Thermogravimetric analysis and structure change of lime-pretreated Spartina alterniflora

Abstract

The thermal behavior and structure change of Spartina alterniflora pretreated with lime were investigated with raw and water-soaked samples for comparisons. Pretreatment significantly changed thermal decomposition behavior and activation energy. The activation energy of S. alterniflora ranged from 100.7 to 128 kJ/mol at the main decomposition stage. FTIR and solid-state 13 C NMR analyses revealed that pretreatment disrupted the carboxyl carbons attached to the lignin side chain. Compared with water soaking, lime pretreatment resulted in more modifications of structure and composition. Furthermore, structure breakage and composition removal change the pyrolysis characteristics of pretreated samples.

Alkali-Based Pretreatment-Facilitated Lignin Valorization: A Review

“…The operating conditions of lime pretreatment are in the range of 25–200 °C and hours to weeks, and the pretreatment time is required to increase along with temperature decreases . During lime pretreatment, the carboxyl carbon on the lignin side chain and ester bonds in p -hydroxy of benzoyl, ferulates, and coumarates can readily succumb to attack, and the S/G ratio of lignin tends to increase. ,, Also, the divalent calcium ions form complexes with lignin as well as carbohydrates . As a result, the extent of lignin removal is limited by the formation of calcium–lignin complexes, while the binding of calcium ions with LCC retains more carbohydrates, facilitates lignin rearrangement, and exposes more accessible area, in the biomass than NaOH delignification methods. , …”