Scalable brine treatment and resource recovery using 3D-printed multichannel thermodiffusion

Abstract Brine—saline wastewater exceeding 1.7 billion tonnes daily—poses serious environmental challenges due to its salinity, toxicity, and energy-intensive treatment. Conventional treatment methods, such as reverse osmosis and evaporation ponds, face limitations in scalability, energy efficiency, and environmental impact. Here, we demonstrate that multichannel thermodiffusion, an emerging membrane- and evaporation-free method driven by temperature gradients, effectively concentrates brines beyond 70 ppt—approaching saturation—with favourable energy performance. Using a liquid Burgers cascade design, we show that thermodiffusive separation becomes more efficient with higher feed concentrations and that the system can be scaled using low-cost, rapidly fabricated 3D-printed components. Furthermore, we demonstrate the versatility of the technique by applying it to industrially relevant solutes including LiI, K2SO4, and NaOH, highlighting its potential for critical resource recovery. Our results indicate that thermodiffusion, previously regarded as a phenomenon too weak for practical use, offers a sustainable, scalable, and energy-efficient pathway toward resource recovery from concentrates and minimal liquid discharge systems. This work paves the way for a broader deployment of thermodiffusion technology for the extraction of resources from complex concentrates.