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"Kebutuhan akan inhibitor korosi ramah lingkungan semakin berkembang, sehingga penelitian untuk mencari alternatif ekstrak tumbuhan sebagai inhibitor korosi semakin meningkat. Kayu secang dipercaya memiliki kandungan antioksidan yang dapat berperan dalam menghambat laju korosi yang pada material. Penelitian ini dilakukan untuk melihat efek penambahan ekstrak Kayu Secang (KS) terhadap laju korosi dari Baja API 5L X52 dalam Larutan 3,5% NaCl dan juga melihat sifat sinergis inhibitor saat ekstrak KS dikombinasikan dengan ekstrak Kubis Merah (KM) yang sebelumnya telah dilaporkan efektif sebagai inhibitor korosi.Beberapa pengujian dilakukan untuk mengevaluasi KS sebagai inhibitor korosi. Metode Polarisasi dan EIS digunakan untuk melihat efektifitas ekstrak KS dan kombinasinya dengan ekstrak KM sebagai inhibitor korosi dengan variasi konsentrasi yang ditambahkan. FTIR digunakan untuk mengkarakterisasi gugus fungsi yang terkandung dalam ekstrak KS dan KM. Model adsorpsi isotherm digunakan untuk melihat mekanisme adsorpsi dari ekstrak.Dari hasil Polarisasi menunjukan penambahan ekstrak KS akan menurunkan laju korosi dari 0,172 mm/tahun menjadi 0,04 mm/tahun hingga konsentrasi 0,75 ml dalam 200 ml 3,5% NaCl, dan pengujian EIS mendukung hasil tersebut. Pengabungan ekstrak KS dengan KM menunjukan efek anti-sinergi melihat dari nilai sinergistik parameter yang didapat <1. Peningkatan efisiensi inhibisi pada komposisi 0,1 ml dan 0,2 ml KS dalam 2,5 ml KM, diperkirakan karena ekstrak yang ditambahkan belum mencapai titik optimum.Hasil FTIR menunjukan ekstrak KS memiliki gugus C=O yang berperan dalam proses adsorpsi dan gugus ?OH (hydroxil) yang menunjukan sifat antioksidan. Ekstrak KS dan juga campurannya teradsorpsi mengikuti model Langmuir isotherm dimana adsorpsi yang terjadi adalah monolayer dan tidak ada reaksi antar molekul. Nilai energi bebas menunjukan bahwa proses adsorpsi terjadi secara spontan dan jenis ikatan yang terjadi dalam proses adsorpsi adalah secara fisik/physicsorption dengan nilai -20,79 KJ/mol untuk ekstrak KS, dan -7,08 KJ/mol untuk Ekstrak KS+KM

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The needs of green corrosion inhibitors is growing, thus searching for the alternative plants extract to be used as corrosion inbitor is increasing. Caesalpinia sappan L (KS) believed to contain antioxidant that may play role in inhibiting the corrosion rate of material. This study was conducted to understand the inhibitive properties owned by the extract of KS on the API 5L X52 Material in 3.5%NaCl and to assess the sinergistic effect when KS is combined with Red Cabbage (KM) extract which already proven as alternative corrosion inhibitor.

Several tests were conducted to evaluate KS as green corrosion inhibitor. Tafel Polarization and EIS methods were used to assess the effectiveness of KS and its combination with KM as corrosion inhibitor at various concentration in 3.5% NaCl. FTIR method was used to characterize the functional groups contained in the extract. Adsorption isotherm was used to recognize the adsorption mechanism of the extracts.

The polarization results shows the inhibitive properties of KS thus reduce the corrosion rate of material from 0.172mm/year to 0.04mm/year with addition of 0.75ml of KS in 200ml 3.5%NaCl, meanwhile EIS result supports the polarization results. Mixing of KS and KM shows anti-synergistic effect, which shown on synergistic parameter value <1 for any volume addition of KS. An increase in inhibition efficiency on 0.1ml and 0.2ml KS composition of the mixture is expected due the mixture has not reached the critical point.

