Direct oxidation of wastewater degradation and hydrogen production simultaneously by a reverse electrodialysis system powered by salinity gradient energy

Reverse electrodialysis (RED) utilizes salinity gradient energy for applications such as hydrogen production and wastewater treatment , offering significant research potential due to its environmentally friendly and pollution-free characteristics. This paper presents a comprehensive mathematical model for a RED system designed to simultaneously produce hydrogen and degrade organic pollutants , leveraging the RED reactor for both processes. The discrepancies between theoretical predictions and practical observations are analyzed, with a focus on assessing the system's efficiency in both hydrogen production and pollutant degradation. Additionally, optimization strategies for the system's operational modes are proposed. The results indicate that the system's actual output power is constrained by factors such as the performance of the anion and cation exchange membranes and concentration polarization phenomena, leading to lower output than ideal conditions. Notably, increasing the output current significantly enhances both hydrogen production and degradation efficiency. Furthermore, employing a narrower concentration gradient between concentrated and dilute solutions achieves a remarkable hydrogen production efficiency of 9.02 %, while concurrently reducing the energy consumption for degradation to 0.48 kWh·kg COD −1 . Moreover, by utilizing a serial configuration of RED systems powered by the working solution, the system demonstrates superior energy utilization efficiency, achieving an impressive 6.78 % efficiency. • Simultaneous wastewater degradation and hydrogen production via RED. • Validated model accuracy through comparison with actual plant data. • Actual output power reduced by membrane limits and polarization effects. • Narrow concentration ratio achieves 9.02 % hydrogen conversion efficiency. • Serial RED configuration enhances energy utilization to 6.78 %.