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All Journal CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Jurnal Kimia (Journal of Chemistry) International Journal of Biosciences and Biotechnology The Journal of Pure and Applied Chemistry Research Jurnal Media Sains Jurnal Ilmu Pendidikan Indonesia Nata Palemahan: Journal of Environmental Engineering Innovations
Oka Ratnayani
Program Studi Kimia, Fakultas Matematika Dan Ilmu Pengetahuan Alam, Universitas Udayana, Jimbaran, Bali, Indonesia
Agriculture, Biological Sciences & Forestry Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education Electrical & Electronics Engineering Engineering Environmental Science Immunology & microbiology Materials Science & Nanotechnology Mathematics Medicine & Pharmacology Physics

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KARAKTERISASI KEASAMAN DAN LUAS PERMUKAAN TEMPURUNG KELAPA HIJAU (Cocos nucifera) DAN PEMANFAATANNYA SEBAGAI BIOSORBEN ION Cd2+ I. A. G. Widihati; Oka Ratnayani; Yunita Angelina
Jurnal Kimia (Journal of Chemistry) Vol. 4, No. 1 Januari 2010
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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Abstract

The characterization of surface acidity and area of green coconut shell (Cocos nucifera) and the applicationof the shell as biosorbent of Cd2+ have been conducted in this study. The physico-chemical characterization of thebiosorbent was observed by surface acidity measurement using gravimetry, acid base titration, and infraredspectrofotometry, and the surface area was determined by spectrofotometer UV-Vis using methylen blue method.The use of this shell as biosorbent of Cd2+ was studied by the equilibrium time, the adsorption isotherms, theadsorption capacity, and the influence of pH on adsorption capacity.The result showed that the acidity surface of the green coconut shell determined using gravimetric and acidbase titration was 39.2647 mmol/g and 39.8843 mmol/g. The surface area was 36.5961 m2/g. The adsorption capacityof green coconut shell (Cocos nucifera) as biosorbent of Cd2+ was 2.5135 mg/g at 4 hours equilibrium time with Cd2+and initial concentration (adsorption isotherms) of 50 ppm. At pH 11.00 the adsorption capacity of biosorbent onCd2+ increased to 2.7857 mg/g.
KARAKTERISASI KARBON AKTIF KOMERSIAL SERTA APLIKASINYA SEBAGAI ADSORBEN ION TIMBAL(II) DAN KROM(III) Ni Ayu Putu Tejawati; Manuntun Manurung; Oka Ratnayani
Jurnal Kimia (Journal of Chemistry) Vol. 11. No.2 Juli 2017
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (202.345 KB) | DOI: 10.24843/JCHEM.2017.v11.i02.p13

Abstract

Pada penelitian ini dilakukankarakterisasi karbon aktif komersial serta aplikasinya sebagai adsorben Pb(II) dan Cr(III). Penelitian ini bertujuan untuk mengetahui kualitas dari karbon aktif komersial berdasarkan SNI (Standar Nasional Indonesia) dibandingkan dengan karbon aktif komersial yang diaktifkan kembali dengan pemanasan pada suhu 6000C selama 2 jam. Hasil penelitian menunjukkan, nilai kadar air adalah 6,8%, kadar zat menguap 13,22%, kadar abu total 1,9% dan kadar karbon terikat sebesar 79,1%. Bilangan iodin 774,2159 mg/g dan luas permukaan 8,9400 m2/g. Dengan pemanasan karbon aktif pada suhu 6000C selama 2 jam, bilangan iodin naik menjadi 864,7238 mg/g dan luas permukaan karbon aktif 9,2511 m2/g. Kapasitas Adsorpsi karbon aktif komersial terhadap Pb(II) adalah 0,3438 mg/g dan Cr (III) 0,1861 mg/g, sedangkan karbon teraktivasi panas kapasitas adsorpsinya adalah 0,6775 mg/g untuk Pb(II) dan 0,3033 mg/g pada Cr(III).
ANALYSIS OF LIMONENE AND OTHER ANTIOXIDANTS IN COMMERCIALESSENTIAL OIL PRODUCTS COMPARED TO HOMEMADE VIRGIN COCONUT OIL Ni Made Suaniti; I Wayan Bandem Adnyana; Manuntun Manurung; Oka Ratnayani; Raisyah Anjani
International Journal of Biosciences and Biotechnology Vol 7 No 1 (2019)
Publisher : Central Laboratory for Genetic Resource and Molecular Biology, Faculty of Agriculture, Udayana University in cooperation with Asia-Oceania Bioscience and Biotechnology Consortium (AOBBC)

