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Teguh Endah Saraswati
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Department of Chemistry, Faculty of Mathematics and Natural Sciences, Sebelas Maret University
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ALCHEMY Jurnal Penelitian Kimia
Published by Universitas Sebelas Maret
ISSN : 14124092     EISSN : 24434183     DOI : -
Core Subject : Science, Social, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Energy Environmental Science Materials Science & Nanotechnology
ALCHEMY Jurnal Penelitian Kimia is a chemistry journal published by Sebelas Maret University, Surakarta. ALCHEMY Jurnal Penelitian Kimia publishes original research articles or review articles in organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, biochemistry, and environmental chemistry.
Arjuna Subject : -
Articles 7 Documents
 1 
Search results for , issue "vol 12, no 2 (2016): september" : 7 Documents clear
REPLACING SODA ASH (NaOH) WITH KALIUM HYDROXYDE (KOH) IN DESTILATION OF BINARY ETHANOL-WATER MIXTURE Istiqomah, Ana Ulfa; Rahmawati, Fitria; Nugrahaningtyas, Khoirina Dwi
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.12.2.1876.179-189

Abstract

Soda ash (NaOH) has been used in bioethanol production in the second step destillation to increase the purity up to 90%. The destillation process will produce waste water with a high sodium content. The soda ash itself serve as an electrolyte to modify the colligative properties of the water-ethanol mixture allowing the disappearance of azeotropic point. This research aims to study the replacement of NaOH with KOH, in which the kalium is a nutrient to maintain soil fertility. This research study the thermodynamics properties, vapor-liquid equilibrium, colligative properties and also its azeotropic point in the destillation of water-ethanol mixture when KOH and NaOH were used as the additive. A model of water-ethanol mixture at a various composition of 0-100 weight % of ethanol was used. The electrolyte addition was 0.1 mol electrolyte/total weight of ethanol-water. The result shows that the addition of electrolyte into ethanol-water mixture eliminate the azeotropic point and allows the ethanol molecules to separate from water. The enthalpy of mixing between water-ethanol is 239.601 kJ/mol. It becomes 259.796 kJ/mol and 264.793 kJ/mol after the addition of NaOH and KOH, respectively. It confirming the endothermic mixing process due to different polarity between water and ethanol. The presence of electrolyte even reduce more their molecular interaction. However, the change to irregularity result a high positive entropy values that result the negative Gibbs free energy. It confirms the spontaneity of mixing. The vaporization enthalpy, Hvap, of water-ethanol mixture is 76.229 kJ/mol and it becomes 235.366 kJ/mol and 126.189 kJ/mol after the addition of NaOH and KOH. It indicates that the presence of electrolyte inhibites vaporization of water as the major component and allowing ethanol molecules to vapor producing more high purity ethanol.
Antibacterial Activity of Germacrone Sesquiterpene from Curcuma Xanthorrhiza Rhizomes Diastuti, Hartiwi; Syah, Yana Maolana; Juliawaty, Lia Dewi; Singgih, Marlia
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.12.2.1726.103-111

Abstract

The aim of this research was to isolate and indentify the terpenoid compound from Curcuma xanthorrhiza rhizomes and its antibacterial activity. Isolation was carried out by using vacuum liquid chromatography and centrifugal chromatography. The structure was determined by NMR spectroscopy (1H-NMR, 13C-NMR 1D and 2D), then compare with data from literatures. Antibacterial test was carried out by using  microdillution methods and evaluated against eight bacteria. They are Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa, Salmonella typhi, Shigella dysentriae and Vibrio cholerae. The result showed that the isolate was a white crystal which was indetified as germacron-type sesquiterpene. Germacron have highest activity againts P. aeruginosa, MIC 15.6 µg/mL and MBC 31.2 µg/mL.
KAJIAN AKTIVASI H2SO4 TERHADAP PROSES PEMILARAN Al2O3 PADA LEMPUNG ALAM PACITAN Khoirina Dwi Nugrahaningtyas; Dian Maruto Widjonarko; Daryani Daryani; Yunita Haryanti
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.12.2.1312.190-203

