Silvester Tursiloadi
Research Center for Chemistry, Indonesian Institute of Science, Kawasan Puspiptek Serpong, Tangerang Selatan 15314, Banten

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CRYSTALLIZATION BEHAVIOR AND MICROMORPHOLOGY OF SOL-GEL DERIVED MESOPOROUS NANO-PARTICLES TITANIA Tursiloadi, Silvester; Hirashima, Hiroshi; Yamanakaz, Yu
Jurnal Sains Materi Indonesia Vol 6, No 1: OKTOBER 2004
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jsmi.2004.6.1.4913

Abstract

CRYSTALLIZATION BEHAVIOR AND MICROMORPHOLOGY OF SOL-GEL DERIVED MESOPOROUS NANO-PARTICLES TITANIA. In this work, effects of drying methods on the micro-morphology ofinesoporpous TiO2 prepared by the sol-gel method has been studied using transmission electron microscopy (TEM), X-ray diffraction analysis (XRD) and N2 gas adsorption. Mesoporous TiO2 consists of anatase nano-particles, about 5nm in diameter, have been obtained by hydrolysis of titanium alkoxide in a methanol solution and supercritical extraction in CO2 at 60°C and 22Mpa. XRD peaks ofrutile have been found after annealing at 600°C. The particle sizes of anatase and rutile are about 13 and 25nm in diameter, respectively. The surface morphology of Ti02 nano-particles has been discussed with the surface fractal dimensions estimated from the N2 gas adsorption isotherms.
MORFOLOGI DAN AKTIFITAS KATALIS LOGAM CU DENGAN PENYANGGA MONODAN BIMETALIK OKSIDA UNTUK KONVERSI GLISEROL MENJADI PROPANDIOL Sarwono, Rachman; Tursiloadi, Silvester; Sembiring, Kiky C.
Jurnal Sains Materi Indonesia Vol 16, No 2: JANUARI 2015
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jsmi.2015.16.2.4214

Abstract

MORFOLOGI DAN AKTIFITAS KATALIS LOGAM Cu DENGAN PENYANGGA MONODAN BIMETALIK OKSIDA UNTUK KONVERSI GLISEROL MENJADI PROPANDIOL. Gliserol merupakan hasil samping dari industri biodiesel. Diperkirakan produksi biodiesel akan terus bertambah, dengan sendirinya produksi gliserol juga akan bertambah, dan akan terjadi kelebihan produk gliserol dan harga gliserol akan cenderung menurun. Untuk meningkatkan nilai tambah gliserol, gliserol dikonversi menjadi monomer seperti propandiol (PDO) sebagai bahan baku polimer yang akan memberi nilai tambah tinggi. PDO bisa dipolimerisasikan menjadi poly methylene terephthalate, poly urethane dan elastic polymers. Katalis logamCu dengan penyangga mono-metalik oksida seperti ZnO dan Al2O3 memberi konversi gliserol yang rendah, sedangkan penyangga bi-metalik oksida ZnO/Al2O3memberi konversi jauh lebih besarmenjadi 49,14%. Logam Cu lebih aktif dibandingakan dengan oksidanya CuO pada penyangga Al2O3 karena partikelnya terpisah, sedangkan pada penyangga ZnO, CuO lebih aktif dibandingkan dengan logamCu. Ukuran partikel katalis yang lebih kecil akan memberi keaktifan yang lebih tinggi. Kristal CuO dan Al2O3 tidak terjadi aglomerasi, jadi kristal terpisah, sedangkan CuO/TiO2 dan CuO/ZnO terjadi aglomerasi dan membentuk partikel yang lebih besar. Pada katalis dengan penyangga bi-metalik Cu-ZnO/Al2O3 terjadi juga aglomerasi, terjadi alloy antara logamCu-Zn dan bukan campuran antara Cu dan ZnO yang bisa meningkatkan aktifitas katalis.
BENZYLTRIMETHYLAMMONIUM CHLORIDE IMMERSION EFFECT ON PHYSICAL PROPERTIES OF TIO2 – AL203 Tursiloadi, Silvester; Hirashima, Hiroshi
Jurnal Sains Materi Indonesia Vol 5, No 2: FEBRUARI 2004
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jusami.2004.5.2.5210

