Effect of Surfactant on CO2 Adsorption of APS-Grafted Silica Gel by One-Pot Process

(3-Aminopropyl)trimethoxysilane (APS)-silica gels were prepared by a one-pot process using sodium silicate as a low-cost source of silica. XRD and SEM analyses revealed that the APS-silica gels were particles with diameters of around 100–200 nm. Furthermore, the introduction of amine groups was confirmed by FT-IR spectroscopy and CO2 uptake measurements. The adsorption properties of the gels were improved by addition of the surfactants hexadecyltrimethylammonium bromide (CTAB), Pluronic F127, and Pluronic P123, which acted as pore forming agents. Using Brunauer–Emmett–Teller (BET) analyses, we confirmed that both the surface area and pore volume were improved on addition of these surfactants. The larger surface area resulted in a greater number of amine groups being exposed on the outer surface of the APS-silica gels; therefore, CO2 uptake increased as the amount of surfactant used was increased. The APS-silica gels with F127 and P123 had pores from the porous particles with 5–11 nm diameters and gaps bet...