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

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Journal : Jurnal Sains Materi Indonesia

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 | Full PDF (801.377 KB) | 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 | Full PDF (500.894 KB) | 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 | Full PDF (773.725 KB) | 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.
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 | Full PDF (224.213 KB) | 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.
PREPARATION OF LEAD MAGNESIUM NIOBATE-LEAD ZIRCONATE TITANATE FILMS AND THEIR CRYSTALLIZATION BEHAVIORS Tursiloadi, Silvester
Jurnal Sains Materi Indonesia Vol 3, No 3: JUNI 2002
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (103.284 KB) | DOI: 10.17146/jsmi.2002.3.3.5058

Abstract

PREPARATION OF LEAD MAGNESIUM NIOBATE-LEAD ZIRCONATE TITANATE FILMS AND THEIR CRYSTALLIZATION BEHAVIORS. The thin films with composition near morpotropic phase boundary (MPB) of the system xPb(Mg1/3, Nb2/3)O3-yPbTiO3-zPbZrO3 (x = 0 ? 0.35, y = 0.47 and z = 0.53), were prepared by sol-gel method. The starting materials were consisted of Pb(iso-OC3H7)2, Zr(n-OC4H9)4, Ti(iso-OC3H7)4, Mg(CH3COO)2 4H2O and Nb(OC2H5)5. The 1-propanol was used as solvent. The concentration of PMN-PT-PZ in coating solution was 0.7 M, and the pH of the solution was 4.5. The thin films were prepared by dipcoating and spincoating. The crystallization behaviors of the PMN-PT-PZ thin films showed that the formation of perovskite phase at low temperature becomes difficult with increasing the content of PMN. The amounts of pyrochlore and perovskite phase in PMN-PT-PZ films depended on the heating temperatures, and PMN contents. Single-phase perovskite was found for the coated films containing 0 and 12.5 mol% after calcinating at 600 oC, 21 mol% after calcinating at 700oC, and 30 mol% after calcinating at 750oC. Single-phase perovskite of coated films will never be found when the content of PMN was 35 mol%.
PREPARATION OF POROUS TITANIA AEROGEL BY CO2 SUPERCRITICAL EXTRACTION TECHNIQUE. Tursiloadi, Silvester
Jurnal Sains Materi Indonesia Vol 5, No 3: JUNI 2004
Publisher : Center for Science & Technology of Advanced Materials - National Nuclear Energy Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1197.273 KB) | DOI: 10.17146/jsmi.2004.5.3.5096

Abstract

PREPARATION OF POROUS TITANIA AEROGEL BY CO2 SUPERCRITICAL EXTRACTION TECHNIQUE. Porous anatase titania that is attractive to its notable functions for photo catalysis and photon-electron transfer. A method for producing the porous anatase titania at low temperature is with dissolving of a titanium alkoxide in a methanol to give a titanium alkoxide solution, adding a mixed solution containing water, nitric acid catalyst and a methanol to the titanium alkoxide solution to perform hydrolysis and simultaneous polymerization to give a polymer solution (gel). The solvent in wet gels was super-critically extracted in CO2 at 60°C and 22 Mpa. Thermal evolution ofthe microstructure ofthe gels were evaluated by TGA?DTA, N2 adsorption, TEM and XRD. A porous titania, which has an anatase-form crystalline structure, an anatase-form particle diameter about 4 nm, average pore diameter of 13 nm, a BET specific surface area of 195 m2/g and a total pore volume of 0.55 cm2/g was obtained as prepared condition. The transformation of anatase phase to rutile phase occurred at 600 °C.