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All Journal Jurnal Ilmu Dasar UNEJ e-Proceeding Keluwih: Jurnal Sains dan Teknologi
Restu Kartiko Widi
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Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Computer Science & IT Control & Systems Engineering Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Mathematics Mechanical Engineering

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Immobilization of Lipase on Surfactant-Modified Bentonite and Its Application for Biodiesel Production from Simulated Waste Cooking Oil Ruth Chrisnasari; Angelina Yonardi; Hesti Lie; Restu Kartiko Widi; Maria Goretti Marianti Purwanto
UNEJ e-Proceeding Indonesian Protein Society (IPS), International Seminar and Workshop 2014
Publisher : UPT Penerbitan Universitas Jember

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Abstract

The influence of bentonite modification by cationic surfactant hexadecyl-trimethyl-ammonium bromide (HDTMA-Br) and tetramethyl ammonium hydroxide (TMAOH) on its capability to immobilize lipase was studied. Modification of bentonite was conducted by the adding of 4-6% (v/v) HDTMA-Br and TMAOH respectively. The obtained immobilized lipases then were characterized to observe the optimum pH and temperature as well as their stability during reuse application. The observed results show that there is no significant difference between the variations of HDTMA-Br concentrations to the percentage of immobilized enzyme which can immobilize lipase up to 75-78%. However, the best concentration of TMAOH is 4% (v/v) which can immobilize lipase up to 97.95%. The obtained immobilized lipases on HDTMA-Br-modified bentonite show the optimum catalytic activity on reaction temperature of 35-40 oC and pH of 7.5. In other hand, the optimum catalytic activity of immobilized lipases on TMAOH-modified bentonite is 40oC of incubation temperature and pH of 7. The immobilized lipases on both HDTMA-Br and TMAOH modified bentonite are stable enough so it could be re-used four times before its activity decreased by 48,565% and 46.83 % respectively. Keywords: Lipase, Cationic Surfactant, Bentonite, HDTMA-Br, TMAOH, Biodiesel, Immobilization.
Combinatorial Technology as a New Method for Chemical Processes Restu Kartiko Widi; Sharifah bee Abdul Hamid; Looi Mei Hong
Jurnal ILMU DASAR Vol 10 No 1 (2009)
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Jember

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The ultimate goal approach to combinatorial catalysis taken in this research is from an academic perspective where the main objective is to accelerate the discovery of catalytic phenomena, i.e. new catalytic materials and catalytic processes, constrained by limited equipment and human resources. A commercially synthesis robotic workstation is used for automated parallel preparation of catalyst libraries, which is able to reproduce a conventional catalyst preparation method used routinely in laboratory, thereby increasing significantly the number of catalysts that can be prepared at once. The aim of this work is to produce libraries of catalysts based on this type of system to be tested and optimized by using the high throughput screening reactors and the selected catalysts are characterized to understand the structural properties. The 12 parallel reactors allows a proper catalyst testing, under more realistic conditions than in conventional combinatorial techniques, especially when the catalyst stage is advanced and quantitative data is required.
Pengaruh jenis Spesies Pillaring Agent Logam Si dalam proses Pilarisasi Bentonit Alam Restu Kartiko Widi; Emma Savitri
Keluwih: Jurnal Sains dan Teknologi Vol. 6 No. 1 (2025): Keluwih: Jurnal Sains dan Teknologi (February) - In Progress
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v6i1.6424

