Adsorption Mechanism of 4-(4,5-diphenyl-1H-imidazole)-N,N-dimethylbenzenamine as a Corrosion Inhibitor Towards Carbon Steel in 1% NaCl Solution

Corrosion inhibitor is one of the materials widely known to effectively minimize damages caused by corrosion. Design and development of corrosion inhibitor have been intensively studied. Understanding the mechanisms responsible in corrosion inhibition is demanded in developing techniques to prevent corrosion. This study employed an imidazole derivate compound, 4-(4,5-diphenyl-1H-imidazole)-N,N-dimethylbenzenamine, as a corrosion inhibitor on carbon steel in a corrosive environment of 1% NaCl at 25 oC. Analysis of the mechanisms underlying the adsorption of the organic inhibitor on metal surface was performed by electrochemical impedance spectroscopy method. The adsorption mechanisms were analyzed by Langmuir and Temkin adsorption isotherm models. The fitting results showed that the linear regression obtained from Langmuir and Temkin adsorption isotherm were 0.9738 and 0.8694, respectively. The adsorption free energy was -34.04 kJ/mol, indicated that Langmuir adsorption isotherm was applied in the adsorption mechanism and that the inhibitor was adsorbed semi-physically or semi-chemically on the metal surface

Synthesis of Oligosuccinimide and Evaluation of Its Corrosion Inhibition Performance on Carbon Steel in CO2-Saturated 1% NaCl Solution

Oligosuccinimide (OSI) is an oligomer with several repeating units of succinimide. In this study, OSI was synthesized by thermal condensation between maleic anhydride and ammonium carbonate. The chemical structure of the synthesized compound was confirmed by FTIR and NMR spectroscopy as well as LC-MS characterization. Evaluation of its performance as corrosion inhibitor and the adsorption mechanism on a carbon steel surface in CO2-saturated 1% (w/v) NaCl solution was performed using electrochemical techniques (electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization) and weight-loss methods. These tests were simultaneously carried out for all fractions without separation. The EIS results showed that the inhibition efficiency (IE) of the OSI increased with increasing concentration but decreased at higher temperatures. The potentiodynamic polarization data indicated that the OSI acted as a mixed inhibitor. Adsorption of OSI on the carbon steel generally obeys the Langmuir adsorption isotherm according to curve linearity, which relates the degree of surface coverage to the inhibitor concentration. The standard Gibbs free energy of the adsorption values (∆G° ads) were negative within the range of -33.14 to -38.73 kJ.mol-1, which indicates the spontaneity of the adsorption process on the carbon steel surface and that OSI molecules interacted with the carbon steel through semi-physisorption

Screening and Characterization of Levan Secreted by Halophilic Bacterium of Halomonas and Chromohalobacter Genuses Originated from Bledug Kuwu Mud Crater

AbstractFive bacterial isolates from the genus of Halomonas and Chromohalobacter isolated from Bledug Kuwu mud crater, located in mainland Purwodadi-Grobogan, Central Java, Indonesia, have been assayed for levan production. Initial screening was conducted on modified Belgith medium using sucrose as the major carbon source, in which the colonies of levan-producing bacteria will have a slimy mucoid appearance when grown on this medium. The screening results showed only one positive bacterial species, which was Chromohalobacter japonicus BK AB18 that identified as potential levan producer. Thermal stability of the isolated levan has been charachterized by TGA, which gave approximate decomposition temperature about 211 oC. The structure of the levan has been elucidated by FTIR and NMR spectroscopies. FTIR spectrum of the isolated levan displayed high similarity to that of levan isolated from Bacillus methylotrophicus. The chemical shifts of carbon and proton NMR spectra of the isolated levan also exhibited high similiarity to those of levan isolated from Pseudomonas fluorescens and Zymonas mobils

Surfactant Flooding for EOR Using Sodium Lignosulfonate Synthesized from Bagasse

Surfactant injection is one of the types of chemical injections used in enhanced oil recovery (EOR) process. Surfactant can increase the interfacial tension between oil and water in the rock matrix. The surfactant used is an anionic surfactant, which is one of the lignosulfonate surfactants known as sodium lignosulfonate (SLS) surfactant derived from lignin. Bagasse is one of the raw materials having a high content of lignin (24–25%). The synthesized bagasse becomes lignosulfonate used as an isolation of lignin and transformed into sodium lignosulfonate by sulfonation process. Based on the characteristic test, the bagasse’s SLS surfactant has some qualified characteristics which are a good aqueous stability, clear solution and not causing turbidity, and capability to form middle-phase microemulsion with light oil. Synthesized SLS has a hydrophilic–lipophilic balance (HLB) value of 11.6 which can be classified as oil in water (O/W) emulsion. Middle-phase emulsion as a characteristic SLS surfactant affects the performance of the SLS surfactant injection. So the use of sodium lignosulfonate surfactant synthesized from bagasse is a challenge to be developed further as a surfactant flooding

Correlation between Phase Behavior and Interfacial Tension for Mixtures of Amphoteric and Nonionic Surfactant with Waxy Oil

Phase behavior tests in the surfactant screening process for EOR applications remain one of the relatively convenient ways to design an optimum surfactant formulation. However, phase behavior studies are unable to provide quantitative data for interfacial tension, which is one of the parameters that must be considered when selecting surfactants for EOR. Several studies related to the prediction of interfacial tension through phase behavior testing have been carried out. In this paper, the Huh correlation was used to estimate the interfacial tension value based on phase behavior tests. It was found that the current form of the Huh correlation may be applied for the below-to-optimum salinity condition. Furthermore, the constants of the equation vary depending on the surfactant type and mixtures. 

