Construction of ternary CuO/CuFe2O4/g-C3N4 composite and its enhanced photocatalytic degradation of tetracycline hydrochloride with persulfate under simulated sunlight.

In this study, a graphitic carbon nitride (g-C3N4) based ternary catalyst CuO/CuFe2O4/g-C3N4 (CCCN) is successfully prepared thorough calcination method. After confirming the structure and composition of CCCN, the as-synthesized composites are utilized to activate persulfate (PS) for the degradation of organic contaminant. While using tetracycline hydrochloride (TC) as pollutant surrogate, the effects of initial pH, PS and catalyst concentration on the degradation rate are systematically studied. Under the optimized reaction condition, CCCN/PS is able to give 99% degradation extent and 74% chemical oxygen demand removal in assistance of simulated solar light, both of which are apparently greater than that of either CuO/CuFe2O4 and pristine g-C3N4. The great improvement in degradation can be assignable to the effective separation of photoinduced carriers thanks to the integration between CuO/CuFe2O4 and g-C3N4, as well as the increased reaction sites given by the g-C3N4 substrate. Moreover, the scavenging trials imply that the major oxidative matters involved in the decomposition are hydroxyl radicals (•OH), superoxide radicals (•O2-) and photo-induced holes (h+).

MOF-Directed Construction of Cu-Carbon and Cu@N-Doped Carbon as Superior Supports of Metal Nanoparticles toward Efficient Hydrogen Generation.

The modulation of electronic behavior of metal-based catalysts is vital to optimize their catalytic performance. Herein, metal-organic frameworks (MOFs) are pyrolyzed to afford a series of different-structured Cu-carbon composites and Cu@N-doped carbon composites. Then a series of CO-resistant catalysts, namely, Co or Ni nanoparticles supported by the Cu-based composites, are synthesized for the hydrogen generation from aqueous NH3BH3. Their catalytic activities are boosted under light irradiation and regulated by the compositions and the fine structures of doped N species with pyridine, pyrrole, and graphitic configurations in the composite supports. Particularly, the optimized Co-based catalyst with the highest graphitic N content exhibits a high activity, achieving a total turnover frequency (TOF) value of 210 min-1, which is higher than all the reported unprecious catalysts. Further investigations verify that the light-driven synergistic electron effect of plasmonic Cu-based composites and Co nanoparticles accounts for the high-performance hydrogen generation.

Nosocomial tuberculosis transmission from 2006 to 2018 in Beijing Chest Hospital, China.

INTRODUCTION: Strong evidence is lacking to support effectiveness of currently implemented tuberculosis infection prevention control (TB-IPC) measures for preventing nosocomial tuberculosis (TB) transmission. This 13-year analysis is the longest follow-up investigation to date to identify risk factors underlying nosocomial TB transmission. METHODS: We monitored all staff of Beijing Chest Hospital each year from 2006 to 2018. Age, gender, duration, department, education, income, respirator, ultraviolet, and ventilation were chosen as variables. Univariate cox regression, correlation analysis, and multivariate cox regression were analyzed sequentially. RESULTS: Using multivariable cox regression analysis, variables of income, ultraviolet germicidal irradiation (UVGI), natural ventilation and mechanical ventilation conferred significant protective effects, with odds ratios of 0.499, 0.058, 0.003, and 0.015, respectively (P < 0.05). Medical N95 respirator conferred an excellent protective effect, with an associated TB infection rate of 0%. Notably, inadequately maintained mechanical ventilation systems were less protective than natural ventilation systems. CONCLUSION: UVGI, adequate ventilation, and use of medical N95 respirator may be risk factors of nosocomial TB transmission.

Electrochemical Properties of Electrospun Ni Doped Carbon Nanofibers.

The materials of Ni nanoparticles/carbon nanofibers (Ni NPs/CNFs) and carbon nanofibers (CNFs) were prepared by electrospinning the Ni doped precursor solutions. The Ni doped nanofibers with the diameter of 200-300 nm possess the uniform morphology and smooth surface. These nanofibers were carbonized at 600 degrees C for 2 h. The Ni NPs/CNFs composite was characterized with SEM (scanning electro microscope), XRD (X-ray diffraction) and FT-IR (Infrared spectroscopy). The Ni NPs/CNFs electrode was investigated through the cyclic voltammetry measurement. The average specific capacity was calculated to be 113 F x g(-1) at the scan rate of 2 mV x s(-1). The high specific capacity was larger than the CNFs owing to the Ni NPs. The specific capacity retention also maintains 72% after 5 cycles, suggesting that the electrode possess good reversibility. The Ni NPs/CNFs composite material with excellent electrochemical properties will be a promising material which can be used for energy storage.