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"Indonesia kaya akan sumber daya alam, terutama daun salam dan cengkeh yang telah terbukti memiliki memiliki sifat antioksidant yang tinggi. Sifat antioksidan ini dapat dimanfaatkan juga sebagai inhibitor korosi ramah lingkungan. Tujuan penelitian mempelajari dan menganalisa pengaruh penambahan ekstrak daun salam dan minyak cengkeh serta campuran keduanya sebagai inhibitor ramah lingkungan pada baja karbon API 5L grade B di larutan HCl 1M. Metode pengujian adalah uji polarisasi dan EIS dengan konsentrasi penambahan ekstrak berbeda, yaitu 13 ml/L, 26 ml/L, 40 ml/L dan 53 ml/L untuk tiap ekstrak dan konsentrasi ekstrak campuran 13 ml/L dengan perbandingan komposisi yaitu 1:1, 1:2, 1:3, 2:1 dan 3:1. Pengujian FTIR juga dilakukan untuk mengetahui golongan senyawa aktif pada lapisan pelindung yang terbentuk. Hasil pengujian Polarisasi didapatkan efisiensi inhibitor tertinggi yang dari ekstrak daun salam adalah EI = 86.27 pada konsentrasi 53 ml/L dan dari minyak cengkeh adalah EI = 82.15 dengan laju pada konsentrasi 53 ml/L. Sementara itu pada ekstrak campuran dari daun salam dan minyak cengkeh didapat efisiensi inhibitor tertinggi EI = 91.51 dengan rasio pencampuran 1:2. Mekanisme inhibisinya diperkirakan secara fisik dan chemisorption. Pengujian FTIR diperkirakan lapisan senyawa aktif yang berperan sebagai lapisan pelindung pada permukaan sampel adalah Flavanoid dan Eugenol.

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Bay leaf and clove oil are very abundant in Indonesia, and have been proven that they have antioxindant and anti aging effect. The antioxidant properties can be utilized as well as environmentall friendly corrosion inhibitor. The aim of this research is to study and analyze the effect of bay leaf extract and cloves oil and a mixture of both as an corrosion inhibitor. Electrochemical polarization test and EIS test were used ini measuring the inhibitor efficiency at a different concentration of extract i.e 13 ml L, 26 ml L, 40 ml L and 53 ml for each extracts, and 13 ml L for their mixture with a composition ratio of bay leaf extract to clove oil, 1 1, 1 2, 1 3, 2 1 and 3 1.

The highest efficiency inhibitor of indonesian bay leaf extract was 86.27 at concentration 53 ml L and for clove oil extract obtained 82.15 at concentration 40 ml L. The addition of their mixture showed good interaction with efficiency inhibitor 91.51 at composition ratio 1 2. FTIR test result on sample which was immersed in HCl 1 M solution had identified primarily the presence of phenolic compound group tannin, flavanoid with bay leaf extract and eugenol compound on clove oil extract."

"Daun salam dan buah salak sangat melimpah di Indonesia, dan dipercaya masyarakat memiliki sifat antioksidan dan anti penuaan. Namun belum ada penelitian mengenai penggunaanya sebagai inhibitor korosi ramah lingkungan. Penelitian ini bertujuan untuk mempelajari dan menganalisa pengaruh penambahan ekstrak daun salam (syzygium polyanthum),, buah salak banjarnegara (salacca zalacca var banjarnegara) dan campuran keduanya sebagai inhibitor ramah lingkungan terhadap baja karbon API 5L grade B dalam larutan HCl 1M. Pengujian polarisasi dan EIS dilakukan untuk mengukur efisiensi inhibitor pada konsentrasi penambahan ekstrak yang berbeda yaitu 2ml/L, 4ml/L, 6ml/L dan 8ml/L untuk masing-masing ekstrak daun salam dan buah salak, dan konsentrasi ekstrak campuran 6ml/L dengan perbandingan komposisi ekstrak daun salam dan buah salak yaitu 1:1, 1:2, 1:3, 3:1 dan 2:1. Pengujian FTIR dilakukan untuk mengetahui golongan senyawa aktif yang terkandung pada ekstrak daun salam dan buah salak, dan mengetahui golongan senyawa aktif yang membentuk lapisan protektif pada permukaan logam. Adsorption isotherm digunakan untuk mengidentifikasi mekanisme adsorpsi dari inhibitor ekstrak daun salam, buah salak dan campuran pada permukaan baja. Hasil pengujian polarisasi pada penambahan inhibitor ekstrak daun salam dan buah salak secara tunggal, sama-sama menunjukan nilai efisiensi inhibitor (EI) tertinggi dan laju korosi (CR) terendah diperoleh pada konsentrasi 6ml/L yaitu masing-masing EI = 58.56%, CR=1.36 mm/tahun untuk ekstrak daun salam dan EI = 74.90%, CR = 0.82 mm/tahun untuk ekstrak buah salak. Hasil pengujian EIS pada penambahan inhibitor ekstrak daun salam dan buah salak secara tunggal juga menunjukan nilai efisiensi inhibitor (EI) tertinggi diperoleh pada konsentrasi 6ml/L yaitu masing-masing EI=76.60% untuk ekstrak buah salak dan EI=66.07% untuk ekstrak daun salam. Sedangkan untuk campuran ekstrak daun salam dan buah salak diperoleh efisiensi inhibitor (EI) tertinggi dan laju korosi (CR) terendah pada perbandingan komposisi 1:1 (50% : 50%) yaitu sebesar EI=73.54% dan CR=0.87 mm/year, berdasarkan pengujian polarisasi dan EI=74.83% berdasarkan pengujian EIS. Pengujian FTIR menunjukkan keberadaan golongan senyawa fenolik (tannin) pada penambahan inhibitor ekstrak daun salam dan keberadaan golongan senyawa alkaloid pada penambahan ekstrak salak dipermukaan logam yang direndam dalam HCl 1M. Kedua jenis ekstrak apabila dicampurkan tidak menunjukan adanya efek sinergis dan juga antagonis sehingga dapat disimpulkan keduanya tidak saling mempengaruhi satu sama lain. Kedua inhibitor ekstrak menunjukan korelasi sesuai dengan Langmuir dan Frumkin Isotherm yang mengindikasinya mekanisme adsorpsi fisik dan chemisorption

