Evaluation of CO₂ absorbent-based draw solution as draw solution for forward osmosis treatment of domestic wastewater

This study investigates the feasibility of using sodium carbonate (Na₂CO₃) and sodium bicarbonate (NaHCO₃), by-products of carbon dioxide (CO₂) capture processes, as draw solutions (DSs) in forward osmosis (FO) systems. The primary objectives were to evaluate the basic performance of these DSs, analyze membrane fouling behaviors, and assess economic feasibility. The FO process demonstrated superior water flux performance with Na₂CO₃, attributed to its high osmotic pressure, followed by NaHCO₃ and sodium chloride (NaCl). Fouling analysis revealed that Na₂CO₃ mitigates fouling due to its alkaline nature, which inhibits biofouling and scaling. Economic evaluations confirmed Na₂CO₃ as the most cost-effective DS, offering significant cost savings over NaHCO₃ and NaCl at all recovery levels. These findings highlight the potential of Na₂CO₃ as a sustainable and efficient DS for wastewater treatment and other FO applications, emphasizing its compatibility with CO₂ capture technologies.