Physicochemical and textural properties of amino-functionalised mesoporous silica nanomaterials from different silica sources

Abstract

A series of MCM-41 nanomaterials that could serve various scientific applications was synthesised from two silica sources, tetraethyl ortho silicate and sodium silicate. Calcination and solvent extraction were employed as surfactant removal methods, while surface functionalisation was done via co-condensation and post-grafting methods. The synthesised nanomaterials were characterised, and their physicochemical properties were compared using X-ray powder diffraction (XRD), Brunauer Emmett Teller (BET) analysis, Fourier Transform Infra-red spectroscopy (FTIR), Thermogravimetric analysis (TGA), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The results showed that the surfactant removal and surface functionalisation methods affected the synthesised nanomaterials' 2θ values, d-spacing, and unit cell parameters. However, surfactant removal methods did not affect the morphology of amino-functionalised nanomaterials. Mesoporous silica nanomaterials of specific surface areas (884.0–17.1 m2/g), pore volumes (1.0–0.1 cm3/g), pore size diameters (7.2–1.5 nm), and less orderly mesoporous structures were produced with co-condensation and amino functionalisation using both silica sources. These methods can produce mesoporous silica nanostructures with different morphologies for wastewater remediation, catalysis, bio-catalysis, drug delivery, CO2 capture, indoor air cleaning, bioanalytical sample preparation, and pervaporation membrane improvement.