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Abstract

Essential oil production in the market is very diverse with various brands labeled as antioxidants that have gained more attention in the society recently. The purpose of this study was to analyze limonene and other antioxidants content of the essential oils in the market compared to homemade virgin coconut oil. The method used was Gas Chromatography-Mass Spectrometry (GC-MS) and Fourier-transform infrared (FTIR) Spectroscopy. The infrared spectrogram showed the presence of alkanes and esters respectively at wave numbers of 3000-2850 and 1750-1730 cm-1. Chromatogram results showed the presence of limonenecompounds and some antioxidants with a fairly good separation in the several types of oils, which was not detected in the homemade virgin coconut oil.
SPESIASI DAN BIOAVAILABILITAS LOGAM BERAT Pb DAN Cu PADA SEDIMET LAUT DI KAWASAN PANTAI CELUKAN BAWANG I Made Siaka; Dwinda Safitri; Oka Ratnayani
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 10 No 2 (2022): Cakra Kimia (Indonesian E-Journal of Applied Chemistry)
Publisher : Graduate Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Karakteristik logam berat pada organisme dan sistem ekologis tidak dapat diterangkan hanya dengan mengetahui kandungan logam total dalam perairan, melainkan dengan penentuan bentuk geokimia atau spesies logam tersebut. Penelitian ini bertujuan untuk menentukan spesiasi dan bioavailabilitas logam berat Pb dan Cu pada sedimen di Kawasan Pantai Celukan BawangBuleleng, Bali. Analisis logam total, spesiasi dan bioavailabilitas ditentukan dengan menerapkan metode digesti dan ekstraksi bertahap. Kandungan logam Pb dan Cu totaldalam sedimen Pantai Celukan Bawang berturut-turut17,2865-39,4533 mg/kg dan 12,9665-56,1346 mg/kg. Spesies logam Pb paling banyak berada sebagaifraksi resistant (29,75-67,10%), diikuti oleh fraksi tereduksi asam (22,45-31,67%), fraksi EFLE (easily, freely, leachable, exchangeable) dengan kisaran dari tidak terdeteksi (ND) hingga 29,33%, dan yang terendahberasosiasi dengan fraksi teroksidasi organik (ND-14,18%). Spesies logam Cu juga didominasi olehfraksi resistant(80,52-90,22%), fraksi teroksidasi organik(4,81-17,20%) berada pada urutan ke dua, diikuti oleh fraksi EFLE (0,88-5,83%), dan terrendahadalah fraksi tereduksi asam (ND-1,14%). Bioavailabilitas logam Pb yang sertamerta bioavailabelberkisar ND-29,33% dan yang berpotensi bioavailabel adalah 33,35-42,78%,sedangkan logam Pb yang nonbioavailabel adalah 29,75-67,10%. Berbeda dengan Pb, logam Cu didominasi oleh bentuk non bioavailabel yaitu berkisar 80,52-90,22%, diikuti oleh Cu yang berpotensi bioavailabel, yaitu 5,95-16,61%, dan terkecil adalah Cu yang bersifat sertamerta bioavailabel (0,88-5,83%). ABSTRACT: The characteristics of heavy metals in organisms as well as on ecological systems cannot be explained by the only knowing total metalcontents in sediments but by determining the geochemical forms or the metal species in the sediments. This study aimed to determine the speciation and bioavailability of heavy metals, Pb and Cu in sediments of Celukan Bawang Beach area of Singaraja, Bali. The total metals, speciation and bioavailability analysiswere determined by applying a digestion and sequential extraction methods. The total metal contents of Pb and Cu in the sediments were 17.2865-39.4533mg/kg and 12.9665-56.1346 mg/kg, respectively. The species distribution of the metals in the sediments was as follows: species of Pb was dominated by the form of resistant fraction (29.75-61.10%), followed by reducible acid fraction (22.45-36.25%), EFLE fraction (easily, freely, leachable, exchangeable) ranging from undetectable (ND) to 29.33%, and the lowest percentagefraction was associated with the organic oxidizable phase (ND-14.18%). The resistant fraction was also the most dominant for Cu (80.52-90.22%), but the oxidizable fraction (4.81-17.20%) was found in the second level, followed by the EFLE fraction (0.88-5.83%), and the lowest was associated with reducible fraction (ND-1.14%). The readily bioavailable Pb ranged from 3.62 to 29.33% and potentially bioavailable Pb was 33.35-42.78%, nonbioavailable Pb was 29.75-61.10%. Different from Pb, Cu metal was dominant as non bioavailable metal (80.52-90.22%) but 0.88-5.83% of the Cu was readily bioavailableand 5.95-16.61% was potentially bioavailable.
PENENTUAN NILAI KM DAN VMAKS DARI ENZIM PAPAIN DALAM HIDROLISIS KONSENTRAT PROTEIN AMPAS TAHU Oka Ratnayani; Sakinatul Fatimah; Ketut Ratnayani; Ni Made Puspawati
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 10 No 2 (2022): Cakra Kimia (Indonesian E-Journal of Applied Chemistry)
Publisher : Graduate Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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Abstract

