Dissolution of organic acids in supercritical CO2 using a CO2-philic Lewis base carrier

Impacts of Organic Ligands on Forsterite Reactivity in Supercritical CO2 Fluids

“…Although the flux of organics transported to the forsterite could not be controlled in this study, the solubilities of the organic ligands were likely not controlling factors in the carbonation reactions. For example, acetic acid is ∼100× more soluble than citric acid in scCO 2 at approximately similar experimental conditions, ,, yet the citrate affected the carbonation process much more than the acetate (EXP 6 vs EXP 2 and EXP 3, and Figure b,c,e). Considering the forsterite mass, surface area, and an estimated 2 nm water film thickness, it is apparent that only small amounts of organic ligands need to diffuse through the scCO 2 to create large effective concentrations in the thin water film environment.…”

“…Although the experiments were not designed to allow direct observation of organic ligands in the scCO 2 fluid or interfacial water film, the organics were likely mobilized by the wet scCO 2 and transported to the mineral–fluid interface, where they impacted the relative amounts of nesquehonite and magnesite. Supercritical CO 2 is an effective solvent for organic compounds, including organic acids, − and organic acids can be extracted from aqueous phases to partition into scCO 2 . − Therefore, organic ligands in these experiments were most likely solvated by the water-saturated scCO 2 as neutral, protonated (acetic, malonic, oxalic, and citric acid) complexes (see p K a values in Table and GWB speciation results in Table ). It is important that the scCO 2 in this study is water-saturated, as the addition of a water cosolvent to scCO 2 fluids enhances their solvation properties .…”

“…It is important that the scCO 2 in this study is water-saturated, as the addition of a water cosolvent to scCO 2 fluids enhances their solvation properties . The organic acids are hydro- and CO 2 -philic, and experience binding interactions with both components of the wet scCO 2 fluid. ,− In fact, once the organics are scavenged by the scCO 2 , they too act as cosolvents, increasing the solubilities of organics in the fluid. ,,, Due to the notoriously poor ability of CO 2 to solvate inorganic metal complexes ,, and the lack of in situ verification of the measurements, the lack of evidence for Ca or Mn in the reacted samples from EXP 2 and EXP 3 is not surprising. Furthermore, we are not aware of any studies that have measured the solubility of metal–acetate complexes in CO 2 .…”

Characteristics of residual organics in municipal solid waste incinerator bottom ash

“…The use of both polar and non-polar solvents in SE may be a possible reason for its capability in extraction of a large number of organics including phthalates and organic phosphates. Generally, the non-polar nature and low dielectric constant of CO 2 may hinder the capability in extracting polar organics [20]. On the contrary, a larger number of aliphatic carboxylic acids were P1/S1,P2/S1,3,P3/S1,2 47…”