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All Journal CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Jurnal Kimia (Journal of Chemistry) Jurnal Sains dan Teknologi Jurnal Penelitian Sains

I. A. Gede Widihati

Department Of Chemistry, University Of Udayana, Jl. Kampus Bukit Jimbaran Bali, Indonesia 80361

Author-ID : 2921132

Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Education Electrical & Electronics Engineering Mathematics Physics

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ADSORPSI KATION Pb(II) DAN Cr(III) OLEH BATU PADAS JENIS LADGESTONE TERAKTIVASI H2SO4 DAN NaOH Novita Rambu Atandawu; Ida Ayu Gede Widihati; I Wayan Suarsa
Jurnal Kimia (Journal of Chemistry) Vol. 7, No. 2 Juli 2013
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Adsorption of Pb (II) and Cr (III) cations by ladgestone activated with 2 N sulfuric acid, and 4 N sodium hydroxide have been studied. The activation aims to increase the adsorption capacity of the ladgestone which was characterized by measuring its specific surface area and the acidity of the ladgestone surface. In addition, equilibrium adsorption time, isotherm adsorption, and the adsorption capacity were also determined using atomic absorption spectrophotometry (AAS). The results showed that activation with 2 N sulfuric acid increased the acidity of ladgestone surface but it decreased the specific surface area, while activation with 4 N sodium hydroxide increased both the acidity and the specific surface area of the ladgestone. Hence, ladgestone activated with 4 N sodium hydroxide gave the highest adsorption capacity both for Pb (II) and Cr (III) which were 12.4976 mg/g and 12.4945 mg/g respectively.

ADSORPSI ION Pb2+ OLEH LEMPUNG TERINTERKALASI SURFAKTAN I. A. Gede Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 3, No. 1 Januari 2009
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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Intercalation of Bentonit clay with quaternary ammonium salt, N-cetyl, N,N,N –trimethyl ammoniumbromide in the presence of palmitic acid was investigated in this research. The aim was to improve the capacity ofBentonit clay as adsorbent for lead ion (Pb2+). The salt used has a capacity of 8 mmol/10kg clay, which equal to itscapacity as cation exchanged. After intercalating process, palmitic acid was added and then clay was ready to beused as adsorbent for lead ion (Pb2+).Characterisation of physical chemistry properties of the intercalated Bentonit clay was performed using Xraydiffractometer for basal spacing distance between interlayer Bentonit clay, infra red spectrometer for Brownsteadacid site, and atomic adsorption spectroscopy to determine the capacity of adsorption by analyzing isothermadsorption and equilibrium temperature data.It was found that the intercalation of Bentonit clay with quaternary ammonium salt, N-cetyl, N,N,N –trimethyl ammonium bromide increased the distance between interlayer Bentonit clay (basal spacing from 15.9236Ao to 21.0554 Ao. The infra red spectra data revealed the appearance of Brownstead acid site at n 1419.5 cm-1. Theresult also found that the capacity of Bentonit clay as adsorbent for lead ion (Pb2+) improved from 1.9565 mg/gbefore intercalation to 4.0263 mg/g (after intercalation process).

STUDI KINETIKA ADSORPSI LARUTAN ION LOGAM KROMIUM (Cr) MENGGUNAKAN ARANG BATANG PISANG (Musa paradisiaca) Ida Ayu Gede Widihati; Ni G. A. M. Dwi Adhi Suastuti; M. A. Yohanita Nirmalasari
Jurnal Kimia (Journal of Chemistry) Vol. 6, No. 1 Januari 2012
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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Adsorption kinetics of chromium (Cr) ion on char from banana stem has been studied. The char used in this research as obtained by pyrolisys at 4000C for 0,5 hours. The parameters studied included the surface area, which was determined by spectrophotometer UV-VIS using methylen blue method, equilibrium time, the adsorption isotherm, the adsorption capacity, the influence of pH on adsorption capacity, and the adsorption kinetics.The result showed that the surface area was 3,4559 m2/g. The adsorption capacity of banana stem (Musa paradisiaca) char on Cr6+ metal was 0,8019 mg/g, obtained at 40 minutes equilibrium time with initial concentration of Cr6+ metal (adsorption isotherm) of 75 ppm. At pH 4,00, it was obtained that the maximum adsorption capacity of the adsorbent on Cr6+ metal was 0,9088 mg/g. The adsorption followed a second-order kinetics with a rate constant of 0,0008 minute-1ppm-1

