The in-situ effect of H2S on the decomposition of natural rubber and catalyst activity

In this work, the pyrolysis of natural rubber (NR) under N2 and H2S atmosphere was performed to illustrate the possible effect of H2S on NR decomposition with and without catalysts. A molecular dynamics simulation based on reactive force field (ReaxFF) was also conducted to understand the interaction mechanism between H2S and intermediates from NR decomposition. Furthermore, the catalytic decomposition of NR under H2S atmosphere and the adsorption characteristics of H2S by zeolites alone were also carried out to investigate the effect of catalysts on sulfur behavior and the reversed effect of H2S on catalyst activity. This work revealed that the introduction of H2S can influence the yields of pyrolytic oil and gas, as well as composition of the oil. Combining experimental and simulation studies, H2S can interact with intermediates from NR decomposition forming sulfur-containing substances in pyrolytic oil. The H2S adsorption experiments by various catalysts revealed that catalysts can chemically adsorb H2S. The introduction of Zn can promote the adsorption ability by reacting with sulfur-containing substances to generate ZnS, with the desulfurization effect following the order of 3Zn/ZSM5 > ZSM5 > 3ZnO/ZSM5.