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Bay leaves and snake fruits are very abundant in Indonesia, and have been believed by local community that they have antioxidant properties and anti-aging effect. However, no studies regarding its use as a enviromental friendly corrosion inhibitor. The aim of this research is to study and analyze the effect of indonesian bay leaf extract (syzygium polyanthum), snake fruit (salacca zalacca var banjarnegara) extract and also these mixed extract as enviromental friendly inhibitor on carbon steel API 5L grade B in hydrochoric acid 1M solution.

Electrochemical polarization test and EIS test were used in measuring the inhibitor efficiency at a different concentration of extract i.e. 2ml/L, 4ml/L, 6ml/L dan 8ml/L for indonesia bay leaf extract and snake fruit extract as single inhibitor, and 6ml/L for their mixture with a composition ratio of indonesian leaf extract to snake fruit extract , 1:1, 1:2, 1:3, 3:1 dan 2:1. FTIR was also used to identify the active compound group contained in both extracts and identify the active compound group which formed protective film on the metal surface. Adsorption isotherm was used to study inhibition mechanism of indonesia bay leaf extract, snake fruit extract and their mixture on metal surface.

Polarization test result of addition of indonesian bay leaf extract and snake fruit extract as single inhibitor in 1M HCl solution showed the highest inhibitor efficiency value (IE) and lowest corrosion rate (CR) IE=58.56%, CR=1.36 mm/year for bay leaf extract, and IE=74.90%, CR=0.82 mm/year for snake fruit extract at concentration 6ml/L, as well as EIS test showed the highest inhibitor efficiency value respectively IE=66.07% for bay leaf extract and IE=76.6% for snake fruit extract at concentration 6ml/L. And the addition of their mixture showed the highet inhibitor efficiency value achieved at a composition ratio 1:1 (50% : 50%) i.e. IE=73.54%, CR=0.87 mm/year based on polarisation test and 74.83% based on EIS test.

FTIR test result on steel sample which was immersed in HCl 1M solution had identified primarily the presence of phenolic compound group (tannin) on the metal surface with an addition of indonesian bay leaf extract and alkaloid compound group on the metal surface with an addition of snake fruits extract. The mixture of the extracts showed no sinergistic and antagonistic interaction. Thus, it can be concluded that these extracts do not interact to each other when they are mixed. These two extracts showed a correlation to Langmuir and Frumkin Isotherm that indicated physical adsorption as well as chemisorption."

"Mekanisme inhibisi korosi pada ekstrak biji saga Abrus precatorius pada baja API 5L Grade B dalam larutan 1M HCl telah dipelajari menggunakan metode polarisasi potensiodinamik dan Electrochemical Impedance EIS pada variasi konsentrasi 2 ml, 4 ml, 6 ml, 8 ml, dan 10 ml. Kandungan flavonoid diidentifikasi terdapat pada ekstrak biji saga melalui pengujian FTIR. Hasil penelitian menunjukkan bahwa kenaikan laju korosi menurun seiring dengan penambahan ekstrak biji saga. Ekstrak biji saga dapat berperan sebagai inhibitor korosi dengan efisiensi maksimum 86 pada pengujian polarisasi potensiodinamik dan 66 pada pengujian EIS. Ekstrak biji saga tergolong ke dalam inhibitor campuran dengan dominan inhibitor katodik. Adsorpsi dari ekstrak biji saga pada permukaan logam sesuai isoterm adsorpsi Langmuir dengan mekanisme adsorpsi fisika.

