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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.
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Search results for , issue "Vol 14, No 1 (2018): March" : 14 Documents clear
Optimasi Pretreatment melalui Metode Hydrothermal Pressure dan Pelarut Alkali pada Produksi Bioetanol dari Lemna minor Abdur Rahman Arif; Andi Evi Erviani; Hasnah Natsir; Ilham Haidir; Maudy Audina Affandy
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.15986.95-106

Abstract

Produk bioetanol dengan bahan dasar biomassa lignoselulosa perlahan banyak dikembangkan sebagai sumber energi alternatif. Tantangan utama dalam produksi lignoselulosa etanol berada pada tahap pretreatment. Pretreatment merupakan tahap yang memegang peranan penting dalam mendegradasi lignoselulosa menjadi selulosa. Pada penelitian ini digunakan Lemna minor yang merupakan gulma perairan dengan kombinasi dua tahap pretreatmen untuk melihat efektivitas degradasi lignoselulosa dalam sampel. Tahap pertama dengan metode hydrothermal pressure pada suhu pemanasan uap 121 °C dan tekanan 15-20 psi dengan variasi waktu proses selama 5, 15, 30, 45, dan 60 menit. Tahap kedua pretreatment dengan metode kimiawi menggunakan NaOH dengan variasi konsentrasi 0,5; 1; 1,5; 2; dan 2,5 M. Hasil penelitian menunjukkan 60 menit merupakan waktu optimum dari metode hydrothermal pressure pada sampel L. minor dengan kadar lignin 11,32%, kadar selulosa 17,39%, kadar hemiselulosa 16,73% dan kadar gula total 0,82%. Untuk tahapan pretreatment dengan pelarut alkali (NaOH) kandungan kadar lignin L. minor setelah pretreatment dengan NaOH 2,0 M sebesar 5,36%, kadar.  Kandungan kadar selulosa, hemiselulosa dan gula total optimum diperoleh pada konsentrasi 2,5 M dengan nilai kadar 31,03%; 5,57% dan 1,74%. Efektivitas penurunan kadar lignin pada pretreatment hydrothermal pressure sebesar 37,04% sedangkan pretreatment dengan NaOH sebesar 70,18%. Kombinasi proses pretreatment memberikan hasil yang cukup baik terhadap proses degradasi lignin yang terkandung dalam sampel Lemna minor sehingga sangat efektif digunakan dalam proses pembuatan bioetanol dengan bahan dasar biomassa.  Optimization Pretreatment through Hidrothermal Preassure and Alkaline Solvent Methods in Bioethanol Production from Lemna minor. Bioethanol products with lignocellulosic biomass feedstock have been developed as an alternative energy source. The main challenge in the production of lignocellulosic ethanol is on the pretreatment stage. Pretreatment is a stage that plays an important role in degrading lignocellulose into cellulose. In this study, we used a Lemna minor which is a water weed with a combination of two stages of pretreatmentt to see the effectiveness of lignocellulosic degradation in the sample. The first stage is hydrothermal pressure method of steam heating temperature 121 °C and pressure 15-20 psi with variation of processing time for 5, 15, 30, 45, and 60 minutes. The second stage of pretreatment with chemical methods using NaOH with a concentration variation of 0.5; 1; 1.5; 2 and 2.5 M. The results showed that 60 minutes was the optimum time of the hydrothermal pressure method in the L. minor sample with the lignin content of 11.32%, the cellulose 17.39%, the hemicellulose 16.73% and the total sugar 0.82%. For the pretreatment stage with alkaline solvent (NaOH) the content of L. minor lignin after pretreatment with 2.0 M NaOH was 5.36%. The content of cellulose, hemicellulose and total sugars was obtained at a concentration of 2.5 M with a grade value of 31.03%, 5.57%, and 1.74%. The effectiveness of lignin decrease in pretreatment hydrothermal pressure was 37.04% while pretreatmentt with NaOH was 70.18%. The combination of pretreatment process gives a good result to the lignin degradation process contained in the L. minor sample in order that it is very effective in the process of making bioethanol with biomass feedstock.
Determination of Vitamin C in Various Colours of Bell Pepper (Capsicum annuum L.) by Titration Method Nerdy Nerdy
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.15738.164-178

