Assembly-reassembly of coal fly ash into Cu-SSZ-13 zeolite for NH3-SCR of NO via interzeolite transformations

Abstract

Coal fly ash (CFA) solid residues can be destructive and cause severe pollution. Here, we report an interzeolite transformations strategy named the “assembly-reassembly” method to convert the CFA into Cu-SSZ-13 zeolite. It is a useful catalyst for NH3 mediated selective catalytic reduction (NH3-SCR) of NO. The raw CFA can be converted to ANA or FAU primary zeolite by an “assembly” step and CHA resultant zeolite by the subsequent “reassembly” step in the hydrothermal alkaline solution. We focus on the mechanism of the CFA-to-CHA process and the NH3-SCR performance of the Cu-SSZ-13 zeolite. The synthesized Cu-SSZ-13 possesses a standard CHA-type framework structure and controllable Al placement. It shows a high NO conversion rate that is comparable to the commercial Cu-SSZ-13. This approach enables the facile transformation of raw CFA waste to Cu-SSZ-13 zeolite with desirable composition and catalytic property, which provides insights into the formation mechanism during the interzeolite transformations process.