Process optimization study of hydrogen evolution from aluminium dross in acidic medium

The sustainable management of aluminium dross presents both an environmental challenge and an opportunity for resource recovery. The present study aims to investigate the feasibility of hydrogen generation from aluminium dross through hydrochloric acid leaching while optimizing the operating parameters for efficient hydrogen recovery. In this study, aluminium dross is recycled as a feedstock for hydrogen generation via controlled reactions with hydrochloric acid. Key process parameters such as acid concentration (0.25–1 M), solid-to-liquid ratio (3.125–12.5) and temperature (40–60 °C) are systematically varied. Analysis of variance (ANOVA) combined with response surface methodology (RSM) highlights acid molarity and temperature as dominant factors influencing hydrogen yield with statistical models confirming reproducibility and reliable parameter correlations. Results show that higher HCl concentrations and elevated temperatures enhance hydrogen generation up to an optimal point, beyond which gas volume decreases, highlighting the critical interplay among parameters. Response surface optimization identified an optimum operating region at 0.75 M HCl, a solid-to-liquid ratio of 3.125 g/L and 55–60 °C, where hydrogen yields approached 350 mL. Optimized solid-to-liquid ratios further minimize acid consumption to ensure resource efficiency. Therefore, this work pioneers acid-mediated hydrogen generation from aluminium dross, breaking the long-standing alkaline paradigm and opening new avenues for sustainable energy research and circular economy integration. The proposed approach offers a sustainable pathway for simultaneous aluminium dross valorization and clean hydrogen production with potential applications in waste-to-energy and industrial resource recovery.