Pyrolysis Characterization Of Organic Solid Waste Catalyzed By ZIF-8 Derived Catalysts

In this study,we explored the use of waste tires and clam meat as organic solid waste materials and employed ZIF-8 from metal-organic frameworks（MOFs）as a precursor to prepare ZIF-8 derived catalysts.The effects of these catalysts on the pyrolysis characteristics and product distribution of the organic solid waste were evaluated.Firstly,the impact of pyrolysis temperature and carrier gas flow rate on the yield of pyrolysis products was analyzed using a thermogravimetric analyzer and a small fixed-bed reactor.Results indicated that the decomposition process of natural and synthetic rubber was the main stage of waste tire pyrolysis and occurred within the temperature range of 300 to 520°C.On the other hand,the decomposition of carbohydrates,proteins and lipids was the main stage of clam meat pyrolysis and took place within the temperature range of 180 to 550°C.The highest yield of pyrolysis oil was achieved at a temperature of 500°C and nitrogen flow rate of 100 m L·min^-1,resulting in 38.61wt%for waste tires and 36.62wt%for clam meat.The main components of the organic solid waste pyrolysis oil were aliphatic hydrocarbons and oxygenated compounds,with 31.33%and 16.89%contents,respectively,for waste tires and 7.59%and 35.05%contents,respectively,for clam meat.Secondly,the ZIF-8 derived C-doped Zn O catalysts ZIF-8-C was then prepared by calcination of ZIF-8 and its effect on the pyrolysis characteristics and pyrolysis oil fraction of the organic solid waste was evaluated.The results showed that the addition of ZIF-8-C catalyst increased the yield of pyrolysis oil to 40.07wt%for waste tires and 38.48wt%for clam meat and simultaneously increased the content of aliphatic.In addition,the addition of ZIF-8-C catalyst promoted the production of ketones.Thirdly,the ZIF-8 derived single metal-loaded catalysts were prepared and their influence patterns on the pyrolysis properties of organic solid waste were investigated.The results showed that the addition of Na-ZIF-8-C catalyst and Mg-ZIF-8-C catalyst increased the yield of pyrolysis oil,while the addition of Ni-ZIF-8-C catalyst increased the yield of pyrolysis gas.Further analysis of the pyrolysis oil components revealed that all three catalysts increased the content of aliphatic hydrocarbons,with Na-ZIF-8-C catalyst increasing the content of phenols and ketones,Mg-ZIF-8-C catalyst increasing the content of ketones,and Ni-ZIF-8-C catalyst increasing the content of alcohols and ketones.Finally,the effects of ZIF-8 derived Na-Mg,Na-Ni,and Ni-Mg composite metal-loaded catalysts on the pyrolysis properties of organic solid waste were investigated.The results showed that the addition of Na/Ni-ZIF-8-C catalyst and Mg/Ni-ZIF-8-C catalyst increased the pyrolysis gas yield,while the addition of Na/Mg-ZIF-8-C catalyst increased the pyrolysis oil yield.The analysis of the pyrolysis oil components showed that the addition of all three catalysts increased the content of aliphatic hydrocarbons,with the addition of Na/Mg-ZIF-8-C further increasing the content of aromatic hydrocarbons.