ABSTRAK: Sisa kandungan protein dalam ampas tahu yang masih cukup tinggi perlu dioptimalkan pemanfaatannya dengan cara mengisolasi komponen protein tersebut sehingga diperoleh konsentrat protein ampas tahu dan digunakan sebagi substrat untuk produksi hidrolisat protein. Penelitian ini bertujuan untuk menentukan kemampuan enzim papain dalam menghidrolisis konsentrat protein ampas tahu yaitu dengan menentukan nilai Km (Konstanta Michaelis-Menten) dan Vmaks (Kecepatan Maksimum). Tahap penelitian diawali isolasi protein total sehingga diperoleh konsentrat proteinnya.yang selanjutnya dihidrolisis secara parsial dengan enzim papain sehingga diperoleh produk hidrolisat protein. Proses isolasi protein ampas tahu menggunakan sampel ampas tahu segar dengan metode ekstraksi alkalik dilanjutkan dengan presipitasi isoelektrik mampu menghasilkan serbuk konsentrat protein dengan nilai kadar protein mencapai 50,36% sehingga memenuhi syarat sebagi konsentrat protein. Hasil penentuan nilai Km dan Vmaks enzim papain dalam menghidrolisis substrat konsentrat protein ampas tahu memperoleh nilai Km sebesar 237,0229 mg/mL dan nilai Vmaks sebesar 5,1975 mg/mL/menit. Hal ini menunjukkan bahwa enzim papain mampu menghidrolisis konsentrat protein ampas tahu sehingga menghasilkan produk hidrolisat protein ampas tahu. ABSTRACT: The remaining protein content in tofu dregs is still quite high, so that its utilization can be optimized by isolating the protein component to obtain the protein concentrate that can be used as a substrate for the production of protein hydrolysates. This study aimed to determine the ability of the papain enzyme to hydrolyze the protein concentrate of tofu dregs through determining the values ??of Km (Michaelis-Menten constant) and Vmax (Maximum Speed). The research steps began with the total protein isolation to obtain the protein concentrate, which was then partially hydrolyzed with papain enzymes to produce protein hydrolysate. The isolation of the tofu dregs protein from fresh tofu dregs samples was done by using an alkaline extraction method followed by isoelectric precipitation resulted in protein concentrate powder with a protein content value of 50.36%, so that it qualified as a protein concentrate. The determination of Km and Vmax values of the papain enzyme in hydrolyzing the protein concentrate substrate of tofu dregs obtained a Km value of 237.0229 mg/mL and a Vmax value of 5.1975 mg/mL/minute. This showed that the papain enzyme was able to hydrolyze the tofu dregs protein concentrate to produce a tofu protein hydrolyzate product.
HIDROLISIS PROTEIN KECAMBAH KACANG MERAH MENGGUNAKAN ENZIM PAPAIN DENGAN VARIASI RASIO ENZIM-SUBSTRAT Oka Ratnayani; Made Ririn Dwi Rahayu; Ketut Ratnayani; Ni Komang Ariati
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 11 No 1 (2023): Cakra Kimia (Indonesian E-Journal of Applied Chemistry)
Publisher : Graduate Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Hidrolisis protein secara enzimatik dapat memproduksi hidrolisat protein yang akan menghasilkan peptida rantai pendek dan asam amino bebas, sehingga memiliki nilai gizi dan protein terlarut lebih tinggi dan lebih mudah dicerna. Penelitian akhir-akhir ini juga menunjukkan bahwa kecambah kacang merah (Phaseolus vulgaris L.) memiliki kadar protein terlarut lebih tinggi dibandingkan dengan kacang merah yang belum dikecambahkan. Maka, pada penelitian ini, kecambah kacang merah dijadikan substrat untuk menghasilkan hidrolisat protein menggunakan enzim papain yang relatif mudah didapat, tidak ada reaksi samping, tidak toksik, relatif tahan terhadap suhu, dan memiliki daya katalitik yang tinggi. Selain itu, salah satu faktor yang memengaruhi proses hidrolisis protein adalah rasio enzim-substrat (rasio E/S). Sehingga, tujuan dari penelitian ini adalah untuk mengetahui kadar ?