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KAJIAN ANALISIS TERMAL KITIN-KITOSAN CANGKANG UDANG MENGGUNAKAN THERMOGRAVIMETRIC ANALYSIS DAN DIFFERENTIAL THERMAL ANALYSIS (TGA-DTA)

Jurnal Sains dan Terapan Kimia Vol 2, No 2 (2008)
Publisher : Jurnal Sains dan Terapan Kimia

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Abstract

Telah dilakukan kajian analisis termal pada kitin-kitosan cangkang udangmenggunakan thermogravimetric analysis dan differential thermal analysis (TGA-DTA).Kitosan dengan derajat deasetilasi (DD) bervariasi diperoleh dari proses deastilasi kitindengan kondisi percobaan yang berbeda. Kitin dan kitosan dengan variasi DD tersebutdianalisis menggunakan TGA-DTA.Berdasarkan perbedaan termogram TGA-DTA kitin dan kitosan, menunjukkanbahwa kitosan lebih higroskopis daripada kitin dan memiliki gugus asetil yang lebihsedikit. Pada proses deasetilasi, kitin dimungkinkan terjadi degradasi rantai polimer danpembentukan rantai polimer yang lebih panjang secara acak sehingga heterogenitaspolimer kitosan lebih besar daripada kitin.Kata kunci: kitin-kitosan, analisis termal, termogram TGA/DTA

Efek Deasetilasi Kitin Secara Bertahap Terhadap Derajat Deasetilasi Dan Berat Molekul Kitosan

Jurnal Sains dan Terapan Kimia Vol 2, No 1 (2008)
Publisher : Jurnal Sains dan Terapan Kimia

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Abstract

Telah dilakukan kajian tentang preparasi kitosan yang dibuat dari kitin melalui proses deasetilasi bertahap menggunakan NaOH. Kitin diisolasi dari kulit udang putih Lampung (Litophenaeus vannamei). Derajat deasetilasi ditentukan dengan menggunakan metode spektroskopi FTIR dan berat molekul ditentukan dengan menggunakan metode viskometri. Efek deasetilasi kitin secara bertahap terhadap derajat deasetilasi dan berat molekul dipelajari dengan cara membandingkannya dengan deasetilasi secara kontinyu. Hasil penelitian menunjukkan bahwa deasetilasi kitin secara bertahap dapat meningkatkan derajat deasetilasi kitosan yang diperoleh secara signifikan dan tidak ada perbedaan berat molekul yang signifikan antara kitosan hasil deasetilasi bertahap dengan kitosan hasil deasetilasi kontinyu. Hal ini mengindikasikan bahwa konsentrasi NaOH sangat berpengaruh terhadap proses deasetilasi, tapi tidak signifikan berpengaruh terhadap proses depolimerisasi.Kata kunci : kitin, kitosan, deasetilasi bertahap, derajat deasetilasi, berat molekul.

PEMBUATAN CONCRETE ZEOLIT-LEMPUNG UNTUK PERVAPORASI CAMPURAN ETANOL/AIR TANPA PEMANASAN

Prosiding Seminar Nasional MIPA Vol 2, No 1 (2012): SEMINAR NASIONAL FMIPA UNDIKSHA 2012
Publisher : Prosiding Seminar Nasional MIPA

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Abstract

ABSTRACTPreparation of zeolite-clay concrete for new ethanol/water pervaporation without heating has been carried out. Concrete was made by mixing natural zeolite, portland cement, natural clay and distilled water in porcelain disk. The mixture was manually stirred until homogenous suspension obtained. The suspension formed was then placed in the mold and allowed to dry in open air for 48 hours. The mass of natural zeolite was varied from 10, 12.5, 15, 17.5, and 20 g meanwhile the mass of natural clay was varied from 0, 1.25, 2.5, 3.75, and 5 g. The mass of portland cement was fixed in the value of 10 g. The concrete was characterized by infrared spectrophotometer (IR) and X-ray diffraction (XRD). Material testing machine was used to determine the compressive strength of the concrete agreeable with decided ASTM C349-08 standard.Based on preparation of zeolite-clay concrete, it was found that the increase of the natural zeolite mass from 15 to 20 g caused fracture to the concrete, but water adsorption percentage increased from 27.7% to 35.2%. Meanwhile, the higher the mass of natural clay, the greater the compressive strength of concrete from 130.3 MPa to 179.9 MPa and water adsorption percentage from 28.9% to 32.3%. The adsorption-desorption data showed that the water was faster to adsorb into the concrete than ethanol, whereas the desorption rate of concrete with respect to ethanol was greater than that to water. The difference on desorption rate was then used to separate ethanol/water mixture through pervaporation without heating. Pervaporation test using the concretes resulted in the increase of ethanol feed concentration from 60%, 70%, 80%, and 90% to 82.9%, 82.5%, 87.8%, and 93.7% respectively.Keywords: concrete, compressive strength, adsorption-desorption, ethanol/water mixture, pervaporation.

