Use of thermogravimetric analysis to monitor the effects of natural laccase mediators on flax pulp.

The effects of 1-hydroxybenzotriazole (HBT) and the natural laccase mediators gallic acid, caffeic acid and p-hydroxybenzoic acid, on the enzymatic bleaching of flax pulp were compared. The treatment was performed under atmospheric air and oxygen pressure, and, for the first time, monitored by thermogravimetric analysis (TGA) for comparison with chemical analysis, FTIR and X-ray diffraction (XRD) spectroscopies. Thermogravimetric data were simulated by applying a nucleation kinetic equation to a combustion model based on four pseudo-components (hemicellulose, amorphous and crystalline cellulose, and lignin).

Simulation of the thermogravimetry analysis of three non-wood pulps.

In a study of three non-wood pulps (rice straw, EFB, and Hesperaloe), the standard pyrolysis model for biomass based on hemicellulose, cellulose, and lignin pseudo-components, was modified to include char volatilization. As a result, abnormally high values for lignin content have been avoided. On the other hand, the consideration of autocatalysis (Prout-Tompkins equation) for TGA data simulation under inert and oxidative atmospheres, allows obtaining a stable set of kinetic parameters that describe volatilization and char oxidation for different heating rates, including char ignition.

Use of autocatalytic kinetics to obtain composition of lignocellulosic materials.

Non-isothermal thermogravimetric analysis (TGA) data of biomasses and pulps originating from non-wood and alternatives materials (i.e., Tagasaste or rice straw) have been fitted with refined models, which include autocatalytic kinetics.