Electronic Theses and Dissertation

Katalis heterogen berbasis oksida anorganik dari batuan magnesit lokal Aceh telah berhasil dipreparasi melalui metode dekomposisi termal suhu tinggi (kalsinasi 900°C selama 3 jam). Batuan magnesit lokal Aceh hasil kalsinasi selanjutnya dimodifikasi dengan ion Natrium (Na+) melalui metode impregnasi basah. Karakterisasi fisika-kimia batuan magnesit, oksida anorganik hasil kalsinasi dan oksida anorganik termodifikasi Na+ dianalisis menggunakan X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) dan Fourier-Transform Infrared (FTIR). Hasil karakterisasi menunjukkan bahwa proses kalsinasi dan modifikasi menyebabkan perubahan sifat fisika-kimia dari katalis oksida anorganik yang dihasilkan. Data difraktogram XRD yang diperoleh menunjukkan bahwa katalis oksida anorganik (kalsinasi batuan magnesit pada suhu 900°C) dan katalis oksida anorganik termodifikasi Na 5% (b/b) memiliki kandungan MgO sebagai komponen utama. Hasil analisis menggunakan EDS mengindikasikan bahwa proses kalsinasi telah berdampak positif terhadap kandungan Magnesium (Mg) pada permukaan oksida anorganik dan mengkonfirmasi bahwa Natrium (Na) telah berhasil terimpregnasi pada permukaan oksida MgO. Pengujian kinerja katalis pada reaksi transesterifikasi minyak Refined Belached Deodorized palm Oil (RBDPO) dengan metanol menunjukkan bahwa katalis oksida anorganik termodifikasi Na 5% (b/b) memiliki aktivitas katalitik terbaik pada reaksi transesterifikasi RBDPO (rasio molar minyak : metanol (1: 9); berat katalis 5% (b/b); waktu reaksi 3 jam pada suhu 65°C) dengan perolehan yield biodiesel sebesar 98,40%. Hasil pengujian produk transesterifikasi menggunakan GC-MS (Gas Chromatography-Mass Spectrometer) menunjukkan bahwa katalis oksida anorganik termodifikasi Na+ juga berdampak positif terhadap peningkatan kandungan metil ester (biodiesel) yang dihasilkan dengan kualitas biodiesel yang dihasilkan memiliki nilai bilangan asam (0,5 mg-KOH/g) dan viskositas (2,8 cSt) sesuai dengan standar kualitas biodiesel yang ditetapkan (SNI 7182:2015).

Kata kunci : Magnesit lokal Aceh, kalsinasi 900°C, oksida anorganik termodifikasi
Na, transesterifikasi RBDPO

Heterogeneous catalysts based on inorganic oxides derived from local magnesite rock obtained in Aceh have been successfully prepared using a high temperature thermal decomposition method (900°C for 3 h). Local Aceh magnesite rocks calcined is then modified with sodium (Na+) ions through a wet impregnation method. The physicochemical properties of magnesite rocks, calcined inorganic oxides and Na+ modified inorganic oxides were evaluated using X-Ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS), Fourier-Transform Infrared (FTIR). The characterization results showed that the calcination and modification processes have changed the physicochemical properties of the inorganic oxides catalyst. The diffractogram of XRD analysis proved that inorganic oxide catalyst and Na 5% (w/w) modified inorganic oxide catalyst were contained MgO as major component. The results of EDS analysis indicated that calcination process had been positive impact on enhancing the Magnesium (Mg) content in inorganic oxide catalyst. Based EDS spectra, there also confirmed that Sodium (Na) has been successfully impregnated on the surface of the MgO oxide. Catalytic performance of the obtained catalyst had been applied in transesterification reaction of Refined Bleached Deodorized palm Oil (RBDPO) with methanol, which showed that the Na 5% (w/w) modified inorganic oxide catalyst had been the best catalytic activity applied in the RBDPO transesterification reaction (molar ratio of oil: methanol (1: 9); catalyst weight 5% (w/w); reaction time 3 hours, temperature 65°C) resulted biodiesel yield of 98.40%. The chemical analysis on the transesterification products using GC-MS (Gas Chromatography-Mass Spectrometer) showed that the Na+ modified inorganic oxide catalyst has positive impact to increase the methyl ester (biodiesel) products, in which the quality of the biodiesel products had been acid number of 0.5 mg-KOH/g and viscosity of 2.8 cSt accorded to quality standards of Indonesian biodiesel (SNI 7182:2015). Key words : Local Aceh magnesite, calcination, Na-modified inorganic oxide, RBDPO transesterification