Katalis Kobalt Terimpregnasi Pada Gamma-Al2O3 Teraktivasi Gelombang Ultrasonik Untuk Hydrotreatment Minyak Nyamplung (Calophyllum inophyllum L.) Menjadi Bioavtur

Rachel Geovani Jatmika, Prof. Dra. Wega Trisunaryanti, M.S., Ph.D., Eng.; Prof. Dr. Triyono, S.U.

2026 | Skripsi | KIMIA

Preparasi dan aplikasi katalis kobalt terimpregnasi pada gamma-Al2O3 teraktivasi gelombang ultrasonik untuk hydrotreatment minyak nyamplung (Calophyllum Inophyllum L.) menjadi bioavtur telah dilakukan. Penelitian ini bertujuan untuk mempelajari pengaruh reduktor gas hidrogen (H2) dan asam sitrat terhadap aktivitas katalis Co/gamma-Al2O3 serta stabilitas katalis dalam penggunaan berulang pada proses hydrotreatment minyak nyamplung menjadi bioavtur. Preparasi katalis Co/gamma-Al2O3 dilakukan dengan impregnasi kering larutan prekursor kobalt(II) nitrat heksahidrat (Co(NO3)2·6H2O) dari limbah baterai Li-NMC ke penyangga gamma-Al2O3 yang dilanjutkan dengan sonikasi. Katalis gamma-Al2O3 dikalsinasi dengan gas nitrogen (N2) selama 3 jam pada suhu 500 oC kemudian direduksi oleh gas H2 dan larutan asam sitrat (C6H8O7) hingga dihasilkan katalis Co/gamma-Al2O3/H2 dan Co/gamma-Al2O3/CA. Katalis Co/gamma-Al2O3/H2 dan Co/gamma-Al2O3/CA kemudian dikarakterisasi dengan instrumen XRD, FTIR, SEM-EDX, NH3-TPD, dan XPS. Uji aktivitas katalis dilakukan dengan reaktor stainles-steel semi-batch. Proses hydrtrotreatment minyak nyamplung dilakukan pada rentang temperatur 200–600 oC dengan kenaikan 20 oC dan dialiri gas H2 dengan laju alir 20 mL/menit. Produk cair hasil proses hydrotreatment dianalisis dengan instrumen FTIR dan GC-MS.

Berdasarkan hasil penelitian, konversi produk cair, selektivitas, dan yield bioavtur tertinggi dihasilkan oleh katalis Co/gamma-Al2O3/CA berturut-turut sebesar 45,19%; 79,71%; dan 36,02%. Sementara itu, konversi produk cair, selektivitas, dan yield bioavtur dari katalis Co/gamma-Al2O3/H2 berturut-turut sebesar 39,50%; 68,59%; dan 27,10%. Keasaman total katalis Co/gamma-Al2O3/CA lebih tinggi dibandingkan katalis Co/gamma-Al2O3/H2, secara berturut-turut sebesar 6,15 mmol g-1 dan 2,09 mmol g-1. Katalis Co/gamma-Al2O3/CA memiliki performa yang menjanjikan setelah uji reuseability dengan konversi produk cair pada penggunaan kedua dan ketiga, secara berurutan sebesar 41,025,09%.

Preparation and application of cobalt catalyst impregnated on gamma-Al2O3 activated by ultrasound waves for hydrotreatment of nyamplung (Calophyllum inophyllum L.) oil into bioavtur have been conducted. This research aims to study the effect of hydrogen gas (H2) and citric acid reducing agents on the activity of the Co/gamma-Al2O3 catalyst, as well as the catalyst's stability during reuseability test in the hydrotreatment process of nyamplung oil into bioavtur. The preparation of the Co/gamma-Al2O3 catalyst was carried out by dry impregnation of a cobalt(II) nitrate hexahydrate (Co(NO3)2·6H2O) precursor solution derived from Li-NMC battery waste onto a gamma-Al2O3 support, followed by sonication. The Co/gamma-Al2O3 catalyst was calcined with nitrogen (N2) gas for 3 hours at 500 °C, and then reduced using H2 gas and citric acid (C6H8O7) solution to produce Co/gamma-Al2O3/H2 and Co/gamma-Al2O3/CA catalysts. The Co/gamma-Al2O3/H2 and Co/gamma-Al2O3/CA catalysts were then characterized using XRD, FTIR, SEM-EDX, NH3-TPD, and XPS instruments. The catalyst activity test was conducted using a semi-batch stainless-steel reactor. The hydrotreatment process of nyamplung oil was carried out in a temperature range of 200–600 °C with 20 °C increments and flowed with H2 gas at a flow rate of 20 mL/min. The liquid product from the hydrotreatment process was analyzed using FTIR and GC-MS instruments.

Based on the research results, the highest liquid product conversion, selectivity, and biojet fuel yield were produced by the Co/?-Al2O3/CA catalyst at 45.19%; 79.71%; and 36.02%; respectively. Meanwhile, the liquid product conversion, selectivity, and bioavtur yield from the Co/?-Al2O3/H2 catalyst were 39.50%; 68.59%; and 27.10%; respectively. Total acidity of the Co/?-Al2O3/CA catalyst was higher than that of the Co/gamma-Al2O3/H2 catalyst, at 6.15 mmol g-1 and 2.09 mmol g-1, respectively. The Co/gamma-Al2O3/CA catalyst demonstrated promising performance after the reusability test, with liquid product conversion in the second and third uses at 41.12% and 35.09%, respectively.

Kata Kunci : asam sitrat, bioavtur, ?-Al2O3, hydrotreatment, minyak nyamplung