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Mechanism of corrosion inhibition on saga Abrus precatorius seed extract on API 5L Grade B in 1M HCl solution has been studied using potentiodynamic polarization and electrochemical impedance spectroscopy EIS with variation concentration of 2 ml, 4 ml, 6 ml, 8 ml, and 10 ml. Flavonoid content in saga seed was identified by FTIR.

The results showed corrosion rate increased with a decrease inhibitor concentration of saga seed extract. Saga seed extract acts as a corrosion inhibitor with maximum efficiency 86 using potentiodynamic polarization and 66 using EIS. Saga seed extract acts as mixed type inhibitor with cathodic inhibitor dominant. Adsorption of saga seed extract on metal surface obeyed Langmuir adsorption isotherm by physical adsorption mechanism."

"Efek penghambatan dari ekstrak Curcuma xanthorhizza pada korosi baja API 5L Grade X42 dalam larutan HCl 1M diselidiki dengan menggunakan metode kehilangan berat, polarisasi tafel, dan metode electrochemical impedance spectroscopy EIS . Uji FTIR digunakan untuk menyelidiki senyawa antioksidan yang berperan penting dalam menghambat korosi. Dalam penelitian ini konsentrasi ekstrak temulawak yang digunakan adalah 0 ppm, 100 ppm, 250 ppm, 500 ppm, dan 1000 ppm.Hasilnya menunjukkan bahwa temulawak dapat menghambat korosi pada baja dan bertindak sebagai penghambat tipe campuran. Laju korosi menurun seiring dengan meningkatnya konsentrasi inhibitor. Sedangkan efisiensi inhibisi meningkat dengan meningkatnya konsentrasi inhibitor. Adsorpsi ekstrak pada permukaan baja mengikuti Langmuir isotherm. Nilai energi bebas ?Gads menunjukkan bahwa adsorpsi molekul inhibitor secara fisika. Dapat disimpulkan bahwa ekstrak Curcuma xanthorhizza dapat digunakan sebagai penghambat alternatif dan ramah lingkungan untuk baja API 5L Grade X42 di lingkungan asam.

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The inhibitory effect of the extract of Curcuma xanthorhizza on the corrosion of API 5L Grade X42 steelin HCl 1M solution was investigated by using weight loss, tafel polarization, and electrochemical impedance spectroscopy methods.FTIR test was used to investigate the antioxidant compound that plays an important role to inhibit corrosion.In this study the concentration of Curcuma xanthorhizza extract used was 0 ppm, 100 ppm, 250 ppm, 500 ppm, and 1000 ppm.

The results show that Curcuma xanthorhizza inhibit the steel corrosion and act as mixed type inhibitors. The corrosion rate decreases with the increasing of inhibitors concentrations. At the same time, inhibition efficiency increases with the increase of inhibitors concentrations.The adsorption of extract on the steel surface was found to obey Langmuir rsquo s adsorption isotherm. The free energy value Gads indicated that the adsorption of inhibitor molecules was typical of physisorption.It can be concluded that Curcuma xanthorhizza extract could be used as an alternative and environmental friendly inhibitor for API 5LGrade X42 steel in acidic environment."

"Ekstrak daun jati cina Cassia angustifolia sebagai inhibitor ramah lingkungan pada Baja API 5L di lingkungan HCl diinvestigasi. Pengujian yang dilakukan adalah polarisasi dan kehilangan berat. Senyawa yang terkandung pada ekstrak adalah senyawa flavonoid, xanthone, dan anthraquinone. Senyawa tersebut diinvestigasi melalui pengujian FTIR. Variabel pengujian merupakan konsentrasi inhibitor, meliputi 10 ml, 20 ml, 30 ml, 40 ml, dan 50 ml. Kemampuan inhibitor untuk menginhibisi optimum pada konsentrasi 40 ml. Ekstrak daun jati cina berperan sebagai inhibitor campuran dengan dominan katodik. Mekanisme adsorpsi pada ekstrak daun jati cina merupakan mekanisme adsorpsi isotherm Langmuir dengan tipe adsorpsi physisorption.