-amino bebas, protein terlarut, dan derajat hidrolisis dari hidrolisat protein kecambah kacang merah hasil hidrolisis menggunakan variasi rasio enzim-substrat. Metode yang digunakan yaitu metode Ninhidrin untuk penentuan kadar ?- amino bebas, metode Biuret untuk penentuan kadar protein terlarut dan metode SN-TCA (Trichloroacetic acid-soluble nitrogen) untuk penentuan derajat hidrolisis. Adapun variasi rasio E/S yang digunakan yaitu 3, 4, 5, dan 6%. Hasilnya menunjukkan bahwa semakin tinggi rasio enzim-substrat, semakin meningkat pula nilai kadar ?-amino bebas, kadar protein terlarut, dan derajat hidrolisis dari hidrolisat protein yang dihasilkan. Hasil terbaik yang didapat, yaitu kadar ?- amino bebas, protein terlarut dan derajat hidrolisis masing masing sebesar 0,5536 mg/mL, 2,0726 mg/mL dan 36,02, diperoleh dari hidrolisis menggunakan rasio E/S 6%. ABSTRACT: The enzymatic protein hydrolysis can produce protein hydrolyzate that will bring out short-chain peptides and free amino acids which contain higher nutritional values and soluble protein content as well as easier to digest. Recently, it has also found that red bean sprouts (Phaseolus vulgaris L.) has higher dissolved protein content than red beans without germination. Thus, in this research, red bean sprouts were used as the substrate to produce protein hydrolysates by using papain enzymes. Papain enzymes are easier to obtain, no side reactions, non-toxic, relatively resistant to temperature, and have high catalytic ability. Moreover, one of the essential factors that affect the protein hydrolysis is the enzyme-substrate ratio (E/S ratio). Therefore, the purpose of this study was to determine the levels of free amino acids, soluble protein, and degree of hydrolysis of the protein hydrolyzate obtained from the hydrolysis of the red bean sprouts using various enzyme-substrate (E/S) ratio. The methods used were Ninhydrin method for determining the free amino acid levels, Biuret test for the soluble protein content and SN-TCA (Trichloroacetic acid-soluble nitrogen) method for the degree of hydrolysis. The variations of the E/S ratio used were 3, 4, 5, and 6%. The results showed that the higher the enzyme-substrate ratio, the higher the value of free amino acids, soluble protein, and degree of hydrolysis in the protein hydrolysate obtained. The highest values of free amino acid, the soluble protein content and the hydrolysis degree of the protein hydrolysate was 0.5536 mg/mL, 2.0726 mg/mL and 36.02%, respectively, obtained by using the hydrolysis with the E/S ratio of 6%.
MINYAK SERAI (Cymbopogon citratus (DC.) Stapf) HASIL ENFLEURASI DAN APLIKASINYA DALAM PEMBUATAN SABUN ANTIBAKTERI DARI VIRGIN COCONUT OIL (VCO) Oktavia, Fadilla; Ratnayani, Oka; Suaniti, Ni Made
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 11 No 2 (2023): Cakra Kimia (Indonesian E-Journal of Applied Chemistry)
