Development of the geopolymer-based zeolite from powdery silica fume and its application in methanol to dimethyl ether

A large number of non-biodegradable powdery silica fume waste produced in industry increase the severity of environmental problems due to their potential harmfulness. The synthesis of geopolymers or zeolitic materials using powdery silica fume as silicon source has become an attractive sustainable solution to remedy this crisis. In this paper, a cost-effective porous ferrierite was synthesized by a facile hydrothermal strategy using silica fume-based geopolymer as precursor and applied to methyl dimethyl ether reaction (MTD). The specific surface area of geopolymer increased from 30.5 to 258.4 m(2)/g of ferrierite, and the methanol conversion rate correspondingly improved from 16.04 % to 78.5 %. Moreover, rare earth (RE) metal ions were introduced to optimize the performance, and the maximum conversions of RE-modified ferrierite were higher than 90 %. The superior catalytic performance of RE-modified ferrierite was related to the synergy of abundant porosity, acidic active sites and metal functions, which could be realized by regulating the crystallization degrees and ion exchange concentrations. Moreover, the abundant active amorphous silica in silica fume is conducive to the preparation of eco-friendly geopolymers and the further development of zeolite materials, realizing the high value-added utilization of solid wastes. (c) 2022 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan.