Summary
Currently, recycling waste aluminum materials are of significant importance for reducing environmental pollution and improving economic efficiency. In this paper, aluminum (Al) powder prepared from waste Al cans with magnetic grinding method was directly used in hydrolysis for hydrogen generation. The prepared waste Al cans powder was characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET), atomic absorption spectrophotometer (AAS), and density analysis. The results showed that grinding time, NaOH concentration, and reaction temperature affected the hydrolysis rate and hydrogen yield markedly; 1 g of Al cans powder with grinding time of 40 minutes could produce 1296‐mL hydrogen within 6 minutes under the optimal reaction conditions. The reaction kinetics study demonstrated that the hydrolysis of Al cans powder is kinetically controlled while hydrolysis of Al cans flakes is diffusively controlled. The hydrolysis mechanism was also predicted based on the experimental results and kinetic study. The generation of hydrogen from hydrolysis of waste Al cans powder with low‐concentrated alkaline solution is a promising way to diminish environmental pollution and instrument corrosion.
Dedicated to Prof. Dr. A. SEEUER on the occasion of his 60th birthday Very often a relationship is observed between activation energies, Q, of diffusion and the corresponding prefactors, Do. Contrary to the Zener-Wert relation, where activation energy and prefactor of different species migrating in the same matrix are compared, one species diffusing in a matrix with different defects or slightly varying composition is considered. It is shown that a linear relationship between In Do and Q very often exists due to the special form of the Arrhenius equation. The slope of the corrosponding graph is close to l/kT,, where T, is the average temperature of the range covered by the experiments. Experimental results are compiled and compared with this prediction.Schr oft wird eine Beziehung zwischen der Aktivierungsenergie Q der Diffusion und dem dazugehorigen Vorfaktor Do beobachtet. I m Gegensatz zur Zener-Wert-Beziehung, wo Q und Do von verschiedenen, diffundierenden Spezies in derselben Matrix verglichen werden, wird eine diffundierende Atomsorte in einer Matrix mit verschiedenen Gitterfehlern oder mit leicht variabler Zusammensetzung betrachtet. Es wird gezeigt, daB eine lineare Beziehung zwischen In Do und Q sehr oft bestehen kann als Folge der besonderen Form der Arrhenius-Gleichung. Die Steigung der dazugehorigen Geraden betragt l/kT,, wobei T , den Mittelwert der MeDtemperaturen darstellt. Verschiedene experimentelle Ergebnisse werden zusammengestellt und mit dieser Vorhersage verglichen.
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