Abstract

BENZYLTRIMETHYLAMMONIUM CHLORIDE IMMERSION EFFECT ON PHYSICAL PROPERTIES OF TiO2 ? Al2O3. Mesoporous TiO2 - Al2O3 powders have potential applications in catalysts or support catalysts. A novel method to control pore size of sol--gel by a cationic surfactant benzyltrimethylammonium chloride (BTAC) Immersion was investigated. The gels of TiO2- Al2O3 in molar ratio of 0.2 of TiO2, and 0.8 of Al2O3 were prepared by hydrolysis of aluminium sec-butoxide, Al(OC4H9sec)3 and titanium isopropoxide Ti(OC3H7iso)4 in an n-propanol solution with acid catalyst. The structures and porosities of the modified TiO2-A|2O3 was depended on the dimensions of surfactant, as long as the calcination was carried out at 500? to avoid aggregation process during removal of excess BTAC. If the calcinations were carried out at 800? no significant change of the pore volume of modified samples was remarkably not observed, even though formation of TiO2 rutile has been taken place. It indicated that samples modi?cation by initial immersion of gel into BTAC may avoid the sintering. These results suggest that during the calcinations TiO2, was segregated from the Al2O3 particles to form nuclei of rutile and was crystallized prior to formation of ?- Al2O3. Therefore, the formation of rutile TiO2 induced the formation of ?- Al2O3.
PERFORMANCE OF MODIFIED NATURAL ZEOLITES BY SODIUM HYDROXIDE TREATMENTS IN THE ESTERIFICATION OF GLYCEROL AND OLEIC ACID Fauzi, Rizky Achmad; Tursiloadi, Silvester; Dwiatmoko, Adid Adep; Sukandar, Dede; Aulia, Fauzan; Rinaldi, Nino; Sudiyarmanto, Sudiyarmanto
Jurnal Kimia Valensi Jurnal Kimia VALENSI Volume 5, No. 2, November 2019
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat Syarif Hidayatullah State Islamic Uni

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (841.828 KB) | DOI: 10.15408/jkv.v5i2.9976

Abstract

Esterification is the reaction of the formation of an ester compound by reacting an alcohol compound and carboxylic acid. In this study, the performance of zeolite-based catalysts has been studied for esterification reactions. Modification of zeolite pore size was done to be hierarchical zeolite, with the aim of increasing the catalytic properties of zeolite. The modification was carried out by desilication by sodium hydroxide treatment with a variation of 0.1; 0.3; 0.5 M. The resulting catalyst was then characterized using BET and XRD. Furthermore, the catalyst was tested for activity for esterification of fatty acids and glycerol and the product was analyzed using GC-MS. Zeolite modification with sodium hydroxide has been proven to improve catalyst performance, without changing their crystal structure. The best catalytic activity was obtained on the catalyst with sodium hydroxide treatment of 0.3 M, resulting glycerol conversion of 92% and selectivity to monoglycerides of 74%.
SOLID ACID CATALYST OF MESOPOROUS ALUMINA-TITANIA MODIFIED GEL AND AEROGEL FOR ESTERIFICATION OF OF FATTY ACID. Tursiloadi, Silvester; Sondari, Dewi
Alchemy Jurnal Penelitian Kimia Vol 3, No 2 (2004)
Publisher : Alchemy Jurnal Penelitian Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Three types of TiO2.Al2O3 gels ([TiO2]/[ Al2O3]=1/4 in mol) wre prepared by hydrolysis of Al(OC4H9sec)3and Ti(OC3H7iso)4 in an n-propanol solution with acid catalyst. Their physical properties and catalytic on the formation of polyethylene glycol ester were investigated. The wet gels were dried (Xerogel), immersed in surfactant solution before dying (Modified Gel), or supercritically extracted with CO2 at 60oC and 24 Mpa for 2h (Aerogel). The pore size and pore volume of these gels hardly decreased after calcinations at 800oC, atlhough those values of the xerogel remarkably decreased after calcination up to 800oC. The thermal stability of the microstructure of mesoporous titania-alumina is improved by surfactant immersion of supercritical extraction. The aerogel had the highest catalytic activity for the reaction of polyethylene glycol and stearic acid. The effects preparation methods on the microstructure and catalytic activity of the gels were disccussed.
STUDI AWAL PENGARUH METODE EKSTRAKSI TERHADAP RENDEMEN DAN KADAR ASIATICOSIDE DARI CENTELLA ASIATICA (L) URB Sondari, Dewi; Irawadi, Tun Tedja; Setyaningsih, Dwi; Tursiloadi, Silvester
Jurnal Sains Materi Indonesia Vol 17, No 3: APRIL 2016
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/jsmi.2016.17.3.4193

