Abstract
Carbons are sustainable and highly abundant materials with prospects of taking over the currently used metallic or inorganic materials, whose widespread employment entail questionable obstacles due to their scarcity and difficult extraction. Carbon materials are physicochemically stable, as well as having other interesting properties such as electrochemical conductivity, as a result of their simple yet efficient structure. Creating composites with these materials can promote even further their employment in a variety of applications. This is especially interesting when these other materials are also environmentally sustainable, such as, for instance, lignin. Even though it is currently considered industrial waste, lignin has many interesting properties, like high aromaticity and redox-active moieties. Combining these two green materials a compound with enhanced properties can be obtained, interesting for energy storage applications, as the non-faradaic nature of carbon combines with the faradaic nature of the redox moieties of lignin. Ultrasonic forces (US) were employed for the surface deposition of both industrially available Kraft lignin (KL) and organosolv lignin extracted on a laboratory scale (OL). The commercially available active carbon (AC) was chemically treated to observe the influence of the deposition efficacy and morphological variations. Moreover, the influence of the lignin type was also studied. These materials were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS), and Thermogravimetric Analysis (TGA). These methods were effective for the verification of both the chemical modification of the carbon and the deposition of lignin, being able also to determine differences in these phenomena depending on the surface of the carbon and lignin type employed.
