Use of Periodic Mesoporous Organosilica-Benzene Adsorbent for CO2 Capture to Reduce the Greenhouse Effect.

The CO2 adsorption of a phenylene-bridged ordered mesoporous organosilica (PMO-benzene) was analyzed. The maximum capture capacity was 638.2 mg·g-1 (0 °C and 34 atm). Approximately 0.43 g would be enough to reduce the amount of atmospheric CO2 in 1 m3 to pre-industrial levels. The CO2 adsorption data were analyzed using several isotherm models, including Langmuir, Freundlich, Sips, Toth, Dubinin-Radushkevich, and Temkin models. This study confirmed the capability of this material for use in reversible CO2 capture with a minimal loss of capacity (around 1%) after 10 capture cycles. Various techniques were employed to characterize this material. The findings from this study can help mitigate the greenhouse effect caused by CO2.

Ternary Blends for Self-Compacting Mortars Production Composed by Electric Arc Furnace Dust and Other Industrial by-Products.

This study is framed within the circular economy model through the valorisation of industrial by-products. This research shows the results of producing self-compacting mortars (SCMs) with electric arc furnace dust (EAFD) and other industrial by-products such as fly ash, conforming (FA) or not conforming (NcFA), from coal-fired power plants, or recovery filler (RF) from hot-mix asphalt plants. Three batches of SCMs, each with one industrial-by product (FA, NcFA, or RF), and three levels of EAFD ratio incorporation (0%, 10%, 20%), were tested. An extra batch with a greater amount of FA was manufactured. When the incorporation ratio of EAFD rose, the mechanical strength decreased, due to the presence of a calcium zinc hydroxide dihydrate phase; nevertheless, this decrease diminished over time. All SCM mixes, except the 40C 40FA 20 EAFD mix, were above 20 MPa at 28 days. All mixes named 70C and 40C reached 40 and 30 MPa, respectively, at 90 days. Mixes with EAFD showed less capillarity and no difference in water absorption by immersion with respect to mixes without EAFD after 91 days. The SCMs designed proved to be stable in terms of leaching of the heavy metals contained in EAFD, where all the hardened SCMs were classified as inert.

Optimum Particle Size of Treated Calcites for CO2 Capture in a Power Plant.

This work has analyzed the influence of the particle size of a calcite from a quarry, whether original, calcined, or rehydrated, on the efficiency of CO2 capture of the gases emitted in a coal-fired power plant. Three different particle sizes 0.5 mm, 0.1 mm, and 0.045 mm have been studied. The calcination had a minimal effect on the particle size of the smaller samples A1045 and A1M1 (<30 µm). The N2 isotherms and the CO2 adsorption isotherms at 0 °C showed a very significant increase in the surface of the calcined and rehydrated samples (A15CH, A1045CH, and A1M1CH) with respect to the calcined or original samples. The results obtained showed that the capture of CO2 for the sample A1M1, with a smaller average particle size (<30 µm, is the most effective. For the sample A1M1 calcined and completely rehydrated (Ca(OH)2), the chemical adsorption of CO2 to form CaCO3 is practically total, under the experimental conditions used (550 °C and CO2 flow of 20 mL min-1). The weight increase was 34.11% and the adsorption capacity was 577.00 mg g-1. The experiment was repeated 10 times with the same sample A1M1 calcined and rehydrated. No appreciable loss of adsorption capacity was observed.