Structural, morphological and physiochemical analysis of SiC₈H₂₀O₄/C₂H₅O/C₇H₁₆ modified mesoporous silica aerogels

Silica Aerogels are well recognized and have attracted a considerable attention due to their unique properties. Using rice husk ash as the main precursor and ambient pressure drying as method, we synthesized and compared the four different mesoporous silica aerogel variants independently modified with TEOS, Ethanol and n-Heptane. The variants were characterized by BET, SEM, EDX, and XRD. According to our results, the highest porosity percentage, surface area, pore volume, average pore size and the lowest volume shrinkage of 85%, 312 m² g^-1, 0.76 cm3 g^-1, 9.6 nm, and 91.16% were observed in sample treated separately with TEOS, ethanol and n-heptane (SGTEH-Iso). However, the mentioned data for the sample treated with simultaneous solvent exchange/n-heptane aging (SGTEH-Sim) were 79.5%, 298 m² g^-1, 0.75 cm³ g^-1, 9.2 nm, and 91.86%. Moreover, TEOS (SiC₈H₂₀O₄), ethanol (C₂H₅O) and n-heptane (C₇H₁₆) enhanced the silica purity, strengthened the gel network and suppressed the crack formation during ambient pressure drying. In conclusion, due to their high porosity, pore volume and average pore size, the SGTEH-Iso and SGTEH-Sim variants have potential application as adsorbents for the removal of heavy metals from wastewater.