Jurnal Ilmu Kimia Universitas Brawijaya
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PENGARUH TEMPERATUR PENGGANTIAN PELARUT TERHADAP HIDROFOBISITAS AEROGEL SILIKA
Get PDFAerogel silika telah disintesis dengan bahan dasar lumpur Lapindo. Sintesis aerogel silika dilakukan melalui beberapa tahapan yang diawali dengan mengekstrak silika yang ada dalam lumpur Lapindo kemudian endapan silika yang masih basah dicetak sehingga terbentuk gel silika. Gel silika selanjutnya direndam dalam metanol dan sebagai variasi adalah temperatur perendaman yakni pada temperatur ruang dan 50 oC, selanjutnya masing-masing gel dimodifikasi permukaannya dengan TMCS (trimethylchlorosilane) sebagai agen sililasi, kemudian  dikeringkan  pada tekanan ambien dengan temperatur 50 oC selama satu jam dan dilanjutkan pemanasan pada temperatur 200 oC selama satu jam. Aerogel silika yang diperoleh dikarakterisasi menggunakan spektrofotometer infra merah dan uji hidrofobisitas. Penggantian pelarut pada temperatur 50 oC menghasilkan aerogel yang lebih hidrofobik daripada aerogel yang diperoleh dari penggantian pelarut pada temperatur ruang berdasarkan spektra infra merah. Aerogel yang dihasilkan bersifat hidrofobik dan buram. Kata kunci: Aerogel silika, lumpur Lapindo, tekanan ambien, penggantian pelaru
PENGARUH pH DAN TEMPERATUR TERHADAP KESTABILAN AKTIVITAS XILANASE DARI Trichoderma viride
Get PDFXylanase is an enzyme that can hydrolyze xylan into reducing sugar xylose and xilo-oligosaccharides. The research was carried out to determine the effect of pH and temperature on stability of xylanase activity of T. viride . Its effects were observed by measuring the residual activity after the enzyme xylanase was incubated for 9 hours at pH variation (4, 5, 6) and the variation of temperature (50, 60, 70 oC ). Enzyme activity is said to be stable if the remaining activity is greater than or equal to 50%. Xylanase activity was determined by measuring the levels of reducing sugars produced during the enzymatic reaction, by spectrophotometry using DNS reagent. The results showed that the xylanase activity remained stable after the enzyme was incubated for 9 hours at pH 4, 5, 6 and at temperatures of 50, 60, 70 oC. The stability of xylanase activity is highest when xylanase was incubated at pH 5 and temperature 60 ° C.Key words: enzyme stability , pH, temperature , Trichoderma viride, xylanase
KINETIKA REAKSI HIDROLISIS PATI BIJI DURIAN (Durio zibethinus Murr.) MENJADI GLUKOSA DENGAN VARIASI TEMPERATUR DAN WAKTU
Get PDFABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh temperatur dan waktu pada proses hidrolisis pati biji durian (Durio zibethinus Murr.) menjadi glukosa serta untuk menentukan kinetika reaksi pada proses hidrolisis tersebut. Proses hidrolisis dilakukan dengan menggunakan katalis HCl 3M. Variasi temperatur yang digunakan yaitu 50 oC dan 70 oC dengan variasi waktu sebesar 30, 60, 90, 120, 150 dan 180 menit. Kadar glukosa larutan hidrolisat kemudian dianalisis menggunakan reagen DNS. Berdasarkan hasil penelitian, dapat diketahui bahwa temperatur dan waktu hidrolisis mempengaruhi kadar glukosa. Semakin tinggi temperatur dan semakin lama waktu hidrolisis maka kadar glukosa larutan hidrolisat semakin meningkat. Kadar glukosa larutan hidrolisat kemudian digunakan untuk menentukan kinetika reaksi hidrolisis. Kinetika reaksi hidrolisis pati biji durian (Durio zibethinus Murr.) menjadi glukosa dapat dinyatakan dengan persamaan: k = 3,593 x 106 . e-10153,812/T M.menit -1 Katakunci: biji durian, glukosa, hidrolisis, kinetika, pati  ABSTRACT  This experiment aim to find out the influence of temperature and time on hydrolysis of durian (Durio zibethinus Murr.) seed starch become glucose and to determine the reaction kinetics of hydrolysis process. Hydrolysis process was conducted by using HCl 3M as catalyst. The temperature varied from 50 oC and 70 oC, while time variation varied from 30, 60, 90, 120, 150 and 180 minutes. Glucose levels of hydrolysate solution was analyzed using DNS reagent. This experiment resulted that temperature and hydrolysis time affected the glucose levels. Increasing of temperature and hydrolysis time produced higher glucose levels of hydrolysate solution. The glucose levels of hydrolysate solution used to determine the reaction kinetics. Reaction kinetics of durian seed hydrolysis become glucose stated with equation: k = 3,593 x 106 . e-10153,812/T M.minutes -1 Keywords: durian seed, glucose, hydrolysis, kinetics, starc