Sintesis Membran Komposit Berbahan Dasar Kitosan dengan Metoda Sol-Gel sebagai Membran Fuel Cell Pada Suhu Tinggi

Kitosan adalah polisakarida kationik yang terdiri dari residu glukosamin dan N-asetil glukosamin yang terikat oleh ikatan β-1,4 glikosidik. Keberadaan gugus alkohol bebas pada kerangka kitosan dapat dimanfaatkan sebagai gugus pembentuk matrik dengan atom lainnya, dalam penelitian ini adalah silika (Si). Kondisi ini dapat dimanfaatkan sebagai bahan dasar sintesis membran sel bahan bakar (Fuel Cell). Sintesis kitosan dilakukan dengan mendeasetilasi kitin yang bersumber dari limbah kulit udang. Membran komposit kitosan-TEOS (Tetraetilortosilikat) telah berhasil disintesis dengan menggunakan variasi nilai konsentrasi kitosan terhadap jumlah TEOS. Membran komposit kitosan-TEOS disintesis dengan menggunakan metoda sol-gel dan pembalikan fasa. Kitosan dan membran komposit yang dihasilkan kemudian dikarakterisasi sifat kimia dan fisika nya yaitu penentuan derajat deasetilasi, penentuan berat molekul rata-rata (Mv), persen kelarutan, analisis struktur dengan menggunakan FTIR, uji ketahanan suhu, analisis morfologi dengan menggunakan SEM, dan kapasitas pertukaran ion (KPI). Hasil karakterisasi menunjukkan derajat deasetilasi kitosan sebesar 79,31% dengan nilai berat molekul rata-rata (Mv) 1,16 x 107 g/mol dan persen kelarutan 1% (v/v) asam asetat. Hasil pengukuran FTIR membran menunjukkan terdapat puncak 1377 cm-1 yang merupakan puncak dari eter siklik, puncak 3454 cm-1 yang merupakan puncak dari O-H, puncak pada 1662-1666 cm-1 yang merupakan puncak dari C=O asetamida, dan 3454-3500 cm-1 yang merupakan puncak N-H, sedangkan puncak 904 cm-1 dan 1091,7 cm-1 menunjukkan adanya ikatan silang antara Si-OH dan Si-O-C (alifatik). Uji ketahanan membran terhadap suhu sebesar 120oC sedangkan nilai konduktivitas ionik terbesar dimiliki oleh tipe membran CTSN-1,5 dengan nilai 0,114 meq/g. Hasil analisis SEM menunjukkan bahwa membran mempunyai struktur yang rapat

Analisa Spektrum Infra Red Pada Proses Sintesa Lignin Ampas Tebu Menjadi Surfaktan Lignosulfonat

Secara umum, lignin adalah salah satu komponen penyusun tumbuhan yang biasa terakumulasi pada batang tumbuhan berbentuk pohon dan semak. Ampas tebu adalah salah satu bahan limbah yang di dalamnya masih terdapat lignin. Ampas tebu adalah hasil samping dari proses ekstraksi cairan tebu. Ampas tebu yang dipergunakan adalah ampas tebu setelah proses penggilingan ke lima kali dari proses pembuatan gula. Selama ini ampas tebu digunakan sebagai bahan bakar pabrik gula dan pakan ternak. Dengan proses pemisahan lignin dari ampas tebu dapat memberi nilai tambah pemanfaatan ampas tebu sekaligus sebagai alternatif mendapatkan surfaktan nabati. Surfaktan komersial yang selama ini telah digunakan umumnya berbahan baku minyak bumi. Lignin merupakan bahan baku pembentuk Lignosulfonat sebagai salah satu jenis surfaktan anionik yang digunakan sebagai bahan baku pada Injeksi Surfaktan untuk meningkatkan perolehan produksi minyak. Salah satu metoda sintesa yang digunakan untuk memisahkan lignin dari ampas tebu adalah menggunakan Natrium Hidroksida. Hasil lignin yang terbentuk dikarakterisasi dengan metode spektroskopis Infra Red untuk mengetahui gugus-gugus fungsi khas yang terdapat pada struktur lignin dan dibandingkan dengan spektrum lignin komersial standar . Selanjutkan dilakukan proses sulfonasi untuk membentuk lignosulfonat yang hasilnya juga diuji dengan Infra Red dan dibandingkan dengan spektrum sulfonat komersial standar sehingga dapat diketahui komponen di dalamya

Laboratory Optimization Study of Sulfonation Reaction toward Lignin Isolated from Bagasse

Bagasse is scientifically defined as waste from the extraction of sugarcane liquid after the grinding process. Bagasse is biomass which is used as raw material to be processed into surfactants. Bagasse fiber cannot be dissolved in water because it consists mostly of cellulose, pentosane and lignin. The optimum conditions for obtaining the highest yield and the best conversion of bagasse to lignin were achieved when used 80 mesh bagasse and 3 M NaOH as a hydrolysis agent. Then lignin is reacted with 0.25 sodium bisulfite to the surfactant sodium lignosulfonate. Lignin and sodium lignosulfonate were further characterized using a FTIR spectrophotometer to determine the components contained therein. The lignin component consists of phenolic functional group elements, aliphatic and aromatic groups, ketone groups, aren functional groups, amine groups and alkyl groups along with standard lignin components. Likewise with lignosulfonates, with indicator components consisting of C═C alkenes, Sulfate S═O, C═O carboxylic acids and S-OR esters. The NMR test was resulted the monomer structure of SLS surfactant bagasse. The results indicate that the lignin isolation process from bagasse has been successfully. Likewise, the sulfonation of lignin to lignosulfonate is also successful