Enhancement of Hydrogen Production by Aluminum Corrosion Using HCl and Promoted by NaOH Solution

Abstract

Utility of aluminum series AA5XXX, 6XXX, and 7XXX emerges. However, scrap waste remains unrecycled and ends up in municipal solid waste landfills. It is known that aluminum related reactions maybe problematic for landfill operations by generating undesired heat, liquid leachate, and gases. Aluminum produces hydrogen as it reacts readily with water at room temperature to form aluminum hydroxide. In most cases, it may not conventionally take place due to the presence of aluminum oxide that naturally coats the materials preventing it from direct contact with water.The layer can be detached using an acidic solution, such as HCl. HCl solution is prepared to remove the Al2O3 protective layer under acidic conditions. NaOH solution is added into the water to promote hydrogen production afterward. Aluminum scrap with a constant mass of 0.5 grams added to 250 ml of NaOH solution in which the concentrations varied by 0.5 M, 1.5 M, and 3 M. As the pretreatment, it was soaked into 1 M, 2 M, and 3 M HCl solutions for 1 minute. The measurement result shows that aluminum treated with 3 M HCl and reacted in 3 M NaOH yielded 532 ml of hydrogen gas. However, hydrogen concentration in total produced gas volume decreases as NaOH and HCl increase. This result is also confirmed using FTIR spectroscopy which shows the reaction with less NaOH concentration yielded more bayerite form.