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Cassia angustifolia leaves extract as green inhibitor for API 5L steel pipe in HCl environment was investigated. This study was experimented by using different types of test, such as polarization and weight loss. The compound in cassia angustifolia are flavonoid, xanthone, and anthraquinone. These compound was investigated by using FTIR. This experiment was investigated with different number of concentrations as its variables, which are 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml inhibitor extracts. The optimum capability of the inhibitor to inhibit the steel surface was in 40 ml concentrations. Cassia angustifolia leaves extract is found to be a mixed type inhibitor with predominant cathodic effectiveness. The adsorption mechanism of cassia angustifolia leaves extract was Langmuir with physisorption as the types of adsorption. "

"[ABSTRAKPenelitian pemanfaatan ekstrak tumbuh-tumbuhan sebagai inhibitor korosibelakangan ini semakin meningkat seiring dengan meningkatnya permintaanpenggunaan bahan-bahan kimia yang ramah lingkungan. Pemanfaatan ekstraktumbuh-tumbuhan sebagai inhibitor korosi menjadi penting mengingatkarakteristiknya ramah lingkungan (green inhibitor), mudah ketersediaannnya,sumberdaya yang melimpah dan dapat diperbaharui, prosedur produksi yangsederhana, dan biaya produksi yang cukup kompetitif. Dalam penelitian inidilakukan pengujian eksperimental efek sinergis jenis inhhibitor baru yaituekstrak ubi ungu (Ipomoea batatas L.) yang memiliki kandungan utamaantosianin dengan inhibitor komersial berbasis amine (aniline) dan denganinhibitor asam askorbat.Penelitian bertujuan untuk menganalisis laju kororsi dan efisiensi inhibisikorosi logam baja (API 5L) di dalam lingkungan air terproduksi menggunakaninhibitor campuran ekstrak ubi ungu dan inhibitor komersial berbasis amine(aniline). Selain itu dilakukan pula analisis laju korosi, efisiensi inhibisi,mekanisme proteksi dan model lapisan inhibisi korosi logam baja (API 5L) didalam lingkungan 3,5% NaCl menggunakan inhibitor campuran ekstrak ubi ungudan asam askorbat.Metode pengukuran laju korosi dan efisiensi inhibisi dilakukanmenggunakan elektrokimia kurva polarisasi. Mekanisme korosi diteliti denganmenggunakan metode Electrochemical Impedance Spectroscopy (EIS). Untukmenganalisis model lapisan inhibisi dilakukan dengan menggunakan metodeFourier Transform Infra Red (FTIR) spectroscopy.Hasil penelitian menunjukan bahwa pencampuran ekstrak ubi ungumemiliki kemampuan sinergis dengan inhibitor komersial berbasis amine (aniline)pada fraksi volume ekstrak ubi ungu sebesar 25% dengan menghasilkan efisiensiinhibisi sebesar 82,14%. Sebagai pembanding, pada sistem yang samapenggunaan esktrak ubi ungu saja menghasilkan efisiensi inhibisi 68,30%,sedangkan penggunaan inhibitor komersial berbasis amine (aniline) sajamenghasilkan efisiensi inhibisi 74,88%.Penambahan volume ekstrak ubi ungu dari 1 mL hingga 4 mL kedalaminhibitor asam askorbat 10-4 M meningkatkan efisiensi inhibisi korosi logam baja(API 5L) dalam larutan 3,5% NaCl dari efisiensi inhibisi sebesar 23,37% menjadi57,52%. Campuran inhibitor korosi tersebut berpengaruh terhadap kurvapolarisasi anodik maupun katodik sehingga dapat berperan sebagai mixedinhibitor. Pengujian EIS menunjukan proses korosi dikontrol oleh mekanismepasivasi yang ditunjukan oleh adanya peningkatan tahanan permukaan korosi.Pada lapisan permukaan terjadi proses adsorpsi dan pembentukan kelatorgano (flavonoid) logam dimana ekstrak ubi ungu dengan kandungan utamaantosianin berperan sebagai pembentuk metal-chelated. Pembentukan kelatekstrak ubi ungu-Fe-asam askorbat terjadi pada gugus hidroksil dan karbonil.Lokasi terjadinya ligan kelat ekstrak ubi ungu dengan kandungan utma antosianinterjadi pada ikatan 3?, 4? Dihydroxy cincin B atau 3-Hydroxy 4-Carbonyl cincin C;

