An attractive property of graphene sheets is that they can be readily chemically functionalized conferring it new chemical and physical properties. This modification or functionalization of graphene sheets may be achieved from the oxidation of graphite in presence of strong acids and oxidants producing graphene oxide (GO). A synthesis widely used to prepare GO is the Hummers method which involves treatment of graphite with potassium permanganate (KMnO4) and sulfuric acid (H2SO4). The GO is electrically insulating material due to their disrupted sp2 bonding networks, however, contains a range of reactive oxygen functional groups such as hydroxyl and epoxy on the basal planes, and carboxylic acid at the edges of the GO structure. The presence of oxygen functional groups and, therefore, its oxidation degree and electrical resistance can be varied changing the ratios between the graphite and KMnO4, modifying the GO sheet size and/or using different chemical agents to tune its reduction grade.
The high reactivity of the oxygen functional groups of GO, and the high specific surface area of GO render it a good candidate for gas adsorbant applications. On the other hand, the polar oxygen functional groups of GO confer it hydrophilicity. All these features of GO together with the possibility of the chemical functionalization of its carbon structure render it a good candidate for adsorbants of impurities for polluted water. In this work, synthesis routes, types of functionalization, chemical, structural, morphological and electrical characterization of reduced GO based materials are presented. Finally results on the capabilities of gas adsorption and water absorption behavior of these materials are discussed.