*Review* **Waste-Glycerol as a Precursor for Carbon Materials: An Overview**

**Mary Batista 1,\*, Silvia Carvalho 1,2,\*, Renato Carvalho 3, Moisés L. Pinto 2 and João Pires 1**


**Abstract:** Biodiesel is produced by the transesterification of animal fats and vegetable oils, producing a large amount of glycerol as a by-product. The crude glycerol cannot be used in the food or pharmaceutical industries. It is crucial to transform glycerol into value-added products with applications in different areas to biodiesel be economically viable. One of the possible applications is its use as a precursor for the synthesis of carbon materials. The glycerol-based carbon materials have distinct properties due to the presence of sulfonic acid groups on the material surface, making them efficient catalysts. Additionally, the glycerol-based activated carbon materials show promising results concerning the adsorption of gases and liquid pollutants and recently as capacitors. Despite their potential, currently, little research has been carried out on the synthesis and application of those materials. This review summarized the preparation and application of carbon materials from glycerol, intending to show the potential of these materials.

**Keywords:** biodiesel production; crude glycerin; carbon materials