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ABSTRACTResearch of utilization of plant extracts as a corrosion inhibitor recentlyincreased along with the increasing demand for the use of chemicals that areenvironmentally friendly. Utilization of plant extracts as a corrosion inhibitorbecomes important given the characteristics of environmentally friendly (greeninhibitor), easy availability, resources are abundant and renewable, the productionprocedure is simple, and the production costs are quite competitive. In thisresearch, experimental testing of the synergistic effects of new types inhibitor ieextract purple potato (Ipomoea batatas L.) which has the main content ofanthocyanin with commercial inhibitor-based amine (aniline) and with ascorbicacid inhibitors.The study aims to analyze the rate of corrosion and metal corrosioninhibition efficiency of steel (API 5L) in the produced water environment using amixed inhibitor purple sweet potato extract and commercial-based inhibitors ofamine (aniline). In addition, the corrosion rate analysis was also performed,inhibition efficiency, protection mechanisms and models of metal corrosioninhibition layer steel (API 5L) in the neighborhood of 3.5% NaCl using a mixedinhibitor purple sweet potato extract and ascorbic acid.Method of measuring the rate of corrosion and inhibition efficiency wasperformed using electrochemical polarization curves. Corrosion mechanismsinvestigated by Electrochemical Impedance Spectroscopy (EIS). To analyze themodel layer of inhibition were calculated using Fourier Transform Infra Red(FTIR) spectroscopy.The results showed that mixing purple sweetpotato extract has the abilityto synergistically with commercial inhibitor-based amine (aniline) in purplesweetpotato extract volume fraction of 25% with a yield of 82.14% inhibitionefficiency. For comparison, the same system using purple sweet potato extractonly produce inhibition efficiency of 68.30%, while the use of commercial-basedinhibitors of amine (aniline) alone resulted in inhibition efficiency of 74.88%.The addition of purple sweet potato extract volume of 1 mL to 4 mL intoascorbic acid inhibitors 10-4 M improving steel metal corrosion inhibitionefficiency (API 5L) in a solution of 3.5% NaCl of inhibition efficiency of 23.37%to 57.52%. The corrosion inhibitor mixture affect the anodic and cathodicpolarization curves so that it can act as a mixed inhibitor. Testing EIS shows thecorrosion process is controlled by the passivation mechanism indicated by anincrease in the surface resistance of corrosion.On the surface layer of a process of adsorption and formation of organochelates (flavonoids) in which the metal purple sweet potato extract with the maincontent of anthocyanins act as forming metal-chelated. Location of the chelatingligand purple sweet potato extract with the main content of anthocyanins occur inbond 3 ', 4' dihydroxy ring B or 3-Hydroxy 4-Carbonyl ring C.;Research of utilization of plant extracts as a corrosion inhibitor recentlyincreased along with the increasing demand for the use of chemicals that areenvironmentally friendly. Utilization of plant extracts as a corrosion inhibitorbecomes important given the characteristics of environmentally friendly (greeninhibitor), easy availability, resources are abundant and renewable, the productionprocedure is simple, and the production costs are quite competitive. In thisresearch, experimental testing of the synergistic effects of new types inhibitor ieextract purple potato (Ipomoea batatas L.) which has the main content ofanthocyanin with commercial inhibitor-based amine (aniline) and with ascorbicacid inhibitors.The study aims to analyze the rate of corrosion and metal corrosioninhibition efficiency of steel (API 5L) in the produced water environment using amixed inhibitor purple sweet potato extract and commercial-based inhibitors ofamine (aniline). In addition, the corrosion rate analysis was also performed,inhibition efficiency, protection mechanisms and models of metal corrosioninhibition layer steel (API 5L) in the neighborhood of 3.5% NaCl using a mixedinhibitor purple sweet potato extract and ascorbic acid.Method of measuring the rate of corrosion and inhibition efficiency wasperformed using electrochemical polarization curves. Corrosion mechanismsinvestigated by Electrochemical Impedance Spectroscopy (EIS). To analyze themodel layer of inhibition were calculated using Fourier Transform Infra Red(FTIR) spectroscopy.The results showed that mixing purple sweetpotato extract has the abilityto synergistically with commercial inhibitor-based amine (aniline) in purplesweetpotato extract volume fraction of 25% with a yield of 82.14% inhibitionefficiency. For comparison, the same system using purple sweet potato extractonly produce inhibition efficiency of 68.30%, while the use of commercial-basedinhibitors of amine (aniline) alone resulted in inhibition efficiency of 74.88%.The addition of purple sweet potato extract volume of 1 mL to 4 mL intoascorbic acid inhibitors 10-4 M improving steel metal corrosion inhibitionefficiency (API 5L) in a solution of 3.5% NaCl of inhibition efficiency of 23.37%to 57.52%. The corrosion inhibitor mixture affect the anodic and cathodicpolarization curves so that it can act as a mixed inhibitor. Testing EIS shows thecorrosion process is controlled by the passivation mechanism indicated by anincrease in the surface resistance of corrosion.On the surface layer of a process of adsorption and formation of organochelates (flavonoids) in which the metal purple sweet potato extract with the maincontent of anthocyanins act as forming metal-chelated. Location of the chelatingligand purple sweet potato extract with the main content of anthocyanins occur inbond 3 ', 4' dihydroxy ring B or 3-Hydroxy 4-Carbonyl ring C., Research of utilization of plant extracts as a corrosion inhibitor recentlyincreased along with the increasing demand for the use of chemicals that areenvironmentally friendly. Utilization of plant extracts as a corrosion inhibitorbecomes important given the characteristics of environmentally friendly (greeninhibitor), easy availability, resources are abundant and renewable, the productionprocedure is simple, and the production costs are quite competitive. In thisresearch, experimental testing of the synergistic effects of new types inhibitor ieextract purple potato (Ipomoea batatas L.) which has the main content ofanthocyanin with commercial inhibitor-based amine (aniline) and with ascorbicacid inhibitors.The study aims to analyze the rate of corrosion and metal corrosioninhibition efficiency of steel (API 5L) in the produced water environment using amixed inhibitor purple sweet potato extract and commercial-based inhibitors ofamine (aniline). In addition, the corrosion rate analysis was also performed,inhibition efficiency, protection mechanisms and models of metal corrosioninhibition layer steel (API 5L) in the neighborhood of 3.5% NaCl using a mixedinhibitor purple sweet potato extract and ascorbic acid.Method of measuring the rate of corrosion and inhibition efficiency wasperformed using electrochemical polarization curves. Corrosion mechanismsinvestigated by Electrochemical Impedance Spectroscopy (EIS). To analyze themodel layer of inhibition were calculated using Fourier Transform Infra Red(FTIR) spectroscopy.The results showed that mixing purple sweetpotato extract has the abilityto synergistically with commercial inhibitor-based amine (aniline) in purplesweetpotato extract volume fraction of 25% with a yield of 82.14% inhibitionefficiency. For comparison, the same system using purple sweet potato extractonly produce inhibition efficiency of 68.30%, while the use of commercial-basedinhibitors of amine (aniline) alone resulted in inhibition efficiency of 74.88%.The addition of purple sweet potato extract volume of 1 mL to 4 mL intoascorbic acid inhibitors 10-4 M improving steel metal corrosion inhibitionefficiency (API 5L) in a solution of 3.5% NaCl of inhibition efficiency of 23.37%to 57.52%. The corrosion inhibitor mixture affect the anodic and cathodicpolarization curves so that it can act as a mixed inhibitor. Testing EIS shows thecorrosion process is controlled by the passivation mechanism indicated by anincrease in the surface resistance of corrosion.On the surface layer of a process of adsorption and formation of organochelates (flavonoids) in which the metal purple sweet potato extract with the maincontent of anthocyanins act as forming metal-chelated. Location of the chelatingligand purple sweet potato extract with the main content of anthocyanins occur inbond 3 ', 4' dihydroxy ring B or 3-Hydroxy 4-Carbonyl ring C.]"

