Rapid synthesis and NH3-SCR activity of SSZ-13 zeolite via coal gangue

Abstract

Coal gangue is a typical waste produced during coal mining and washing. Synthesis of zeolites via coal gangue can contribute to resource recycling and environmental protection. In this study, high-silica SSZ-13 was synthesized by one-step hydrothermal synthesis from coal gangue without the traditional pretreatment methods of high-temperature roasting and alkali melting, making it more convenient and energy efficient. The synthesis time, gel silicon–aluminum ratio and silicon source were systematically studied to optimize the synthesis of SSZ-13. Experimental results indicated that the nucleation time of SSZ-13 could be shortened to 7 h, which was half the synthesis time by using chemicals. Tetrahedral aluminum was the main factor for rapid synthesis, which also accelerated the transformation of octahedral aluminum and further accelerated the synthesis of SSZ-13. The DeNOx activity of the synthesized Cu-SSZ-13 was over 90% across a broad range from 180 to 400 °C, and it remained over 85% in this temperature range even after hydrothermal treatment for 12 h. It also demonstrated good water resistance (over 95% DeNOx in the range of 200 to 400 °C) and sulfur resistance (over 95% DeNOx in the presence of 100 ppm SO₂).