J Behin - Chemical Engineering Department, Faculty of Engineering, Razi University, Kermanshah, Iran
S Masoudifar
M Hosseini

Urea is one of the soluble granular fertilizers. This solubility property leads to environmental pollution. One method to reduce environmental pollution involves the use of slow-releasefertilizers. These fertilizers are coated with materials, which reduce their dissolution rate. The aim of this study was to develop a biodegradable coating biopolymer film to reduce release rate ofnitrogen. For this purpose, modified lignin was selected as coating material. The fluidized bed was used to coating process with modified lignin. Two different mass percentages of coating material, including 2.1% and 3.4% was used to investigate the effect of the coating thickness on nitrogenrelease. Experimental results showed when the percentage of coating film was increased from2.1% to 3.4%, the nitrogen release decreased from 80% to 45% after 40 minutes, whereas the corresponding value for urea was 100%. Also, 105 minutes and 5 hours needed to release thenitrogen totally for the samples of 2.1% and 3.4% coating, respectively. This coated fertilizer, with nearly 5 hr delay in dissolution rate, not only is matched to the demand rate of the very precious plants, but also is environment friendly from point of view nitrate pollution losses

Slow-release Fertilizer, Polymer Coating, Urea, Fluidized bed, Biopolymer