Preparation And Characterization Of Attapulgite-Fly Ash-Based Binuclear Slow-Release Fertilizer Encapsulated By Eudragit

To enhance the effectiveness of urea, a novel, binuclear, slow-release urea fertilizer was developed with the application of drum-coating technology, which used large granular urea as the core carrier, attapulgite (APT)-fly ash (FA) as the inner coating, and Eudragit as the outer coating. The nutrient-release characteristics of the binuclear slow-release fertilizer with 10% coating synthesized under optimized conditions were studied in soil and water, and the relationships between pH, electrical conductivity, and nitrogen release rate were determined through fitting function. The structure and properties of the samples were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The results indicated that the optimum preparation conditions were as follows: the inner coating shall be 4% binder concentration, 10 g APT and FA in total, APT/FA = 7:3; coating film material of Eudragit E100, 75% ethanol concentration, with coating accounting for >9% and plasticizer accounting for 1%. The product showed excellent release performance, with 65.74% of the nutrients leaching in the soil column within 28 d. Therefore, this work has demonstrated the potential of this new double-coated fertilizer system in agriculture for improving the effectiveness of fertilizers.