ADSORPSI ANION Cr(VI) OLEH BATU PASIR TERAKTIVASI ASAM DAN TERSALUT Fe2O3 I. A. Gede Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 2, No. 1 Januari 2008
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 research is about adsorption of three sand type (river, black beach, and white beach) wated with Fe2O3with and without H2SO4 activated Cr(VI) in water. The research covers the determination of surface acidity of sandby acid-base titration method, their specific surface area by blue methylene method, and of the adsorption,equilibrium adsorption isotherm, and adsorption capacities to Cr(VI) by atomic absorption spectrophotometer.The results indicate that activated white beach sand (AA2) has highest surface acidity (0.4741 mmole/g).The highest specific surface area is given by the sand control (A) (30.8969 m2/g), of beach sand is given by white tosand of AA2 (30.1203 m2/g). Adsorption capacity of sand on Cr(VI) increases with H2SO4 activation. Hignesscapacities is shown by the white beach sand of AA2 (1.0601 mg/g). Free energy adsorption (GoAds) on Cr(VI) ofwhite beach sand is -15.5053 kJ/mole indicating a weak chemical adsorption.

OPTIMASI KONDISI REAKSI HIDROGENASI METIL ESTER DALAM PENINGKATAN AKTIVITAS SURFAKTAN BERBASIS MINYAK JELANTAH I Made Siaka; Yuky Astary Hermanto; Ida Ayu Gede Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 6, No. 2 Juli 2012
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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This paper discusses the optimization of reaction condition of methyl ester hydrogenation in the process of making surfactant from used cooking oil. The synthesis of surfactant involved the esterification reaction of used cooking oil, base-catalyzed transesterification, and hydrogenation reaction of methyl ester (methyl laurate), followed by the sulfatation using sulfuric acid and neutralization using sodium hydroxide. The hydrogenation reaction was performed in the presence of Zn, as the catalyst, at various temperatures (200oC, 220oC, and 240oC) and reaction times (1, 1½, and 2 hours). The surfactant activities testing was conducted through surface tension measurement using the drop weight method and emulsion stability duration testing to find out the optimum condition of each variable.The result indicated that the temperature of the hydrogenation reaction had no effect to the activities of surfactant produced, but the time reaction had. The surfactant activities testing showed that the reaction time of the hydrogenation reaction needed to give the smallest surface tension of water (32 dyne/cm average) was 1½ to 2 hours. More over, the reaction times ware also able to give the longest emulsion stability of 450.6 seconds for cooking oil-water emulsion and 454.6 seconds for used cooking oil-water emulsion. Therefore, the reaction times of 1½-2 hours could be categorized as the optimum reaction time.

FOTODEGRADASI FENOL MENGGUNAKAN KOMPOSIT Ag/ZnO YANG DISINTESIS DENGAN METODE KOPRESIPITASI Ni Putu Diantariani; Ida Ayu Gede Widihati
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

