Poly(amido amine) dendrimer-incorporated organoclays as efficient adsorbents for capture of NH3 and CO2

- The adsorption behavior of gases on dendrimer-loaded organoclays is reported.
- NH3 gas is preferably adsorbed on carboxyl-terminal of dendrimer in organoclay.
- Similarly CO2 gas is adsorbed on amine-terminal moiety of dendrimer in organoclay.
- Formation of carbamate species in the latter case is confirmed by solid-state NMR.
- Dendrimer-loaded organoclay is a favorable adsorbent for selective capture of gas.

The adsorption performance of gases on poly(amido amine) dendrimer-loaded organoclays has been investigated. In particular, the capture of NH3 gas on anion-exchange (hydrotalcite) organoclays were assessed and compared to that of CO2 gas on cation-exchange (sericite and laponite) organoclays, Differently from the adsorption of NH3 on pristine hydrotalcite, from which NH3 gases were completely released, the retention of NH3 on hydrotalcite organoclays was observed. The increase in adsorption capacity for NH3 with increasing the loading of dendrimer indicated the preferable adsorption of NH3 on carboxyl-terminated dendrimer moieties and was accompanied by decreases in surface area and pore volume of the organoclays. Similar behaviors were referred for the selective adsorption of CO2 on amine-terminated dendrimer moieties of laponite and sericite organoclays. Measurements by solid-state 13C NMR of adsorbed isotope-enriched 13CO2 confirmed the formation of carbamate species. These results show that dendrimer-loaded organoclays are favorable solid adsorbents for the efficient and recognized capture of gases such as NH3 and CO2.

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