In recent years, chemical industries have been focusing on sustainable development approaches, promoting materials that offer performance at lower costs and reducing significantly the environmental impact. In connection to these approaches, mesoporous materials have been synthesized and extensively studied for various applications. Nevertheless, the use of powders present different handling and recycling limitations. To overcome these problems there are two possible options: (i) the preparation of pellets starting from the pre-synthesized silica powders, or (ii) the direct preparation of monoliths. Among the different types of mesoporous materials, silicas have been widely used for environmental application, since meet most of the criteria for selection of adsorbents such as high specific surface area, large pore–size and chemical inertness; for these reason, mesoporous silicas have been used for adsorption of both organic and inorganic pollutants [1]. The preparation of silica monoliths can be a convenient way to fully exploit the structural and functional properties of the material by saving, at the same time, both reactants and time, in that a single-step synthesis is required [2]. In this work, mesoporous silica monoliths have been prepared by spinodal condensation reaction [3] and then tested as adsorbents of organic pollutants from aqueous or gaseous phase. The physico-chemical features of the silica monoliths have been determined by using different experimental techniques [4]. Textural properties were found to be homogeneous over the entire length of the monolith, which has an average surface area of ca. 850 m2 g−1 and a total pore volume of 1.2 cm3 g−1. The monoliths were tested for the removal of toluene, chosen as a model molecule of aromatic hydrocarbons, from gas phase. A combination of FT-IR spectroscopy and volumetric analysis was adopted to study the adsorption process and gain knowledge on the interactions between adsorbent surface and toluene molecule. Silica monoliths were found to be stable to water treatment (36 h at 50 °C), even if the treatment reduced the specific surface area. Finally, the ability of the same monoliths, before and after the water treatment, to remove Rhodamine B from aqueous solution was also studied by using UV-visible spectroscopy. After water treatment, the material was able to adsorb 50% of the Rhodamine B with respect to 70% of the control sample.
Silica Monolith for the Removal of Pollutants from Gas and Aqueous Phases
Miglio V.;Zaccone C.;Braschi I.;Marchese L.;Bisio C.
2021-01-01
Abstract
In recent years, chemical industries have been focusing on sustainable development approaches, promoting materials that offer performance at lower costs and reducing significantly the environmental impact. In connection to these approaches, mesoporous materials have been synthesized and extensively studied for various applications. Nevertheless, the use of powders present different handling and recycling limitations. To overcome these problems there are two possible options: (i) the preparation of pellets starting from the pre-synthesized silica powders, or (ii) the direct preparation of monoliths. Among the different types of mesoporous materials, silicas have been widely used for environmental application, since meet most of the criteria for selection of adsorbents such as high specific surface area, large pore–size and chemical inertness; for these reason, mesoporous silicas have been used for adsorption of both organic and inorganic pollutants [1]. The preparation of silica monoliths can be a convenient way to fully exploit the structural and functional properties of the material by saving, at the same time, both reactants and time, in that a single-step synthesis is required [2]. In this work, mesoporous silica monoliths have been prepared by spinodal condensation reaction [3] and then tested as adsorbents of organic pollutants from aqueous or gaseous phase. The physico-chemical features of the silica monoliths have been determined by using different experimental techniques [4]. Textural properties were found to be homogeneous over the entire length of the monolith, which has an average surface area of ca. 850 m2 g−1 and a total pore volume of 1.2 cm3 g−1. The monoliths were tested for the removal of toluene, chosen as a model molecule of aromatic hydrocarbons, from gas phase. A combination of FT-IR spectroscopy and volumetric analysis was adopted to study the adsorption process and gain knowledge on the interactions between adsorbent surface and toluene molecule. Silica monoliths were found to be stable to water treatment (36 h at 50 °C), even if the treatment reduced the specific surface area. Finally, the ability of the same monoliths, before and after the water treatment, to remove Rhodamine B from aqueous solution was also studied by using UV-visible spectroscopy. After water treatment, the material was able to adsorb 50% of the Rhodamine B with respect to 70% of the control sample.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
