(374p) Intensified Water Purification Via Closed Loop Carbon Dioxide-Mediated Diffusiophoresis

Traditional water purification systems often require large energy inputs to achieve particle separation. To address the expanding need for access to clean drinking water, less energy intensive separations methods must be developed. A novel concentric tube-in-tube-in-tube separator was developed to remove colloidal water contaminants. The system utilizes carbon dioxide (CO₂) to generate an ion gradient across the inner most annulus and induce diffusiophoretic migration of charged colloids to the outer edge of the annulus. Clean water is withdrawn from the center of the inner most annulus using a capillary. An investigation was conducted into system parameters such as split ratio between clean and concentrate streams, recoverable CO₂, and capillary position to maximize clean water production. The effect on performance and throughput were evaluated across a multidimensional parameter space including operating pressure (150–250 kPa) and residence time (10–1000 s). Additionally, a computational fluid mechanics model was developed and validated against experimental flux measurements and used to evaluate key performance parameters. The results revealed a viable pathway for removal of colloidal contaminants while recovering CO₂ in a closed loop system.