"ABSTRAKKorosi merupakan suatu proses degradasi material akibat interaksi denganlingkungannya. Inhibitor korosi merupakan suatu zat yang dapat menghambatproses korosi. Bahan organik dipilih sebagai alternatif karena bersifat aman,mudah didapatkan, bersifat biodegradable, biaya murah, dan ramah lingkungan.Penelitian ini merupakan studi tentang inhibitor korosi menggunakan senyawaorganik yang dilakukan pada material baja API 5L di lingkungan larutan NaCl3,5%. Penelitian ini dilakukan untuk mempelajari efek penggunaan campuranekstrak daun sirsak dan ubi ungu sebagai inhibitor korosi dengan variasikonsentrasi. Ekstrak daun sirsak dan ubi ungu dipilih sebagai inhibitor korosikarena mengandung senyawa antioksidan yang dapat menghambat laju korosi.Pengukuran laju korosi dilakukan dengan menggunakan metode kehilangan beratdan polarisasi. Mekanisme terjadinya korosi diuji dengan menggunakanElectrochemical Impedance Spectroscopy (EIS) sementara karakterisasi darimaterial inhibitor organik dilakukan dengan menggunakan metode FourierTransform Infra-Red (FTIR). Tipe ikatan kimia yang terbentuk di lapisanpermukaan baja dianalisa dengan metode FTIR yang mengindikasikan adanyagugus fungsi karbonil (C=O) dan hidroksil (O-H) yang berkombinasi membentuksuatu lapisan. Di dalam larutan 100 mL NaCl 3,5%, penambahan ekstrak daunsirsak sebanyak 1 mL menghasilkan efisiensi inhibitor sekitar 73,38% (melaluipengujian polarisasi) dan di dalam larutan 520 mL NaCl 3,5%, penambahanekstrak daun sirsak sebanyak 1 mL menghasilkan efisiensi inhibitor sekitar 50%(melalui pengujian kehilangan berat). Kemudian, penambahan ekstrak ubi ungusebanyak 1-5 mL menyebabkan terjadinya penurunan efisiensi inhibitor. Ekstrakdaun sirsak dan ubi ungu bekerja dengan membentuk suatu lapisan tipis yangmengendap (adsorpsi) pada permukaan logam sebagai lapisan pelindung yangdapat menghambat reaksi logam tersebut dengan lingkungannya. Mekanisme inijuga didukung dengan meningkatnya nilai tahanan polarisasi dari permukaan bajasetelah ditambahkan inhibitor.

