Sintesis Dan Karakterisasi Urea-Hidroksiapatit Dengan Variasi Ca(OH)2 Sebagai Kandidat Pupuk Lepas Lambat

Urea-hydroxyapatite can be used as fertilizer which was efficient and environmentally friendly. The variation of Ca(OH) 2 in the urea-hydroxyapatite’s synthesis and its characterization would provide information for manufacturing slow release fertilizer. The material used were urea (99.5 %); Ca(OH) 2 ; H 3 PO 4 0.67 M and distilled water. The synthesis technique used in this study is bottom-up with Ca(OH) 2 variation of 6, 8, 10 and 12 grams. The results of the synthesis with 6 grams of Ca(OH) 2  was not able to produce sediment powder. The results of the Scanning Electron Microscopy (SEM) showed that the urea packaging with hydroxyapatite was better for variations of Ca(OH) 2  8 grams and 10 grams. The results of the Energy Dispersive X-Ray Spectrometry (EDX) showed more elemental composition in the variation of Ca(OH) 2  8 grams and 10 grams which were 35.7 Wt% and 40.4 Wt%. The results of the Fourier Transform Infrared Spectrometer (FTIR) showed that the variation of Ca(OH) 2  8 gram has a good bonding of urea and hydroxyapatite. The Particle Size Analyzer (PSA) measurement for all samples of urea-hydroxyapatite yielded the particle size of about 0.5–2.5 mm and 10–15 mm for urea and hydroxyapatite, respectively. As a conclusion, the variation of Ca(OH) 2  8 grams could be recommended as a reference in the composition of urea-hydroxyapatite fabrication for slow release fertilizer.