Thermal decomposition kinetics and characteristics of Spartina alterniflora via thermogravimetric analysis

• We studied the thermal behavior of smooth cordgrass by TGA.
• A significant variation of thermal behavior was observed with heating rate.
• Kinetic analysis was performed by using the isoconversional and master-plots methods.
• The activation energy of smooth cordgrass was 183.5 kJ/mol.
• The reaction model function of smooth cordgrass was f (a) = (1 − a)3.37.

Pyrolysis of Spartina alterniflora (smooth cordgrass) was investigated by thermogravimetric analysis in a nitrogen atmosphere at heating rates of 5, 10, 20, and 40 °C/min. Main weight-loss was observed in smooth cordgrass at temperatures ranging from 200 °C to 360 °C, owing to release of 72%–74% of total volatiles. Pyrolysis characteristics such as distribution of pyrolysis products and thermal-decomposition rate significantly changed based on heating rate, but had no significant effect on the total yield of volatile matters. Activation energy was evaluated by four model-free methods, namely, Friedman, Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and Kissinger methods. Experimental results showed that the activation energy obtained from the Kissinger method was in agreement with the average value of activation energy (183.6 kJ/mol to 183.4 kJ/mol) determined by FWO and KAS methods. Results of the master-plots method indicated that the most probable reaction model function was f (a) = (1 − a)3.37 under activation energy of 183.5 kJ/mol.