Penelitian ini mengenai fotodegradasi fenol dengan menggunakan komposit Ag/ZnO yang disintesis dengan metode kopresipitasi. Penelitian yang dilakukan meliputi sintesis komposit Ag/ZnO, penentuan kondisi optimum fotodegradasi, penentuan efektivitas dan laju fotodegradasi fenol dengan menggunakan fotokatalis komposit Ag/ZnO. Hasil penelitian menunjukkan bahwa metode kopresipitasi dapat menghasilkan komposit Ag/ZnO dengan persentase Ag dalam komposit sebesar 3,4%. Komposit Ag/ZnO yang dihasilkan mempunyai aktivitas fotokatalitik yang tinggi. Kondisi optimum proses fotodegradasi fenol dengan komposit Ag/ZnO yaitu menggunakan komposit Ag/ZnO sebanyak 50 mg, pH larutan fenol 7 dan diradiasi dengan sinar UV selama 8 jam. Efektivitas fotodegradasi fenol rata-rata dengan fotokatalis komposit Ag/ZnO pada kondisi optimum sebesar (82,88±0,41)%.

FOTODEGRADASI ZAT WARNA TEKSTIL METHYLENE BLUE DAN CONGO RED MENGGUNAKAN KOMPOSIT ZnO-AA DAN SINAR UV Ni Putu Diantariani; Iryanti Eka Suprihatin; Ida Ayu Gede Widihati
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

Research on photodegradation of textile dyes of methylene blue (MB) and congo red (CR) using ZnO-Activated Carbon composite and ultraviolet (UV) light has been done. This research included synthesis zinc oxide (ZnO), synthesis ZnO-Activated Carbon, and the application of composite to degrade textile dyes of MB and CR. In this research studied the effect of pH, concentration and time of UV radiation towards photodegradation percentages of dyes. Then it determined the rate and the effectivity of photodegradation of MB and CR dyes using ZnO-Activated Carbon composite. The result showed that photodegradation of MB reach optimal condition at pH 11 with radiation time 4 hour, whereas CR is at pH 5 with the same radiation time. The more initial concentration of MB and CR applicated, the lower of photodegradation percentages. Constanta of photodegradation rate of MB and CR dyes using ZnO-Activated Carbon composite are 0.8316 and 1.4938 hour-1 respectively. ZnO-Activated Carbon composite as a photocatalyst can degrade effectively MB and CR dyes with photodegradation percentages of 99.40±0.23 % and 99.61±0.24% respectively.

SPESIASI DAN BIOAVAILABILITAS LOGAM BERAT TIMBAL (Pb) DAN TEMBAGA (Cu) DALAM SEDIMEN SUNGAI TUKAD BADUNG Nanik Wijayanti; I Made Siaka; Ida Ayu Gede Widihati
Jurnal Kimia (Journal of Chemistry) Vol. 9, No. 2 Juli 2015
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

A study of speciation and bioavailability of heavy metals, Pb and Cu in sediments of Tukad Badung river with sequential extraction method has been carried out. This study aimed to determine the levels of bioavailability of both Pb and Cu heavy metals. The determination of total heavy metal contents was performed by digestion technique with the use of a mixture of HNO3 and HCl (3:1) in ultrasonic bath for 45 minutes at 60oC followed by heating on a hotplate for 45 minutes at 140oC. The mesurement of total heavy metals and heavy metal species was established with the use of Atomic Absorption Spectrophotometer (AAS) with calibration curve method. Concentration of total Pb and Cu in the sediments of Tukad Badung river ranged from 4.2669 to 27.9171 mg/kg and 20.5240 to 69.3782 mg/kg respectively. The speciation of Pb obtained in carbonate fraction of the EFLE (easly, freely, leachable and exchangable) fractions ranged from 1.5952-11.6315 mg/kg, in Fe/Mn oxide fraction ranged from 0.4001 to 6.7680 mg/kg, in organic/sulfide fraction ranged from 0.8759 to 13.6600 mg/kg, and in the silicate fraction (resistant) ranged between Nd (not detected) to 4.6598 mg/kg. The level of bioavailability Pb in sediments ranged from 9 to70% while the non-bioavailability levels ranged from 0 to 30%. Carbonate fraction (EFLE) of Cu ranged between Nd (not detected) to 6.3527 mg/kg. The fraction of Fe/Mn oxides ranged from 0.7331 to 9.9033 mg/kg, organic sulfide fraction ranged from 8.1790 to 41.5756 mg/kg, and the silicate fraction was foud vary between 7.5138 and 21.0200 mg/kg. The level of Cu bioavailability in sediments ranged from Nd (not detectable) to 18%, while the level of non bioavailability ranged from 15 to 44%.

