A method to enhance the CO 2 storage capacity of pyroxenitic rocks

Investigation of new efficient pathways for CO 2 sequestration is of great significance for the mitigation of climate change. Ultramafic rocks are considered among the most promising lithotypes for the safe storage of CO 2 via mineral carbonation. This paper investigates a powerful method for the optimization of the ex situ carbonation of pyroxenitic rocks, which comprise part of ultramafic lithologies occurring in ophiolite complexes. The ball milling process was applied to a sample of pyroxenite from the Troodos ophiolite (Cyprus) for the first time, in order to create novel nanomaterials with enhanced CO 2 storage capacity. The goal was to accelerate the kinetics of rock‐fluid reactions during the carbonation process. The starting rock material and the ball‐milled samples were characterized using a variety of methodologies. The experimental results imply that only a few hours of wet ball milling with ethanol as process control agent can substantially increase the CO 2 storage capacity of pyroxenites. Through temperature‐programmed desorption of CO 2 (CO 2 ‐TPD) experiments, we show that the optimum milling conditions are 4 h of ball milling with 50 wt% ethanol, leading to an increase of the CO 2 uptake of the studied rock material by 41 times. This notable increase designates that pyroxenites are very promising lithologies for CO 2 storage via ex situ carbonation, and that ball milling can be an effective preparation technique for this process, providing an efficient and secure carbon storage solution.© 2015 Society of Chemical Industry and John Wiley & Sons, Ltd