Perovskite-based catalyst for sustainable wastewater treatment and seawater desalination through microbial desalination cell

The bioelectrochemical systems are sustainable solutions to face energy, water, and wastewater-related challenges. A three-chambered bioelectrochemical system, known as a microbial desalination cell (MDC), operates on the combined principles of a microbial fuel cell and electrodialysis. This self-powered system is capable of simultaneously treating wastewater and desalinating seawater. In the anodic compartment, microbial digestion of organic substrate treats wastewater. At the same time, the potential generation across the anode and cathode, resulting from electron production during the degradation process, leads to seawater desalination. Additionally, the oxygen reduction reaction (ORR) in the cathodic chamber significantly contributes to the overall performance of the system. Enhancing the ORR of the cell through catalyst incorporation has been shown to improve the system’s performance. The addition of a Sr-Mn-based perovskite, an abundant transition metal oxide compound, was synthesized using a facile method to be used as a cathode catalyst. The performance of the catalyzed reactor was compared to a non-catalyzed system with carbon electrodes. The addition of a catalyst resulted in a COD removal of 81.1 ± 0.5%, which was 35.5% higher than that recorded in the scenario without a catalyst. Similarly, in terms of desalination, the MDC with catalyzed cathode exhibited an 83.3 ± 1.2% desalination efficiency compared to the control MDC (45.76 ± 1.4%). This improved electrocatalytic performance of the system due to the catalyst was explained through the electrochemical analysis of the synthesized perovskite. The non-reliance of the MDC system on any external power source makes it a self-sustained and green technology for performing wastewater treatment and saltwater desalination, contributing to the Sustainable Development Goal 6 of clean water and sanitation.