Combined Effects of Temperature and Triethanolamine on Carbon Dioxide Mineralization into Calcium Carbonate

Carbon mineralization, which transforms gaseous carbon dioxide (CO₂) into calcium carbonate (CaCO₃), is a viable technological strategy to lessen the effects of climate change and cut greenhouse gas emissions. A comprehensive understanding of the kinetic crystal nucleation and growth is essential to the process’s effectiveness. In this study, the effect of triethanolamine (TEA), at different concentrations (0, 10, 30, and 50 wt.%), on the transformation of CO₂ into CaCO₃ was evaluated under varying temperature conditions (25, 45, and 65 °C). The experiments were carried out in a jacketed glass reactor with constant stirring and thermostatic bath-controlled temperature. The reactor was filled with an aqueous solution that contained calcium hydroxide and TEA mixes, and it was heated to the desired temperature. The system was then continuously bubbled with CO₂ (200 mL min^-1) for 30 minutes. Every five minutes, samples were taken. Inductively coupled plasma–optical emission spectrometry (ICP-OES) was used to investigate the liquid phase, while scanning electron microscopy (SEM) and was used to characterize the solid phase. The results showed that at all assessed concentrations, rising temperatures caused system supersaturation, which encouraged CaCO₃ precipitation. As a nucleation promoter, TEA influenced crystal shape also speeding up precipitation kinetics. Its dissolution in the aqueous medium raised the pH of the solution and improved the availability of carbonate ions. The results showed that temperature promoted supersaturation and CaCO₃ precipitation under all conditions. Without TEA, calcium conversion remained limited and decreased with increasing temperature. In contrast, TEA increased conversion all temperatures. SEM analysis indicated temperature-dependent changes in particle morphology.