Diseño de aerogeles de óxido de grafeno reducido para la absorción de aceites de motor.

Abstract

Nowadays, water pollution due to oil spills and organic solvents is a matter of great importance. Physical absorption using reduced graphene oxide aerogels as absorbent materials has become an effective, environmentally friendly, and user-friendly method for removing these contaminants from water. This is because aerogels are materials with a large surface area, a network of pores, and robustness, facilitating the absorption of contaminant molecules. Although hydrothermal and chemical synthesis methods have been used to manufacture reduced graphene oxide aerogels, poor results have been found in terms of motor oil absorption capacity. Therefore, in this research, a lightweight reduced graphene oxide aerogel with tailored properties for motor oil absorption was fabricated using a combined reduction synthesis. Variables such as the type of graphene oxide, the type of reduction (hydrothermal, chemical, and combined), and the freezing process of the hydrogel at -5°C and -196°C were considered. In addition, a post-synthesis heat treatment at 600°C was performed. Once the aerogel was synthesized, the morphology, structure, porosity, and degree of reduction of the aerogels were evaluated using Fourier-transform infrared spectroscopy, Raman spectroscopy, and scanning electron microscopy techniques. The characterization results indicated that the type of precursor (graphene oxide), the reduction type in the hydrogel synthesis, and the freezing temperature influence the morphology, porosity, and degree of reduction of the aerogel, as well as the motor oil absorption percentage, speed, and capacity. Finally, the characterization results of the post-synthesis stage suggested that the resulting aerogel with improved properties was obtained using a graphene oxide precursor with a higher degree of oxidation through combined reduction synthesis with a freezing process at -5°C and a heat treatment at 600°C for 1 hour, presenting a robust three-dimensional structure with low density, a superior absorption capacity of over 270 g g-1 , and a 94% pore filling.