KATALIS HETEROGEN K2CO3/γ-ALUMINA DAN CaCO3/γ- ALUMINA DALAM PEMBUATAN BIODIESEL

ARUM DWI AGUSTIN, Prof. Dra.Wega Trisunaryanti, M.S., Ph.D.Eng

2014 | Tesis | S2 Ilmu Kimia

Telah dipelajari tentang katalis heterogen K2CO3/γ-alumina dan CaCO3/γ- alumina dalam pembuatan biodiesel melalui transesterifikasi minyak jarak (Riccinus communis). Garam K2CO3 dan CaCO3 (10% b/b) diembankan pada γ- alumina dengan metode impregnasi basah, diikuti dengan kalsinasi dan oksidasi menghasilkan katalis K2CO3/γ-alumina dan CaCO3/γ-alumina. Katalis yang telah dipreparasi selanjutnya dikarakterisasi dengan X-Ray Diffraction (XRD), Surface Area Analyzer (SAA) dan Barret Joyner Halenda (BJH) untuk menganalisis kristalinitas, luas permukaan, volume pori total dan rerata jejari pori dari katalis secara berurutan. Basisitas katalis ditentukan dengan metode Hammett. Reaksi transesterifikasi minyak jarak dilakukan dengan sistem batch reactor pada 60oC selama 2 jam. Parameter seperti rasio berat katalis terhadap minyak dan waktu reaksi, divariasikan untuk memperoleh konversi minyak jarak menjadi biodiesel. Kandungan metil ester dalam produk biodiesel dianalisis dengan menggunakan GC-MS dan American Standard of Testing Materials (ASTM) biodiesel. Hasil penelitian menunjukkan impregnasi K2CO3 dan CaCO3 pada γ-alumina mampu menurunkan luas permukaan, meningkatkan basisitas dan rerata jejari pori γ-alumina. Aktivitas katalitik tertinggi menghasilkan konversi biodiesel sebesar 95% pada kondisi 5% b/b K2CO3/γ-alumina selama 150 menit. Selektivitas katalis terhadap metil risinoleat dari analisis GC dan produk cair sebesar 91,81% dan 87,22%.

Heterogeneous catalysts of K2CO3/γ-alumina and CaCO3/γ-alumina for biodiesel production via transesterification of castor oil (Riccinus communis) have been studied. The K2CO3 and CaCO3 salt (10 wt.%) was loaded on γ-alumina by wet impregnation method, followed by calcination and oxidation produced K2CO3/γ-alumina and CaCO3/γ-alumina catalysts. The prepared catalysts were characterized by X-Ray Diffraction (XRD), Surface Area Analyzer (SAA) and Barret Joyner Halenda (BJH) to analyze cristalinity, specific surface, total pore volume and average pore radius of catalysts, respectively. Basicity of catalysts were determined by the Hammett method. Transesterification reaction of castor oil was conducted in a batch reactor system at 60oC for 2 h. The parameters of catalyst to oil weight ratio and reaction time were varied for conversion of the castor oil to biodiesel. The methyl esther content on biodiesel product was analyzed with GC-MS and American Standard of Testing Materials (ASTM) of biodiesel. The result show that impregnation of K2CO3 and CaCO3 to γ-alumina were decreased specific surface area and increased basicity and average pore radius of γ-alumina. The highest catalytic activity yielded 95% biodiesel under the condition of 5 wt.% K2CO3/γ-alumina for 150 min. The catalyst selectivity toward methyl ricinoleate of GC analysis and liquid product were 91.81% and 87.22%.

Kata Kunci : biodiesel, transesterifikasi, dan Riccinus communis