Hydrogen production by hydrolysis of aluminum

• NaOH promotes hydrogen evolution and the bubbles prevent Al(OH)3 precipitation.
• Pretreatments affect the area of exposed matrix and the size of aluminum particles.
• The used cans with different brands exhibit good performance of hydrogen generation.
• The Al scrap dealt with calcination method generates more hydrogen.
• The Al scrap treated with mechanical method releases hydrogen most quickly.

Hydrogen production using the hydrolysis of aluminum is studied. The used aluminum cans are pretreated with different methods, such as mechanical rubbing, soaking in concentrated sulfuric acid and heat treatment, and characterized with XRD and SEM techniques. The results show that higher alkali concentration is benefit for the hydrolysis of aluminum, because the generated hydrogen bubbles on the aluminum materials prevent the precipitations from attaching on the reaction zones. Gibbsite and bayerite are present on the Al scraps surface. Pretreated Al scraps generate hydrogen much more quickly than sodium borohydride and un-pretreated Al scrap. The Al scrap pretreated with mechanical method releases hydrogen faster, while the Al scrap dealt with calcination method generates more hydrogen than other Al scraps. The area of exposed aluminum matrix and the sizes of aluminum particles are different with various pretreatment methods.

The effects of different pretreatment of the used cans, such as mechanical rubbing, dissolution extraction and heat treatment, on the hydrogen evolution of Al scraps are investigated. It is shown that pretreated Al scraps generate hydrogen much more quickly than sodium borohydride and un-pretreated Al scrap. Different pretreatment methods affect the area of exposed aluminum and the sizes of aluminum particles. The Al scrap pretreated with mechanical method releases hydrogen most quickly, while the Al scrap dealt with calcination method generates more hydrogen than other Al scraps.Figure optionsDownload as PowerPoint slide