Effect of silicon source and temperature on the formation of zeolites obtained from salt slag

Abstract

Considering its numerous applications and searching for alternatives to reduce production costs and alleviate environmental impacts, the manufacture of zeolites from waste has increased in recent years. In the present study, the effect of the silicon source and temperature on the formation of waste-based zeolites are reported. Hazardous aluminum salt slag and rice husk ash as silicon source were used as alternative raw materials for synthesize zeolites through a sustainable single-step hydrothermal process. It was found that the variation on the silicon source (rice husk ash or Na2SiO3) greatly affects the zeolite crystallization process, as well as temperatures variations, whose increase (80-120 ºC) leads to the formation of more stable and crystalline zeolitic materials. The synthesis of zeolites represents a promising route for recycling hazardous aluminum- and agri-food wastes, generating added-value products and reducing process costs and environmental impacts.