While FTIR results show KS and KM both has a C = O functional groups that play a role in the adsorption process and the -OH (hydroxil) which shows antioxidant properties. From the verification plot of several isotherm models, the KS extract and its mixture follows Langmuir Isotherm, which mean the inhibitive layer adsorbed is considered monolayer and there is no reaction between the active molecules. Thus from the calculation of adsorption free energy we have -20.79KJ/mol for KS and - 7.08KJ/mol, thereof the adsorption process considered as physicsorption and the adsorption occurs due to electrostatic bond. The minus (-) sign indicates the adsorption process is spontaneous."

"Ekstrak kubis merah telah dievaluasi sebagai inhibitor korosi ramah lingkungan untuk baja API 5L grade X60 dilingkungan larutan NaCl 3,5% menggunakan metode Tafel polarisasi dan Electrochemical Impedance Spectroscopy. Pengujian Tafel Polarisasi menunjukkan ekstrak kubis merah bertindak sebagai inhibitor campuran sedangkan pengujian Electrochemical Impedance Spectroscopy menunjukkan terbentuknya lapisan film dari molekul inhibitor pada permukaan baja API 5L grade X60, dari kedua pengujian ini effisiensi inhibisi meningkat dengan meningkatnya jumlah konsentrasi inhibitor yang ditambahkan. Hasil evaluasi menunjukkan bahwa molekul inhibitor teradsorpsi secara fisika dengan mengikuti model adsorpsi Langmuir Isoterm, senyawa Cyanidin diketahui sebagai senyawa utama yang teradsorpsi pada permukaan baja API 5L grade X60.

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Red cabbage extract has been evaluated as green inhibitor corrosion for API 5L grade X60 steel on 3.5% NaCl environment using Tafel polarization and Electrochemical Impedance Spectroscopy. Tafel polarization methode shows red cabbage extract acts as an mixed inhibitor and Electrochemical Impedance Spectroscopy methode showed the formation of a layer of film of the inhibitors molecule on the surface of the API 5L grade X60 steel, from both this methode inhibition efficiency increases with increasing concentration of inhibitor. Results of the evaluation showed that the inhibitor molecules is physically adsorbed by following the Langmuir isotherms model, cyanidin compounds are known as major compounds are adsorbed on the surface of API 5L grade X60 steel."

"Tesis ini untuk mempelajari pengaruh ekstrak batang secang (caesalpinia sappan l) sebagai inhibitor korosi ramah lingkungan terhadap baja karbon API 5L Gr B di lingkungan 3.5% NaCl. Metode pengujian dilakukan dengan Linier Polarisasi dan EIS (Electroscopy Impedance Spectroscopy). Ekstrak batang secang dapat menurunkan laju korosi sampai dengan efisiensi sebesar 53.18% berdasarkan hasil pengujian polarisasi dan efisiensi sebesar 84.64% sesuai hasil pengujian EIS. Efisiensi inhibitor paling efektif dihasilkan pada konsentrasi 2.0 ml/400 ml NaCl. Dari hasil pengujian kinerja inhibitor berkurang seiring dengan kenaikan temperatur larutan ekstrak secang. Inhibitor merupakan tipe campuran (mixed inhibitor) dengan kecenderungan lebih dominan ke arah katodik. Hasil evaluasi menunjukan fenomena mekanisme absorbsi molekul inhibitor secang terjadi secara fisika (physicasorption) berdasarkan model Langmuir Isother.

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This thesis is to investigate secang hearthwood extraction (caesalpinia sappan l) as a corrosion inhibitor on carbon steel metal (API 5L Gr B) in 3.5% NaCl environment. This research utilize polarization linier and EIS (Electrochemical Impedance Spectroscopy) for the measurement method. Secang extraction is adequate to reduce corrosion rate until efficiency of 53.18% based on polarization measurement and efficiency of 84.64% as EIS measurement result. The most effective concentration of inhibitor reducing the corrosion rate is reached at 2.0 ml/400 ml 3.5% NaCl. Investigation show inhibitor efficiency will decrease as temperature increasing. Polarization study indicate secang is mixed type inhibitor, with predominant cathodic effectiveness. As the evaluation, the phenomena of inhibitor molecule adsorption is physicsorption mechanism and obeys Langmuir Isotherm model."

