Synthesis of Mn3O4/ZSM-5 zeolite from natural aluminosilicate minerals and its application as heterogeneous catalyst for α-cellulose conversion to levulinic acid

Abstract

Microporous ZSM-5 was successfully synthesized using Bayat-Klaten natural zeolite and Belitung kaolin as its mineral source through 2 stages of treatment, i.e. pre-treatment of natural zeolite and kaolin followed by synthesis of ZSM-5 zeolite. Bayat-Klaten natural zeolite as source of Si and Al was first treated as follows: activation, purification, fragmentation, and dealumination, whereas Belitung kaolin as the source of Si, to cover Si deficiency in the synthesis, was treated as follows: activation, purification, and Si extraction. Based on Energy Dispersive X-Ray (EDX) analysis, the Si/Al ratio was 24.8 in dealuminated natural zeolite and 98 % of Si after kaolin extraction. ZSM-5 zeolite was synthesized and characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy-Energy Dispersive X-Ray (SEM-EDX), and Brunauer-Emmett-Teller (BET) analysis. The XRD pattern showed a similarity with typical ZSM-5 zeolites. Impregnation with Mn(II) followed by calcination at 550 °C giving Mn3O4/ZSM-5 (2.2 wt.% of Mn), that then employed as catalyst for α-cellulose conversion to levulinic acid. High Performance Liquid Chromatography (HPLC) analysis in product reaction showed that the conversion reaction for 6 h resulting in the highest yield of levulinic acid (7.2 %). Therefore, it was revealed that the natural mineral-based ZSM-5 has potential to be used as heterogeneous catalyst.