Zeolites synthesized from agro-industrial residues applied in agriculture: A review and future prospects

Zeolites have been widely applied as catalysts, wastewater treatment agents, gas adsorbents, and fertilizers, among others. However, the use of natural zeolites or those synthesized from oversaturated commercial solutions are more explored commercially than the zeolites synthesized from residues. Therefore, the aim of this review is to highlight the importance of zeolites synthesized from agro-industrial residues and their use in agriculture. This review has been divided into three different sections, i.e., zeolites, agriculture applications, synthesis of zeolites from residues, and their application in plant growth. In the first section, the definition, types, and the critical properties of zeolites are explained. The second section gives a brief review of the application of zeolites in agriculture. Finally, the synthesis of zeolites from residues, such as coal ash, rice husk ash, and sugarcane ash, with special attention to renewable sources is presented. The optimization of the synthesis of zeolites from residues with the incorporation of specific nutrients necessary for the cultivation of soybeans, corn, and sugarcane (considered the most significant crops in Brazilian agriculture in terms of the planted area) can significantly contribute to the concept of circular economy at the industries and the fulfillment of Sustainable Development Objectives, especially, the number 12 (SDO – 12 - Responsible consumption and production).