Comparison among technical and milled wood lignins through principal component analysis of FTIR spectra

With the growth of biomass processing in biorefineries, there is an increasing need to develop rapid and simple methods for biomass characterization. One important component of biomass that is of signification interest in pyrolysis and liquefaction research is lignin, which is the world’s predominant source of renewable aromatic carbon. Due to its complex, heterogeneous nature and distinct variations among different biomass feedstocks, the characterization of lignins presents a unique challenge. In this study, we will show that clear divisions and comparisons can be made among a variety of lignins based on their FTIR spectra quantitatively assessed through principal component analysis (PCA). The eight lignins so far characterized are: two varieties of softwood kraft, one hardwood kraft, corn stover milled wood lignin (MWL), Douglas fir MWL, hybrid poplar MWL, wheat straw soda, and wheat straw organosolv. These samples were analyzed using a Bruker Alpha FTIR-ATR instrument (in addition to other characterization techniques). The spectra were baseline corrected and normalized, and the intensities of 15 peaks were recorded. The 15 spectral peaks were chosen based on previous work published by Li and McDonald (Industrial Crops and Products, 62, 2014, 67-76). PCA and data visualization was done using Python in the Jupyter Notebook environment. Fig. 1: Explained Variance of Each PC Principal component analysis revealed that among the eight lignins, they can be qualitatively grouped based on both their feedstock variety (e.g., hardwood, softwood) and isolation method (i.e., kraft, MWL, soda, organosolv). Quantification of the explained variances for each principal component (PC) suggests that three PC’s are necessary to capture over 90% of the variation among the samples (Figure 1). The principal component plots (Figure 2) show that softwood kraft lignins are clustered, corn stover and Douglas fir MWLs are clustered, and hardwood kraft and wheat straw soda are clustered. The two wheat straw and two hardwood samples tend to have positive values for PC1, while the softwoods and corn stover are negative. The MWLs are closely grouped along PC2, and the organosolv wheat straw is uniquely large along PC3. Depending on which of the three PC plots are assessed, other possible groupings can be reasonably drawn, suggesting that the FTIR spectral characteristics of lignins are distinctly affected by both their original biomass feedstock and isolation or extraction method. The analysis of FTIR spectra with PCA is a simple and efficient way to quickly assess the characteristics of an unknown or poorly-understood lignin sample, based on its comparison with other well-studied lignins. Previous work has shown that PCA is a robust technique for analyzing bio-oil MS data (Jia, et al., Energy & Fuels, 29, 2015, 7364-7374; Pattiya, et al., Fuel, 89(1), 2010, 244-253), and this work shows that such analysis can easily be extended to FTIR spectra of contrasting lignins. Continuing research will further assess the FTIR data for other important characteristics (both qualitative and quantitative), as well as to include additional technical lignins in the analyses. Please click Additional Files below to see the full abstract

Effect of pressure and gas velocity on biochar formation: hindered tar evaporation or tar cracking?

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Moroccan Two-phase olive mill wastes hydrothermal carbonization: effect of water phase recycling on hydrochar yields and properties

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Problemas de agresividad canina. Estudio preliminar en las ciudades de Corrientes y Resistencia

La agresión canina es un problema de comportamiento que supone un riesgo potencial para la sociedad. En este estudio se evaluó el comportamiento de 120 perros mediante el “Cuestionario de Evaluación e Investigación del Comportamiento de los Caninos” (C-BARQ) con el objeto de evidenciar la presencia de conductas agresivas en perros cuyos propietarios acudieron a la consulta clínica privada por causas ajenas a este problema, en las ciudades de Corrientes y Resistencia (Argentina). Del análisis descriptivo de los datos se pudo apreciar que un 55% de los perros mostró agresión hacia los propietarios. Si bien la frecuencia promedio no fue alta, la presencia de conducta agresiva implica un riesgo potencial para las personas. Además, se debe tener en cuenta que ninguno de los propietarios de los canes acudió a la clínica veterinaria para consultar por un problema asociado al comportamiento. Se observa que los dueños de los perros no consideran importantes a las señales sutiles de agresión, ignorando el peligro que podrían significar. Ello impone la necesidad de continuar realizando estudios sobre el tema y de analizar una forma efectiva de educación e información

Pyrolysis of plastics: highlighting the potential interest of a reflux to control liquid products

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Effects of mass transfers and heating rates during bark and wood hydrothermal treatment

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Multi-technique characterization of biochar formation

It is known that biomass forms an intermediate liquid before forming the solid “char” (figure 1) but the role of this intermediate liquid on the structure of char and on the mechanisms of pyrolysis is still poorly understood. In this talk we will present how in-situ rheology and 1H NMR analysis [2] are interesting technique to understand the mechanism of biochar formation through an intermediate “visco-elastic” material. These techniques allow assessing the physical-chemistry of biomass conversion to char at real-time and high temperature conditions. Please click on the file below for full content of the abstract

Characterization and catalytic performances of biochars synthesized from a hyperaccumulator plant: Alyssum murale

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Physico-chemical qualities and potentials for biochar agro- environmental valorization

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