Abstract

PUENTE SILLER, Damaris Margarita et al. Electrochemical generation of hydrogen using industrial ammonia water and recycled graphite electrodes. Rev. cienc. tecnol. [online]. 2024, vol.7, n.4, e304.  Epub Mar 30, 2025. ISSN 2594-1925.  https://doi.org/10.37636/recit.v7n4e304.

The pursuit of fuels that do not emit greenhouse gases has made the use of hydrogen in the steel industry increasingly necessary. This study represents an ecological commitment, wherein both researchers and the company aim to generate hydrogen for use in the steel production process. An acrylic cell, ammoniacal solution, and power source were used in the experimental setup, which consists of three parts: first, the evaluation of hydrogen generation by varying the applied voltage and electrolysis duration; second, the replacement of ammoniacal water with a synthetic ammonia solution to understand system behaviour and minimize the effects of solution components unrelated to ammonia; and third, the substitution of graphite electrodes with steel electrodes to assess their impact on the electrolytic process. Hydrogen quantification was carried out indirectly using a Venturi tube, which captured the generated gases, and through a copper sulphate solution (producing precipitates) to stoichiometrically determine the mass of produced hydrogen. The results of evaluating time, current density, and solution concentration defined an optimal electrolysis time of 30 minutes, a current density of 100 A/m², and indicated that the initial ammonia concentration in the solutions influences the results. The best results corresponded to 1.130 g of H₂ in a solution with an initial concentration of 2.6 g/l NH₃. In conclusion, this study determined optimal processing conditions, established the effect of initial ammonia concentration on the electrochemical generation of hydrogen, observed a decrease in ammonia concentration across all solutions, and successfully calculated the generated gas mass through indirect hydrogen quantification.

Keywords : Electrolysis; Hydrogen; Ammonia solutions.

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