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Indonesian Journal of Chemistry

ijc
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Published by Universitas Gadjah Mada

ISSN : 14119420 EISSN : 24601578 DOI : -

Core Subject : Science, Engineering,

Chemical Engineering, Chemistry & Bioengineering Chemistry

Indonesian Journal of Chemistry is an International, peer-reviewed, open access journal that publishes original research articles, review articles, as well as short communication in all areas of chemistry including applied chemistry. The journal is accredited by The Ministry of Research, Technology and Higher Education (RISTEKDIKTI) No : 21/E/KPT/2018 (in First Rank) and indexed in Scopus since 2012. Since 2018 (Volume 18), Indonesian Journal of Chemistry publish four issues (numbers) annually (February, May, August and November).

Arjuna Subject : -

Articles 1,981 Documents

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Preconcentration of Chromium(VI) at Trace Levels Using Acid Alumina Resin with Column Method Aman Sentosa Panggabean; Subur P Pasaribu; Bohari Bohari; Nurhasanah Nurhasanah
Indonesian Journal of Chemistry Vol 14, No 1 (2014)
Publisher : Universitas Gadjah Mada

Trace analysis of Chromium(VI) ions using acid alumina resin as a filler material column in preconcentration system by off-line method has been carried out. Alumina resin was activated with H2SO4 at pH 1 before being filled to the column. This research showed retention capacity of alumina acid resin was 3.955 mg Cr(VI)/g resin. The analytical performance of this method is good, shown with the limit of detection value was 3.648 µg/L. The reproducibility of this method shown as percentage of coefficient variance was 2.06%. Acid alumina used as resin filler column can increase the signal up to 15.36 times for direct Cr(VI) ions measurement. The accuracy of this method is very good with the recovery percentage value > 95%, shown the matrices of water samples didn’t effect the results of measurements and this method was capable to analyze Cr(VI) ions in water samples at the trace levels.

Synthesis of Mn(II)-Loaded TixSi1-xO4 Composite Acting as a Visible-Light Driven Photocatalyst Misriyani Misriyani; Eko Sri Kunarti; Masahide Yasuda
Indonesian Journal of Chemistry Vol 15, No 1 (2015)
Publisher : Universitas Gadjah Mada

The synthesis and characterization of Mn-loaded TixSi1-xO4 (x= 0.4-0.8) composites and a preliminary study of an activity testing their ability to work as photocatalysts for the degradation of methylene blue (MB) have been studied. Synthesis was conducted by the sol-gel method at room temperature using tetraethyl orthosilicate, titanium tetraisopropoxide, and manganese(II) chloride as precursors followed by thermal treatment at 500 °C. The characterizations were performed by X-ray diffraction, FT-IR spectrometry, UV-Vis diffuse reflectance spectrometry and a surface area analyzer. The photocatalytic activity test of composites for degradation of MB was carried out in a closed reactor equipped with UV and visible lights. In this test, the effects of ratio of Ti/Si composites, Mn2+ ion concentration, pH, and time of irradiation on the effectiveness of photodegradation of MB were studied. The results indicated that Mn-Ti0.6Si0.4O4 composite could be synthesized through the sol-gel method followed by thermal treatment with a molar ratio of Ti/Si=60/40 and the optimum concentration of manganese was 2.5 wt%. The Mn-Ti0.6Si0.4O4 composite significantly increased the photodegradation of MB at pH 10, with a percent degradation of 84.41% for 30 min under irradiation of visible light. The percent degradation of Ti0.6Si0.4O4 was only 18.23% under irradiation of visible light.

Synthesis and Characterization of Chitosan/Phosphotungstic Acid-Montmorillonite Modified by Silane for DMFC Membrane Dian Permana; Muhammad Purwanto; La Ode Ahmad Nur Ramadhan; Lukman Atmaja
Indonesian Journal of Chemistry Vol 15, No 3 (2015)
Publisher : Universitas Gadjah Mada

Montmorillonite was functionalized by (3-glycidyloxypropyl) trimethoxy silane (GPTMS). Subsequently, chitosan (CS) membranes filled by GPTMS-modified montmorillonite particles were prepared and characterized by FTIR. The result of FTIR obtained the peak wavenumber of 2940, 1471 and 1390 cm-1 referring to vibration stretching of CH2, bending of CH2 and CH3 form epoxy groups in silane, respectively which indicated modification of montmorillonite by silane. Compared with the pure CS and CS/PWA-MMT membrane, these CS/PWA-MMT/Silane hybrid membranes show apparently high proton conductivity and the lower methanol permeability, which could be assigned to the better interfacial morphology and compatibility between chitosan matrix and GPTMS-modified montmorillonite. In all the prepared CS/PWA-MMT/Silane hybrid membranes, the CS membrane filled by 10% GPTMS-modified montmorillonite particles exhibits the highest proton conductivity and the lowest methanol permeability, which is 19.15 x 10-3 S.cm-1 at 80 °C and 4.33 x 10-8 cm2.s-1, respectively. The results imply that CS/PWA-MMT silane 10% membrane has better interaction of interfacial morphology and compatibility between chitosan matrix and GPTMS-modified montmorillonite particles.

