Synthesis of Nitrogen Slow Released Fertilizer Based Biochar Derived from Durian Shell

¹ Demonstration School of Khon Kaen University, Thailand
² Department of Chemical Engineering, Faculty of Engineering, Khon Kaen University, Thailand

^* Corresponding author: duangkanok@kku.ac.th

Abstract

This study aims to synthesize slow-release fertilizer using biochar derived from durian shell which is the main contributor to agricultural waste and become an environmental problem. Therefore, the utilization of the durian peel was carried out. Biochar was synthesized through the pyrolysis process at 450, 500 and 550°C, then impregnated with urea fertilizer and encapsulated with a biopolymer. Nutrient release rate of biochar coated with chitosan by dissolution method was studied. The result showed that yield of biochar decreased with increasing pyrolysis temperature. The BET showed that 500°C gives the highest surface area and pore volume at 0.34 m²/g and 1.86 x 10-3 cm³/g. The FT-IR analysis indicated that N₂ impregnated fertilizer had higher nitrogen amount resulting from amine functional groups where the peak at 3456 cm^-1 was observed. This confirms that high porosity biochar can absorb urea fertilizer. There was some increase in functional groups representing chitosan after encapsulation, at 1156, 1453, and 1682 cm^-1, indicating chitosan was successfully coated on the biochar fertilizers. Nitrogen release results showed that synthetic biochar fertilizer can slow down the release of nitrogen by 60%. In conclusion, durian shell can be used to synthesize biochar and slow released fertilizer which prolong the release of the nutrient.