Development of Photovoltaic-Powered Autonomous MCDI System for Heavy Metals Removal

The deployment of off-grid photovoltaic (PV) systems in autonomous water treatment applications remains challenging due to fluctuations in solar irradiance and the need for site-specific adaptation. Capacitive deionization (CDI) offers a viable solution, as it is highly energy-efficient and capable of operating under low-power conditions. The integration of these technologies enables the development of a modular, automated water treatment system based on membrane CDI (MCDI) powered by solar energy, suitable for deployment in rural areas with limited infrastructure. In this study, a PV-powered water purification system with a capacity of 50 L·day⁻¹ was constructed and tested under real conditions, incorporating real-time in situ monitoring via ion-selective electrodes. Using high-surface-area activated carbon derived from rice husks (2900 m 2 ·g -1 ), the system demonstrates a high salt adsorption capacity for lead, reaching up to 113.8 mg·g -1 . This value, obtained from ion-selective electrode measurements, provides a more accurate assessment of lead electrosorption under dynamic flow conditions. To ensure adaptation to local operating conditions, solar insolation in Almaty, Kazakhstan, was evaluated. Calculations based on prototype data indicate that the proposed system design can be effectively scaled for larger applications. Additionally, a computational model of the system’s energy consumption was developed using experimental data from the prototype.