Treatment of petroleum spills and organic solvent pollution in general is an important issue; several techniques are under development to remove oil from water. The use of absorbents is one of the most common techniques to tackle this problem. These absorbents can be classified based on their characteristics of recyclability into irreversible and reversible ones. In this review, we discuss the application of several materials as oil absorbents, according to their classification and characteristics such as hydrophobicity, surface area and oil absorption capacity. Also, the fabrication methods for some materials are presented and analyzed.

In this work, the desorption of furfural, which is a competitive intermediate during the production of biofuel and valuable aromatic compounds, was studied using pure alumina, as well as alumina impregnated with iron and platinum oxides both individually and in combination, using thermogravimetric analysis (TGA). The bimetallic sample exhibited the lowest desorption percentage for furfural. High-resolution transmission electron microscopy (HRTEM) imaging revealed the intimate connection between the iron and platinum oxide species on the alumina support. The mechanism of furfural desorption from the Pt-Fe/Al₂O₃ 0.5%-0.5% sample was determined using physisorbed furfural instead of chemisorbed furfural; this mechanism involved the oxidation of the C=O group on furfural by the catalyst. The oxide nanoparticles on γ-Al₂O₃ support helped to stabilize the furfural molecule on the surface.

Less-comon nanostructures (nanoforms) such as “nanodumbbells”, “nanorices”, “nanolines”, “nanotowers”, “nanoshuttles”, “nanobowlings”, “nanowheels”, “nanofans”, “nanopencils”, “nanotrees”, “nanoarrows”, “nanonails”, “nanobottles”, or “nanovolcanoes”, among many others, have been reviewed. A considerable part of these nanoforms corresponds to gold, zinc oxide, and several binary inorganic compounds that are widely used in electronics. Synthesis methods for obtaining less-common nanoforms include wet-chemistry and electrochemical techniques, laser ablation, ultrasonic treatment, electron and ion beam irradiation, arc discharge, lithography, CVD and related routes, among others.