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ABSTRACTCorrosion is a degradation of the material due to its interaction with theenvironment. Corrosion inhibitor is a substance that can inhibit the corrosionprocess. The use of organic corrosion inhibitor become a new alternative toachieve that goal, it happen because the organic corrosion inhibitor is safe, cheap,biodegradable, and environmentally friendly. This research is the study ofcorrosion inhibitor using organic compounds for API 5L steel in 3.5% NaClsolution. This research was conducted to study the use of mixture of annonamuricata leaves and purple sweet potato extracts as corrosion inhibitor withvariable concentration. Annona muricata leaves and purple sweet potato extractsare selected as corrosion inhibitor because they contain antioxidant compoundsthat can inhibit the corrosion rate. Corrosion rate measurement method wasconducted by using the weight loss and polarization methods. Corrosionmechanism was examined by Electrochemical Impedance Spectroscopy (EIS)while the characterization of organic inhibitor material was carried out using themethod of Fourier Transform Infra-Red (FTIR). The type of chemical bonds onthe steel surface layer was analyzed by FTIR method which indicated the presenceof functional groups carbonyl (C=O) and hydroxyl (O-H) which combined as filmforming. In a solution containing 100 mL 3.5% NaCl, the addition of 1 mLannona muricata leaves extract resulted in approximately 73.38% inhibitorefficiency (using the polarization method) and in a solution containing 520 mL3.5% NaCl, the addition of 1 mL annona muricata leaves extract resulted inapproximately 50% inhibitor efficiency (using the weight loss method). Then, theaddition of 1-5 mL purple sweet potato extract resulted the decreasing of inhibitorefficiency. Annona muricata leaves and purple sweet potato extracts work byforming a thin layer which settles (adsorption) to metal surfaces as a protectivelayer that can inhibit the reaction of the metal with its environment. Thismechanism is also supported by the increased value of the polarization resistanceof the steel surface after addition of inhibitor."

"Pengaruh kombinasi ekstrak daun Physalis angulata daun ciplukan dan daun Cassia angustifolia daun jati cina sebagai inhibitor ramah lingkungan dengan perbandingan 50:50 pada baja karbon API 5L diinvestigasi. Pengujian dilakukan dalam lingkungan HCl 1M. Pengujian yang dilakukan meliputi polarisasi potensiodinamik, kehilangan berat, dan EIS. Senyawa antioksidan diinvestigasi melalui pengujian FTIR. Sesuai dengan pengujian FTIR, senyawa antioksidan yang terkandung pada kombinasi ekstrak ini adalah flavonoid. Variabel yang digunakan adalah konsentrasi inhibitor, yaitu 10 ml, 30 ml, dan 50 ml. Diketahui bahwa semakin tinggi konsentrasi yang diberikan, maka semakin tinggi kemampuan inhibitor dalam menginhibisi permukaan baja dimana efisiensi inhibitor paling tinggi didapatkan dengan konsentrasi 50 ml. Kombinasi ekstrak daun ciplukan dan daun jati merupakan inhibitor jenis campuran yang lebih dominan ke katodik. Metode adsorpsi inhibitor ini mengikuti adsorpsi isotherm Langmuir dengan tipe adsorpsi fisika atau physisorption.

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The effect of combination of Physalis angulata leaf and Cassia angustifolia leaf extract as green inhibitor with a 50:50 ratio for API 5L steel was investigated. This experiment was carried in 1M HCl solution by using different concentrations as variables which is 10 ml, 30 ml, and 50 ml inhibitor extracts. This experiment was evaluated using potentiodynamic polarization, EIS, and weight loss. The antioxidant compound was investigated using FTIR and was found to be flavonoid. It was found that the capability of the inhibitor to inhibit the steel surface from the environment increases with increasing concentration, which 50 ml concentration is found to have the best efficiency of all concentrations. Combination of physalis angulata leaf and cassia angustifolia leaf extract is found to be a mixed type inhibitor with predominant cathodic effectiveness. The adsorption of this inhibitor on the steel surface was predominantly through physisorption and obeyed Langmuir adsorption isotherm."

