Preparation of Ce-MnOx Composite Oxides via Coprecipitation and Their Catalytic Performance for CO Oxidation.

Ce-MnOx composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60-140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation performance of CO was investigated using X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), H2 temperature programmed reduction (H2-TPR), CO-temperature programmed desorption (CO-TPD), and in situ infrared spectra. The experimental results reveal that under the same test conditions, the CO conversion rate of pure Mn3O4 reaches 95.4% at 170 °C. Additionally, at 140 °C, the Ce-MnOx series composite oxide catalyst converts CO at a rate of over 96%, outperforming single-phase Mn3O4 in terms of catalytic performance. With the decrement in Ce content, the performance of Ce-MnOx series composite oxide catalysts first increase and then decrease. The Ce MnOx catalyst behaves best when Ce:Mn = 1:1, with a CO conversion rate of 99.96% at 140 °C and 91.98% at 100 °C.

The toxic activities of Arisaema erubescens and Nerium indicum mixed with Streptomycete against snails.

The comparative molluscicidal activities of Arisaema erubescens tuber extracts and Nerium indicum leaf extracts mixed with Streptomycete violacerruber dilution (SD) against the snail Oncomlania hupensis and the responses of the isozymes, esterase (EST) and superoxide dismutase (SOD) to the A. erubescens extracts and the mixtures were investigated. The molluscicidal activity of A. erubescens water extracts mixed with S. violacerruber dilution was 4-5 times higher than a single A. erubescens or S. violacerruber dilution after 24-h exposure, and is also higher than that of N. indicum leaf water extracts mixed with S. violacerruber dilution. At the end of exposure to the N-butanol extracts of A. erubescens tubers (NEAT), the EST activity in snail liver decreased and some enzyme bands (EST 1 and EST 3 in exposure to NEAT) disappeared but the activities of SOD 1 increased. The effect was more obvious in mixture treatment than in single NEAT or SD treatment. The results indicated that molluscicidal activities of plant and microorganism could be more effective than single plant. The decline of the detoxic ability in snail liver cells could be the reason of the snail dying.