Dynamic Breathing of CO₂ by Hydrotalcite

Abstract

The carbon cycle of carbonate solids (e.g., limestone) involves weathering and metamorphic events, which usually occur over millions of years. Here we show that carbonate anion intercalated layered double hydroxide (LDH), a class of hydrotalcite, undergoes an ultrarapid carbon cycle with uptake of atmospheric CO2 under ambient conditions. The use of (13)C-labeling enabled monitoring by IR spectroscopy of the dynamic exchange between initially intercalated (13)C-labeled carbonate anions and carbonate anions derived from atmospheric CO2. Exchange is promoted by conditions of low humidity with a half-life of exchange of ~24 h. Since hydrotalcite-like clay minerals exist in Nature, our finding implies that the global carbon cycle involving exchange between lithosphere and atmosphere is much more dynamic than previously thought.

Impact of size, secondary structure, and counterions on the binding of small ribonucleic acids to layered double hydroxide nanoparticles

“…A past study showed that when HT containing CO 3 2À as the exchangeable anion is exposed to air, the anion can be exchanged with carbonate derived from atmospheric CO 2 . 35 The authors of this study suggested that CO 2 most likely adsorbs to the Mg-OH sites mediated by reversible acid-base interactions. 35 The carbonate ion, being planar and divalent, binds strongly in the gallery and will displace most other anions.…”

“…35 The authors of this study suggested that CO 2 most likely adsorbs to the Mg-OH sites mediated by reversible acid-base interactions. 35 The carbonate ion, being planar and divalent, binds strongly in the gallery and will displace most other anions.…”

“…A possible contributor to the apparent absorbance is the trace amounts of carbonate ion that are adsorbed from the atmosphere. 35 There may also be some contribution from light scattering.…”

“…35 We tested the abilities of carbonate ions and sulfate ions to compete with ssRNA 25mers for binding to HT. In addition, we assessed whether bound RNAs could be easily displaced by addition of increasing concentrations of the two inorganic anions.…”

Photocatalytic Reduction of Carbon Dioxide over Self‐Assembled Carbon Nitride and Layered Double Hydroxide: The Role of Carbon Dioxide Enrichment

“…[24,50,51] As found in a recent study by Ishihara and co-workers, the anions in the interlayer of LDH undergo dynamic exchange with atmospheric CO 2 even under atmospheric conditions. [52] Based on the elemental analysis (Table S1), there is 0.73 wt % of carbon in LDH, which can be attributed to CO 2 contamination during sample preparation to form interlayer CO 3 2À . The amount of interlayer CO 3 2À was estimated to be around 12.2 mmol in 200 mg of Pd/ (10 wt % LDH/C 3 N 4 ) photocatalyst used during the reaction.…”