Abstract

STUDI AWAL PENGARUH METODE EKSTRAKSI TERHADAP RENDEMEN DAN KADAR ASIATICOSIDE DARI CENTELLA ASIATICA (L) URB. Proses ekstraksi Centella asiatica (L) Urb dengan metode maserasi, sonikasi, sokletasi dan CO2 superkritik telah dilakukan. Pengaruh proses ekstraksi terhadap rendemen dan kadar asiaticoside dari Centella asiatica (L) Urb (pegagan) telah dipelajari. Hasil dari perhitungan rendemen asiaticoside terlihat bahwa kandungan asiaticoside (% berat) dari proses ekstraksimaserasi, sonikasi, sokletasi dan CO2 superkritik berturut-turut sebagai berikut: 6,723%; 0,187%; 3.648%dan 9,24%. Rendemen asiaticoside paling tinggi diperoleh dari teknologi ekstraksi CO2 superkritik, karena teknologi ini dilakukan pada tekanan dan suhu tertentu sehingga kualitas hasil ekstraksi ditentukan oleh seberapa kritis penggunaan tekanan dan suhunya. Karena pada kondisi ini, selain mengubah densitas CO2, juga berpengaruh terhadap kelarutan dan selektivitas dari zat yang akan terekstrak. Semakin tinggi tekanan dan kelarutan, total hasil ekstraksi akan semakin tinggi. Untukmengetahui adanya senyawa asiaticoside dalam Centella asiatica (L) Urb (pegagan) digunakan analisis HPLC. Dari hasil analisis kromatogram bahwa ada dua puncak yang terdeteksi, dan secara kualitatif senyawa asiaticoside yang diperoleh denganmenggunakan ekstraksi CO2 superkritik lebih tinggi kadarnya dibanding metode ekstraksi lainnya, karena teknologi proses ekstraksi CO2 superkritik memanfaatkan kekuatan pelarut dan sifat fisik dari komponenmurni atau campuran, sehinggamudahmelakukan penetrasi ke dalam dinding material yang di ekstrak dan melarutkan komponen senyawa aktif secara selektif dengan kualitas produk tinggi dan tidakmengandung residu pelarut sehingga lebih murni.
THE STABILIZING OF ANATASE AEROGEL AT HIGH TEMPERATURE Tursiloadi, Silvester; Hirashima, Hiroshi
Indonesian Journal of Chemistry Vol 4, No 2 (2004)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.21863

Abstract

Stable anatase is attractive to its notable functions for photo catalysis and photon-electron transfer.   Stable anatase TiO­2 containing amorphous SiO2 aerogel was prepared by hydrolysis of Ti (OC3H7)4 and Si (OC3H7)4 in a 2-propanol solution with acid catalyst. The solvent in wet gels was supercritically extracted in CO2 at 60 oC and 22 Mpa. Thermal evolutions of the microstructure of the gels were evaluated by TGA-DTA, N2 adsorption and XRD. A stable anatase TiO2 containing amorphous SiO2 aerogel with a BET specific surface area of 365 m2/g and a total pore volume of 0.20 cm3/g was obtained as prepared condition. The anatase phase was stable after calcination up to 1000 oC, and BET specific surface area, total pore volume and average pore diameter did not change significantly after calcination up to 900 oC.
SOL-GEL PROCESS FOR THE MANUFACTURING OF TRANSLUCENT LEAD ZIRCONATE TITANATE GEL-MONOLITH Tursiloadi, Silvester; Imai, Hiroaki; Hirashima, Hiroshi
Jurnal Kimia Terapan Indonesia Vol 6, No 1-2 (1996)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (5234.829 KB) | DOI: 10.14203/jkti.v6i1-2.231

