Abstract:
Hybrid mesoporous materials with high surface area (1144 m
2
/g) and enhanced thermal stability were
achieved through ultrasonication assisted sol–gel-intercalation technique using bentonite clay and PEG
grafted sol gel silica. Solvent extraction with mixed solvents showed efficient aerogel formation of the
hybrids. The products were characterised by small angle X-ray diffraction, Fourier transform infrared
spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, zeta potential measurement and BET surface area analysis. The XRD analysis showed interlayer
spacing of 43.28 Å. The increasing spacing is interesting in a way that the available interior pore volume
can be tailored for the enhanced adsorption of different pollutants. Clay-hybrid porous materials showed
hydrophobic nature with high adsorption capacities for organic dyes (methylene blue and malachite
green), volatile organic pollutants (phenol and toluene) and petrochemical derivatives (kerosene, engine
oil and diesel). The contact time necessary to attain adsorption equilibrium and the optimum pH were
found to be 2 h and 5.0–6.0, respectively. Kinetics of adsorption was rapid film diffusion with a
pseudo-second-order rate constant. The best interpretation for the equilibrium data was given by the
Langmuir isotherm indicative of homogenous surface and maximum adsorption capacity of clay-hybrid
towards methylene blue, malachite green, phenol and toluene from aqueous solution was found to be
101.55, 98.42, 116.75 and 114.10 mg/g, respectively, and was found to be greater than commercial adsorbents like activated carbon, zeolite and activated alumina. Thermal regeneration studies were carried out
by calcinating the exhausted adsorbents. Clay-hybrid aerogels were then demonstrated using different
petroleum products to exhibit excellent oil absorption properties
