Chemometric Evaluation of Pyrolysis Parameters Affecting Sugarcane Bagasse Biochar Properties for Environmental Remediation

Biochar has received increasing attention due to its potential to improve soil quality, mitigate environmental contamination, and promote carbon sequestration. However, its properties are strongly influenced by production conditions. In this study, a central composite design (CCD) combined with response surface methodology (RSM) was used to evaluate the effects of pyrolysis temperature (T; 349–601 °C), residence time (RT; 0.8–4.2 h), and biomass particle size (PS; 0.34–3.68 mm) on the properties of biochar produced from sugarcane bagasse. The following biochar properties were considered response variables in the CCD: gravimetric yield; fixed carbon, volatile matter and ash contents; polarity (O/C ratio) and aromaticity (H/C ratio) indices; surface area; pH; and methylene blue (MB) removal efficiency. The results showed that pyrolysis temperature was the most influential variable, leading to reductions in yield, volatile matter content, and polarity, while increasing fixed carbon content, aromaticity, pH, surface area, and MB removal efficiency. Particle size influenced biochar friability and its MB removal capacity. Additionally, the combined use of principal component analysis (PCA) and Fourier-transform infrared (FTIR) spectroscopy enabled the effective discrimination of materials produced under different pyrolysis conditions.