Direct Carbonation of Mg2+-rich Brines as Alternative CO2 Storage Opportunity

Desalination is the leading technology that provides fresh water in arid and semi-arid regions of the world. Desalination plants, however, produce also concentrated salty solutions (brines), whose disposal has raised environmental concerns. Several authors have investigated the use of desalination b...

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Main Authors: Michela Cardella, Giuseppe Battaglia, Melissa Salvo, Andrea Cipollina, Alessandro Tamburini, Giorgio Micale
Format: Article
Language:English
Published: AIDIC Servizi S.r.l. 2025-07-01
Series:Chemical Engineering Transactions
Online Access:https://www.cetjournal.it/index.php/cet/article/view/15324
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Summary:Desalination is the leading technology that provides fresh water in arid and semi-arid regions of the world. Desalination plants, however, produce also concentrated salty solutions (brines), whose disposal has raised environmental concerns. Several authors have investigated the use of desalination brines as a potential source for CO2 mineralization, aiming at reducing CO2 emissions through indirect and direct carbonation processes. The present work deeply examines the performance of the poorly investigated direct carbonation process of Mg2+-rich solutions at room temperature and atmospheric pressure. These solutions, referred to as bitterns, are generated after a concentration process of seawater desalination brines in evaporative ponds or after the production of table salt in saltworks. Synthetic magnesium chloride solutions with a Mg2+ concentration of ~2.00 mol/L, mimicking the Mg2+ concentration in real bitterns, were adopted. Sodium hydroxide solutions were employed as alkaline reactant. For comparison, the indirect carbonation process of commercial magnesium hydroxide powders was studied. Tests were carried out in a 1 L semi-batch stirred jacketed reactor. The influence of different impellers, namely a 6-blade Rushton turbine and a marine propeller, on the crystal morphology of synthesized products was also investigated.
ISSN:2283-9216