"[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.]"

"80% kegagalan material baja pada fasilitas produksi industri minyak dan gas bumi disebabkan oleh proses korosi. Salah satu pengendalian proses korosi material baja API 5L Grade X60 dengan menggunakan inhibitor ramah lingkungan. Pada penelitian ini, ekstrak kayu secang (Caesalpinia Sappan L.) dievaluasi sebagai inhibitor ramah lingkungan untuk baja API 5L X60 di lingkugan HCl 1M dengan variasi volume ekstrak 0,5 ml, 1 ml, 1,5 ml, 2 ml, 3ml dan variasi temperatur 302K, 312K, 322K, dan 332K menggunakan metode polarisasi tafel, Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infra-red Spectroscopy (FTIR), dan Stimultaneous Thermal Analysis (STA). Hasil dari pengujian polarisasi tafel dan EIS menunjukan ekstrak kayu secang bertindak sebagai inhibitor campuran (Mixed Inhibitor). Efisiensi optimal dihasilkan dari penambahan volume ekstrak sebesar 1,5 ml dalam 400 ml HCl 1M. sebesar 91 % polarisasi tafel, dan sebesar 94% EIS. Rapat arus korosi material pada volume 1,5 ml ekstrak kayu secang sebesar 57 µA/cm2 dan nilai resistivitas larutan 841 ?.cm2. Kenaikan temperatur lingkungan sebesar 332 K menaikan rapat arus korosi material menjadi 139 µA/cm2 dan menurunkan nilai resistivitas larutan sampai 121 ?.cm2, sehingga nilai efisiensi inhibitor turun sampai 50%. Gugus fungsi keton (C=O) muncul dari hasil karakterisasi pengujian FTIR yang menandakan keberadaan senyawa brazilein dan dan sappanchalcone.

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80 % failure of carbon steel at oil and gas production facility was caused by corrosion. One of corrosion mitigation of carbon steel was used green inhibitor. In this study, Caesalpinia Sappan L. extract has been evaluated as green inhibitor corrosion for API 5L X60 in HCl 1M environment with variation of volume extract 0,5 ml, 1ml, 1,5 ml, 2ml, 3ml and variation of temperature 302K, 312K, 322K, and 332K using Tafel polarization and Electrochemical Impedance Spectroscopy (EIS), Fourier Transform Infra-red Spectroscopy (FTIR), dan Stimultaneous Thermal Analysis (STA).The Result show the tafel polarization and EIS show caesalpinia sappan extract acts for inhibit corrosion process in the system with mixed type inhibitor. Optimal inhibiton efficiency occurs at volume 1.5 ml extract caesalpinnia sappan/400 ml HCl 1M, 91% for tafel polarization and 94% for EIS. Current density at volume extract 1,5 ml was 57 µA/cm2 and resistivity of solution 841 ?.cm2. Increasing temperatur of environment will increase current density to 139 µA/cm2 and decrease resistivity to 121 ?.cm2. So, the inhibition efficiency decrease to 50%. Keton fuctional group was found showed exisstance of showed that brazilein dan dan sappanchalcone"

