The mechanism of the mechanically assisted mineral carbonation of commercial olivine under the flow of a carbon dioxide (CO₂)/nitrogen (N₂) mixture has been elucidated by ex situ powder X-ray diffraction and Fourier-transform infrared spectroscopy. The overall CO₂ conversion depends on the rotational frequency of the mill’s engine, and it reaches 85% within 90 min of mechanical treatment at a flow rate of 2.5 L min⁻¹. By tuning the frequency of rotation, the kinetics of CO₂ conversion unveil a complex reaction pathway involving subsequent steps. Structural analyses suggest that clinochlore, a magnesium (Mg-)- and iron (Fe-)-containing aluminosilicate gathered among the components of olivine, is formed and consumed in different stages, thus promoting the CO₂ sequestration that eventually results in the formation of hydrated and anhydrous Mg-based carbonates.

Se rods decorated with SnO₂ nanoparticles have been synthesized via a facile hydrothermal approach to bridge the gap between ultraviolet-only and visible-only photocatalysis and to enhance reactive oxygen species generation under visible illumination. Structural and morphological analyses using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy have confirmed the coexistence of cassiterite SnO₂ particles intimately interfaced with trigonal selenium rods. Diffuse-reflectance spectroscopy revealed a long absorption tail extending into the 400–550 nm range. Under 450 nm sample illumination, the composite produced singlet oxygen in higher yields than either bare SnO₂ or Se, as evidenced by the indocyanine green assay. The system alone does not produce free radicals, as shown by the terephthalic acid test; however, the addition of rhodamine B acts as an effective sensitizer, enabling hydroxyl radical generation. Photodegradation tests using rhodamine B have shown that the SnO₂–Se system outperforms both its single components, Se and SnO₂, as a catalyst. The synergistic interplay underscores the potential of SnO₂–Se heterostructures in photochemical applications under visible light.

The mechanism of the mechanically assisted mineral carbonation of commercial olivine under flow of CO2/N2 mixture has been elucidated by ex situ powder X-ray diffraction and Fourier-transform infrared spectroscopy. The overall CO2 conversion depends to the rotation frequency of the mill’s engine, and reached 85% within 90 minutes of mechanical treatment, at a flow rate of 2.5 l min-1. By tuning the frequency rotation, the kinetics of CO2 conversion changed from a sigmoid behaviour into a more complex reaction pathway, involving subsequent steps. The structural analyses suggest the clinochlore, a Mg- and Fe- containing aluminosilicate gathered among the components of olivine, is formed and consumed in different stages, thus promoting the CO2 sequestration that eventually results into the formation of hydrated and anhydrous Mg-based carbonates.