Deactivation and Regeneration of Ni/ZA Catalyst in Hydrocracking of Polypropylene Imam Khabib; Sri Kadarwati; Sri Wahyuni
Indonesian Journal of Chemistry Vol 14, No 2 (2014)
Publisher : Universitas Gadjah Mada

The phenomena of catalyst deactivation and the effects of regeneration method on the characteristics and activity of Ni/ZA catalyst after being used in a continuous cracking reaction of polypropylene have been studied. Ni/ZA catalyst was prepared using sonochemical method with total metal intake of 4%. Characteristics and activity of fresh, spent, and regenerated catalyst were evaluated to get a better understanding about the catalyst deactivation. Characteristics which have been observed include catalyst acidity, porosity, crystallinity, and surface morphology. Catalytic activity test of Ni/ZA catalyst on polypropylene cracking reaction at temperature of 500 °C with H2 flow rate of 20 mL/min and catalyst:feed ratio of 1:2 (w/w) showed the decrease of some catalyst characteristics such as specific surface area, total pore volume, and acidity due to coke fouling over a five-times continuous experiment. Regeneration of catalyst with oxidation-reduction method has been able to increase the activity and acidity of catalyst up to 7.47% and 38.54%, respectively, compared to those of spent catalyst, while the catalyst surface area and total pore volume decreased up to 32.83% and 26.92%, respectively.

CARBON PASTE ELECTRODE HEXADECYLTRIMETHYLAMMONIUM BROMIDE MODIFIED NATURAL ZEOLITE FOR CHROMIUM(VI) DETECTION Budi Riza Putra; Latifah K Darusman; Eti Rohaeti
Indonesian Journal of Chemistry Vol 13, No 2 (2013)
Publisher : Universitas Gadjah Mada

A simple voltammetric technique for quantification of chromium(VI) is presented in this work. The technique is based on linear sweep voltammetric reduction Cr(VI) on hexadecyltrimethylammonium bromide (HDTMABr) modified Lampung zeolite carbon paste electrode. Selected HDTMABr concentration for natural zeolite modification is obtained 200 mM. Working electrode for chromium(VI) detection is made by graphite, paraffin oil and HDTMABr modified Lampung zeolite. The effect of supporting electrolyte matrix, pH and also scan rate is also investigated. The calibration curve for chromium(VI) detection using the proposed method shows linearity from 0.2 to 1.0 mM with sensitivity, detection and quantification limit, and precision was 0.4294 mM, 3.63 x 10-4 mM, 1.197 x 10-3 mM, 4.49%, respectively.

KINETICS OF THE OXIDATION OF VITAMIN C Sitti Rahmawati; Bunbun Bundjali
Indonesian Journal of Chemistry Vol 12, No 3 (2012)
Publisher : Universitas Gadjah Mada

Vitamin C or ascorbic acid is needed by the human body but it is already damaged by the rise in temperature due to be oxidized to L-dehydroascorbic acid. This research aims to determine the kinetics of oxidation of ascorbic acid due to an increase if temperature (40-80 °C) and to design an ascorbic acid oxidation reaction laboratory module to be applied in the senior high school reaction kinetics curriculum. The determination of the kinetics of the oxidation of ascorbic acid applies the integral and half-change time methods, while the concentration of the remained ascorbic acid in sixty minute intervals is determined by iodimetric titration method. Decomposition of ascorbic acid was measured at 40, 50, 60, 70 and 80 °C. The results of this research indicate that at 40, 50, 60, 70 and 80 °C the kinetics of the oxidation of ascorbic acid is a first-order reaction with rate constants of 4.55 x 10-4, 5.85 x 10-4, 8.4 x 10-4, 1.1 x 10-3 and 1.015 x 10-3 min-1, respectively. Pre-exponential factor or the frequency of collisions is a factor which is a measure of the collision rate. The activation energy and the pre-exponential factor for the oxidation of ascorbic acid were found to be 20.73 kJ.mol-1 and 1.372 min-1. The procedure used in this study was modified into a laboratory module will be applied in the teaching of reaction kinetics at the senior high school level.

