Aplicação da espectroscopia de reflectância no infravermelho próximo (NIRS) na determinação do potencial bioquímico de metano – Revisão

Abstract

The production of methane from the biodegradability of a waste can be determined by the biochemical potential of methane generation (BMP). This varies considerably between different raw materials, and their knowledge is crucial before implementation in an anaerobic biodigestion process. Several experimental and theoretical methods can be used to determine PBM, with its advantages and disadvantages regarding simplicity, effectiveness, time and costs. There are several conditioning factors of the results of the PBM tests, with evident variability in the duration of the experiments. These initiatives create difficulties in the procedures and problems in the comparison of the effects obtained using similar substrates, in addition to the high costs with chemical analysis. The use of Near Infrared Reflectance Spectroscopy (NIRS) for the determination of BMP is a relatively new application, very useful for speed, not requiring reagents and a non destructive technique. This work offers a review of the NIRS technique, based on computational development and chemometrics, which is based on the increment of calibration and validation models. Several studies were conducted with the application of multivariate statistical tools. Through the use of mathematical parameters one can correlate spectral characteristics of the chemical composition of the substrates (independent variables) with the prediction models should consider the sources of variability and the careful selection of samples. The NIRS-based technology is a support tool in the BMP research where several studies demonstrate the advantages in predicting the results, being possible to use the models generated for the management and optimization of biogas plants.