"Pada proses pre-commisioning jaringan pipa bawah laut diperlukan pencegahan korosi dimana laju korosi material baja API 5L grade B di dalam larutan 3,5 % NaCl teraerasi pada kondisi steady masih relatif tinggi yang dapat mencapai lebih dari 20 mpy (0,5 mm/tahun). Upaya pencegahan korosi pada saat proses hydrotest dengan media air laut dilakukan dengan penambahan inhibitor anorganik yang mengandung zat corrosion inhibitor, oxygen scavenger dan biocide sehingga diperlukan bahan organik alternatif ramah lingkungan dengan kinerja yang lebih baik. Tujuan utama dari penelitian ini adalah untuk menginvestigasi efisiensi dari penggunaan campuran ekstrak sarang semut dan sirih merah sebagai alternatif inhibitor ramah lingkungan atau bahan campuran untuk mengurangi penggunaan inhibitor anorganik pada perlindungan korosi material baja API 5L Grade B dalam lingkungan 3,5% NaCl.Kemampuan inhibisi korosi dari hasil ekstrak bahan alami diinvestigasi dengan menggunakan pengujian Tafel polarisasi dan Electrochemical Impedance Spectroscopy (EIS) serta diverifikasi dengan pengujian kehilangan berat. Kandungan senyawa aktif dalam ekstrak sarang semut dan sirih merah beserta senyawa teradsorpsi pada permukaan logam dan mekaniseme inhibisi elektrokimia diinvestigasi dengan pengujian EIS, FTIR dan model adsorpsi isoterm. Pada konsentrasi campuran green inhibitor 2ml sarang semut + 1ml sirih merah, effisiensi inhibitor dapat mencapai 73,66%. Pada penggunaan sebagai inhibitor campuran dengan inhibitor kimia pada konsentrasi campuran 1ml kimia + 2ml green inhibitor, dapat menurunkan laju korosi secara signifikan dari 0,42 mm/year menjadi 0,03 mm/year dengan efisiensi mencapai 93,15%. Inhibitor korosi tersebut berpengaruh terhadap kurva polarisasi anodik maupun katodik sehingga dapat berperan sebagai mixed inhibitor.Pengujian FTIR menunjukan adanya gugus-gugus fungsi ikatan kimia yang berkombinasi sebagai pembentuk lapisan (film forming) seperti Gugus hidroksil, karbonil, aromatik, alkane dan amina. Adsorpsi senyawa-senyawa terkandung dalam inhibitor sarang semut dan sirih merah pada permukaan logam terjadi spontan mengikuti Langmuir adsorpsi isoterm. Hasil ini sesuai dengan hipotesis awal bahwa ekstrak sarang semut dan sirih merah yang mengandung senyawa antioksidan dapat mencegah proses oksidasi pada permukaan logam sehingga akan mengurangi laju korosi.

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During pre-commissioning of subsea pipeline are require corrosion prevention since the corrosion rate of steel material of API 5L grade B in 3.5% NaCl aerated solution under steady state condition is still relatively high (can reach more than 0,5 mm/year). Method to prevent the corrosion during subsea pipeline hydrotest using seawater is generally by the addition of inorganic inhibitor containing corrosion inhibitor agent, oxygen scavenger and biocide, so that require to find out the alternative eco- friendly materials with better performance. The main objective of this study is to investigate the efficiency of the use of mixture of extract of myrmecodia pendans and piper crocatum as an alternative of eco-friendly inhibitor or a compound for reducing the use of inorganic inhibitors for corrosion protection of steel material API 5L Grade B in 3,5% NaCl Environmental.

The corrosion inhibition ability of natural ingredient extraction are investigated by using tafel polarization test and electrochemical impedance spectroscopy (EIS) and verified by weight loss test. The content of the active compounds in the extract of Myrmecodia Pendans and Piper Crocatum along with adsorption compound on metal surfaces and electrochemical inhibition mekaniseme are investigated by EIS, FTIR testing and model of the Langmuir adsorption isotherm. The addition of mixed green inhibitor concentration of 2ml myrmecodia pendans and 1ml piper crocatum is resulted in approximately 73.66% inhibitor efficiency while the addition of mixed green inhibitor into chemical inhibitor with concentration of 1ml for chemical and 2ml for green inhibitor are significantly reduce the corrosion rate from 0.42 mm/year to be 0.03 mm/year with approximately 93.15% inhibitor efficiency.

