Catalytic depolymerization of lignin from wood waste biomass over natural sourced ZSM-5 catalysts

Abstract

Lignin isolated from wood waste biomass, contains 61.07 % of lignin, was converted to vanillin using ZSM-5 catalysts. Prior to use, wood waste biomass was delignified to enrich its lignin contents followed by added 10 % H2SO4 to isolate the lignin such as solid black material. Three types of ZSM-5 catalysts i.e. hierarchical ZSM-5, NiO/hierarchical ZSM-5 and CuO/hierarchical ZSM-5 zeolites were used as catalysts in this study. Hierarchical ZSM-5 zeolite was prepared through TPAOH template synthesis methods followed by PDDAM as secondary template. Silicate and aluminate source based on a natural source to form hierarchical ZSM-5 zeolite. Hierarchical ZSM-5 zeolite is modified with NiO and CuO by using impregnation method with Ni nitrate and Cu nitrate solution followed by calcination at 550 °C. The characterization of catalysts employed FTIR, XRD, andSEM-EDX. The reaction was carried out in 200 mL-batch reactor at 100 °C, 150 °C, 200 °C, 250 °C and 300 °C in the presence of ethanol and water (v/v) for 30 min. CuO/hierarchical ZSM-5 zeolite gave the highest % yield of vanillin as product (4.68 %) followed by NiO/hierarchical ZSM-5 zeolite (3.82 %) for the variation of temperature, compared to other ZSM-5 catalysts.