A Multifunctional Device for Simultaneous Hypersaline Wastewater Desalination, Waste Acid-Base Neutralization, and Electricity Generation

Industrial wastewater treatment is a pressing global challenge that requires sustainable and energy-efficient solutions. Conventional methods for treating industrial wastewater are often energy-intensive and limited to specific types of wastewater. Therefore, there is a need for innovative approaches that can simultaneously treat multiple types of wastewater while minimizing energy consumption. Herein, we report a circular wastewater-economy approach in which a multifunctional device is utilized to simultaneously treat three types of industrial wastewater (i.e., hypersaline wastewater, waste acid, and waste base). Remarkably, the proposed device exhibits a high salt removal performance (e.g., 87.7% for 80856.39 mg L-1 hypersaline wastewater while 98.8% for natural seawater), along with a significant reduction in acidity/alkalinity of waste acid/base and a decent amount of electricity. The experimental results validate the device performance of treating artificially produced and complex wastewater solutions. It also demonstrates a highly stable operation in continuous flow mode over 100 hours, verifying its potential scalability and long-term stability. The comprehensive theoretical and experimental analyses provide deeper insights into the influence of key properties of ions on the ion transport mechanism and performance. Techno-economic analyses show that the proposed device holds great promise for addressing sustainability challenges associated with industrial wastewater treatment.