Mineral carbonation in seawater desalination brine: Review and future perspective

The growing use of desalination to meet water demands has led to the generation of large amounts of concentrated brine rich in calcium and magnesium. While this brine is often seen as an environmental challenge, it also represents an untapped source of valuable minerals. Simultaneously, processes that can capture and utilize carbon dioxide in a stable form are gaining interest due to rising concerns over CO 2 emissions. Mineral carbonation offers a possible solution by using Ca 2+ and Mg 2+ in brine to form solid carbonates that permanently store CO 2 . In the past decade, many studies have investigated brine-based mineral carbonation using approaches ranging from simple alkaline carbonation to more advanced hybrid processes. These studies showed promising conversion efficiencies for Ca 2+ . However, it also highlighted the limitations associated with Mg 2+ recovery. Unlike conventional carbonation systems, using brine directly introduces additional challenges but also creates new opportunities. As a result, brine-based carbonation remains an emerging and relatively underexplored pathway in carbon utilization research. This review summarizes and compares existing studies on Ca 2+ and Mg 2+ recovery from brine. Based on this comparison, two main directions are discussed for future research. First is an alkaline brine system that promotes CO 3 2− formation through pH control, and second is a pressurized CO 2 spray system that could improve gas-liquid contact and CO 2 dissolution. Hence, the review aims to provide guidance for developing mineral carbonation as a combined approach for CO 2 utilization and mineral recovery from desalination brine. • Brine has high levels of Ca 2+ and Mg 2+ , making it suitable for CO 2 mineralization. • Comparison of alkaline carbonation and pressurized CO 2 spray carbonation. • Highlights the role of pH and CO 2 availability in controlling brine carbonation • Pressurized droplet system improves gas-liquid contact and reaction rate. • Brine carbonation enables simultaneous CO 2 utilization and mineral recovery.