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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).

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Articles 1,981 Documents

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Modified Silica Adsorbent from Volcanic Ash for Cr(VI) Anionic Removal Endang Tri Wahyuni; Roto Roto; Firda Ainun Nissa; Mudasir Mudasir; Nurul Hidayat Aprilita
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

In the present research, cetyltrymethyl ammonium bromide (CTAB)-modified silica from Kelud’s volcanic ash has been prepared and examined as adsorbent for removal of the hazardous Cr(VI) anion. The research was initiated with purification of SiO2 from the volcanic ash that was carried out by reacting the volcanic ash with NaOH powder at 900 °C for 2 h, followed by dissolving the ash to water at 100 °C, and then was acidified with HCl 1 M to form hydrogel. By calcination of the hydrogel, silica (SiO2) gel was obtained. The next step was modification of the silica with CTAB, that was performed by interacting the CTAB solution with the gel, in which the concentration of the CTAB was varied. Then the CTAB-modified silica samples were characterized by using FTIR, XRD, and SEM machines. The activity of the adsorbent was examined for adsorption of CrO4= in the solution. The results of the research demonstrate that the amorphous silica gel and the amorphous CTAB-modified silica have been obtained. The CTAB-modified silica was found to possess much higher ability in the adsorption of CrO4= anion, that was 48.90 mg/g, compared to that of the unmodified silica gel, as much 5.68 mg/g. These findings strongly prove that the negative surface of the CTAB-modified silica adsorbent has been successfully formed. Furthermore, it is also observed that increasing concentration of CTAB in SiO2-CTA can promote more effective adsorption of the CrO4= from the solution, but the further enlargement of the CTAB concentration leads to the adsorption decreased, and the highest adsorption was shown by CTAB-modified silica prepared with 0.10 mole of CTAB/1 mole SiO2.

Heavy Metal Removal from Aqueous Solution Using Biosurfactants Produced by Pseudomonas aeruginosa with Corn Oil as Substrate Venty Suryanti; Sri Hastuti; Tutik Dwi Wahyuningsih; Mudasir Mudasir; Dian Kresnadipayana; Inge Wiratna
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

The batch removal of Cu(II), Cd(II) and Pb(II) from individual heavy metal ion aqueous synthetic solution using biosurfactants produced by Pseudomonas aeruginosa with corn oil as substrate was investigated. The metal ion removal process of crude preparation biosurfactants (CPB) was established to be dependent on the initial pH and contact time. The optimum metal removal was observed at pH 6.0 of the initial metal solution and 10 min of contact time. The affinity sequence for metal ion removal was Pb(II)>Cd(II)>Cu(II). The removal capacity value of biosurfactant for Cu(II), Cd(II) and Pb(II) from single metal ions solution were 0.169, 0.276 and 0.323 mg/g, respectively. The removal capacity value of biosurfactant for Cu(II), Cd(II) and Pb(II) from multi metal ions solution were 0.064, 0.215 and 0.275 mg/g, respectively. The removal capacity of individual metal ion was diminished by the presence of other metal ions in multi metal ions from synthetic aqueous solution. The removal capacity value of biosurfactant for Cu(II), Cd(II) and Pb(II) from silver industry wastewater were 0.027, 0.055 and 0.291 mg/g, respectively. The results indicated that biosurfactants have potential to be used in the remediation of heavy metals in industrial wastewater.

