TGA-FT-IR Analysis of Evolution of Oxygenated Organics by Isothermal Low-Temperature Decomposition of Rice Straw Hydrolysis Residue

The study presents a TGA-FT-IR analysis of low-temperature thermochemical transformations of Rice straw hydrolysis residue (RSHR). Isothermal decomposition of RSHR was carried out for ۳ h, at decomposition temperatures of ۲۰۰, ۲۵۰, ۳۰۰, and ۳۵۰ oC. At ۲۰۰ oC, the rate of mass loss never exceeds %۱/min and except for the first five minutes, it is less than %۰.۵/min. The initial rate of mass loss at ۲۵۰ oC is %۱.۶/min which quickly drops to %۰.۶/min in the first ۱۰ minutes and goes on further decreasing thereafter. At ۳۰۰ oC, there is a rapid initial mass loss with the initial rate peaking at %۸.۸/min. At ۳۵۰ oC, there is an initial burst of volatiles accounting for most of the mass loss with the initial rate of mass loss being %۵۰/min. The residual mass obtained after these runs was ۸۱.۵, ۳۸, ۲۴, and ۱۵%, respectively. FT-IR spectra of evolved gases suggest that volatile oxygenated organics along with non-condensable components like CO۲, and CO are evolved during low-temperature thermal decomposition of RSHR. Carbonyls – acids, esters, aldehydes, and ketones – are the main functional groups in the volatiles. Strong absorption bands ranging ۳۴۰۰ – ۳۹۰۰ cm-۱ indicated the presence of alcohols and phenols as other functional groups. Decomposition residues, the biochar, were demethoxylated and dehydrogenated compared to RSHR but retained their basic lignocellulosic nature.

کلیدواژه ها:

isothermal decomposition ، evolved gases ، volatiles ، biochar