Candlenut shell is an agricultural waste which can be processed into low-cost active carbon. Activated carbon cannot be used directly as a heterogeneous catalyst in transesterification of biodiesel because of its low alkalinity, thus treatment is required. In this study, the carbonization of candlenut shells was conducted at 500°C for 4 h. The activated carbon obtained was modified by impregnation with potassium hydroxide (KOH) solution. KOH concentration used was 50g/150 ml aqua des and impregnation time was 24 h. The impregnated activated carbon was characterized by Scanning Electron Microscopy - energy dispersive spectroscopy (SEM-EDS), Fourier Transform Infrared (FTIR) spectroscopy, and was further tested as a heterogeneous catalyst for biodiesel production.

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In this study, chicken bone was used as starting material for hydroxyapatite (HAp) synthesis. Chicken bone was calcined in electric furnace at 1000°C for 5 hours in order to obtain calcium oxide. Calcium oxide was reacted with aquadest to form calcium dioxide which was used as calcium precursor. Calcium dioxide was reacted with phosphoric acid which was used as phosphorus precursor. This reaction was conducted at pH 10 and reaction temperature was 40°C. The obtained results of this reaction were calcined at 500°C and 900°C for 2 hours and 6 hours. Then it was characterized by using FTIR, XRD and SEM. The increasing of temperature and time of calcination lead to low carbonate content and good morphology. Different result occurs in particle size which increased with increasing temperature and time of calcination. HAp that synthesized from this study had low purity. Best result was obtained in calcination at temperature 900°C and in 6 hours long where crystal size and crystallinity degree from this sample were 63.021 nm and 87.30% respectively.