FOTODEGRADASI METILEN BIRU DENGAN SINAR UV DAN KATALIS Al2O3 Ida Ayu Gede Widihati; Ni Putu Diantariani; Yuliana Farhatun Nikmah
Jurnal Kimia (Journal of Chemistry) Vol. 5, No. 1 Januari 2011
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 research was conducted to observe the photodegradation of methylene blue by UV light and Al2O3 catalyst. The research determinated the optimum Al2O3 catalyst weight, the optimum pH, the optimum radiation duration and the effectivity of photodegradation at optimum conditions. Degradation of methylene blue were analyzed by UV-Vis spectrophotometer. The results showed that the optimum Al2O3 catalyst weight was 40 mg the optimum of pH was 11, and the optimum of radiation duration was 4 hours. The effectivity of photodegradation was (30.22 ± 1.17)%.

PEMANFAATAN LIMBAH SERBUK KAYU MERBAU (Instia spp.) SEBAGAI PEWARNA KAIN KATUN DENGAN PENAMBAHAN KAPUR SIRIH I Wayan Suirta; Ida Ayu Gede Widihati; I Putu Eka Suwita Hegara
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

Telah dilakukan penelitian mengenai pemanfaatan limbah serbuk kayu merbau (Instia spp.)sebagai pewarna kain katun dengan penambahan mordan kapur sirih. Ekstraksi zat warna limbah serbuk kayu merbau dengan pelarut air perbandingan 1:20 (b/v) (10 gram sampel : 200 mL pelarut) menghasilkan ekstrak berwarna coklat kemerahan yang selanjutnya digunakan untuk mewarnai kain katun dengan variasi penambahan mordan kapur sirih sebanyak 2, 3, 5, 8, dan 12 gram. Ekstrak dapat mewarnai kain katun dengan warna yang bervariasi yakni coklat muda, coklat kemerahan, dan coklat tua. Penambahan mordan kapur sirih mampu membentuk ikatan yang kuat antara zat warna dengan serat pada kain katun serta dapat mempertajam warna pada kain yang dihasilkan. Uji ketahanan warna kain katun dilakukan dengan perendaman menggunakan air deterjen 1% yang dalam waktu 10 menit menunjukkan kain katun yang diwarnai tanpa penambahan mordan mudah luntur, sedangkan pewarnaan dengan penambahan kapur sirih tidak mudah luntur.

Co-Authors Asih, I. A. R. A. Cahyanti, N. N. A. T. Emmy Sahara G. S. U. Mahaputra I G. A. A. Ratih Megasari I G. A. K. S. P. Dewi I Gede Darma Putra I Gusti Agung Gede Bawa I Made Siaka I Nengah Wirajana I Putu Eka Suwita Hegara I Wayan Suarsa I Wayan Suirta I. A. R. Astiti Asih I. Apriliyanto Ida Bagus Putra Mahardika Ika Juliana Iryanti Eka Suprihatin James Sibarani Juniari, Tjokorda Istri Trisna K. R. Pangestu Luh De Dwi Jayanthi M A Yohanita Nirmalasari Manuntun Manurung N. P. A. H. Saraswati N. P. A. J. S. Putri Nanik Wijayanti Ni G. A. M. Dwi Adhi Suastuti Ni Made Puspawati Ni Putu Diantariani Ni Wayan Sekarini Novita Rambu Atandawu Oka Ratnayani P. Suarya Sari, A. A. D. P. Tri Rahayu Widia Purwaningrum Yuky Astary Hermanto Yuliana Farhatun Nikmah Yunita Angelina

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