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All Journal CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Jurnal Kimia (Journal of Chemistry) International Journal of Biosciences and Biotechnology The Journal of Pure and Applied Chemistry Research Jurnal Media Sains Jurnal Ilmu Pendidikan Indonesia Nata Palemahan: Journal of Environmental Engineering Innovations

Oka Ratnayani

Program Studi Kimia, Fakultas Matematika Dan Ilmu Pengetahuan Alam, Universitas Udayana, Jimbaran, Bali, Indonesia

Author-ID : 2922209

Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education Electrical & Electronics Engineering Engineering Environmental Science Immunology & microbiology Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Physics

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KARAKTERISASI KATALIS BATU PADAS LEDGESTONE TERAKTIVASI ASAM DAN APLIKASINYA PADA PEMBUATAN BIODIESEL DARI MINYAK JELANTAH Ika Juliana; Ida Ayu Gede Widihati; Oka Ratnayani
Jurnal Kimia (Journal of Chemistry) Vol. 10, No. 1 Januari 2016
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

This research aims to improve characteristics of ledgestone catalyst by using acid activation with various concentrations. The acid used for activation was H2SO4 with concentrations of 1, 2 and 3M. The characterization of catalysts was carried out by acid-base titration method to determine the surface acidity, methylene blue adsorption to measure the spesific surface area of ??the catalyst, and the NH4OAc extraction method to measure the value of cation exchange capacity of the catalyst. Ledgestone catalyst with the best character was applied to convert waste cooking oil into biodiesel. The characterization of biodiesel was carried out by densitometry to determine the density of biodiesel, Oswald viskosimetry to measure the viscosity, and Gas Chromatography-Mass Spectrometry (GCMS) to determine the composition of chemical compounds of the biodiesel. The results showed that the concentration of acid used to activate ledgestone catalyst with the best character was 1M. This acid-activated ledgestone (catalyst A1) had a value of surface acidity, surface area, active sites number, and high cation exchange capacity were 0.3530 ± 0.0011 mmol / gram and35.7581 m2/gram, 2.1258 x 1020 atoms/gram, and 5.88 me/100 g, respectively. The concentration of catalyst A1 producing the highest biodiesel yield was 1% w/v. The produced biodiesel was 74,71% with 0.02% FFA, acid value of 0.0438 mg KOH/gram biodiesel, density of 0.7850 g/mL, kinematic viscosity of 0.4650 cSt. Two major compounds of the biodiesel were methyl hexadecanoate with area of 71.84% and cis methyl-9-octadecenoate with area of 28.16%.

IDENTIFIKASI SENYAWA AKTIF ANTIMAKAN BIJI SIRSAK (Annona muricata L.) TERHADAP ULAT KUBIS (Plutella xylostella) Lusiana Tabuni; Sri Wahjuni; Oka Ratnayani
Jurnal Kimia (Journal of Chemistry) Vol. 8, No. 2 Juli 2014
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Identification of antifeedant active compounds from Soursop seeds (Annona muricata Linn) as natural pesticides against Plutella xylostella has been carried out. 1800 g Soursop seed powder maceration was applied using methanol and n-hexane resulted in 46.42 g extract of methanol and 94.19 g extract of n-hexane. Viscous extract of methanol was diluted with the mixture of methanol:water (7:3), then evaporated until the entire methanol was removed, and after that it was partitioned with chloroform. The antifeedant activity of viscous extract of n-hexane, chloroform and water was tested which showed that the extract of n-hexane had highest activity compared to the others. Separation of 2 g viscous n-hexane extract with Coloumn Chromatography using Gel Silica 60 and n-hexane:aceton (4:1) as the mobile phase resulted in 5 fractions. The fractions were tested against Plutella xyllostella. The results showed that fraction C had the highest antifeedant activity. The isolate of fraction C was then identified using Gas Chromatography-Mass Spectrometry (GC-MS) based on the data base (Database\NISTO2.L and Database\wiley7n.1) suggested the active compounds were ethyl hexadecanoate ester and 11-octadecanoic acid.

ISOLASI SENYAWA GOLONGAN TRITERPENOID DAN UJI TOKSISITAS EKSTRAK ETANOL BATANG PRANAJIWA (Euchresta horsfieldii (Lesch) Benn) TERHADAP LARVA UDANG (Artemia salina Leach) I Wayan Gede Gunawan; Oka Ratnayani; I Putu Gede Suwindra Putra
Jurnal Kimia (Journal of Chemistry) Vol. 10, No. 2 Juli 2016
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Isolasi dan identifikasi senyawa toksik berpotensi sebagai antikanker dari batang pranajiwa (Euchresta horsfieldii (Lesch) Benn) telah dilakukan pada penelitian ini. Sebanyak 800 g sampel batang pranajiwa diekstraksi dengan 5000 mL etanol 96% menghasilkan 40,19 g ekstrak pekat etanol, dan hasil uji toksisitasnya terhadap larva udang Artemia salina Leach menunjukan LC50 79,43 ppm. Partisi ekstrak etanol dengan n-heksana, kloroform, dan air menghasilkan 1,50 g ekstrak n-heksana (LC50 50,11 ppm), 1,20 g ekstrak kloroform (LC50 630,95 ppm), dan 30,06 g ekstrak air (LC50 158,48 ppm). Ekstrak n-heksana bersifat paling toksik selanjutnya dipisahkan, dimurnikan, dan diidentifikasi. Pemisahan ekstrak n-heksana secara kromatografi kolom dengan fase diam dan fase gerak n-heksana-kloroform (5:5) menghasilkan empat fraksi (F1-F4). Fraksi F1 dengan noda tunggal pada kromatografi lapis tipis bersifat paling toksik (LC50=79,43 ppm). Hasil identifikasi fraksi F1 dengan uji fitokimia, spektrofotometer UV-Vis, dan FTIR, diduga F1 positif mengandung senyawa golongan triterpenoid.

