Carbon-13 CP/MAS NMR and DR-FTIR spectroscopic studies of sugarcane distillery waste

The application of a sugarcane distillery waste known as vinasse to agricultural land has become a common practice in Brazil. The vinasse samples used in this study were collected from several sugarcane distilleries in Northeastern Brazil. These samples were fractionated into dissolved organic carbon (DOC) and particulate organic carbon (POC) fractions. Unfractionated and fractionated vinasse were studied using 13C cross-polarization and magic-angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy as well as diffuse reflectance Fourier-transform infrared (DR-FTIR) spectroscopy. Approximately 79 to 92% of the total unfractionated vinasse dry matter was in the form of DOC fraction. O-alkyl C (42–53% of the total C) and carboxyl C (12–25% of the total C) comprised a significant portion of the 13C NMR spectra of the DOC fraction. The presence of carbohydrates and COOH/COO− was suggested by the DR-FTIR as well. Both 13C NMR and DR-FTIR spectra of this fraction were generally similar to the spectra...