Publisher : Graduate Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Minyak serai dapur (Cymbopogon citratus (DC.) Stapf) merupakan salah satu minyak atsiri bersifat antibakteri yang dapat menghambat pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Pada pembuatan sabun padat, minyak serai dapur dapat meningkatkan sifat antibakteri pada sabun. Tujuan dari penelitian ini ialah untuk mengetahui karakteristik (bobot jenis dan indeks bias) dari minyak serai yang diekstraksi dengan metode enfluerensi, mutu sabun yang dihasilkan dengan penambahan minyak serai, serta aktivitas antibakteri sabun minyak serai. Sabun padat dibuat dengan 5 macam formula, masing-masing dengan konsentrasi minyak serai dapur yang berbeda yaitu 0, 1, 2, 3, dan 4 g per 200 g sediaan sabun. Sabun padat minyak serai kemudian diuji kualitas dan sifat antibakterinya. Minyak serai yang dihasilkan dari metode enfleurasi memiliki bau yang khas, berwarna kekuningan dan dengan rendemen sebesar 13,43%, bobot jenis sebesar 0,9209 g/mL, dan nilai indeks bias sebesar 1,459. Sabun yang dihasilkan memiliki kadar air berkisar 1,75-4,25%; kadar alkali bebas berkisar 0,08-0,10%; kadar asam lemak berkisar 0,10-0,17%; pH sabun berkisar 10,2-10,7; serta kandungan minyak mineralnya negatif, yang sesuai dengan SNI 06-3532-1994. Selain itu, sabun minyak serai memiliki aktivitas antibakteri terhadap E. coli pada sabun tanpa dan dengan penambahan minyak serai masing-masing adalah 11,30 mm dan 11,68-12,08 mm, sedangkan aktivtas antibakteri terhadap S. aureus masing-masing adalah 11,69 mm dan 13,87-14,53 mm. Hal ini menunjukkan bahwa sabun dengan penambahan minyak serai dapur mempunyai sifat antibakteri yang lebih tinggi dibandingkan sabun tanpa penambahan minyak serai. ABSTRACT: Lemongrass oil (Cymbopogon citratus (DC.) Stapf) is one of the essential oils with antibacterial properties that can inhibit the growth of Escherichia coli and Starhylococcus aureus bacteria. In the manufacture of solid soap, lemongrass oil can increase the antibacterial properties of the soap. The purpose of this study was to determine the characteristics (specific gravity and refractive index) of the lemongrass oil extracted by using enfleurage method, the quality of the soap added with the lemongrass oil, as well as the antibacterial activity of the lemongrass soap produced. The solid soap were prepared with five formulas of different concentrations of lemongrass oil, namely 0, 1, 2, 3, and 4 g per 200 g preparation. The enfleurage process resulted in lemongrass oil with yellowish color and had a distinctive odor with a yield of 13.43%, specific gravity of 0.9209 g/mL, and the refractive index value of 1.459. The resulting solid soap with the addition of lemongrass oil was tested for its quality and antibacterial properties. The soap produced had the water content ranged from 1.75 to 4.25%; alkaline level from 0.08 to 0.10%; fatty acid content from 0.10 to 0.17%; the pH from 10.2 to 10.7; and the mineral oil content was negative, in accordance with the national standard of SNI 06-3532-1994. Furthermore, the soap with the addition of lemongrass oil had an antibacterial activity against E. coli for the soap without and with the addition lemongrass oil was 11.30 mm and 11.68-12.08 mm, respectively, while the antibacterial activity against S. aerus was 11.69 mm and 13.87-14.53 mm, respectively. The results showed that the soap with the addition of lemongrass oil had higher antibacterial properties than the soap without the addition of lemongrass oil.
PEMANFAATAN BIJI PEPAYA (Carica papaya L) TERAKTIVASI H2SO4 SEBAGAI BIOSORBEN DALAM PENGOLAHAN AMONIA PADA LIMBAH CAIR TAHU Ratnayani, Oka; Simanjuntak, Kartika; Puspawati, Ni Made
CAKRA KIMIA (Indonesian E-Journal of Applied Chemistry) Vol 11 No 2 (2023): Cakra Kimia (Indonesian E-Journal of Applied Chemistry)
Publisher : Graduate Program of Applied Chemistry, Udayana University, Bali-INDONESIA

