Preparasi Katalis Kalsium Oksida Terimpregnasi Besi(III) Oksida dan Terfungsionalisasi Aminosilan untuk Konversi Minyak Nyamplung (Calophyllum inophyllum L.) menjadi Fatty Acid Methyl Esters

Putri Nur Rohmah, Prof. Dr. Triyono, S.U.; Prof. Dra. Wega Trisunaryanti, M.S., Ph.D. Eng.

2026 | Skripsi | KIMIA

Penelitian ini berhasil mensintesis dan mengkarakterisasi katalis CaO–Fe2O3–APTMS, mengevaluasi performanya dalam produksi fatty acid methyl esters (FAME) dari minyak nyamplung, mengoptimasi kondisi reaksi menggunakan metode Response Surface Methodology (RSM), serta menguji reusability katalis. Katalis disintesis melalui metode ultrasound-assisted spray impregnation untuk impregnasi Fe2O3 dan ultrasound-assisted grafting untuk fungsionalisasi 3-APTMS. Karakterisasi katalis dilakukan menggunakan XRD, FTIR, SEM-EDX, SAA, NH?-TPD, dan CO?-TPD. Optimasi kondisi reaksi dilakukan menggunakan metode RSM berbasis Hybrid Central Composite Design (Hybrid CCD) dengan waktu reaksi, konsentrasi katalis, dan rasio molar metanol terhadap minyak sebagai variabel bebas, sementara yield FAME sebagai respons utama.

Hasil penelitian menunjukkan bahwa katalis CaO–Fe2O3–APTMS memiliki sifat asam–basa yang lebih baik dibandingkan CaO dan CaO–Fe2O3, dengan total kebasaan sebesar 3,73 mmol CO? g?¹ dan total keasaman sebesar 1,73 mmol NH? g?¹. Karakterisasi SAA menunjukkan bahwa katalis memiliki luas permukaan spesifik sebesar 2,83 m² g?¹, volume pori total sebesar 2,84 × 10?² cm3 g?¹, dan rerata diameter pori sebesar 401,44 Å. Pada kondisi operasi yang sama, katalis CaO–Fe2O3–APTMS menghasilkan yield FAME sebesar 80,61%, lebih tinggi dibandingkan CaO dan CaO–Fe2O3. Hasil optimasi menunjukkan bahwa kondisi optimum diperoleh pada waktu reaksi 4,83 jam, konsentrasi katalis 3,71%, dan rasio molar metanol terhadap minyak 12:1 dengan yield FAME sebesar 88,62%. Uji reusability menunjukkan bahwa katalis masih dapat digunakan hingga tiga siklus reaksi meskipun terjadi penurunan aktivitas katalitik. Secara keseluruhan, katalis CaO–Fe2O3–APTMS berpotensi digunakan sebagai katalis heterogen bifungsional yang efektif untuk produksi FAME dari minyak nyamplung dengan asam lemak bebas (FFA) yang tinggi. 

This study successfully synthesized and characterized the CaO–Fe?O?–APTMS catalyst, evaluated its performance in the production of fatty acid methyl esters (FAME) from nyamplung oil, optimized the reaction conditions using the Response Surface Methodology (RSM), and investigated the catalyst reusability. The catalyst was synthesized through ultrasound-assisted spray impregnation for Fe2O3 impregnation and ultrasound-assisted grafting for 3-APTMS functionalization. Catalyst characterization was carried out using XRD, FTIR, SEM-EDX, SAA, NH?-TPD, and CO?-TPD. Reaction optimization was performed using RSM based on Hybrid Central Composite Design (Hybrid CCD) with reaction time, catalyst concentration, and methanol-to-oil molar ratio as independent variables, while FAME yield was used as the main response.

The results showed that CaO–Fe2O3–APTMS exhibited better acid–base properties than CaO and CaO–Fe2O3, with total basicity and total acidity of 3.73 mmol CO? g?¹ and 1.73 mmol NH? g?¹, respectively. SAA characterization revealed that the catalyst possessed a specific surface area of 2.83 m² g?¹, total pore volume of 2.84 × 10?² cm3 g?¹, and average pore diameter of 401.44 Å. Under the same operating conditions, CaO–Fe2O3–APTMS produced a FAME yield of 80.61%, which was higher than those of CaO and CaO–Fe2O3. Optimization results indicated that the optimum conditions were achieved at a reaction time of 4.83 h, catalyst concentration of 3.71%, and methanol-to-oil molar ratio of 12:1, resulting in a FAME yield of 88.62%. Reusability testing demonstrated that the catalyst could still be reused for up to three reaction cycles despite a decrease in catalytic activity. Overall, CaO–Fe2O3–APTMS shows potential as an effective bifunctional heterogeneous catalyst for FAME production from nyamplung oil with a high free fatty acid (FFA) content.

Kata Kunci : fatty acid methyl esters, kalsium oksida termodifikasi besi(III) oksida dan 3–APTMS, katalis bifungsional, minyak nyamplung.