Dongsu Song

Gaseous carbon dioxide conversion and calcium carbonate preparation by magnesium phyllosilicate

Magnesium phyllosilicate (Mg–APTES) was developed and explored for its applicability as a potent carbonation catalyst that converts CO2 into carbonate ions. Careful investigation of its surface properties revealed a lamellar structure and the existence of an amine group, which is the expected CO2 capture site. The prepared magnesium phyllosilicate was found to successfully convert gaseous CO2 into HCO3− (bicarbonate ion), actively forming CaCO3 (calcium carbonate) when Ca2+ (calcium ion) was supplied. This study shows that the magnesium phyllosilicate, a new type of carbonation agent and a concept of an artificial mimetic catalyst, can be a good candidate catalyst for CO2 capture.

A direct ammonium carbonate fuel cell with an anion exchange membrane

Direct ammonium carbonate- and ammonia-based fuel cells with an anion exchange membrane (AEM) and Pt/C catalyst have been constructed and their performance has been evaluated. Ammonium carbonate, which has never been used as a fuel, can become massively available when CO2 is captured with ammonia as a non-recyclable, single-use adsorbent. It is a solid at ambient conditions and thus as a fuel option, has the advantages of volumetric energy density, ease of transportation, and storage safety. In this paper, the oxidative activities of the Pt/C catalyst on ammonium carbonate, along with ammonia, were evaluated by means of a half-cell test. Ammonium carbonate exhibited approximately 75% of the oxidation activity of ammonia; this reduced activity was likely attributable to the existence of the carbonate. This was also observed in a single cell test: the direct ammonium carbonate fuel cell generated approximately 50% lower maximum power density than that of an ammonia-based counterpart. Although its performance is seemingly inferior, it turns out that the energy power is comparable to pure ammonia or at least in the same order of magnitude. We showed that ammonium carbonate has enough potential as a fuel in low temperature polymer fuel cells.

Fe-aminoclay-entrapping electrospun polyacrylonitrile nanofibers (FeAC-PAN NFs) for environmental engineering applications

Electrospun polyacrylonitrile nanofibers (PAN NFs) with entrapped water-soluble Fe-aminoclay (FeAC) [FeAC-PAN NFs] were prepared. Slow dropwise addition of water-soluble FeAC into a PAN solution, less aggregated of FeAC into electrospun PAN NFs was one-pot evolved without FeAC post-decoration onto as-prepared PAN NFs. Taking into consideration both the Fe3+ source in FeAC and the improved surface hydrophilicity, the feasibility of Fentonlike reaction for decolorization of cationic model dye methylene blue (MB) under 6 hrs UV-light irradiation was established. In the case where FeAC-PAN NFs were enhanced by hydrogen peroxide (H2O2) injection, the apparent kinetic reaction rates were increased relative to those for the PAN NFs. Thus, our flexible FeAC-PAN NF mats can be effectively utilized in water/waste treatment and other environmental engineering applications.

CO2 Capturing and Mineralization by (Mg)-Phyllosilicate Coated with Fabrics.

To promote the practicality of magnesium (Mg)-phyllosilicate as a potent carbonation agent, two inexpensive cotton and nylon fabrics are selected and examined to assess their feasibility for use as supporting media of Mg-phyllosilicate. Mg-phyllosilicate is coated onto the fabrics via a sol-gel method, whose mechanism is explained. The characteristics of the Mg-phyllosilicate coated cotton, along with those of the carbonation products, are explored. Mg-phyllosilicate is found to mediate the carbon dioxide (CO2) mineralization process actively, even on cotton of a supporting material. Conclusively, the obtained results clearly support the potential of mineralization as a feasible option for capturing CO2, in particular with the abiotic catalyst of Mg-phyllosilicate coated onto flexible cotton.