AMOBILISASI PEKTINASE DARI Bacillus firmus MENGGUNAKAN MATRIKS OPP (OXIDIZED POLYPROPYLENE)-KITOSAN
Get PDFA Pectinase is an enzyme that can hydrolyze pectin compounds into galacturonic acid. In order to enhance the pectinase efficiency, the enzyme can be immobilized in certain matrix. The pectinase was isolated from Bacillus firmus, and then purified with ammonium sulphate with 20-60% saturated level, followed by dialysis. The aims of the research were to determine the optimum conditions of immobilized pectinase by physical adsorption on oxidized polypropylene (OPP) coated chitosan, which included the shaking time and enzyme concentration. Initial protein used for immobilizing free pectinase was 1.367 mg/mL and the activity was 241.1 units. The results showed that the optimum condition of pectinase immobilization was achieved on shaking time of 3 hours and pectinase concentration of 1.094 mg/mL with amount of pectinase adsorbed at 53,98 mg/g within activity of 220.2 units
STUDI PENGARUH WAKTU REAKSI TERHADAP SINTESIS SENYAWA ORGANONITROGEN BERBASIS α-PINENA MELALUI REAKSI RITTER
Get PDFThe aim of this research is to synthesize organonitrogen compound using α-pinene as starting material which reacted with acetonitrile and acid catalysts through Ritter reaction. The reactions were optimized by modifying a reaction time varied from 6, 10, and 15 hours. α-Pinene used in this reaction was isolated from turpentin oil by fractional distillation in 88.46%. There were three major products obtained from reaction of α-pinene, acetonitrile and H2SO4 97%, that is, N-(2,6,6-trimethylbicyclo[3.1.1]heptan-2-yl)acetamide as product 1, N-(2-(4-methylcyclohex-3-enyl)propan-2-yl) acetamide as product 2, and N-(1,7,7-trimethylbicyclo[2.2.1] heptan-2-yl)acetamide as product 3. The percentage of product 2 and product 3 were increased by the increasing of reaction time, while product 1 was decreased. This result is considered by different stability of product structure. Product 2 and 3 should be the most stable structure than product 2. The other acetamide derivatives were also produced but in low percentage. Key words: α-pinena, Ritter reaction, acetamide compound, organonitrogen compound, reaction tim
ADSORPSI TEMBAGA(II) MENGGUNAKAN BIOMASSA Azolla microphylla DIESTERIFIKASI DENGAN ASAM SITRAT
Get PDFThe research about adsorption of copper(II) using Azolla microphylla biomass esterified with citric acid has been conducted. The aim of this research was to determine the optimum conditions of copper(II) adsorption by Azolla microphylla biomass esterified with citric acid and adsorption capacity of esterified biomass toward copper(II). Esterification of biomass was conducted by suspending 5 g of biomass in 50 mL of 0.8 M citric acid solution followed by drying the suspension in the oven at 60 oC. Then, the dried suspension was heated at 120 oC for 3.5 hours. Batch experiments were carried out using dry biomass of 120-150 mesh at various pH of 3; 4; 5; and 6, various contact time of 30; 45; 60; 75; 90; and 120 minutes, and various copper(II) concentration of 50; 75; 100; 125; 150 mg/L. The results showed that the optimum conditions for the adsorption of copper(II) by biomass Azolla microphylla esterified with citric acid occurred at pH 5 and contact time 60 minutes. According to the Langmuir adsorption isotherm equation, it was found that the adsorption capacity (Qmax) of esterified biomass (15.625 mg/g) was smaller than that of non-esterified biomass (24.390 mg/g). Keywords: Azolla microphylla, biosorption, citric acid, copper(II), esterification
STUDI PENGARUH KONSENTRASI NaOH DAN pH TERHADAP SINTESIS SILIKA XEROGEL BERBAHAN DASAR PASIR KUARSA