Abstract

Vitamin C is needed by human body to improve the immune system and can be obtained from the bell pepper. Bell pepper has a different color according to the level of maturity, ranging from green, yellow, orange, and red. Differences in color also make possible differences in vitamin C content. The purpose of this study was to determine vitamin C levels in various colors of bell fruit. Measurement of vitamin C was done by titration method with metaphosphoric acid as the solvent and 2,6 dichloroindophenol as the standardized solution. The samples used were green bell pepper, yellow bell pepper, orange bell pepper, and red bell pepper taken from Gundaling, Berastagi, Karo, Sumatera Utara, 22152, Indonesia. The results show that vitamin C level in various colors of bell pepper respectively, for green bell pepper 16.52 mg vitamin C per 100 g green bell pepper; yellow bell pepper 159.61 vitamin C per 100 g yellow bell pepper; orange bell pepper 121.38 vitamin C per 100g orange bell pepper; red bell pepper 81.19 vitamin C per 100 g red bell pepper. These results indicate that different levels of bell pepper maturity have different vitamin C content.
Uji Aktivitas Antioksidan N-Metil Kitosan Berkelarutan Tinggi Mardiyah Kurniasih; Purwati Purwati; Ratna Stia Dewi; Susi Fatimah
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.15100.107-118

Abstract

Telah dilakukan uji aktivitas antioksidan dari N-metil kitosan yang memiliki kelarutan tinggi. Uji aktivitas antioksidan dilakukan dengan menggunakan metode DPPH (1,1-diphenyl-2-pikrilhidrazil) dan metode FTC (ferric thiocyanate). Optimasi sintesis dilakukan untuk memperoleh N-metil kitosan dengan kelarutan tinggi. Hasil penelitian menunjukkan bahwa N-metil kitosan yang berkelarutan paling tinggi adalah N-metil kitosan yang disintesis dengan 1,7 mL formaldehid 10%. Berdasarkan hasil uji aktivitas antioksidan menggunakan metode DPPH dapat diketahui bahwa N-metil kitosan merupakan antioksidan sedang dengan nilai IC50 sebesar 145,398 ppm. Hasil pengujian antioksidan metode FTC menunjukkan bahwa N-metil kitosan memiliki kemampuan menghambat terbentuknya senyawa radikal bebas yang disebabkan oleh oksidasi asam lemak.An Antioxidant Activity Test of High Solubility N-Methyl Chitosan. An antioxidant activity test of high solubility N-methyl chitosan has been performed. The antioxidant activity test was performed using DPPH (1,1-diphenyl-2-pikrilhidrazil) and FTC method (ferric thiocyanate). The synthesis optimization was performed to obtain high N-methyl chitosan solubility. The results showed that N-methyl chitosan with the highest solubility in 1% acetic acid solvent was N-methyl chitosan which was synthesized with 1.7 mL formaldehyde 10%. Based on the results of antioxant activity test using DPPH method can be seen that N-methyl chitosan is a medium antioxidant with IC50 value of 145.398 ppm. The result of antioxidant test of FTC method showed that N-methyl chitosan has antioxidant activity with tendency to increase along with the increase of N-methyl chitosan concentration.
Pelarutan Selektif Tembaga dari Limbah Printed Circuit Board dengan Hidrogen Peroksida Gatut Ari Wardani; Rokiy Alfanaar; Sri Juari Santosa
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.11168.51-59

Abstract

Pelarutan selektif tembaga dari limbah printed circuit board (PCB) telah berhasil dilakukan. Logam tembaga yang terkandung di dalam papan PCB dapat dipisahkan menggunakan campuran hidrogen peroksida dan asam sulfat dengan variasi perbandingan volume 0 : 1, 1 : 1, 2 : 1, 3 : 1, 4 : 1, dan 5 : 1. Pemisahan optimal dilakukan dengan sistem perendaman selama 3 hari dengan campuran H2O2/H2SO4 = 3 : 1 (v/v). Jumlah tembaga yang terkandung di dalam papan PCB dianalisis menggunakan X-ray fluorescense. Tembaga yang terkandung di dalam PCB sebesar 57,7%. Pelarutan selektif dapat menurunkan kadar tembaga sehingga tembaga yang masih tersisa adalah sebesar 7,7 x 10-4 %. Penurunan kadar tembaga yang terkandung di dalam PCB mencapai 99,999%. Analisis spektrometri serapan atom dilakukan untuk mengetahui jumlah tembaga yang terlarut yaitu sebesar 25,415 mg/kg PCB.Leaching of Copper from Printed Circuit Board Waste with Hydrogen Peroxide. Leaching of copper from printed circuit board (PCB) waste has been successfully performed. The copper metal contained in the PCB can be separated using a mixture of hydrogen peroxide and sulfuric acid with a variation of volume ratio is 0 : 1, 1 : 1, 2 : 1, 3 : 1, 4 : 1, and 5 : 1. Optimal separation is carried out by the immersion system for 3 days using H2O2/H2SO4 = 3:1 (v/v). The amount of copper contained in the PCB was analyzed using X-ray fluorescence. The copper contained in the printed circuit board is 57.7%. The leaching process can decrease the copper content so that the remaining copper is 7.7 x 10-4%. The decrease of copper content contained in PCB reaches 99.999%. Analysis of atomic absorption spectrometry was conducted to determine the amount of dissolved copper that is 25.415 mg/kg PCB.
Desulfurisasi Katalitik Tiofen Menggunakan Katalis CoMo/USY dalam Reaktor Batch Khoirina Dwi Nugrahaningtyas; Nanda Pratiwi; Eddy Heraldy
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.2368.119-130