Abstract

Abstract—The pillarization process of natural bentonite from Pacitan, East Java has been carried out using the metal species Si in Na-silicate and TEOS. The pillarization process is carried out using direct pillarization and indirect pillarization methods. In this research, the number of moles of metal pillaring agent used was 5 mmol/gram bentonite. The pillarization process is carried out by mixing the natural bentonite suspension and pillaring agent at a temperature of 80oC and stirring for 5 hours using a hot plate stirrer. Pillars were formed in the calcination and oxidation stages at a temperature of 500oC using N2 and O2 gas flows for 1 hour and 5 hours respectively. The resulting material was characterized using the FTIR spectroscopy method, X-ray diffraction and N2 gas adsorption using the BET method. The characterization results show that TEOS species can form better and more homogeneous pore structures compared to silicate species. The direct pillarization method provides better and more homogeneous pillar heights compared to the indirect pillarization method. However, the pore size obtained is still on the micropore size scale observed using the N2 gas adsorption method with the BET method. Keywords: pillarization, si, teos, bentonite Abstrak—Telah dilakukan proses pilarisasi bentonit alam asal Pacitan, Jawa Timur menggunakan spesies logam Si dalam Na-silikat dan TEOS. Proses pilarisasi yang dilakukan menggunakan metode pilarisasi langsung dan pilarisasi tidak langsung. Pada penelitian ini jumlah mol logam pillaring agent yang digunakan adlah 5 mmol/gram bentonit. Proses pilarisasi dilakukan dengan mencampurkan suspensi bentonit alam dan pillaring agent pada suhu 80oC dan diaduk selama 5 jam menggunakan hot plate stirrer. Pilar dibentuk pada tahap kalsinasi dan oksidasi pada suhu 500oC menggunakan aliran gas N2 dan O2 masing-masing selama 1 jam dan 5 jam. Material yang dihasilkan dikarakterisasi menggunakan metode spektroskopi FTIR, difraksi sinar-X dan adsorpsi gas N2 dengan metode BET. Hasil karakterisasi menunjukkan bahwa spesies TEOS dapat membentuk struktur pori lebih baik dan lebih homogen dibandingkan dengan spesies silikat. Metode plarisasi langsung memberikan tinggi pilar lebih baik dan lebih homogen dibandingkan dengan metode pilarisasi tidak langsung. Namun demikian ukuran pori yang diperoleh masih dalam skala ukuran mikropori yang diamati menggunakan metode adsorpsi gas N2 dengan metode BET. Kata kunci: pilarisasi, si, teos, bentonit
Sintesis Oksida Logam Ganda TiO2 dan Fe3O4 dalam Struktur Lapisan Bentonit Alam sebagai Material Fotokatalis Restu Kartiko Widi
Keluwih: Jurnal Sains dan Teknologi Vol. 7 No. 2 (2026): Keluwih: Jurnal Sains dan Teknologi (September) - In Progress
Publisher : Direktorat Penerbitan dan Publikasi Ilmiah, Universitas Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24123/saintek.v7i1.8861

Abstract

Abstract—The synthesis of double metal oxides TiO₂ and Fe₃O₄ within the layered structure of natural bentonite as a photocatalyst material has been successfully conducted. This study aims to investigate the effect of the Ti and Fe mole ratio on the properties and structure of the resulting material. The background of this research is the successful synthesis of iron oxide in the natural bentonite layer structure without destroying the overall bentonite structure. In this research, the synthesis method used was using the sol-gel method in an inert nitrogen gas atmosphere system. The photocatalyst material was calcined using a pipe furnace at a temperature of 500 oC for 3 hours with a flow of nitrogen and oxygen gas to obtain a better metal oxide. The photocatalyst material obtained was characterized using XRD, surface analysis using N2 gas and BET and SEM-EDX methods to determine the presence and amount of Ti and Fe metal oxides formed in the bentonite layer structure. The XRD results indicate that the optimum material was obtained from the sample with a Ti : Fe mole ratio of 50 : 25 mmol, as evidenced by the presence of TiO₂ diffraction peaks in the anatase phase. In addition, the gas adsorption–desorption analysis revealed that the material exhibits mesoporous characteristics. The photocatalyst performance test was carried out on the photodegradation process of basic blue dye by providing the best removal percentage of 88% using the Bent-Ti : Fe = 50 : 25 catalyst. Keywords: photocatalyst, TiO2, Fe3O4, bentonite Abstrak—Sintesis oksida logam ganda TiO2 dan Fe3O4 dalam struktur lapisan bentonit alam sebagai material fotokatalis telah dilakukan. Penelitian ini bertujun untuk mempelajari efek rasio mol Ti dan Fe terhadap sifat dan struktur material yang dihasilkan. Latar belakang dari penelitian ini adalah keberhasilan sintesis oksida besi dalam struktur lapisan bentonit alam tanpa merusak struktur bentonit secara keseluruhan. Adapun dalam penelitian ini metode sintesis yang dilakukan adalah menggunakan metode sol-gel dalam sistem atmosfer inert gas nitrogen. Material fotokatalis dikalsinasi menggunakan tungku pipa pada suhu 500 oC selama 3 jam dengan aliran gas nitorgen dan oksigen untuk memperoleh oksida logam yang lebih baik. Material fotokatalis yang diperoleh dikarakterisasi menggunakan XRD, analis permukaan menggunakan gas N2 dan metode BET dan SEM-EDX untuk mentukan keberadaan dan jumlah oksida logam Ti dan Fe yang terbentuk dalam struktur lapisan bentonit tersebut. Dari data XRD ditunjukkan bahwa material terbaik diberikan oleh sampel dengan ratio mol Ti : Fe = 50 : 25 mmol, yang ditandai dengan munculnya puncak difraksi TiO2 fasa anatase dan kurva adsorpsi dan desorpsi gas menunjukkan material memiliki karakter mesopori. Uji keinerja fotokatalis dilakukan pada proses fotodegradasi zat warna basic blue dengan memberikan persen removal terbaik sebesar 88% menggunakan katalis Bent-Ti : Fe = 50 : 25. Kata kunci: fotokatalis, TiO2, Fe3O4, bentonit
Co-Authors Angelina Yonardi Emma Savitri Hesti Lie Looi Mei Hong Maria Goretti Marianti Purwanto Ruth Chrisnasari Sharifah bee Abdul Hamid