Synthesis and Grafted NH2-Al/MCM-41 with Amine Functional Groups as Humidity Control Material from Silicon Carbide Sludge and Granite Sludge

Abstract

Mesoporous Al/MCM-41 was synthesized by extracting silicon carbide sludge and granite sludge as the sources of silicon and aluminum. Different concentrations of aminosilane (2.5, 5, 7.5 vol.%) were used to reflux the grafted NH2-Al/MCM-41 with amine functional groups (NH2-Al/MCM-41). The physical and chemical characteristics were analyzed. The results confirmed that silicon carbide sludge and granite sludge can effectively synthesize Al/MCM-41 with low cost and environmental protection. Reflow grafted amine functional groups can effectively improve the surface properties of NH2-Al/MCM-41. The moisture adsorption and desorption capacity of grafted NH2-Al/MCM-41 with amine functional groups was also studied. Based on moisture adsorption and desorption capacity, the surface properties of NH2-Al/MCM-41 were studied. When 5 vol.% of NH2-Al/MCM-41 amine functional groups is added, the moisture adsorption and desorption capacity is best. When the relative humidity = 95%, the equilibrium moisture content is 39.4 kg/kg, which complies with the standard of Japanese Industrial Standard (JIS A 1475). Therefore, the use of waste derived from the industry to replace expensive commercial materials was simple and environmentally friendly, and the grafted NH2-Al/MCM-41 with amine functional groups can be utilized in multiple applications, particularly as moisture regulation materials in building engineering.

Impregnation of Fe³⁺ into MCM-41 Pores: Effect of Fe³⁺ Concentration on the Weight Percent of Fe-Frameworks and Fe-Non-Frameworks

“…In general, silica precursors such as tetraethyl orthosilicate (TEOS) [5][6][7] and sodium silicate [8][9][10][11] are used in the synthesis of MCM-41, which is relatively expensive. Iron ore tailing [12][13], siliceous sugar industry waste [14], silicon carbide sludge and granite sludge [15], bentonite [16] and rice husk ash [17][18][19] have all been investigated for use as a silica precursor in the manufacture of MCM-41 to minimize production costs. Rice husk ash (RH) is the most potent natural substance because it contains SiO 2 at concentrations of over 90% [20][21][22].…”

Grafting Going Green: Toward a Sustainable Preparation of Organic–Inorganic Hybrid Materials

“…For these reasons, toluene is generally employed in grafting procedures. , Toluene has an acceptable boiling point, allowing the reaction mixture to be heated up to 111 °C if necessary but can be easily removed from the material, afterward. Moreover, toluene is cheap and widely available on the market.…”