Cost-effective and facile one step synthesis of ZSM-5 from silica fume waste with the aid of metakaolin and its NOx removal performance

Abstract

The disposal of powdery silica fume waste has become an urgent environmental problem, the synthesis of zeolitic materials using silica fume is a commendable remedy to this crisis. In this study, a cost-effective and facile one-step strategy was proposed for the first time for hydrothermal synthesis of ZSM-5 zeolite using silica fume waste with the aid of inexpensive metakaolin in the absence of organic templates. This method allowed the total transformation of silica fume into ZSM-5 which exhibited similar characteristics to those obtained from conventional chemical reagents. The as-synthesized ZSM-5 under the optimized condition was used to prepare Ni, Cu and Zn/ZSM-5 catalysts by means of ion exchange and calcination treatments for NOx removal by NH3-SCR, and they exhibited high NO conversion of 92, 100, and 95%, respectively. This study would be a promising candidate for cost-effective and environment friendly synthesis of zeolite using silica fume waste in large scale.