Abstract

Telah dilakukan uji aktivitas katalis CoMo/USY pada reaksi desulfurisasi tiofen. Reaksi dilakukan pada reaktor sistem batch dengan tekanan gas N2 sebesar 1 bar gas N2 dan waktu reaksi selama 1 jam. Penelitian ini bertujuan untuk mengetahui pengaruh variasi temperatur dan variasi karakter katalis pada reaksi desulfurisasi tiofen. Product desulfurisasi dianalisis dengan Gas Chromatography - Mass Spectra (GC-MS). Karakter kestabilan struktur katalis dilihat dengan analisis menggunakan instrumen Fourier Transform Infrared Spectroscopy (FT-IR). Hasil analisis terhadap uji aktivitas desulfurisasi menunjukkan bahwa pada rentang temperatur 200-300°C, rendemen bertambah dengan meningkatnya temperatur. Pada penelitian telah berhasil menghidrogenasi tiofen, tetapi belum bisa menghilangkan kandungan sulfurnya. Adapun efek karakter katalis terhadap aktivitas katalitiknya menunjukkan bahwa karakter katalis yang paling dominan adalah sifat keasaman. Katalis dengan keasaman tertinggi, yaitu katalis CoMo/USY, memiliki aktivitas tertinggi dengan rendemen produk sebesar 2,88%. Hasil analisis FT-IR terhadap katalis bekas menunjukkan bahwa struktur cukup stabil dan tidak ada pengotor yang terikat pada katalis.Catalytic Desulfurization of Thiophene using CoMo/USY Catalyst in Batch Reactor. CoMo/USY catalyst activity has been tested for thiophene desulfurization reaction. The reaction was carried out in batch system reactor with N2 gas pressure of 1 bar and reaction time for 1 hour. This study aims to determine the effect of temperature variation and catalyst character variation in thiophene desulfurization reaction. The desulfurization products were analyzed by Gas Chromatography - Mass Spectra (GC-MS). The characters of structure catalyst were analyzed by Fourier Transform Infrared Spectroscopy (FT-IR). The results of the analysis of the desulfurization activity test showed that in the temperature range 200-300 °C, the yield raised with increasing temperature. The analysis results of the desulfurization activity test showed that in the temperature range of 200-300°C, the yield raised with increasing temperature. The study has successfully hydrogenated thiophene, but has not been able to eliminate the sulfur content. The effect of the catalysts character on its catalytic activity shows that the most dominant character of the catalysts was its acidity. The highest acidity catalyst, CoMo/USY catalyst, has highest activity with the product yield of 2,88%. The result of the FTIR analysis on the used catalyst show that the structure was stable and no impurities were attached the catalyst.
Electronic Structure of Vanadium-Doped TiO2 of Both Anatase and Rutile Based on Density Functional Theory (DFT) Approach Hari Sutrisno
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.11374.60-71