The Effect of Caramelization and Carbonization Temperatures toward Structural Properties of Mesoporous Carbon from Fructose with Zinc Borosilicate Activator Tutik Setianingsih; Indriana Kartini; Yateman Arryanto
Indonesian Journal of Chemistry Vol 14, No 3 (2014)
Publisher : Universitas Gadjah Mada

Mesoporous carbon was prepared from fructose using zinc borosilicate (ZBS) activator. The synthesis involves caramelization and carbonization processes. The effect of both process temperature toward porosity and functional group of carbon surface are investigated in this research. The caramelization was conducted hydrothermally at 85 and 100 °C, followed by thermally 130 °C. The carbonization was conducted at various temperatures (450–750 °C). The carbon-ZBS composite were washed by using HF 48% solution, 1M HCl solution, and aquadest respectively to remove ZBS from the carbon. The carbon products were characterized with nitrogen gas adsorption-desorption method, FTIR spectrophotometry, X-ray diffraction, and Transmission Electron Microscopy. The highest mesopore characteristics is achieved at 100 °C (caramelization) and 450 °C (carbonization), including Vmeso about 2.21 cm3/g (pore cage) and 2.32 cm3/g (pore window) with pore uniformity centered at 300 Å (pore cage) and 200 Å (pore window), containing the surface functional groups of C=O and OH, degree of graphitization about 57% and aromaticity fraction about 0.68.

Adsorption Isotherm Studies on Acid Orange-10 Dye Removal using Cerium Dioxide Nanoparticles Harry Budiman; Oman Zuas
Indonesian Journal of Chemistry Vol 14, No 3 (2014)
Publisher : Universitas Gadjah Mada

The adsorption capacity of AO-10 from aqueous solution onto CeO2-NPs was investigated under various reaction parameters. Batch mode experiments were conducted to assess the potential of the CeO2-NPs as adsorbent for the removal of AO-10 dye from aqueous solution. Equilibrium isotherm studies were carried out under an optimum reaction condition (i.e., AO-10 dye concentration = 15 mg/L, CeO2-NPS dosage = 2 g/L, pH of dye solution = 2) obtained from this study. The equilibrium data obtained were fitted to Langmuir, Freundlich, and Redlich-Peterson isotherm models. The results shows that, the linear transform model provided the highest regression coefficient (R2 = 0.991) with the Langmuir model. The maximum monolayer adsorption capacity was found to be 33.33 mg/g at 30 °C, which is higher than some data from published literature.

SECONDARY METABOLITE FROM ENDOPHYTIC FUNGI Chochlibus lunatus OF THE RHIZOME OF TUNJUK LANGIT (Helmynthostachys zaylanica) Fitrya Fitrya; Muharni Muharni
Indonesian Journal of Chemistry Vol 13, No 3 (2013)
Publisher : Universitas Gadjah Mada

Helmynthostachys zaylanica which is locally known as tunjuk langit is included Ophioglosaceae genus. The rhizome of tunjuk langit is traditionally used as anticancer. Chochlibolus lunatus was isolated from the tissues of tunjuk langit rhizome. Fungal strain was identified based on the characteristics of its colony and cell morphology. Chochlibolus lunatus was cultured in Potato Dextrose Broth (PDB) medium and it was then extracted using ethylacetate (EtOAc). A secondary metabolite compound was isolated from EtOAc extract. This isolation was done by chromatography technique and the structure of this compound was determined by mean of UV, IR and NMR spectroscopic technique. Isolated compound is like oil. Based on spectra analyses, we concluded that this isolated compound was 11,12,13-trimethylheksyl-2-methylhexa-2,4-dienoat.

IN VITRO INHIBITION OF CELERY (Apium graveolens L.) EXTRACT ON THE ACTIVITY OF XANTHINE OXIDASE AND DETERMINATION OF ITS ACTIVE COMPOUND Dyah Iswantini; Tuti Hayati Ramdhani; Latifah K Darusman
Indonesian Journal of Chemistry Vol 12, No 3 (2012)
Publisher : Universitas Gadjah Mada

The objective of this study was to determine the inhibition effect of celery extracts toward xanthine oxidase by in vitro method, and its active compounds. Roots and herb of celery were extracted using water and ethanol solvents. Results indicated that the herbal ethanol extract had the highest inhibition effect (91.40%) at 1400 ppm. The components contained in the herbal ethanol extract were then separated by column chromatography using the best eluent (chloroform : ethyl acetate at 7:3). All of the fractions had inhibition effect greater than 50%. The fraction number 4 was the one with the highest inhibition effect followed by fraction 5 with inhibition percentage of both fractions at 200 ppm were 88.62 and 85.44%, respectively. The analysis of the ultraviolet spectrum of fraction 4 showed the presence of π-π* transition which was resulted by the aromatic C=C, -OH, and C-O chromophores, and also showing the n-σ* transition which was given by -C=O chromophore. The infrared spectrum analysis indicated the presence of aromatic -C=C, -OH, and C=O functional groups. Based on the phytochemical assay and both instrumental spectrums, it was thought that the active compounds of fraction 4 and 5 were in the flavonoid group.

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