Microwave-assisted catalytic fast pyrolysis of spent edible mushroom substrate for bio-oil production using surface modified zeolite catalyst

In order to minimize coke yield and improve hydrocarbon production during microwave-assisted catalytic fast pyrolysis of spent edible mushroom substrate, ZSM-5 zeolite catalyst is modified with pre-coking treatment, chemical vapor deposition of SiO 2 , and ethylene diamine tetraacetie acid (EDTA) chemical modification method, respectively (labeled PC-ZSM-5, SiO 2 -ZSM-5 and EDTA-ZSM-5). Experimental results show that all the modification methods result in a loss of external acid sites of ZSM-5. Among the three modified catalysts, the maximum oil fraction yield and the minimum coke yield are obtained with SiO 2 -ZSM-5. The relative content of hydrocarbons in oil fraction increases in the following order: SiO 2 -ZSM-5   >   EDTA-ZSM-5   >   PC-ZSM-5   >   original ZSM-5. Moreover, SiO 2 -ZSM-5 shows the highest relative contents of toluene and xylene, whereas original ZSM-5 produces the lowest ones. Besides, the selectivity of benzene in aromatics follows the order of original ZSM-5   >   EDTA-ZSM-5   >   PC-ZSM-5   >   SiO 2 -ZSM-5, while the selectivity of toluene   +   xylene presents the opposite trend.