Abstract

Translucent Lead Zirconate Titanate (PZT) gel-monolith was prepared by partially hydrolyzing metal alkoxides solution which modified with acetylacetone(acacH). Metal alkoxides, lead di-i-propoxide, zirconium tetra-nbutoxide and titanium tetra-i-propoxide were used as starting materials. In Infrared spectra for the translucent monolithic gel after aging at room temperature for several days or drying at 90C for 18h, the most significant feature is the presence of band at around 1554 cm-1 which can be assigned to the v (C-O) and v (C-C) vibrati-ons of acetylacetanate group coordinated to the metal cations Ti and Zr. The diffraction peaks of PbO were found after heating at 300C for 2h. After heating at 450 C for 2 h, diffraction peaks of pyrochlore Pb2 Ti206 and perovskite PZT phase were observed. The diffraction peaks of PbO and pyrochlore phase disappeared after heating at 600C, and tetragonal perovskite phase was stable up to 1000 C. The diffraction peaks of perovskite phase were also found after heating at 430 for 24 h. The density of the compacted pulverizedgel after heating at 1000C for 30 min. was 6.9 g/cm3 , about 86% of the theoretical value.
Proses Dekomposisi untuk Pembuatan Serbuk Alumina dari Aluminium Format Tursiloadi, Silvester
Jurnal Kimia Terapan Indonesia Vol 9, No 1-2 (1999)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2254.842 KB) | DOI: 10.14203/jkti.v9i1-2.187

Abstract

The high purity excellent chemical stability and mechanical properties, is quite important for alumina ceramic products. The alumina ceramic products was made from aluminium formate in this study. Decomposition of organic salts is a useful method for preparation of pure and fine ceramic powder without using of expensive metal alkoxides and without producing air pollution. The aluminium formate alt was prepared from reagent grade AlCl3.6H2O,AlCl3.6H2O was dissolved in H2O and then NH4OH was added to the solution. The white precipitates formed were washed with distilled water repeatedly, then dissolved in formic acid solution. Alumina powders prepared by decomposition of aluminium formate had high chemical purity and had small size of agglomerates with a narrow size distribution. The spesific surface area and the equivalent spherical diameter calculated from the value of spesific surface area were 60 m2/gr and 0.03um. The value of equivalent spherical diameter of Al2O3 powder in cumulative mass percent for finer particle were diameter (10%) of 1.7um and diameter (50%) of 5,5um. The average diameter of particles was 5.5um. For the alumina powders which was prepared by docomposition of aluminium formate, the x- Al2O3 and x- Al2O3 did not appear as intermediate phase between y- Al2O3 and a- Al2O3 when calcinated from 800C to 900C .However a- Al2O3 phase appeared at 800C, so that this could reduce the transition temperature from y- Al2O3 to a- Al2O3. The single phase of a- Al2O3 was obtained after calcinating at 1100C or more for 2 hours.
Pembuatan dan Karakteristik Serbuk Piezoelektrik Pb(Zr,Ti)03 tanpa subtitusi dan dengan Nb substitusi Tursiloadi, Silvester
Jurnal Kimia Terapan Indonesia Vol 8, No 1-2 (1998)
Publisher : Research Center for Chemistry - LIPI

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4909.51 KB) | DOI: 10.14203/jkti.v8i1-2.202

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The characteristics of chemically prepared piezoelectric PZT and doped PZT with niobium (PNZT) were investigated. PZT 55/45, both unmodified and doped with Nb2O5 were prepared by the hydrolysis of metal alkoxides and solid state reaction from PbO, ZrO, and TiO,. The average particle size was 0.45 um. X-ray diffraction results indicated that transformation of the amorphous precipitate be came well crystallized PZT after heating at 500 C for 6 hours. DTA results suggested theformation of an intermediate PbTiO3 phase at 490 C. Using X-ray diffractton can be investigated occurring of both tetragonal and rombohedral ferroelectric PZT phases. That case depends on the initial mixing of chemical composition. The PZT powders which prepared from alkoxides were agglomerated easly at low temperature calcining. Poor sintered bodies will he resulted it was calcinated above 600C. Powders calcined at 500 C for 6 hours and sintered at 1200 C produced high body densities approaching 95% of theoretical density.The experimental results suggest that intimate mixing of constit uents during the hdrolyt ic decomposition produces a homogeneous powder. However, differences in the rate hydrolysis or polymerization of the respective metal alkoxides fend to couse the stoichiometric results difficult to be found.