Abstract
Different transition metals (Ni, Co, Fe, and Mn) at different amounts (0 mmol/g to 1 mmol/g) were introduced into the co-pyrolysis of rice straw and polyethylene. The thermal behavior and the kinetics of rice straw, polyethylene, transition metal-treated rice straw, rice straw/polyethylene, and transition metal-treated rice straw/polyethylene were comparatively investigated via thermogravimetric analysis. The Ni, Co, Fe, and Mn promoted the decomposition of rice straw and polyethylene in mixtures compared with non-transition metal-treated mixtures in terms of the initial decomposition temperature. The presence of these transition metals catalyzed the synergistic interaction between the rice straw and the polyethylene in mixtures, which resulted in a reduction of residue yield from 14.9 wt% for rice straw/polyethylene to 12.6 wt% to 14.5 wt% for transition metal-treated mixtures. Moreover, the difference in weight loss suggested that the negative influence of the softened polyethylene on the rice straw in mixtures could be greatly reduced after the involvement of transition metals. Kinetic analysis revealed that the pyrolysis of rice straw, polyethylene, and transition metal-treated rice straw were well fit by a single first order reaction; two consecutive first order reactions were needed to describe the co-pyrolysis of rice straw/polyethylene with or without transition metals.