strains involved in biofouling under two culture conditions were identified by applying both physiological and biochemical tests and further molecular biology techniques with phylogenetic affiliation analysis. Enterobacter (family Enterobacteriaceae), Staphylococcus (family Micrococcaceae), Bacillus (family Bacillaceae), Proteus (family Enterobacteriaceae), Neisseria (family Neisseriaceae) and Pseudomonas (family Pseudomonadaceae) were dominant in the conditions of lower carbon concentration (30 mg/L). Enterobacter are autotrophs, but the other five bacteria are all heterotrophs. In the conditions of higher carbon concentration (70 mg/L), Klebsiella (family Enterobacteriaceae), Enterobacter and Microbacterium (family Microbacteriaceae) were dominant; Enterobacter and Microbacterium are heterotrophs.
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