The role of surface and structural properties on the adsorptive behavior of vinyl-methyl decorated silica aerogel-like hybrids for oil/organic solvent clean-up practices

Abstract

The uncontrolled release of oil and organic solvents into aquatic environment is becoming a growing concern for ecosystems. This underscores the need for the improvement and development of efficient functional sorbents.The primary objective of this work was to design vinyl/methyl-decorated silica aerogel-like hybrids as novel adsorbents for oil and organic solvents and to uncover the relationship between the physicochemical and microstructural changes induced by organic substitution in silica backbone and the adsorption performance of these hybrids. The silica hybrids were prepared in two series through co-condensation of vinyltrimethoxysilane (VTMS) and methyltrimethoxysilane (MTMS) or tetraethylorthosilicate (TEOS). Gradual vinyl substitution was used to monitor the changes in the physicochemical and morphological properties. These changes were investigated using a variety of complementary characterizations techniques such as 29Si-MAS-NMR, and small angle neutron/X-ray scattering (SANS and SAXS) analyses, and basic characterization techniques like FTIR, SEM, N2 porosimetry and contact angle measurements. The results confirmed significant structural changes in VT series as VTMS content increased, while it had only a limited effect on the network formation in VM series. In the VT series, the samples exhibited predominantly mesoporous characteristics, resulting in large specific surface areas (792–1021 m2/g). In the VM-series, the samples were mostly macroporous and appeared in a sponge-like monolithic form. Successful vinyl/methyl substitution led to good hydrophobicity (up to 147°) in each series and contributed to an excellent self-cleaning ability. Thanks to their lightweight structure and hydrophobicity, the samples VT-100 and VM-50 exhibited the highest adsorption capacities (up to 11.63 g/g for VM-50 and 10.92 g/g for VT-100) for most organic pollutants and demonstrated stable performance along 10 cycles. The free-standing monolithic structure, well-developed porous network, high hydrophobicity, easy-to-clean property, and superior adsorption performance establish these materials as prime candidates for oil spill remediation practices. Additionally, their potential applications extend to various sectors, including the textile industry for protective clothing, transportation for oil spill response equipment on ships and aircraft, marine and coastal protection to prevent contamination, as green building materials to reduce maintenance needs and enhance energy efficiency, and as protective materials for cultural heritage buildings.