Redox-mediated electrochemical desalination for waste valorization in dairy production

Abstract

With the rapidly growing global population, achieving sustainable food production is a key challenge to mitigate the closely coupled environmental and nutrition crises. As demand for dairy products increases, large volumes of whey are produced – a highly polluting byproduct from food manufacturing, with strict disposal regulations. However, whey has been recognized as an attractive nutrient source; and as such, sustainable separation technologies for demineralizing the highly concentrated salts in whey waste can provide a pathway for the valorization of whey proteins from food processing waste. Herein, we propose a sustainable and energy-efficient strategy to valorize whey waste via a redox-mediated electrodialysis system. As a net-zero waste process, our system leverages reversible redox reaction for continuous desalination and salt concentration for reuse, as well as the simultaneous recovery of highly purified protein contents. The system demonstrates up to 99% salt removal with > 98% of whey proteins retained at various operating parameters: voltages, pHs, and salt concentrations. Remarkably, the performance of protein purification and salt recovery was maintained over multiple cycles, demonstrating outstanding stability and cyclability. Furthermore, a techno-economic analysis confirms the economic potential of our system with 51-73% lower energy consumptions and 51-62% lower operating expenditure than conventional desalination systems. Overall, our redox-electrochemical process offers a sustainable and electrified platform for the recovery of valuable proteins from dairy production waste, with envisioned integration with renewable electricity in the future.