Organic template-free synthesis of ZSM-5 zeolite from coal-series kaolinite

• Adopt acid leached kaolinite as the only Si and Al resources.
• Synthesize ZSM-5 without an organic template.
• Mechanical treatment with ball milling.
• Synthesize ZSM-5 in a solid-liquid heterogeneous phase system.

ZSM-5 was successfully synthesized by a template-free method using coal-series kaolinite as the only silica and alumina source. The physicochemical properties of obtained samples were characterized by XRD, SEM, FT-IR and nitrogen adsorption. According to the results, the relative crystallinity of template free ZSM-5 was ca. 94.2%, and crystal size was about 4.0 μm. Due to the absence of an organic template during the synthesis process, the obtained ZSM-5 samples have an opened pore system and could avoid calcination, which could reduce the cost and avoid generating environmental pollution. Furthermore, the process of heterogeneous synthesis for ZSM-5 using kaolinite as a silica source without an organic template has been discussed.