Extraction of Alumina from Red Mud for Synthesis of Mesoporous Alumina by Adding CTABr as Mesoporous Directing Agent Eka Putra Ramdhani; Tri Wahyuni; Yatim Lailun Ni’mah; Suprapto Suprapto; Didik Prasetyoko
Indonesian Journal of Chemistry Vol 18, No 2 (2018)
Publisher : Universitas Gadjah Mada

Mines in Bintan were producing bauxite for many years. The production process of bauxite to alumina produced much red mud. From X-ray Fluorescence (XRF), alumina content on Bintan’s red mud was 28.87 wt.%. This research was studying on the extraction alumina from red mud with reduction of hematite (Fe2O3) and desilication processes. After extraction process alumina was collected about 52.89 wt.%. Synthesis of mesoporous alumina from red mud using sol-gel method at the room temperature for 72 h with cetyltrimethylammonium bromide (CTABr) as mesoporous directing agent. The CTABr/Al-salt ratio, i.e. 1.57; 4.71 and 7.85 with the sample code of AMC-1, AMC-3, AMC-5, respectively. The product was calcined at 550 °C for 6 h. The synthesized materials were characterized by X-ray Diffraction (XRD), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), transmission electron microscopy (TEM), and N2 adsorption-desorption techniques. XRD pattern of AMC-1, AMC-3, and AMC-5 showed that all synthesized materials have amorphous phase. The morphology were wormhole aggregate that were showed by SEM and TEM characterization. N2 adsorption-desorption characterization showed the distribution of pore size of about 3.2 nm. The highest surface area and pore volume were obtained in solid-solid ratio CTABr/GM-AL by 1.57 (AMC-1) i.e. 241 m2/g and 0.107 cm3/g, respectively.

Synthesis and Characterization of Lignin-Based Polyurethane as a Potential Compatibilizer Salma Ilmiati; Jana Hafiza; Jaka Fajar Fatriansyah; Elvi Kustiyah; Mochamad Chalid
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

Lignin is one of the most abundant biopolymer on earth. It has polar and non-polar side due to its hyperbranched structure, but the polarity of lignin has a higher tendency than non-polarity. Lignin has potential to be compatibilizer if the portion of non-polar can be increased. This research is focused on investigate the synthesis of lignin-based polyurethane to enhance the portion of non-polarity in lignin. Lignin-based polyurethane was prepared by reacting variation 4,4'-Methylenebis(cyclohexyl isocyanate) (HMDI) and polyethylene glycol (PEG), then lignin was added to the reaction. In this study, the structure of lignin-based polyurethane was confirmed by NMR and FTIR. NMR and FTIR showed that lignin successfully grafted. NMR, also used to investigate the variation molar mass of PEG and isocyanate contents effects to polarity of lignin-based polyurethane. The polarity of lignin-based polyurethane decrease as the composition of HMDI and molecular weight of PEG increase. This result also occurs on the sessile drop test that used to determine surface tension of lignin-based polyurethane. The thermal properties of lignin-based polyurethane also investigate using STA. Based on STA, enhancement of composition of HMDI and PEG increase thermal degradation and resistance of lignin-based polyurethane.

Water Molecular Adsorption on the Low-Index Pt Surface: A Density Functional Study Wahyu Tri Cahyanto; Aris Haryadi; Sunardi Sunardi; Abdul Basit; Yulin Elina
Indonesian Journal of Chemistry Vol 18, No 2 (2018)
Publisher : Universitas Gadjah Mada

We report the different way to explain the nature of water molecule (H2O) adsorption on the platinum (Pt) surfaces with low Miller index, i.e., (100), (110) and (111). Here, we perform periodic density functional theory (DFT) calculations to analyze the correlation between water-surface bonding strength and the observed charge transfer occurring in the systems. The results show that Pt-H2O interaction strength at the most stable adsorption sites, i.e., the atop site for each surfaces, follows the order of H2O/Pt(110) > H2O/Pt(100) > H2O/Pt(111). This order has the same pattern with the order of observed charge transfer contributed to the bonding formation. The differences in adsorption geometrical structures in these three surfaces are suggested to responsible for the order of bond strength since Coulomb interaction plays dominant roles in our electrostatic model. Furthermore, H2O-Pt interaction mechanism, which occurs through water 3a1 orbital releasing electron density (charge) followed by Pt-O bonding formation, is clarified.