Study of Structural Properties of Mesoporous Carbon From Fructose with Zinc Borosilicate Activator

The Journal of Pure and Applied Chemistry Research Vol 3, No 3 (2014)
Publisher : Chemistry Department, The University of Brawijaya

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Abstract

Structural properties, including pore structure, functional group of carbon surface, and crystal structure of carbon built by zinc borosilicate (ZBS) and ZnCl2 (Z) have been investigated in this work. Physically, ZBS and ZnCl2 may act as template of carbon, whereas the Zn(II) cation act as chemical activator of carbonization. All precursors of ZBS (silicagel, boric acid, and ZnCl2) may act as catalysts of caramelization. The caramelization was conducted hydrothermally at 85oC and thermally 130oC. The carbonization was conducted at 450oC. The resulted carbons were washed by using HF 48% solution, 1M HCl solution, and aquadest respectively. The solid products were characterized by using nitrogen gas adsorption, infrared spectrophotometry, X-ray diffraction, and Transmition Electron Microscopy. Result of research showed that ZBS built larger mesopore volume, larger pore domination of pore size, more hydrophobic carbon, and more amorf than ZnCl2.

Sensitization of Xanthophylls-Chlorophyllin Mixtures on Titania Solar Cells

International Journal of Science and Engineering Vol 8, No 2 (2015)
Publisher : Chemical Engineering Diponegoro University

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Abstract

Co-sensitization of natural dyes on TiO2 for dye-sensitized solar cell (DSSC) was proposed between chlorophyllin (C) and xanthophylls (X at various volume ratios of C/X. Chlorophyllin is chlorophyll derivative providing -COOH groups essential for binding to TiO2. The chlorophyll was extracted from dried spinach (amaranthus viridis) leaves in a mixture of methanol-acetone (70%:30%). Chlorophyll extract dye was obtained after partition of the crude extracts in diethyl ether solution. Then, it was hydrolyzed under alkaline condition to get chlorophyllin. Xanthophyll was extracted from fresh petal of chrysanthemum (chrysanthemum indicum) flowers. Blending of chlorophyllin and xanthophyll was carried out at various volume ratios of C to X (1:0, 5:1, 1:1, 1:5, 0:1). Titania solar cells were constructed in sandwich system of conducting glass-titania/dyes as the photoanode and conducting glass-platinum as the photocathode. Electrolyte solution containing I-/I3- was inserted between the electrodes by capillary action. All dye extracts and blending solutions were analyzed by UV-Vis spectrophotometer. It is shown that the absorption spectra of blending dyes are complimentary in the visible region resulted in a panchromatic response of the dyes. From the cyclic voltammogram of the dyes and blended-dyes, it is found that the energy level of xanthophyll is the lowest. The I-V test at 100 mw/cm2 irradiation confirmed that the energy conversion efficiency (h) of the blended dyes of xanthophyll and chlorophyllin-sensitized solar cell resulted in significant improvement than those of the single dye. Beneficially, the mixed dyes can be adsorbed from solution blend using single dipping step.

PENINGKATAN AKTIVITAS FOTOKATALITIK TiO2 MESOPORI DENGAN SENSITISASI TiO2 MENGGUNAKAN SENYAWA KOMPLEKS BERWARNA

Alchemy Jurnal Penelitian Kimia Vol 7, No 1 (2008)
Publisher : Alchemy Jurnal Penelitian Kimia

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Abstract

Peningkatan aktivitas fotokatalitik TiO2 mesopori telah dapat dilakukan dengan modifikasi permukaan TiO2 melalui penambahan senyawa kompleks berwarna M2+ (SiPA)n(PAR)m (M2+ = Co2+ dan Fe2+) (SiPA = sililpropilamin). Penambahan senyawa kompleks sensitiser pada permukaan TiO2 dilakukan dengan cara pembentukan senyawa kompleks in situ dengan penambahan berturut-turut ligan primer aminopropiltrimetoksisilan (APTS), Ion logam transisi (Co2+ atau Fe2+) dan ligan sekunder 4-(2-piridilazo)resorsinol (PAR). Dibandingkan dengan TiO2 mesopori sebelum disensitisasi, TiO2 setelah disensitisasi (TiO2/SiPA-Co2+-PAR dan TiO2/SiPA-Fe2+ -PAR) menunjukan peningkatan aktivitas fotokatalitik  ~20% untuk fotodegradasi metilen blue dengan radiasi cahaya visibel.

