A Simple Study of Hydrogen Production from Recycled Aluminum Microparticles in Alkaline Media

Hydrogen (H2) was produced using recycled aluminum (Al), with particle sizes of 180-250 μm, 300-420 μm and 420-530 μm. A 1.0 M NaOH solution was employed to enhance aluminum dissolution and maximize hydrogen release. During a 30-minute evaluation, peak hydrogen flow rates of approximately 14, 16, and 23 ml/min were obtained, depending on particle size reduction. The H₂ flow behavior for the three size ranges can be divided into two distinct stages: the first corresponds to the initial contact between Al and the NaOH solution, where hydrogen production increases until reaching a maximum; the second stage follows, characterized by a gradual decline in H₂ generation to nearly zero toward the end of the test. These findings indicate that smaller particle sizes promote a more intense hydrogen release during the first stage, due to the higher aluminum dissolution rate, while in the second stage, production decreases significantly as the formation of an oxide layer slows down Al dissolution. For fuel cell applications, particle size and sample mass can thus be adjusted to regulate the desired hydrogen flow rate. XRD and SEM analysis demonstrated the consistency of the equations describing the hydrogen production reaction phenomenon in these aluminum-based equations.