The green inhibitor affected the cathodic as well as the anodic polarization curves which were known as mixed corrosion inhibitor type. The type of chemical bonds on the steel surface layer was analyzed by FTIR method which indicated hydroxyl, carbonyl, aromatic, alkane and amine group. The adsorption of compounds contained in the myrmecodia pendans and piper crocatum inhibitor on a metal surface are occur spontaneously follows the Langmuir adsorption isotherm. These results are consistent with the initial hypothesis that the extract of myrmecodia pendans and piper crocatum contains antioxidant compound which can prevent the oxidation process in the metal surface thereby will reducing the corrosion rate."

"Ekstrak areca flower telah diteliti sebagai inhibitor korosi pada baja API 5L Gr. B pada lingkungan 1 M HCl dengan menggunakan pengujian Linear Polarisasi dan Electrochemical Impedance Spectroscopy EIS. Penambahan konsentrasi inhibitor 4 ml, 8 ml, 12 ml, 16 ml, dan 20 ml dapat meningkatkan efisiensi inhibitor. Efisiensi inhibitor optimum terjadi pada saat penambahan konsentrasi inhibitor 20 ml sebesar 96.6 pada pengujian Electrochemical Impedance Spectroscopy EIS. Senyawa polifenol dan flavonoid yang terkandung dalam areca flower dapat menginhibisi korosi secara adsorpsi fisika yang membentuk lapisan monolayer yang dapat menghambat terjadinya korosi. Adsorpsi terjadi secara spontan sesuai dengan adsorpsi isotermal Langmuir. Sesuai hasil pengujian polarisasi menunjukkan ekstrak areca flower memiliki tipe inhibisi campuran mixed-type . Nilai energi bebas adsorpsi -7.026 kJ/mol menunjukkan bahwa adsorpsi molekul inhibitor adalah adsorpsi fisika.

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Areca flower has been investigated as green corrosion inhibitor on API 5L Gr B in solution 1 M HCl acidic using Linear polarization and Electrochemical Impedance Spectroscopy EIS . Addition of 4 ml, 8 ml, 12 ml, 16 ml, and 20 ml inhibitor corrosion increase efficiency of the inhibitor. Optimum inhibition efficiency occurs at addition at concentration 20 ml is 96.6 on Electrochemical Impedance Spectroscopy EIS testing. Polyphenolic and flavanoid compounds contained in the areca flower inhibit corrosion by physical adsorption, to form a monolayer which can inhibit corrosion. Adsorption occurs spontaneously in accordance with Langmuir isothermal adsorption. The polarization showed that the areca flower extract acts through mixed ndash type inhibition. The value of the free energy 7.026 kJ mol of adsorption indicated that the adsorption of inhibitor molecules was typical of physical adsorption."

"Korosi merupakan kegagalan yang sering terjadi pada industri minyak dan gas bumi Menghambat terjadinya korosi dengan mengisolir logam dari lingkungan terkorosi pada industri minyak dan gas bumi merupakan salah satu cara efektif untuk menghindari terjadi kegagalan korosi. Penggunaan inhibitor alami menjadi pihan utama belakang ini karena aman murah dan yang terpenting bahan tersebut biodegradable dan tidak berbahaya bagi lingkungan. Penelitian ini dilakukan untuk melihat efek dari penambahan teh rosella merah terhadap inhibitor ubi ungu yang memang dapat digunakan menjadi inhibitor pada baja API 5L pada lingkungan NaCl 3 5. Pengujian ini dilakukan dengan menggunakan metode kehilangan berat dan polarisasi untuk melihat laju korosi yang terjadi pada logam lalu dilengkapi dengan data tambahan yaitu pengujian Electrochemical Impedance Spectroscopy untuk melihat tahan permukaan yang berbubah pada penelitian tersebut. Pengujian Fourier Transform Infra Red juga dilakukan untuk melihat kandungan yang menginhibisi dari ubi ungu ataupun campuran ubi ungu dan teh rosella merah Pemilihan teh rosella merah dan ubi ungu berdasarkan kandungan antocyanin dan asam askorbat yang dimiliki kedua bahan tersebut Kandungan tersebut bersifat anti oksidan yang berarti dapat menghambat terjadi proses oksidasi yang berarti juga dapat mencegah korosi. Kandungan anti oksidan tersebut bekerja dengan cara adsoprsi pada permukaan logam membentuk lapisan tipis untuk mencegah kontak antara permukaan logam dengan lingkungan korosif. Salah satu faktor pembentukan lapisan tipis pada permukaan adalah konsentrasi kandungan tersebut sehingga pengaruh konsentrasi dijadikan acuan pada penelitian ini. Penelitian ini akan dibandingkan dengan inhibitor ubi ungu yang hanya dicampur dengan kandungan asam askorbat saja.