Effect of Washing Treatment on the Morphology of Vertically Aligned ZnO Nanorods

Berkala Ilmiah MIPA Vol 23, No 2 (2013)
Publisher : FMIPA UGM

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Abstract

Vertically oriented ZnO nanorods were synthesized in a two steps technique involving the preparation of ZnO seed layer and the growth of ZnO nanorod on the glass substrate. ZnO seed layer was firstly deposited on the glass substrate by dip coating method, while well aligned ZnO nanorod were grown on seed layer coated substrate by hydrothermal method at 110 oC for 20 min. Crystalline structure, morphologies and band gap energy of the as-prepared ZnO nanorod were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and specular reflectance UV-Visible spectrophotometer, respectively. The XRD results showed that ZnO nanorods were wurtzite-structured with preferential orientation along (002) plane. It is shown that washing treatment on the as-prepared ZnO films provides a facile way to eliminate randomly oriented ZnO nanorods and results in vertically oriented nanorods on the glass substrate. Its textural coefficient is almost two times higher than ZnO nanorods previously reported. 

ANEKSASI RUSIA DI KRIMEA DAN KONSEKUENSI BAGI UKRAINA

Jurnal Penelitian Politik Vol 11, No 2 (2014): Tantangan Politik Lokal Pasca SBY
Publisher : Pusat Penelitian Politik

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Abstract

Aneksasi wilayah Krimea oleh Rusia terjadi menyusul jatuhnya Presiden Ukraina Viktor Yanukovych yangdianggap pro Rusia oleh kelompok oposisi. Referendum yang dilakukan rakyat Krimea pasca aneksasi menegaskankembali tuntutan kemerdekaan Krimea dari Ukraina dan pilihan untuk bergabung dengan Rusia. Meski referendumtersebut dianggap tidak sah oleh Kiev, secara de facto Krimea kini berada di bawah penguasaan Kremlin. Tulisanini memfokuskan pada aksi aneksasi Rusia di Krimea dengan menganalisis kepentingan strategis Rusia di wilayahKrimea yang mendorong aksi aneksasi; termasuk menganalisis posisi Ukraina, Krimea, dan Rusia pasca runtuhnyaUni Soviet; serta konsekuensi lepasnya Krimea dari Ukraina yang merubah konstelasi politik domestik, sosial, danekonomi, serta batas wilayah Ukraina-Krimea-Rusia.Kata Kunci : aneksasi, Rusia, Krimea, Ukraina.

Pemilu Presiden Iran 2009 dan Upaya Destabilisasi Iran

Jurnal Penelitian Politik Vol 6, No 1 (2009): Kisruh Pemilu 2009
Publisher : Pusat Penelitian Politik

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Abstract

Iran s 2009 presidential election became a big challenge for President Mahmud Ahmadinejad to preserve hispowerfor a second term The challenges were not only comefrom reformist groups but alsofrom conservative groups of which his political affiliation belong In addition international society also concerned with Ahmadinejad political statement andpolicy that could harm Iran national interests This paper will examine Iran s 2009 presidential election and the efforts offoreign forces to destabilize the Islamic Republic of Iran In this paper the electoral process including electoral competition between conservative and reformist groups and allegation offraud will be analyzed This paper will argue that tense competition between conservative and reformist groups in presidential elections has sharpened political division in Iran.

MINORITAS MUSLIM DI AUSTRALIA DAN INGGRIS

Jurnal Penelitian Politik Vol 3, No 1 (2006): Papua Menggugat
Publisher : Pusat Penelitian Politik

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Abstract

The war against terrorism has become the main topic and spread a ll over the w orld since the bombing o f WTC building in September 11" 2001. The issue is that rather fighting terrorist as the actor o f terrorism, the war is blured with fighting M oslem people as the most victimized as the actor o f terrorism. Moslems in Australia and United Kingdom, two countries that become close supporter o f USA in the war against terrorism, has suffered o f negative public perception. It is interesting to analyse policy in those two U S close allies. The research that has been conduct compares p o lic y o f Australia and Britain after the bombing. Image o f Moslem community in those countries is shaped by the role o f mass media as the source o f opinion. The war against terrorism has negative effect that it is victimizing Moslem community as the source o f terror.