APTES-Based Silica Nanoparticles as a Potential Modifier for the Selective Sequestration of CO2 Gas Molecules

Abstract

In this work, we have described the characterization of hybrid silica nanoparticles of 50 nm size, showing outstanding size homogeneity, a large surface area, and remarkable CO2 sorption/desorption capabilities. A wide battery of techniques was conducted ranging from spectroscopies such as: UV-Vis and IR, to microscopies (SEM, AFM) and CO2 sorption/desorption isotherms, thus with the purpose of the full characterization of the material. The bare SiO2 (50 nm) nanoparticles modified with 3-aminopropyl (triethoxysilane), APTES@SiO2 (50 nm), show a remarkable CO2 sequestration enhancement compared to the pristine material (0.57 vs. 0.80 mmol/g respectively at 50 °C). Furthermore, when comparing them to their 200 nm size counterparts (SiO2 (200 nm) and APTES@SiO2 (200 nm)), there is a marked CO2 capture increment as a consequence of their significantly larger micropore volume (0.25 cm3/g). Additionally, ideal absorbed solution theory (IAST) was conducted to determine the CO2/N2 selectivity at 25 and 50 °C of the four materials of study, which turned out to be >70, being in the range of performance of the most efficient microporous materials reported to date, even surpassing those based on silica.

Synthesis and Characterization of Thermosensitive P(NIPAAm-co-AAc)-Grafted Silica Nanocomposites for Smart Architectural Coatings

“…The absorption bands of the nonmodified silica powder at 470, 798, 1103, 1631, and 3420 cm –1 are attributable to the bending vibration of Si–O–Si bonds, symmetric stretching vibration of Si–O–Si bonds, asymmetric stretching vibration of Si–O–Si bonds, silanol stretching bonds, and O–H vibration of the absorbed H 2 O, respectively, as presented in Figure a. After APTES functionalization, Figure b reveals that in addition to the peaks of the original silica powder, the APTES-modified silica powder peaked at 2954 cm –1 (CH 2 ) and 690 cm –1 (deformation of CH out of plane) . The APTES–ACVA–silica powder produced new peaks at 1540 cm –1 (N–H amide), 1647 cm –1 (CO amide), 1700–1710 cm –1 (CO carboxylic acid), and 2995 cm –1 (CH 3 ), as displayed in Figure c …”

“…After APTES functionalization, Figure 4b reveals that in addition to the peaks of the original silica powder, the APTES-modified silica powder peaked at 2954 cm −1 (CH 2 ) and 690 cm −1 (deformation of CH out of plane). 50 The APTES−ACVA−silica powder produced new peaks at 1540 cm −1 (N−H amide), 1647 cm −1 (CO amide), 1700−1710 cm −1 (CO carboxylic acid), and 2995 cm −1 (CH 3 ), as displayed in Figure 4c. 51 The morphologies of the silica and m-silica powder were examined using SEM, and the results are displayed in Figure 5.…”

Upcycling of Plastic Wastes and Biomass for Sustainable Graphitic Carbon Production: A Critical Review

“…Graphitic carbons exhibit higher electrical and thermal conductivities. 66 The exceptional electrical conductivity of these materials is due to the free delocalized electrons and relatively short energy band gap between the valence and conduction bands. Charge carriers in graphene, for example, have long free paths and, hence, can have high mobility over long distances without disorder or disrupting the electron−electron interactions.…”

“…The electrical conductivity of quad-layer graphene film was found to be 1.9 × 10 5 S/m at room temperature. 66,67 Similarly, single-particle electrical conductivity of graphene powder, measured in parallel orientations, was reported to reach as high as 10 8 S/m. 68 These conductivity values are too high as compared to the typical silver or copper-based metals, which are in the range of (5 to 6) × 10 4 S/m.…”

Infrared spectroscopic monitoring of solid-state processes

“…Due to the importance of the process, publications focused on IR monitoring of the sorption of CO 2 197–207 or methane 208–211 by solids are numerous. In principle, qualitative or semi-quantitative monitoring of the changes in solid samples due to gas sorption does not require any additional accessories.…”