Improvement in vitro Dissolution Rate of Quercetin Using Cocrystallization of Quercetin-Malonic Acid Dwi Setyawan; Sukma Adhi Permata; Ahmad Zainul; Maria Lucia Ardhani Dwi Lestari
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

The aim of the study was to improve the in-vitro dissolution rate of quercetin (Qu) using cocrystallization of quercetin. Cocrystals of quercetin (Co Qu) were produced with malonic acid (Ma) as coformer at ratio 1:2 using solvent evaporation method. Cocrystals quercetin-malonic acid (Co Qu-Ma) was characterized using Differential Thermal Analysis (DTA), Powder X-Ray Diffraction (PXRD), Scanning Electron Microscope (SEM), and Fourier Transforms Infrared Spectrophotometer (FTIR) and in-vitro dissolution study. A new endothermic peak at 277.9 °C was shown from the thermogram. Diffractogram of Co Qu-Ma showed a new diffraction peak at 2θ 9.81, 12.99, and 19.80°. Microphotograph showed that Qu and Ma exhibited a columnar-shaped and a pebble-shaped crystal, respectively, and FTIR wavenumber of O-H functional group of quercetin was shifted from its original position at 3411 to 3428 cm-1 in the physical mixture (pm) of Qu-Ma and 3418 cm-1 in Co Qu-Ma, respectively. The physicochemical characterizations using DTA, PXRD, SEM and FTIR indicated that Co Qu-Ma were successfully obtained through solvent evaporation method. The in-vitro dissolution rate of Co Qu-Ma was 95.30% at 60 min. Cocrystals effectively increased dissolution rate and dissolution efficiency in comparison to the pure quercetin and physical mixture of quercetin-malonic acid.

Electrically Conductive Nanocomposites Polymer of Poly(Vinyl Alcohol)/Glutaraldehyde/Multiwalled Carbon Nanotubes: Preparation and Characterization Fitri Khoerunnisa; Hendrawan Hendrawan; Yaya Sonjaya; Rizki Deli Hasanah
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

Electrically conductive nanocomposites polymer of poly(vinyl alcohol)/PVA, glutaraldehyde (GA) and multiwalled carbon nanotubes (MWCNT) has been successfully synthesized. The polymer nanocomposites were prepared by mixing PVA, GA (crosslinker), and MWCNT dispersion with an aid of ultrasonic homogenizer at 50 °C. The content of MWCNT, in particular, was varied in order to determine the effect of MWCNT on electrical conductivity of polymer composites. The polymer mixture was casted into a disc to obtain thin film. The electrical conductivity, surface morphology, and mechanical properties of the composites film were investigated by means of four probes method, FTIR spectroscopy, X-ray diffraction, SEM, AFM, and tensile strength measurement, respectively. It was found that the optimum composition of PVA (10%): GA (1%): MWCNT (1%) was 20:20:3 in volume ratio. The addition of MWCNT induced the electrically conductive network on polymer matrix where the electrical conductivity of nanocomposites film significantly increased up to 8.28 x 10-2 S/sq due to reduction of the contact resistance between conductive filler. Additionally, the mechanical strength of nanocomposites polymer were significantly increased as a result of MWCNT addition. Modification of morphological structure of composite film as indicated by FTIR spectra, X-ray diffraction patterns, SEM, and AFM images verified the effective MWCNT filler network in the polymer matrix.

Heat Treatment of Pitch Obtained from Atmospheric Fixed-Bed Coal Gasification Phiciato Phiciato; Ika Monika; Arie Hardian
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

A medium temperature pitch obtained from atmospheric fixed-bed gasifier was distilled at a various time (1, 2, 3 and 4 h) to induce polymerization and the results were compared with a commercial pitch. Aromaticity level of pitches was examined using infrared spectroscopy, elemental analysis and simultaneous thermal analysis (TG-DSC). Longer heating time promoted lower moisture content, lower residue yield, higher insoluble fractions, as well as higher ash and carbon content. Although prolonged heat treatments lead to higher aromatization, there was no significant change in aromatization for heat treatment longer than 1 h. The index of aromaticity measured by using elemental analysis was ranged between 0.47 to 1.01, while the result from FTIR spectra showed stagnant value at 0.52. These values were slightly higher than that of pressurized Sasol-Lurgi gasification pitch (0.27).