"Indonesia memiliki potensi cengkeh yang melimpah,daunnya dapat gugur setiap minggunya 0.96 kg/pohon. Inhibitor yang digunakan adalah ekstrak daun cengkeh dengan konsentrasi 1ml,2ml,3ml,4ml,5ml dan minyak cengkeh dengan konsentrasi 2ml,4ml,6ml,8ml,10ml. Pengujian dilakukan dengan metode linear polarisasi, Fourier Transform Infrared Spectroscopy ( FTIR ), Gas Chromatography Mass Spectroscopy ( GCMS ), dan Eletrochemical Impedance Spectroscopy ( EIS ). Konsentrasi optimum pada ekstrak daun cengkeh berada pada konsentrasi 4 ml dengan laju korosi 0.042 mm/year dan efisiensi 46.6 % sedangkan minyak cengkeh konsentrasi optimumnya berada pada konsentrasi 8 ml dengan laju korosi 0.001 mm/year dengan efisiensi 98.6 %. FTIR menunjukkan gugus - gugus fungsi yang berada di dalam inhibitor dan diperkuat dengan hasil GCMS untuk mengetahui senyawa aktif yang berada dalam inhibitor. Pengujian FTIR juga menunjukkan bahwa gugus - gugus fungsi pada inhibitor menempel pada permukaan sampel ketika sampel di rendam. Mekanisme adsorpsi dari kedua inhibitor adalah physical adsorption dengan nilai ΔGads pada inhibitor ekstrak daun cengkeh sebesar -7.575 kJ/mol, dan - 12.142 kJ/mol untuk inhibitor minyak cengkeh. EIS menunjukkan adanya peningkatan nilai tahanan charge transfer pada setiap kenaikan konsentrasi inhibitor dan nilai dari Cdl menurun yang menunjukkan bahwa terjadi pembentukan lapisan protektif. Nilai charge transfer dari inhibitor minyak cengkeh lebih besar yang berarti minyak cengkeh memiliki kemampuan inhibisi lebih baik dan ini diperkuat dari hasil polarisasi. Kedua jenis inhibitor ini termasuk dalam jenis inhibitor campuran (mix type inhibitor).

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Indonesia has abundant potential clove, leaves can fall every week 0.96 kg/tree. Inhibitor which used on this research are clove leave extract with concentration 1ml,2ml,3ml,4ml,5ml and clove oil with concentration 2ml,4ml,6ml,8ml,10ml. Inhibitor are examined by linear polarization, Fourier Transform Infrared Spectroscopy ( FTIR ), Gas Chromatography Mass Spectroscopy ( GCMS ), and Electrochemical Impedance Spectroscopy ( EIS ). The result show that optimum concentration of clove leave extract is at 4 ml with corrosion rate 0.042 mm/year and efficiency 46.6% where as optimum concentration of clove oil is at 8 ml with corrosion rate 0.001 mm/year and efficiency 98.6 %. FTIR obtain functional group which contained in inhibitor and GCMS result also show active compound in inhibitor. FTIR show that functional group in inhibitor adsorp on the metal surface when sample is soaked in inhibitor. Adsorption mechanism of these inhibitor is physical adsorption with ΔGads of clove leave extract inhibitor is -7.575 kJ/mol, and - 12.142 kJ/mol for clove oil inhibitor. EIS show increasing charge transfer resistance with increasing inhibitor concentration and decreasing Cdl also show there are protective film forming. The charge transfer resistance of clove oil inhibitor higher, means clove oil has better inhibition than clove leaves extract. Both of these inhibitor are included in mix type inhibitor."

"Teknik Metalurgi dan MaterialJudul : Studi Ketahanan Korosi Pipa Baja API 5L X42 dengan Green Inhibitor Ekstrak Bawang Dayak Eleutherine americanna Merr. dalam Lingkungan 1M HCl. Ketahanan korosi pipa baja API 5L X42 dengan inhibitor ramah lingkungan ekstrak bawang dayak Eleutherine americanna Merr. dalam lingkungan 1M HCl diinvestigasi dengan pengujian polarisasi tafel, weight loss, dan Electrochemical Impedance Spectroscopy EIS . Senyawa flavonoid yang bersifat antioksidan yang berperan untuk menginhibisi korosi diinvestigasi melalui pengujian FTIR. Variabel yang digunakan adalah konsentrasi inhibitor, yaitu 0 ppm, 100 ppm, 250 ppm, 500 ppm, dan 1000 ppm. Ekstrak bawang dayak yang mempunyai gugus flavonoid merupakan inhibitor jenis campuran, dan dominan katodik. Efisiensi inhibisi paling tinggi didapatkan dengan konsentrasi 1000 ppm. Inhibitor ekstrak bawang dayak dapat digunakan sebagai alternatif inhibitor ramah lingkungan untuk baja API 5L X42 pada lingkungan 1M HCl.

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Metallurgy and Materials EngineeringTitle Study of Corrosion Resistance of Pipeline API 5L X42 Using Green Inhibitor Bawang Dayak Eleutherine americanna Merr. in 1M HCl. This study aimed to investigate the ability of Eleutherine americanna Merr. extract as an environment friendly inhibitor for API 5L X42 in 1M HCl. Corrosion inhibition ability of this extract was tested using tafel polarization, weight loss and electrochemical impedance spectroscopy methods. FTIR test was used to investigate flavonoid and antioxidant compound that plays an important role to inhibit corrosion. In this study the concentration of Eleutherine americanna Merr. extract used was 0 ppm, 100 ppm, 250 ppm, 500 ppm, and 1000 ppm. It can be concluded that Eleutherine americanna Mer. extract can be used as an alternative and environmental friendly inhibitor for API 5L X42 in 1M HCl. "