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ABSTRAK: Tujuan penelitian ini adalah untuk mengetahui karakteristik biosorben biji pepaya tanpa aktivasi dan teraktivasi H2SO4 10% yang meliputi luas permukaan, keasaman permukaan dan situs aktif, dan juga menentukan efisiensi adsorpsi amonia limbah cair tahu serta daya serap adsorpsinya pada kondisi optimum. Biosorben teraktivasi dibuat dengan cara merendam biji pepaya dalam larutan H2SO4 10% selama 12 jam. Hasil penelitian menunjukkan luas permukaan spesifik biosorben tanpa aktivasi dan teraktivasi asam sulfat masing-masing sebesar 10,9416 m2/g dan 56,3179 m2/g. Keasaman permukaan masing-masing biosorben tanpa aktivasi dan teraktivasi adalah 1,7944 mmol/g dan 3,1880 mmol/g. Situs aktif biosorben tanpa aktivasi dan teraktivasi masing-masing adalah 10,8058 x 1020 molekul/g dan 19,1981 x 1020 molekul/g. Kondisi optimum yang didapatkan untuk mengadsorpsi amonia limbah cair tahu yaitu pada waktu kontak 90 menit dengan berat biosorben sebanyak 0,5 gram. Efisiensi dan daya serap adsorpsi amonia pada kondisi optimum menggunakan biosorben tanpa aktivasi adalah 51,02% dan 0,2951 mg/g, sedangkan menggunakan biosorben teraktivasi masing-masing sebesar 82,63%, dan 0,4779 mg/g. Dari hasil penelitian ini dapat disimpulkan bahwa efisiensi dan daya serap adsorpsi amonia pada kondisi optimum menggunakan biosorben teraktivasi asam sulfat lebih tinggi daripada biosorben tanpa aktivasi. ABSTRACT: The purpose of this study was to characterize the non-activated and activated papaya seed biosorbents, that included the surface area, surface acidity and active sites, as well as to determine the adsorption efficiency and capacity of ammonia (in the form of ammonium ions) of the tofu liquid waste. Activated biosorbents were prepared by soaking papaya seeds in a H2SO4 10% solution for 12 hours. The results showed the specific surface area of the biosorbents without activation and activated with H2SO4 10% was 10.9416 m2/g and 56.3179 m2/g, respectively. The surface acidity of non-activated and activated biosorbents was 1.7944 mmol/g and 3.1880 mmol/g, respectively. The active sites of non-activated and activated biosorbents were 10.8058 x 1020 molecules/g and 19.1981 x 1020 molecules/g, respectively. The optimum conditions required to adsorb the ammonia of the tofu liquid waste were at a contact time of 90 minutes with the biosorbent mass of 0.5 grams. The adsorption efficiency and capacity at the optimum conditions for the non-activated biosorbent were 51.02% and 0.2951 mg/g, respectively, while for activated biosorbents were 0.4779 mg/g and 82.63%, respectively. The adsorption efficiency and capacity activated biosorbents were higher than the non-activated ones.
UTILIZATION OF CINNAMON BARK (CINNAMOMUM BURMANNI) EXTRACT AS A NATURAL INHIBITOR FOR THE CONTROL OF CORROSION RATE IN IRON METAL Sembiring, Aggryppyne Keyne Oberta; Putra, Anak Agung Bawa; Ratnayani, Oka
Jurnal Ilmu Pendidikan Indonesia Vol 11 No 3 (2023): JURNAL ILMU PENDIDIKAN INDONSIA
Publisher : Program Magister Pendidikan IPA, Program Pascasarjana Universitas Cenderawasih