Abstract

Study of the theoretical  approah to calculate the band structure and density of states (DOS) of vanadium-doped TiO2 of both anatase and rutile have been done. The first-principle calculations were done using supercell (2x1x1) method. The first-principle calculation of V-doped TiO2 of both anatase and rutile were analyzed by density-functional theory (DFT) with generalized gradient approximation from Perdew-Burke-Ernzerhof (GGA+PBE), Perdew-Wang’s 1991 (GGA+PW91) and local density approximation (LDA) for exchange-correlation functionals. The calculation of electronic structures show that the V-doped TiO2-anatase with high concentration (7.93%) in 24 atoms are direct- and indirect-gap semiconductor, whereas the V-doped TiO2-rutile with high concentration (15.79%) in 12 atoms is direct-gap semiconductor. The V-doped TiO2 of both anatase and rutile produce the intermediate bands in the upper states. Ihe V-doped anatase produces intermediate band, which is 2.05, 2.04, 2.06 eV above the valence band for GGA+PBE, GGA+PW91 and LDA, respectively. Meanwhile the V-doped rutile producesintermediate band, which is 1.76, 1.82, 1.74 eV above the valence band for GGA+PBE, GGA+PW91 and LDA, respectively.
Formulasi dan Uji Aktivitas Krim Pengkelat Merkuri Berbahan Dasar Ekstrak Etanol Alga Coklat (Sargassum sp.) Inda Putrinesia; Yoga Pratama; Nurul Asyikin; Winda Rahmalia
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.12242.152-163

Abstract

Telah dilakukan penelitian tentang formulasi dan uji aktivitas krim pengkelat merkuri berbahan dasar ekstrak etanol alga coklat (Sargassum sp.) telah dilakukan. Krim diformulasikan dengan beberapa bahan seperti vaselin, gliserol, asam askorbat, karbomer, setil alkohol, dan NaOH. Parameter yang dievaluasi diantaranya organoleptik krim, homogenitas, pH, daya sebar, tipe krim, iritasi kulit, dan daya tercuci krim. Aktivitas pengkelatan diamati dengan menganalisis kandungan merkuri pada kulit tikus yang sebelumnya diberikan krim bermerkuri dibandingkan dengan kulit tikus yang telah dioleskan krim pengkelat merkuri berbahan dasar ekstrak etanol alga coklat. Spektrum Fourier Transform Infrared Spectroscopy (FT-IR) menunjukkan bahwa ekstrak etanol alga coklat diindikasikan mengandung glutation. Berdasarkan parameter evaluasi krim, formulasi terbaik adalah krim dengan komposisi ekstrak alga coklat sebanyak 0,035% w/v terhadap volume krim, yang ditandai dengan krim yang berbentuk gel kental dan tidak berbau serta memiliki tekstur seperti krim wajah pada umumnya, yaitu lembut dan sedikit berminyak. Krim bersifat homogen dan stabil hingga hari ke 21 percobaan dengan pH=5. Krim juga tidak menimbulkan iritasi dan dapat tercuci habis tanpa bekas. Hasil analisis AAS membuktikan bahwa penggunaan krim pengkelat merkuri berbahan dasar esktrak etanol alga coklat selama kurang dari 2 minggu dengan dosis pemberian 1 kali sehari mampu menyerap merkuri pada tikus dengan aktivitas penyerapan sebesar 50%.Formulation and Activity Test of Mercury Chelator Cream of Ethanol Extract of Brown Algae (Sargassum Sp.). Research on the study of formulation an activity test of mercury chelator cream from ethanol extract has successfully done. The cream was formulated with ingredients such as vaseline, glycerol, ascorbic acid, carbomer, cetyl alcohol, and sodium hydroxide. Parameters were evaluated against organoleptic, homogenity, pH, dispersion type of cream, skin irritation test and washing test. The mercury chelating activity was observed by analyzing mercury concentration in mercury induced mouse skin. The FTIR spectrum shows that ethanol extract of brown algae was dominated by glutathione functional group. The best cream formulation was composed by 0,035% (w/v) brown algae, formed as a creamy gel that was thick and odorless and had a texture like soft facial cream in general with slightly oily.The cream was homogeneous and stable until the 21st day of the experiment with pH = 5. The cream produced no skin irritation and could be washed out without a trace. The results of AAS analysis proved that the use of brown algae ethanol extract-based mercury chelating cream for less than 2 weeks with a dose of 1 time a day could absorb mercury in mouse skin with absorption activity of 50%.
Pemurnian Parsial dan Karakterisasi Urease dari Biji Kacang Panjang (Vigna unguiculata subsp sesquipedalis L.) Zusfahair Zusfahair; Dian Riana Ningsih; Amin Fatoni; Darul Santri Pertiwi
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.13000.72-83

