SELMANI AbderrahmaneKERBOUA Kaouther (Encadrant)2025-11-182025-11-182025http://dspace.ensti-annaba.dz:4000/handle/123456789/931Reverse osmosis (RO) is a widely adopted desalination method, but its large-scale use raises environmental concerns due to the discharge of concentrated brine into marine ecosystems, reducing dissolved oxygen and harming aquatic biodiversity. This study proposes a valorization pathway using asymmetric zero-gap electrolysis to convert brine into value-added products such as hydrogen (H₂), sodium hydroxide (NaOH), and hypochlorite ions (ClO⁻). The system employs a Nafion Perl 500 diaphragm with low-cost electrodes namely carbon foam (anode) and nickel foam (cathode). A parametric study exploring supply potential, temperature, feed flow rate, and water type effect identified optimal performance using RO water as the electrolyte at 2.3 2.5 V, achieving over 96% Faradaic efficiency. Anode activation using a nickel-based catalyst reduced internal resistance by 80% at 2.3 V and 25% at 6 V, enhancing H₂ and OH⁻ generation kinetics. Synthetic brine provided more stable and efficient results compared to industrial brine, which exhibited greater complexity. Photovoltaic (PV) integration demonstrated the potential for decentralized, off-grid green hydrogen and chemical co-production. However, further investigation is required to elucidate the coupled effects of ion transport, reaction kinetics, and gas evolution in zero-gap architectures.enThesis