Get PDFIn this research, the influence of NaOH concentration and gelation pH of the xerogel silica synthesized from quartz sand. It was extracted by NaOH 1, 2, and 3 M to obtain sodium silicate solution and was added by HCl 1M to reach pH value 7, 8, and 9 to become gel. After that it was heated at 80° C for 18 hours (aging process) to get xerogel silica. This result xerogel silica were characterized by FT-IR and XRD and its surface area was characterized by methylene blue. The optimum concentration of NaOH is 1 M with silica yield 33%. Surface area which was obtained by concentration variation of NaOH is 7 to 8 m2 / g. Surface area was not influenced by pH variation and NaOH. Characteristics using FT-IR show typical absorption of Si - O at 400 to 3000cm-1 and phase of silica xerogel by XRD is amorphous. Determination of surface area xerogel silica by methylene blue methode 7.364 m2 / g.  Key words: Xerogel, NaOH Variation, pH variation
PENGARUH VARIASI TEMPERATUR TERHADAP SINTESIS SENYAWA ORGANONITROGEN BERBASIS α-PINENA DARI HASIL ISOLASI MINYAK TERPENTIN
Get PDFTelah dilakukan sintesis senyawa organonitrogen dari bahan dasar α-pinena hasil isolasi dari minyak terpentin. Sintesis dilakukan dengan variasi temperatur yaitu (-15) – (-10) °C, 27 °C dan 90 °C. Pemilihan temperatur tersebut bertujuan untuk membandingkan senyawa produk organonitrogen yang terbentuk. α-Pinena diisolasi dari minyak terpentin dengan metode distilasi fraksinasi menggunakan pengurangan tekanan, diperoleh kadar kemurnian sebesar 88,46 %. Reaksi Ritter ini menghasilkan senyawa yang beragam, akibat adanya penataan ulang posisi karbokation pada struktur α-pinena. Produk utama yang dihasilkan berupa N-(1,7,7-trimetilbisiklo[2.2.1]heptan-2-il)asetamida; N-(2-(4-metilsikloheks-3-enil)propan-2-il)asetamida dan N-(2,6,6-trimetil bisiklo[3.1.1]heptan-2-il)asetamida. Secara umum, semakin bertambahnya temperatur maka akan meningkatkan energi molekul untuk melakukan reaksi. Akan tetapi senyawa yang terbentuk juga dipengaruhi oleh kestabilan strukturnya
PENGARUH pH DAN TEMPERATUR TERHADAP KINERJA ELEKTRODA SELEKTIF ION Cd(II) TIPE KAWAT TERLAPIS BERBASIS D2EHPA
Get PDFABSTRAK Pengaruh pH dan temperatur terhadap kinerja elektroda selektif ion (ESI) Cd(II) tipe kawat terlapis berbasis D2EHPA telah dipelajari. ESI Cd(II) tipe kawat terlapis dibuat dari kawat platina (Pt) dilapisi membran yang tersusun atas D2EHPA sebagai ionofor, berpendukung campuran polimer PVC dan pemlastis DBP dengan perbandingan % b/b = (16:28:56) yang dilarutkan dalam pelarut tetrahidrofuran (THF) (1:3 b/v). ESI Cd(II) tipe kawat terlapis berbasis D2EHPA menunjukkan sifat Nersntian dengan harga faktor Nernst 27,70 mV/dekade konsentrasi, rentang konsentrasi linier 1x10-5 – 1x10-1 M, limit deteksi 6,6x10-6 M atau setara dengan 0,316 ppm, waktu respon 40 detik serta usia pemakaian 42 hari. Penentuan pengaruh pH dilakukan dengan mengukur potensial larutan CdCl2 dengan konsentrasi 1x10-5 – 1x10-1 M pada pH 3, 4, 5, 6 dan 7 menggunakan bufer asetat. Pengaruh temperatur dipelajari dengan mengukur potensial larutan CdCl2 dengan rentang konsentrasi 1x10-5 – 1x10-1 M pada variasi temperatur (20, 25, 30, 35, 40, 45, 50, 55 dan 60)°C. Hasil penelitian menunjukkan bahwa ESI Cd(II) tipe kawat terlapis dapat digunakan pada rentang pH 4 – 6 dan temperatur 20 – 50°C. Kata kunci: D2EHPA, ESI tipe kawat terlapis, kadmium, membran, potensiometr
PEMBUATAN ELEKTRODA SELEKTIF ION KADMIUM TIPE KAWAT TERLAPIS BERMEMBRAN D2EHPA
Get PDFABStract Preparation of coated wire cadmium(II) ion selective electrodes Cd(II) CWE) membranous Di (2-Ethyl Hexyl) Phosporic Acid (D2EHPA) has been done to obtain the optimum membrane composition ratio and optimum soaking time that produce cadmium(II) CWE have Nerntstian character. Preparation of cadmium(II) CWE was conducted by three kinds of membrane composition comprising an active ingredient D2EHPA, matrix material consist of polyvinylchloride (PVC) polymer and plasticizer dibutylphtalate (DBP) dissolved in tetrahydrofuran (THF) solvent with a ratio of 1:3 by weight/volume. Potential measurements made​​ in the CdCl2test solution in the concentration range10-8-10-1M at pH 5. Optimization of time soaking in a solution of CdCl2 0.1M performed at optimum membrane composition in the time range of 0-80 minutes with 10 minutes intervals. The results showed that the optimum composition of the membrane is a membrane with the composition ratio of D2EHPA : PVC : DBP = 16 : 28 : 56 produces Nernstian properties with prices Nernst factor of 27.26mV/decade of concentration needed optimum soaking time in a solution of CdCl2 0.1M for 20 minutes.  Key words: cadmium CWE, D2EHPA, membrane, potentiometr