Mild activation of spent fluid catalytic cracking (FCC) catalysts for the pilot synthesis of zeolite a with commercial quality and excellent Co2+ removal ability

Fluid catalytic cracking (FCC) plays a pivotal role in the transformation of crude oil into fuels and bulk chemicals, crucial within petroleum refining. However, it also generates a substantial volume of hazardous spent FCC catalysts. Thus, developing an effective method to convert these hazardous spent catalysts into high-value products is essential for the sustainable advancement of the petrochemical industry. In this study, we introduce a simple, mild, and environmentally friendly activation approach for spent FCC catalysts, followed by a straightforward synthesis of zeolite A meeting commercial standards. The resulting zeolite A (referred to as SFCC-A) exhibited high crystallinity, exceptional selectivity, and efficient Co2+ removal capabilities from wastewater. Even at a solid/liquid ratio of 1/1000 g·mL−1, a removal efficiency of approximately 99 % was achieved. SFCC-A demonstrated a high adsorption capacity (180.5 mg·g−1) for Co2+ and a broad operational pH range (4–8). Furthermore, the pilot synthesis was successfully scaled up to 100 L, maintaining consistent product performance compared to lab-scale production. Additionally, we investigated the evolution of species during the activation of spent FCC catalysts using multiple characterization techniques, elucidated the phase diagram of SFCC-A and the crystallization process under optimal conditions. The combination of a simple, mild, and eco-friendly activation method with a convenient synthesis process, yielding high-value zeolite A products, transforms spent FCC catalysts into valuable resources rather than hazards.