Influence of drying and calcination temperatures for Ce-Cu-Al trimetallic composite catalyst on simultaneous removal H2S and PH3: Experimental and DFT studies

This work explored the influences of the drying and calcination temperatures on a Ce-Cu-Al trimetallic composite catalyst for the simultaneous removal of H₂S and PH₃. The effects of both temperatures on the structural features and activity were examined. The density functional theory method was used to calculate adsorption energies and further analyze their adsorption behavior on different slabs. Experiments revealed suitable drying and calcination temperatures to be 60 and 500°C, respectively. The capacity reached 323.8 and 288.1 mg/g. Adjusting drying temperature to 60°C is more inclined to form larger and structured grains of CuO. Rising calcinating temperature to 500°C could increase the grain size and redox capacity of CuO to promote performance. Higher temperatures would destroy the surface structure and lead to a crystal phase transformation, which was that the CuO and Al₂O₃ were gradually recombined into CuAl₂O₄ with a spinel structure. The exposed crystal planes of surficial CuO and CuAl₂O₄ were determined according to characterization results. Calculation results showed that, compared with CuO (111), H₂S and PH₃ have weaker adsorption strength on CuAl₂O₄ (100) which is not conducive to their adsorption and removal.     

THE HUDSON BAY AIR MASS TYPE–SOME CLIMATOLOGICAL IMPLICATIONS

A substantial percentage of days with below normal temperatures in central Illinois during May and June (1956-1965) appear to be associated with polar air masses which traverse the Hudson Bay area before entering the Midwest. January departures, in contrast, are related to polar air masses that enter the United States near the Mackenzie River in western Canada. The general influences of the Hudson Bay area on climate are discussed.     

Combustion characteristics of pure aluminum and aluminum alloys powders

In this work, the explosion and combustion characteristics of aluminum and some aluminum alloys AlSi7Mg0.6, AlSi10Mg, AlMg5 under powders conditioning were studied. The idea was to compare the combustion of pure aluminum and aluminum alloys. The Minimum Ignition Energy (MIE) and explosion severity ΔP_max and (dP/dt)_max which represents the dust explosion parameters were measured for all powders using Hartman tube and 20 L spherical bomb. The particles temperature and flame temperature were determined by using IR pyrometer and spectroscopy respectively. The results showed that pure aluminum was more sensitive and severe than its alloys. MIE were: 4 mJ for pure aluminum, 13–23 mJ for aluminum alloys. For severity parameters, the overpressure ΔP_max were around 7–8 bars with maximum rate of pressure rise at 1170 bar/s for aluminum and 5–7 bars with 250–360 bar/s for alloys. However, it has been observed that flame temperatures were similar for aluminum and alloys and vary around 2800–3300 K as a function of concentration.