Electronic Theses and Dissertation

Penelitian ini bertujuan untuk mensintesis dan mengkarakterisasi nanopartikel oksida
anorganik berbasis CaO dari limbah tulang sapi Aceh serta mengkaji aplikasinya
sebagai katalis pada reaksi transesterifikasi minyak Refined Bleached and Deodorized
Palm Oil (RBDPO) menjadi biodiesel. Sintesis katalis dilakukan menggunakan
metode presipitasi dengan variasi agen pengendap, yaitu natrium hidroksida (NaOH)
dan amonium hidroksida (NH4OH). Partikel hasil presipitasi selanjutnya dikalsinasi
pada suhu 700◦C selama 4 jam dan dikarakterisasi menggunakan X-Ray Diffraction
(XRD), Fourier Transform Infrared Spectroscopy (FTIR), serta Scanning Electron
Microscope-Energy Dispersive X-Ray Spectroscopy (SEM-EDS). Hasil karakterisasi
XRD menunjukkan bahwa partikel oksida anorganik hasil presipitasi menggunakan
agen pengendap NaOH maupun NH4OH mengandung beberapa fasa, yaitu
hidroksiapatit (Ca10(PO4)6(OH)2), kalsium karbonat (CaCO3), kalsium oksida (CaO)
dan kalsium hidroksida (Ca(OH)2). Katalis yang disintesis menggunakan agen
pengendap NaOH memiliki ukuran kristalit sebesar 38,36 nm, sedangkan penggunaan
agen pengendap NH4OH menghasilkan ukuran kristalit yang lebih kecil, yaitu 22,15
nm. Spektrum FTIR menunjukkan keberadaan gugus fosfat (PO43-), karbonat (CO32-),
dan hidroksil (-OH) yang mengonfirmasi terbentuknya senyawa berbasis kalsium.
Analisis SEM-EDS memperlihatkan morfologi partikel yang cenderung berbentuk
bulat dengan komposisi unsur utama berupa Ca, P, dan O. Oksida anorganik berbasis
CaO yang dihasilkan selanjutnya diaplikasikan sebagai katalis pada reaksi
transesterifikasi RBDPO dengan metanol. Analisis GC-MS menunjukkan bahwa
biodiesel yang menggunakan katalis dengan agen pengendap NaOH didominasi oleh
metil palmitat dan metil oleat, sedangkan biodiesel yang menggunakan katalis dengan
agen pengendap NH4OH didominasi oleh metil miristat dan metil oleat. Biodiesel hasil
sintesis dengan agen pengendap NaOH memiliki bilangan asam sebesar 0,36 mg
KOH/g, viskositas 2,30 cSt, dan massa jenis 0,775 g/mL, sedangkan biodiesel hasil
sintesis dengan agen pengendap NH4OH memiliki bilangan asam 0,36 mg KOH/g,
viskositas 4,37 cSt, dan massa jenis 0,778 g/mL. Yield biodiesel tertinggi diperoleh
pada penggunaan katalis dengan agen pengendap NaOH sebesar 88,64%, lebih tinggi
dibandingkan katalis dengan agen pengendap NH4OH sebesar 81,11%. Hasil
penelitian menunjukkan bahwa perbedaan jenis agen pengendap berpengaruh terhadap
fasa kristal, ukuran kristalit, serta kinerja katalis dalam reaksi transesterifikasi
biodiesel.

This study aims to synthesize and characterize CaO based inorganic oxide nanoparticles derived from Aceh cattle bone waste and to evaluate their application as catalysts in the transesterification reaction of Refined Bleached and Deodorized Palm Oil (RBDPO) into biodiesel. The catalysts were synthesized using a precipitation method with variations of precipitating agents, namely sodium hydroxide (NaOH) and ammonium hydroxide (NH4OH). The resulting precipitates were calcined at 700◦C for 4 h and characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDS). XRD analysis revealed that the inorganic oxide particles precipitated using both NaOH and NH4OH contained several phases, including hydroxyapatite (Ca10(PO4)6(OH)2), calcium carbonate (CaCO3), calcium oxide (CaO), and calcium hydroxide (Ca(OH)2). The catalyst synthesized using NaOH as the precipitating agent exhibited a crystallite size of 38.36 nm, whereas the use of NH4OH resulted in a smaller crystallite size of 22.15 nm. FTIR spectra confirmed the presence of phosphate (PO43-), carbonate (CO32-), and hydroxyl (-OH) functional groups, indicating the formation of calcium-based compounds. SEM-EDS analysis showed that the particles exhibited a predominantly spherical morphology, with Ca, P, and O as the main constituent elements. The synthesized CaO based inorganic oxide was subsequently applied as a catalyst in the transesterification of RBDPO with methanol. GC-MS analysis indicated that biodiesel produced using the catalyst synthesized with NaOH as the precipitating agent was dominated by methyl palmitate and methyl oleate, whereas biodiesel produced using the catalyst synthesized with NH4OH was dominated by methyl myristate and methyl oleate. Biodiesel produced using the NaOH precipitated catalyst exhibited an acid value of 0.36 mg KOH/g, a viscosity of 2.30 cSt, and a density of 0.775 g/mL. In contrast, biodiesel produced using the NH4OH precipitated catalyst showed an acid value of 0.36 mg KOH/g, a viscosity of 4.37 cSt, and a density of 0.778 g/mL. The highest biodiesel yield was achieved using the catalyst synthesized with NaOH as the precipitating agent, reaching 88.64%, which was higher than that obtained using NH4OH (81.11%). These results indicate that the type of precipitating agent significantly influences the crystalline phases, crystallite size, and catalytic performance in biodiesel transesterification reactions.