Nanoporous and hydrophobic new Chitosan-Silica blend aerogels for enhanced oil adsorption capacity

Herein, we report a facile synthesis, characterizations, and applications of silica, chitosan, and chitosan–silica (CS) blend novel aerogels with enhanced surface properties. The surface morphology, surface area, compression resistance test, and oil adsorption capability of the prepared aerogels were evaluated. Hexamethyldisilazane (HMDS) was used as a modifier to make the surface of the three aerogels more hydrophobic, which further increase their oil adsorption capability. The Fourier transform infrared (FTIR) studies of the aerogels were carried out and a comparison was done which authenticated the new Si–O–C bond formation. TGA tests revealed that the obtained aerogels were stable at 250 °C. The morphologies of the prepared aerogels were examined by scanning electron microscopy (SEM) while the surface area was calculated using Sears method and it was highest (275.8 m2g-1) for 25% CS aerogel. The Langmuir and Freundlich adsorption isotherm models were applied to the oil uptake data which exhibited the R2 value = 0.99 and qmax = 37 mLg−1 with 100% removal in 6 cycles. Among all the three prepared aerogels, the 25% CS blend aerogel showed the highest mechanical strength, maximum porosity, high pore volume and great surface area with extremely low bulk density and maximum oil adsorption capacity. The oil removal using chitosan-silica blend aerogels is a unique and simple technology that might be employed to clean oil-contaminated soils/water bodies at micro-level to macro-level.