Abstract

Urease merupakam enzim yang digunakan dalam hidrolisis urea menjadi amoniak dan asam bikarbonat dan telah banyak digunakan dalam proses industri. Tujuan penelitian adalah isolasi dan pemurnian urease dari kacang panjang serta karakterisasinya. Penelitian dimulai dengan melakukan perkecambahan biji kacang panjang selama 8 hari. Kecambah biji kacang panjang selanjutnya diekstraksi dengan menggunakan buffer fosfat pH 7 dan dipisahkan menggunakan sentrifugasi sehingga diperoleh ekstrak kasar urease. Ekstrak kasar urease selanjutnya difraksinasi menggunakan aseton pada tingkat konsentrasi 20, 40, 60 dan 80%. Fraksi yang mempunyai aktivitas spesifik paling tinggi selanjutnya dianalisis menggunakan metode SDS-PAGE untuk menentukan berat molekulnya dan dikarakterisasi lanjut meliputi: pengaruh suhu, pH, konsentrasi substrat dan penambahan ion logam terhadap aktivitas urease. Aktivitas urease ditentukan dengan metode Nessler. Hasil penelitian menunjukkan aktivitas spesifik urease dari kacang panjang paling tinggi ditemukan pada fraksi aseton (FA) 20. Hasil analisis berat molekul dengan metode SDS-PAGE diperoleh beberapa pita protein yang diduga berukuran sekitar 25 KDa dan 17 KDa. Kondisi optimum dari aktivitas urease diperoleh pada suhu 30 ºC, pH 7 dan konsentrasi urea 16,6 mM dengan nilai aktivitas 407,62 U/mL. EDTA dan ion logam dalam CaCl2, NaCl, NiCl2 dan CuCl2 pada variasi konsentrasi 10-3, 10-4  dan 10-5 M merupakan inhibitor urease FA 20 dari kacang panjang.Partial Purification and Characterization of Urease from Asparagus Bean (Vigna unguiculata subsp sesquipedalis L.). Urease is an enzyme used in urea hydrolysis to ammonia and bicarbonate acid and has been widely used in industrial processes. The study focused on isolation and purification of urease from asparagus beans and its characterization. The study was started with germination of asparagus beans for 8 days. Germinated asparagus beans were further extracted using phosphate buffer pH 7 and separated by centrifugation to obtain a crude extract of urease. The crude extract of urease was further fractionated using acetone at concentrations of 20, 40, 60 and 80%. The fraction with highest specific activity was then analyzed using SDS-PAGE method to determine its molecule weight and characterized further including the influence of temperature, pH, substrate concentration, and metal ion addition to urease activity. The urease activity was determined by the Nessler̕ s method. The results showed that the specific activity of urease from asparagus beans was found with highest activity in fraction of acetone (FA) 20. Analytical result using SDS-PAGE method was obtained some protein bands having molecular weights about 25 KD and 17 KDa. The optimum conditions of urease activity was obtained at 30 °C, pH 7, incubation time 20 min and urea concentration 16.6 mM with activity value 407.62 U/mL. EDTA and metal ions contained in CaCl2, NaCl, NiCl2 and CuCl2 at concentrations of 10-3, 10-4 and 10-5 M were FA 20 urease inhibitors.
Konduktivitas Apatit Lantanum Silikat La9.33Si6O26 Hasil Sintesis Hidrotermal dengan Mineraliser NaOH dan KOH Atiek Rostika Noviyanti; Dani Gustaman Syarif; Riansyah Amynurdin; Iwan Hastiawan; Iman Rahayu; Yati B. Yuliyati
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.8468.1-15

