Amine-Functionalized Porous Silicas as Adsorbents for Aldehyde Abatement

Abstract

A series of aminopropyl-functionalized silicas containing of primary, secondary, or tertiary amines is fabricated via silane-grafting on mesoporous SBA-15 silica and the utility of each material in the adsorption of volatile aldehydes from air is systematically assessed. A particular emphasis is placed on low-molecular-weight aldehydes such as formaldehyde and acetaldehyde, which are highly problematic volatile organic compound (VOC) pollutants. The adsorption tests demonstrate that the aminosilica materials with primary amines most effectively adsorbed formaldehyde with an adsorption capacity of 1.4 mmol HCHO g −1 , whereas the aminosilica containing secondary amines showed lower adsorption capacity (0.80 mmol HCHO g −1 ) and the aminosilica containing tertiary amines adsorbed a negligible amount of formaldehyde. The primary amine containing silica also successfully abated higher aldehyde VOC pollutants, including acetaldehyde, hexanal, and benzaldehyde, by effectively adsorbing them. The adsorption mechanism is investigated by 13 C CP MAS solid-state NMR and FT-Raman spectroscopy, and it is demonstrated that the aldehydes are chemically attached to the surface of aminosilica in the form of imines and hemiaminals. The high aldehyde adsorption capacities of the primary aminosilicas in this study demonstrate the utility of amine-functionalized silica materials for reduction of gaseous aldehydes.

Superior Adsorption and Regenerable Dye Adsorbent Based on Flower-Like Molybdenum Disulfide Nanostructure

“…Hence, adsorption technique deserves extensive investigation due to its low consumption of energy, simple operation, high efficiency, low cost as well as the wide suitability for diverse dyes1314. As most common adsorbents, polymer microspheres, mesoporous SiO 2 , and activated carbon were synthesized to study their adsorption properties151617. Though activated carbon is widely used as an excellent adsorbent due to its large surface area and high adsorption capacity1819, its high cost and regeneration difficulties restricted its application seriously.…”

Synthesis and characteristics of SBA-15 with thick pore wall and high hydrothermal stability

“…Emphasis has already been placed on the fact that mesoporous materials have superior structure properties, such as large specific surface area, uniformity large pore diameter and thick silica wall, and potential apply in the fields of catalysis, adsorption, separation, drugs delivery and optical devices [1][2][3][4]. However, one main reason that these mesoporous materials have not been widely applicated in industry is their relatively poor hydrothermal stability.…”

Efficient removal of gaseous formaldehyde in air using hierarchical titanate nanospheres with in situ amine functionalization

“…8,9,54 The reaction is reversible under acidic conditions. 8,9,54 The reaction is reversible under acidic conditions.…”