Bulk Polymerization Kinetics of Hydroxy Terminated Polybutadiene and Toluene Diisocyanate with Infrared Spectroscopy Heri Budi Wibowo; Widhi Cahyo; Ratih Sanggra
Indonesian Journal of Chemistry Vol 18, No 3 (2018)
Publisher : Universitas Gadjah Mada

A study on bulk polymerization kinetics of HTPB (Hydroxy Terminated Polybutadiene) and TDI (Toluene Diisocyanate) with infrared (IR) spectroscopy has been conducted. The investigations included the molar ratio of 2,4-TDI to 2,6-TDI isomers, the initial molar ratio of isocyanate group to a hydroxyl group, and the reaction temperature. The polymerization rate constant was calculated based on the decrease rate of TDI. Kinetics model had been evaluated through the following reaction steps: (1) 2,4-urethane production, (2) 2,6-urethane production, (3) the reaction between 2,4-urethane and the isocyanate group of 2,4-TDI, (4) the reaction between 2,4-urethane and the isocyanate group of 2,4-TDI, (5) the reaction between 2,6-urethane and isocyanate group of 2,4-TDI, and (6) the reaction between 2,6-urethane and the isocyanate group of 2,6-TDI. Those reaction steps were assumed to be the first order reaction with the reaction rate constants k1, k2, k3, k4, k5, and k6, respectively. The reaction rate constants obtained at molar ratio of 2,4-TDI to 2,6-TDI of 80:20, isocyanate group to hydroxyl group (RNCO/OH) initial molar ratio of 1:1, and reaction temperature of 40 °C were 6.2 × 10-5, 5.8 × 10-5, 3.1 × 10-5, 2.8 × 10-5, and 2.5 × 10-5 L.mole-1.min-1 for k1, k2, k3, k4, k5, and k6, respectively, with the activation energy of 1152, 952, 1001, 656, and 1001 kJ/mole for reaction (1)–(6), respectively. The results show that the polymerization reaction rate-determining step was the reaction of 2,6-urethane and isocyanate group of 2,6-TDI (reaction (6)).

Cadmium(II) Removal from Aqueous Solution Using Microporous Eggshell: Kinetic and Equilibrium Studies Behzad Shamsi Zadeh; Hossein Esmaeili; Rauf Foroutan
Indonesian Journal of Chemistry Vol 18, No 2 (2018)
Publisher : Universitas Gadjah Mada

Heavy metals are soluble in the environment and can be dangerous for many species. So, removal of heavy metals from the water and wastewater is an important process. In this study, an adsorbent made of eggshell powder was employed to remove cadmium ions from aqueous solution. A number of parameters were studied including pH of the aqueous solution, adsorbent dosage, contact time, the initial concentration of cadmium ion and mixing rate. The best efficiency for the removal of Cd(II) was obtained 96% using this adsorbent. The optimal parameters were ambient temperature of 30 °C, mixing rate of 200 rpm, pH of 9, an adsorbent dosage of 5 g/L and initial concentration of cadmium was 200 ppm. In order to study the kinetics of adsorbent, the pseudo-first-order and pseudo-second-order kinetic models and intra-particle diffusion model were applied. According to the pre-determined correlation coefficients (R2), the pseudo-second-order kinetic model showed a better correlation between the kinetic behaviors of the adsorbent. Furthermore, to study the equilibrium behavior of adsorbent, Langmuir and Freundlich models used and both models showed high efficiency in isotherm behavior of the adsorbent. So, this adsorbent can be used as a natural and cheap adsorbent.

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