KARAKTERISASI KEASAMAN DAN LUAS PERMUKAAN TEMPURUNG KELAPA HIJAU (Cocos nucifera) DAN PEMANFAATANNYA SEBAGAI BIOSORBEN ION Cd2+ I. A. G. Widihati; Oka Ratnayani; Yunita Angelina
Jurnal Kimia (Journal of Chemistry) Vol. 4, No. 1 Januari 2010
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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The characterization of surface acidity and area of green coconut shell (Cocos nucifera) and the applicationof the shell as biosorbent of Cd2+ have been conducted in this study. The physico-chemical characterization of thebiosorbent was observed by surface acidity measurement using gravimetry, acid base titration, and infraredspectrofotometry, and the surface area was determined by spectrofotometer UV-Vis using methylen blue method.The use of this shell as biosorbent of Cd2+ was studied by the equilibrium time, the adsorption isotherms, theadsorption capacity, and the influence of pH on adsorption capacity.The result showed that the acidity surface of the green coconut shell determined using gravimetric and acidbase titration was 39.2647 mmol/g and 39.8843 mmol/g. The surface area was 36.5961 m2/g. The adsorption capacityof green coconut shell (Cocos nucifera) as biosorbent of Cd2+ was 2.5135 mg/g at 4 hours equilibrium time with Cd2+and initial concentration (adsorption isotherms) of 50 ppm. At pH 11.00 the adsorption capacity of biosorbent onCd2+ increased to 2.7857 mg/g.

KARAKTERISASI KARBON AKTIF KOMERSIAL SERTA APLIKASINYA SEBAGAI ADSORBEN ION TIMBAL(II) DAN KROM(III) Ni Ayu Putu Tejawati; Manuntun Manurung; Oka Ratnayani
Jurnal Kimia (Journal of Chemistry) Vol. 11. No.2 Juli 2017
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Pada penelitian ini dilakukankarakterisasi karbon aktif komersial serta aplikasinya sebagai adsorben Pb(II) dan Cr(III). Penelitian ini bertujuan untuk mengetahui kualitas dari karbon aktif komersial berdasarkan SNI (Standar Nasional Indonesia) dibandingkan dengan karbon aktif komersial yang diaktifkan kembali dengan pemanasan pada suhu 6000C selama 2 jam. Hasil penelitian menunjukkan, nilai kadar air adalah 6,8%, kadar zat menguap 13,22%, kadar abu total 1,9% dan kadar karbon terikat sebesar 79,1%. Bilangan iodin 774,2159 mg/g dan luas permukaan 8,9400 m2/g. Dengan pemanasan karbon aktif pada suhu 6000C selama 2 jam, bilangan iodin naik menjadi 864,7238 mg/g dan luas permukaan karbon aktif 9,2511 m2/g. Kapasitas Adsorpsi karbon aktif komersial terhadap Pb(II) adalah 0,3438 mg/g dan Cr (III) 0,1861 mg/g, sedangkan karbon teraktivasi panas kapasitas adsorpsinya adalah 0,6775 mg/g untuk Pb(II) dan 0,3033 mg/g pada Cr(III).

Co-Authors Dewik Setiyawati Dwinda Safitri Emmy Sahara I Made Siaka I Nengah Simpen I Nengah Wirajana I Putu Gede Suwindra Putra I Wayan Bandem Adnyana I Wayan Gede Gunawan I Wayan Sudiarta I. A. Gede Widihati Ika Juliana Iryanti Eka Suprihatin Ketut Ratnayani Lusiana Tabuni Made Ririn Dwi Rahayu Manuntun Manurung Ni Ayu Putu Tejawati Ni Komang Ariati Ni Made Puspawati Ni Made Puspawati Ni Made Suaniti Oktavia, Fadilla Olivia Carolyn Sitepu Putra, Anak Agung Bawa Putu Elvira Yulianthi Raisyah Anjani Rizgyandhaka Artha Prawira Rizgyandhaka Artha Prawira Sakinatul Fatimah Sembiring, Aggryppyne Keyne Oberta Simanjuntak, Kartika Sri Wahjuni Veliyana, Ayu Kadek Wahyu Irwansyah Yenni Ciawi Yunita Angelina

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