Co-pyrolysis of pine sawdust with nickel formate for understanding interaction mechanisms and enhancing resistance toward biochar deposition

The objective of this work was to further understand the interaction mechanisms between pine sawdust (PS) and nickel formate (NF). As a result, the thermal behaviour of PS, NF, and PS/NF blends was determined by thermogravimetric analysis (TGA) using mass changes as monitoring parameters. Activation energies were obtained using model-free integral methods, and reaction models were estimated employing Criado mater plots (hereinafter referred to as mater plots). Besides, with the obtained activation energies, variation in preexponential factor (A), enthalpy (DH), Gibbs free energy (DG), and entropy (DS) were calculated. In higher temperatures, the presence of NF favors the decomposition of PS. When the value of PS content divided by NF content falls below 1, the temperature at which positive synergy occurs gradually decreased. Besides, the existence of NF enhanced resistance toward biochar deposition. Predominant reaction mechanisms for the samples were different at low (a < 0.5) and high (a > 0.5) conversion rates. Notably, the A value was linearly positively related to the activation energy. Positive DG and DH values were obtained from the pyrolysis of PS, NF, and PS/NF blends. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The objective of this study was to understand better the interaction mechanisms between pine sawdust and nickel formate by investigating their thermal behavior and calculating activation energy and other parameters. The results showed that the presence of nickel formate facilitated the decomposition of pine sawdust at high temperatures, and the temperature at which positive synergy occurred decreased when the content ratio of the two materials was below 1. Additionally, nickel formate enhanced the resistance to biochar deposition.