Preconditioning strategies for mineral dissolution and remineralization in desalinated seawater post-treatment: Acid, CO2 and synergistic pathways

• Development of a systematic approach for designing re-mineralization strategies for desalinated seawater via pre-addition-driven mineral dissolution while meeting stringent water quality criteria. • Formulation of a multiscale differential algebraic framework integrating dissolution reactor configuration, thermodynamic equilibria, dissolution kinetics, and water quality monitoring in re-mineralization systems. • H 2 SO 4 -induced dissolution achieves higher calcium ion concentrations. CO 2 -induced dissolution yields higher carbonate alkalinity. The synergistic efficacy of CO₂ and H₂SO₄ induced dissolution demonstrates intermediate performance when compared to their individual applications. • CO 2 -induced system achieve reduced reagent consumption and minimized post-treatment p H adjustment requirements while maintaining water quality indicators within recommended thresholds. This study presents a comprehensive technical-economic comparison of pre-addition strategies: acid (H 2 SO 4 ), carbon dioxide (CO 2 ), and their synergistic addition into desalinated seawater to dissolve limestone-like minerals. Desalinated water, characterized by low mineral content, alkalinity, and buffering capacity, poses risks of pipeline corrosion and health impacts, necessitating re-mineralization to meet water quality standards. A mathematical model based on thermodynamic and kinetic principles was developed to simulate dissolution processes in an up-flow packed-bed reactor, evaluating key parameters such as alkalinity, calcium hardness, p H, dissolved inorganic carbon ( DIC ) concentration, calcium carbonate precipitation potential ( CCPP ), Langelier Saturation Index ( LSI ), buffer capacity μ pH and CaCO 3 saturation buffer strength μ S . Under constraint of water quality stability objectives, the model precisely maps and optimally selects mineral dissolution strategies for desalinated seawater re-mineralization. Modelling results indicate that H 2 SO 4 -induced dissolution achieves higher calcium ion concentrations compared to CO 2 -induced methods. Conversely, CO 2 -induced dissolution yields higher bicarbonate alkalinity compared to H 2 SO 4 -induced methods. The performance of their synergistic action lies between the performances of their individual actions. CO 2 -induced system achieve reduced reagent consumption and minimized post-treatment p H adjustment requirements while maintaining water quality indicators within recommended thresholds. This study offers critical insights into the optimization of mineral dissolution strategies for the re-mineralization of desalinated seawater in municipal water supply systems.