Sintesis Komposit Biochar Ranting Kayu, Ampas Tebu, Dan Bentonit Untuk Pemurnian Minyak Jelantah Sebagai Bahan Baku Biodiesel

Wijayanti, Avissa Auryn (2026) Sintesis Komposit Biochar Ranting Kayu, Ampas Tebu, Dan Bentonit Untuk Pemurnian Minyak Jelantah Sebagai Bahan Baku Biodiesel. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Minyak jelantah merupakan limbah rumah tangga dan industri yang mengalami degradasi termal dan oksidatif akibat penggorengan berulang, yang ditandai dengan peningkatan asam lemak bebas (ALB), bilangan peroksida, serta perubahan warna. Kandungan ALB dan bilangan peroksida yang tinggi menurunkan mutu minyak, berpotensi membahayakan kesehatan dan lingkungan, serta menghambat pemanfaatannya sebagai bahan baku biodiesel. Penelitian ini mengevaluasi kinerja tujuh adsorben, yaitu bentonit, RK, RKB, RKBN, AT, ATB, dan ATBN, dalam menurunkan bilangan asam, bilangan peroksida, dan intensitas warna minyak jelantah. Metode penelitian mencakup sintesis ranting kayu (RK) dan ampas tebu (AT) sebagai biochar, kemudian dikompositkan dengan bentonit dan diaktivasi menggunakan NaOH untuk menghasilkan RKB, RKBN, ATB, dan ATBN. Seluruh adsorben dikarakterisasi menggunakan FTIR dan SEM-EDX. Uji adsorpsi dilakukan dengan variasi massa adsorben (2–10 g) selama 180 menit dan variasi waktu kontak (0–180 menit) pada massa adsorben 10 g. Analisis bilangan asam dan bilangan peroksida dilakukan menggunakan metode titrasi (SNI 7707:2019), sedangkan perubahan warna dianalisis menggunakan spektrofotometri UV-Vis. Hasil penelitian menunjukkan bahwa ATBN memberikan performa adsorpsi tertinggi dengan penurunan bilangan asam sebesar 61,66–65,3%, bilangan peroksida sebesar 82,33–84,5%, serta intensitas warna sebesar 24–24,3%. Analisis isoterm menunjukkan bahwa mekanisme adsorpsi bilangan asam dan bilangan peroksida mengikuti model Harkins–Jura yang mengindikasikan adsorpsi multilapis pada permukaan heterogen, sedangkan adsorpsi warna mengikuti model Temkin yang mencerminkan penurunan energi adsorpsi seiring meningkatnya penutupan permukaan. Studi kinetika menunjukkan bahwa seluruh parameter mengikuti model PSO, yang menandakan bahwa proses adsorpsi dikendalikan oleh mekanisme kemisorpsi. Berdasarkan hasil uji kinerja adsorpsi, uji rasio komposit dilakukan pada tahap akhir dan menunjukkan bahwa perbandingan biochar:bentonit 1:2 merupakan kondisi optimum, yang dikaitkan dengan keseimbangan antara luas permukaan biochar dan jumlah situs aktif polar bentonit (Si–O–Al dan –OH), sehingga meningkatkan efisiensi interaksi adsorpsi tanpa menghambat akses pori. Secara keseluruhan, ATBN berpotensi diaplikasikan sebagai adsorben efektif untuk pemurnian minyak jelantah pada skala laboratorium.
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Used cooking oil is household and industrial waste that undergoes thermal and oxidative degradation due to repeated frying, characterized by an increase in free fatty acids (FFA), peroxide value, and color change. High FFA and peroxide value content reduces oil quality, potentially endangering health and the environment, and hindering its use as a biodiesel feedstock. This study evaluated the performance of seven adsorbents, namely bentonite, RK, RKB, RKBN, AT, ATB, and ATBN, in reducing the acid value, peroxide value, and color intensity of used cooking oil. The research method included the synthesis of wood chips (RK) and bagasse (AT) as biochar, which were then composited with bentonite and activated using NaOH to produce RKB, RKBN, ATB, and ATBN. All adsorbents were characterized using FTIR and SEM-EDX. Adsorption tests were conducted with variations in adsorbent mass (2–10 g) for 180 minutes and contact time (0–180 minutes) at an adsorbent mass of 10 g. Acid number and peroxide number analyses were performed using the titration method (SNI 7707:2019), while color changes were analyzed using UV-Vis spectrophotometry. The results showed that ATBN provided the highest adsorption performance with a decrease in acid number of 61.66–65.3%, peroxide number of 82.33–84.5%, and color intensity of 24–24.3%. Isotherm analysis showed that the adsorption mechanism of acid number and peroxide number followed the Harkins–Jura model, which indicates multilayer adsorption on a heterogeneous surface, while color adsorption followed the Temkin model, which reflects a decrease in adsorption energy as surface coverage increases. The kinetic study showed that all parameters followed the PSO model, indicating that the adsorption process was controlled by chemisorption mechanisms. Based on the adsorption performance test results, a composite ratio test was conducted at the final stage and showed that a biochar:bentonite ratio of 1:2 was the optimum condition, which was associated with a balance between the surface area of biochar and the number of active polar sites of bentonite (Si–O–Al and –OH), thereby increasing the efficiency of adsorption interactions without inhibiting pore access. Overall, ATBN has the potential to be applied as an effective adsorbent for waste oil purification on a laboratory scale.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	Minyak jelantah, bilangan asam, bilangan peroksida, ranting kayu, ampas tebu, dan bentonit, Used cooking oil, acid value, peroxide value, wood brances, sugarcane bagasse, and bentonite
Subjects:	T Technology > TD Environmental technology. Sanitary engineering T Technology > TD Environmental technology. Sanitary engineering > TD195.B56 Biomass energy T Technology > TD Environmental technology. Sanitary engineering > TD898.8.C67 Waste disposal
Divisions:	Faculty of Civil Engineering and Planning > Environment Engineering > 25101-(S2) Master Thesis
Depositing User:	Avissa Auryn Wijayanti
Date Deposited:	22 Jan 2026 06:09
Last Modified:	22 Jan 2026 06:09
URI:	http://repository.its.ac.id/id/eprint/130046

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