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Corrosion is major cause failure in oil ad gas industry Isolate the metal from corrosion of materials is the most effective way to prevent corrosion for this industry. Nowadays the use of green corrosion inhibitor become a new alternative to achieve that goal it happen because the green inhibitor is safe cheap biodegradable and especially environmental friendly.

This study was conducted to study the effect of addition rosella red tea in purple sweet potato inhibitor which is can be use as inhibitor at API 5L in NaCl 3 5 solution. This study use weight loss and polarization method to see that effect and Electrochemical Impedance Spectroscopy test to prove alteration surface resistance when we add the inhibitor.

Fourier Transform Infra Red test also perform in this study to see which one the chemical substance in purple sweet potato and mixture rosella red tea and purple sweet potato can inhibit corrosion. Purple sweet potato and rosella red tea are selected as corrosion inhibitor in this study because they contain antocyanin and ascorbid acid. They are antioxidant compound which is can inhibit oxidation process it means they can prevent corrosion process. That substance inhibit metal by forming layer and isolate metal surface On the important factor to forming thin layer is concentration of the substance so the concentration substance become variable in this study. In the end this study will compared with the addition ascorbid acid in purple sweet potato"

"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."

"Ekstrak kulit kentang diteliti sebagai inhibitor korosi ramah lingkungan pada baja karbon di lingkungan 3,5% NaCl menggunakan uji kehilangan berat, polarisasi, dan Fourier transform infrared spectroscopy. Pada pengujian kehilangan berat menunjukkan konsentrasi 6mL memberikan nilai efisiensi paling optimal sebesar 73,33 % dengan laju korosi paling rendah sebesar 1,59 mpy. Pada pengujian polarisasi terjadi penurunan rapat arus korosi sebesar 9.79 µA/cm2 menjadi 3.27 µA/cm2, sehingga memperkuat hasil uji kehilangan berat bahwa ekstrak kulit kentang dapat menghambat korosi baja karbon rendah pada lingkungan 3,5% NaCl. Penambahan ekstrak kulit kentang menyebabkan pergeseran potensial korosi (Ecorr) mengarah kearah anodik dengan tipe inhibisi campuran (mixed). Pengujian FTIR menunjukkan ekstrak kulit kentang teradsorpsi pada permukaan baja karbon rendah melalui gugus fungsi yang dimiliki ekstrak. Mekanisme adsorpsi ekstrak kulit kentang mengikuti Langmuir adsorption isotherm yang mengindikasikan terbentuknya lapisan monolayer pada permukaan baja karbon rendah.

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Potato peel extract as green corrosion inhibitor on low carbon steel in 3.5% NaCl environment has been investigated using weight loss, polarization, and fourier transform infrared spectroscopy. The result of weight loss that showed that optimum inhibition is 73,33% in 6 mL concentration with corrosion rate 1,59 mpy and 9 days of immersion time.

Polarization show that decrease in current density 9.79 to 3.27 µA/cm2, with the result that confirm the results of weight loss that potato peel extract inhibit corrosion low carbon steel on 3.5% NaCl environment. Additional of potato peel extract showed displacement of potential corrosion to anodic direction, and act as mixed type inhibition.

FTIR showed that potato peel extract adsorbed to surface of low carbon steel through functional group extract. The mechanism of adsorption followed the Langmuir isothermal adsorption which indicated formation of monolayer film on low carbon steel surface."