Abstract

Telah dilakukan penelitian tentang lempung alam (bentonit) yang diaktivasi dengan berbagai variasi konsentrasi H2SO4, dan dengan proses interkalasi menggunakan larutan Al2O3.H2O. Tujuan dari penelitian ini adalah untuk menentukan konsentrasi optimum untuk aktivasi lempung, berdasarkan karakter persentase montmorillonite dan keasaman total. Hal ini juga didukung oleh karakterisasi setelah proses interkalasi, yaitu karakter luas permukaan spesifik, volume pori total, radius pori rata-rata dan kandungan aluminium. Analisis persentase-Montmorilonit dilakukan dengan menggunakan difraksi sinar X; keasaman total ditentukan secara gravimetri; luas permukaan spesifik, volume pori total, dan jari-jari pori rata-rata diukur dengan Surface Area Analyzer NOVA dan kandungan aluminium ditentukan oleh Analisis Aktivasi Neutron.Hasil penelitian menunjukkan bahwa aktivasi optimum pada konsentrasi H2SO4 1,5 M mempunyai persentase montmorillonite optimum (91.335%) dan nilai keasaman meningkat 193.955% dari nilai keasaman bentonit alam. Karakter fisik dan kimia setelah interkalasi juga menunjukkan bahwa terjadi peningkatan kadar aluminium (57,540%), luas permukaan spesifik (150,586%), volume total pori (73,236%) dan keasaman Total (203,504%) dari bentonit alam. Rerata jejari pori mengalami penurunan 10,274% setelah aktivasi dan penurunan 30,868% setelah proses interkalasi.
Evaluasi Potensi Sedimen Perairan Sebagai Sumber Kontaminan Logam Berat (Pb, Cu, Zn) Di Badan Air Pada Wilayah Reklamasi Lumpur Lapindo Novi Anitra; Barlah Rumhayati; Catur Retnaningdyah
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.12.2.1390.142-154

Abstract

Tujuan dari penelitian ini adalah mengevaluasi potensi sedimen perairan di wilayah reklamasi lumpur Lapindo sebagai sumber kontaminan logam berat (Pb, Cu, Zn) di badan air muara Sungai Porong, Kabupaten Sidoarjo. Evaluasi dilakukan dengan menentukan nilai faktor kontaminasi (Contamination Factor, CF) dan kode penilaian resiko (Risk Assessment Code, RAC) berdasarkan konsentrasi fraksi geokimia logam berat dalam sedimen. Fraksi logam berat ditentukan dengan metode ekstraksi bertahap (sequential extraction) BCR dimodifikasi oleh Chakraborty. Sampel sedimen diambil pada dua lokasi di muara Sungai Porong, yaitu pada lokasi 1 yaitu 7°34'26.76" LS, 112°52'53.76" BT dan lokasi 2 yaitu 7°33'31.35" LS, 112°51'05.56"BT. Sampel diambil dengan menggunakan Eickman Grab sampler, disimpan dalam wadah gelap pada suhu 40C. Konsentrasi logam berat ditentukan dengan Spektrofotometri Serapan Atom. Hasil penelitian menunjukkan bahwa pada kedua lokasi nilai CF(Cu) lebih tinggi dibandingkan CF(Pb) dan CF(Zn). Hal ini menunjukkan bahwa Cu memiliki waktu retensi lebih singkat dibandingkan kedua logam lainnya dalam sedimen. Dengan kata lain, Cu lebih mudah terlepas dari sedimen dan menuju badan air sehingga dapat mengkontaminasi badan air. Berdasarkan nilai RAC, sedimen di lokasi 2 memiliki potensi lebih besar melepaskan logam Cu dalam  fraksi 1 (fraksi logam berat terlarut dalam air pori sedimen) dan fraksi 2 (fraksi logam berat mudah tertukar dan dalam bentuk karbonat) yang dapat dimanfaatkan langsung oleh biota di badan air. Dapat disimpulkan bahwa meskipun mangrove yang ditanam di wilayah reklamasi Lumpur Lapindo dapat mengabsorpsi logam berat tetapi sedimen perairan di wilayah tersebut memiliki potensi sebagai sumber kontaminan Cu, terutama di wilayah reklamasi yang berhubungan dengan laut.
Microbial Fuel Cell Based Polystyrene Sulfonated Membrane as Proton Exchange Membrane S Muljani; A Wulanawati
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.12.2.1818.155-166