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31957/jipi.v11i3.2341

Abstract

Iron is a metal that is very susceptible to corrosion. Corrosion of iron can occur due to reaction with the surrounding environment, causing damage to ferrous metal. The use of organic inhibitors such as cinnamon bark is considered to be able to suppress the corrosion rate, because in the inhibitor there are tannin compounds that are able to form complex compounds with Fe(III) on the metal surface. Bark consists of an tannins, makes this cinnamon bark capable of being an organic inhibitor. The purpose of this riset was to determine the effect of inhibitor concentration and variation of corrosive media on the corrosion rate, and to determine whether cinnamon bark extract had the potential to be used as an inhibitor. The method used is weight loss in which iron is immersed in various corrosive media for 48 hours without the addition of inhibitors and with the addition of inhibitors of 10; 20; 30; 40; 50; 60; 70; 80; 90; and 100 ppm. The highest corrosion rate without the addition of inhibitors occurred in iron immersed in salt media (NaCl 3.5%) of 53.5371 mpy, and the lowest corrosion rate occurred in iron immersed in neutral media (aquadest) of 15.6342 mpy. The corrosion rate also decreases with the increase in the concentration of the added inhibitor. In other words, this cinnamon bark extract has the potential to be used as an organic inhibitor.
Activated Bamboo Charcoal by ZnCl2 as Remazol Yellow FG Adsorbent: Isotherm, Kinetic, and Thermodynamic Studies Manurung, Manuntun; Suaniti, Ni Made; Ratnayani, Oka
The Journal of Pure and Applied Chemistry Research Vol. 13 No. 2 (2024): Edition May-August 2024
Publisher : Chemistry Department, The University of Brawijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21776/ub.jpacr.2024.013.02.3311

Abstract

The aim of this study was to determine the isotherm, kinetics, and thermodynamics of remazol yellow FG dye adsorption by ZnCl2-activated bamboo charcoal. The research was started by making charcoal from bamboo stems, then the quality was checked against SNI. Adsorption isotherms were tested against Langmuir and Freundlich models. The adsorption kinetics were examined against pseudo-1st and pseudo-2nd orders and thermodynamic parameters were determined by measuring the values of enthalpy (∆Ho), entropy (∆So), and free energy (∆Go). The values of ∆Ho, ∆So, and ∆Go are -29.747 KJ/mol, -93.798 J/mol, and -1.327 KJ/mol respectively. The adsorption of remazol yellow FG by activated bamboo charcoal was spontaneous. Keywords: adsorption, kinetics, chromium, bamboo charcoal, thermodynamics
Co-Authors Dewik Setiyawati Dwinda Safitri Emmy Sahara I Made Siaka I Nengah Simpen I Nengah Wirajana I Putu Gede Suwindra Putra I Wayan Bandem Adnyana I Wayan Gede Gunawan I Wayan Sudiarta I. A. Gede Widihati Ika Juliana Iryanti Eka Suprihatin Ketut Ratnayani Lusiana Tabuni Made Ririn Dwi Rahayu Manuntun Manurung Ni Ayu Putu Tejawati Ni Komang Ariati Ni Made Puspawati Ni Made Puspawati Ni Made Suaniti Oktavia, Fadilla Olivia Carolyn Sitepu Putra, Anak Agung Bawa Putu Elvira Yulianthi Raisyah Anjani Rizgyandhaka Artha Prawira Rizgyandhaka Artha Prawira Sakinatul Fatimah Sembiring, Aggryppyne Keyne Oberta Simanjuntak, Kartika Sri Wahjuni Veliyana, Ayu Kadek Wahyu Irwansyah Yenni Ciawi Yunita Angelina