Green Tools Based on Graphitic-Like Carbon/TiO2/CaCO3 Biocomposites as a High-Performance Platform for CO2 Capture

The development of materials with multiple environmental functions has been an immense challenge for researchers in view of current climate conditions. Thinking about contributing to the worrying current scenario, this study focused on addressing material production (bio-oil and carbon-based biocomposites) from the pyrolysis of cigarette filters waste for CO2 capture. Structural characterizations demonstrated that the chemical composition of the solid materials pyrolyzed at different times (4, 8, 12, 24 and 48 h) consists of TiO2, CaCO3 and graphitic-like carbon. Graphiticlike carbon/TiO2/CaCO3 biocomposite pyrolyzed at 4 h (BC-4h) showed the highest specific surface area (SBET = 342 m2 g-1) and lowest graphitization degree (ID/IG = 1.05). However, the biocomposite pyrolyzed in 8 h (BC-8h) presented the lowest ID/IG ratio of 0.82 (highest graphitization degree), spherical morphology and best performance to CO2 capture, adsorbing about 1.33 mmol g-1 at 298 K. These findings suggest that CO2 capture does not depend exclusively on specific surface area, but also the graphitization degree that can be induced by optimal pyrolysis times. In addition, reducing the temperature from 298 to 273 K increased CO2 capture to 1.76 mmol g-1 due to better physical interaction between the gas and the biocomposite surface, which was subsidized by the application of nonlinear models over the experimental data. The results demonstrate that it is possible to produce functional biocomposites from hazardous waste without the common adding organic solvents and/or inert gases, and use them as efficient CO2 capture platforms due to their advantageous cost-benefit.