Abstract

Microbial fuel cell (MFC) represents a major bioelectrochemical system that converts biomass spontaneously into electricity through the activity of microorganisms. The MFC consists of anode and cathode compartments. Microorganisms in MFC liberate electrons while the electron donor is consumed. The produced electron is transmitted to the anode surface, but the generated protons must pass through the proton exchange membrane (PEM) to reach the cathode compartment. PEM, as a key factor, affects electricity generation in MFCs. The study attempted to investigate if the sulfonated polystyrene (SPS) membrane can be used as a PEM in the application on MFC. SPS membrane has been characterized using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM) and conductivity.  The result of the conductivity (σ) revealed that the membrane has a promising application for MFC.
EFFECTS OF HEATING TEMPERATURE AND BINDER IN THE PRODUCTION OF CHAR-BASED ELECTRICAL CONDUCTOR Teguh Endah Saraswati; Achmad Bahrudin; Miftahul Anwar
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.12.2.708.167-178

Abstract

Graphite as one alotrof carbon is widely used as an electrode material for a good electrical conductivity properties. Charcoal as a carbon source material was found very abundant in nature. Charcoal has the potential application for electrode material in energy storage such as in a battery or supercapacitor. For this purpose, charcoal amorphous structure needs to be converted into a graphite structure so that it has better electrical conductivity property. This research aims to prepare the electrical conductor material derived from wood charcoal that could potentially be used as an electrode. Preparation was made by mixing charcoal powder with asphalt binder with a weight ratio of 3:1, 4:1, 5:1 and followed by heat treatment under an inert atmosphere at temperature of 600°C, 800°C and 1000°C. Charcoal material which was originally to be an electrical insulator has been successfully converted into an electrical conductor. The achievement of the optimum temperature to produce electrodes with the smallest electrical resistance is then applied to the manufacture of carbon electrodes by heating a mixture of charcoal and fructose binder in a weight ratio of 1:1 (w/w). The results showed electrodes with a mixture of charcoal powder and fructose with heat treatment at 1000°C has the better electrical conductivity among other variations.
Aktivitas Antibakteri TiO2-Anatas Terdadah -Vanadium dan -Kromium Hari Sutrisno; Ariswan Ariswan; Dyah Purwaningsih
ALCHEMY Jurnal Penelitian Kimia Vol 12, No 2 (2016): September
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (462.186 KB) | DOI: 10.20961/alchemy.12.2.1744.112-127

Abstract

Samples of vanadium- and -chromium doped TiO2-anatas have been conducted antibacterial activity against the bacteria Escherichia coli (E. Coli). The minimum kill concentration (MBC) against the bacteria of E. Coli is determined  by liquid dilution method. The antibacterial activity test of 0; 2.3; 3.3; 4.9% wt. vanadium doped TiO2-anatas and 0; 1.1; 3.9; 4.4% wt. chromium doped TiO2-anatas have been performed against bacteria of E. Coli in the absence of light (dark). The test results indicate that the presence of 3.3 and 4.9 in %wt. vanadium-TiO2-anatas are able to inhibit the growth of bacteria E. Coli, contrary all chromium doped TiO2-anatas are not able to inhibit the growth of bacteria of E. Coli.

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