Abstract

Apatit lantanum silikat banyak digunakan sebagai elektrolit pada sel bahan bakar padatan (SOFC). Beberapa oksida apatit lantanum silikat La9.33Si6O26 telah disintesis dengan metode hidrotermal guna mengamati pentingnya peranan mineraliser terhadap karakternya. Penelitian ini bertujuan untuk mengetahui pengaruh jenis dan konsentrasi mineraliser terhadap kristalinitas, ukuran partikel dan hubungannya dengan sifat konduktivitas oksida apatit lantanum silikat. Struktur, ukuran partikel dan konduktivitas oksida apatit masing-masing dikarakterisasi dengan XRD, PSA dan spektroskopi impedansi. Oksida apatit lantanum silikat diperoleh dengan melarutkan La2O3 dan Na2SiO3 dengan mol ratio 1,555 menggunakan mineraliser NaOH (3-5 M) dan KOH (0,3-0,7 M). Hasil penelitian menunjukkan bahwa kinerja elektrolit sangat ditentukan oleh kristalinitas dan morfologi apatit lanthanum silikat yang dipengaruhi oleh jenis dan konsentrasi mineralizer. Ukuran apatit lantanum silikat terkecil diperoleh dari hasil sintesis dengan menggunakan mineraliser NaOH 3 M yaitu 1,7889 µm, dengan nilai konduktivitas tertinggi yaitu 1,99×10-6 S/cm pada suhu operasi 600 ºC. Berdasarkan hasil tersebut NaOH 3 M merupakan mineraliser yang paling baik untuk menghasilkan apatit lanthanum silikat La9.33Si6O26.Conductivity of Lanthanum Silicate Apatite Phase of La9.33Si6O26 Prepared by Hydrothermal Synthesis using NaOH and KOH as Mineralizer. Lanthanum silicates are used as electrolytes in solid oxide fuel cells (SOFC). Some oxide-based apatite has been synthesized by hydrothermal method to observe mineralizer effect on the process of crystallization. The effect of type and amount of mineralizers for preparing apatite –type lanthanum silicate of La9.33Si6O26 was investigatedon its crystallinity, particle size, as well as on the conductivity properties relationship were investigated. The structure, particle size and conductivity of La9.33Si6O26 was characterized using X-ray diffraction, particle size analyzer and impedance spectroscopy respectively. The results show that the electrolyte performance is strongly dependent on the crystallinity and the morphology textural of lanthanum silicate apatite affected by the type and amount of mineralizer. The lanthanum silicate apatiteprepared by La2O3 and Na2SiO3 (molar ratio of La2O3 and Na2SiO3 = 1.555), and NaOH (3; 4; 5 M) and KOH (0,3-0,7 M) as mineralizer. As a result, apatite-type lanthanum silicate was prepare using NaOH 3 M shows smallest particle (1.7889 μm) and highest conductivity (1.99 × 10-6 S / cm at 600 ºC). With respect to both particle size and conductivity, the NaOH 3 M can be selected as a suitable type and amount mineralizer for the preparation of excellent lanthanum silicate apatite La9.33Si6O26.
Aktivitas Antibakteri dan Antioksidan Asam Galat dari Kulit Buah Lokal yang Diproduksi dengan Tanase Eka Junaidi; Yunita Arian Sani Anwar
ALCHEMY Jurnal Penelitian Kimia Vol 14, No 1 (2018): March
Publisher : UNIVERSITAS SEBELAS MARET (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/alchemy.14.1.11300.131-142

Abstract

Penelitian ini mempelajari tentang produksi asam galat menggunakan enzim tanase dari limbah kulit buah lokal di Lombok. Limbah kulit buah lokal yang digunakan yaitu kulit buah kepundung (Baccaurea racemosa Muell.Arg), kulit buah juwet (Syzygium cumini), dan kulit buah manggis (Garcinia mangostana). Pada penelitian ini dilakukan pengujian asam galat yang dihasilkan, untuk mengetahui aktivitas antioksidan dan antibakteri. Pengujian sifat antioksidan dilakukan dengan menggunakan metode DPPH, sedangkan aktivitas antibakteri diuji dengan menggunakan metode difusi agar pada bakteri Escherichia coli dan Staphylococcus aureus. Hasil penelitian menunjukkan bahwa asam galat dari ketiga kulit buah memiliki aktivitas antioksidan. Asam galat dari kulit buah kepundung, kulit buah juwet dan kulit buah manggis memiliki IC50 masing-masing sebesar 5.95; 5,96; dan 5,92 ppm. Berbeda dengan kemampuan sebagai antioksidan, asam galat resistan terhadap bakteri Escherichia coli dan Staphylococcus aureus yang menunjukkan bahwa asam galat tidak memiliki aktivitas sebagai antibakteri.Antibacterial and Antioxidant Activity of Gallic Acid Extracted from Local Fruit Peels Produced by Tannase. This research studied the gallic acid production using tannase enzym from fruit local peels in Lombok. The local fruit waste used are kepundung rind (Baccaurea racemosa Muell.Arg), juwet rind (Syzygium cumini) and mangosteen rind (Garcinia mangostana). The produced Gallic acid was tested to determine its antioxidant and antibacterial activity. The antioxidant test conducted by DPPH method, meanwhile, the antibacterial activity was performed by agar diffusion method against bacteria Escherichia coli and Staphylococcus aureus. The results showed that the produce gallic acid from those three rind provide antioxidant activity. Gallic acid from kepundung rind, juwet rind, and mangosteen rind have IC50 values of 5,95; 5,96; and 5,92, respectively. Gallic acid does not showed inhibitory actions against the growth of Escherichia coli and Staphylococcus aureus. This result showed that gallic acid from local fruit waste provided no an antibacterial activity.

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