Valorization of urban biosolids for sustainable hydrogen production through steam gasification over silicon oxide sand

¹ Mohammed V University, Faculty of Sciences, Department of Chemistry, Laboratory of Materials, Nanotechnologies and Environment, Rabat, Morocco
² INSA Rouen Normandie, University of Rouen Normandie, UNIROUEN, Laboratoire de Sécurité des Procédés Chimiques LSPC EA-4704, 76000 Rouen, France
³ ENSAM, Laboratory of Spectroscopy, Molecular Modelling, Materials, Nanomaterials, Water and Environment, Environmental Materials Team, Rabat, Morocco
⁴ Mohammed V University, Faculty of Sciences, Department of Chemistry, Laboratory of Spectroscopy, Molecular Modeling, Materials, Nanomaterials, Water and Environment, Rabat, Morocco

^* Corresponding author: youssef.boutarba@um5r.ac.ma

Abstract

The present work addresses sustainable development and energy goals by investigating the valorization of urban biosolids into clean Hydrogen (H2) through steam gasification in a fluidized bed reactor at 850°C. From a materials science standpoint, the study employs silicon oxide (SiO₂) as a low-cost and inert bed material. This latter was selected thanks to its high thermal stability and ability to ensure optimal fluidization, which is crucial for reactor hydrodynamics. The generated syngas analysis revealed high yield of H₂ and CO (22.05 and 372.53 g/Kg of raw urban biosolids respectively), confirming significant organic matter conversion. The residual hydrocarbons yield was found relatively high (up to 20 vol%), due to incomplete steam reforming, notwithstanding, steam effectively cracked heavy components into lighter, usable gases. The elevated CO₂ generation provides also a clear opportunity for Carbon Capture and Reutilization for miscellaneous application. This research demonstrates the technical and material feasibility of a novel waste-to-energy solution, offering a direct, interdisciplinary contribution to energy, sustainable development, and materials science.