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Abstrak :
The effect of metal doping on the hydrogen physisorption energy of a single walled carbon nanotube (SWCNT) is investigated. Unlike many previous studies that treated metal doping as an ionic or charged element, in this study, lithium and magnesium are doped to an SWCNT as a neutral charged by substituting boron on the SWCNT (Boron substituted SWCNT). Using ab initio electronic structure calculations, the interaction potential energies between hydrogen molecules and adsorbent materials were obtained. The potential energies were then represented in an equation of potential parameters as a function of SWCNT diameters in order to obtain the most precise potential interaction model. Molecular dynamics simulations were performed on a canonical ensemble to analyze hydrogen gas adsorption on the inner and outer surfaces of the SWCNT. The isosteric heat of the physical hydrogen adsorption on the SWCNT was estimated to be 1.6 kcal/mole, decreasing to 0.2 kcal/mole in a saturated surface condition. The hydrogen physisorption energy on SWCNT can be improved by doping lithium and magnesium on Boron substituted SWCNT. Lithium-Boron substituted SWCNT system had a higher energy physisorption that was 3.576 kcal/mole compared with SWCNT 1.057–1.142 kcal/mole. Magnesium-Boron substituted SWCNT system had the highest physisorption energy that was 7.396 kcal/mole. However, since Magnesium-Boron substituted SWCNT system had a heavier adsorbent mass, its physisorption capacity at ambient temperature and a pressure of 120 atm only increased from 1.77 wt% for the undoped SWCNT to 2.812 wt%, while Lithium-Boron substituted SWCNT system reached 4.086 wt%.

Abstrak :
The series of hybrid organic-inorganic silica materials have been prepared by introducing organic ligands materilas based on sol-gel processing of alkoxysilanes for potential applications in membrane design for pervaporation.....

Abstrak :
Mekanisme inhibisi korosi dari inhibitor berbahan dasar triazine pada baja API 5L Grade X60 di lingkungan NaCl 3,5% diinvestigasi dengan menggunakan metode model adsorpsi yang didapat dari hasil pengujian Tafel Polarisasi, Linier Polarisasi dan Electrochemical Impedance Spectroscopy (EIS) dengan menggunakan variasi konsentrasi 0 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm dan 250 ppm. Senyawa triazine yang teradsorpsi pada permukaan logam diinvestigasi dengan menggunakan pengujian Fourier Transform InfraRed (FTIR). Hasilnya didapatkan bahwa proses adsorpsi inhibitor triazine terjadi secara spontan mengikuti mode adsorpsi Langmuir isoterm. Berdasarkan nilai Nilai Goads berada pada rentang -11.0697 kJ/mol sampai -19.7833 kJ/mol menunjukkan bahwa inhibitor triazine menginhibisi korosi dengan cara adsorpsi fisika (interaksi elektrostatis antara muatan molekul inhibitor dengan muatan permukaan logam) membentuk lapisan tunggal di permukaan logam sehingga dapat menghambat proses korosi. Besarnya efisiensi inhibisi inhibitor berbahan dasar triazine bergantung pada konsentrasi inhibitor. Efisiensi inhibisi tertinggi diperoleh pada konsentrasi triazine 150 ppm sebesar 68,674% berdasarkan hasil pengujian Electrochemical Impedance Spectroscopy. ......Corrosion inhibition mechanism of triazine-based corrosion inhibitor on API 5L Grade X60 steel in 3.5% NaCl environment was investigated by using adsorption method from the results of tafel polarization, linier polarization resistance (LPR), and Electrochemical Impedance Spectroscopy (EIS) tests with 0 ppm, 50 ppm, 100 ppm, 150 ppm, 200 ppm and 150 ppm concentration variation. Triazine compounds which adsorbed on metal surface was also investigated by Fourier Transform InfraRed (FTIR) test. It was found that adsorption process of triazine-based inhibitor occurs spontaneously and follow the Langmuir adsorption isotherm. From the calculation of Goads (around -11.0697 kJ/mol to -19.7833 kJ/mol), it indicates that the inhibitor inhibited corrosion by physisorption (involving electrostatic attraction between the charged of inhibitor molecules and the charged of metal surface) to form a monolayer on the metal surface so that corrosion will be obstructed. Inhibition efficiency of triazine-based inhibitor was concentration dependent. The optimum inhibition efficiency is 68,674% in 150 ppm concentration of triazine as a result of Electrochemical Impedance Spectroscopy test.

Abstrak :
ABSTRAK
Kemampuan ekstrak daun Physalis angulata daun ciplukan sebagai inhibitor ramah lingkungan di lingkungan HCl 1 M diinvestigasi menggunakan pengujian polarisasi linear dan weight loss. Adapun diinvestigasi flavonoid dan antioksidan yang menginhibisi permukaan Baja API 5L melalui pengujian FTIR. Variabel bebas yang dipakai yaitu ekstrak konsentrasi inhibitor dalam HCl 1 M, yakni 10 mL, 20 mL, 30 mL, 40 mL, dan 50 mL. Ekstrak daun ciplukan mengandung senyawaan flavonoid yang merupakan inhibitor campuran yang dominan katodik. Inhibitor ini mampu mencegah kerusakan catastrophic akibat agresivitas HCl 1 M dengan mekanisme physisorption hingga 192 jam. Efisiensi inhibitor yang paling tinggi ada di konsentrasi 50 mL sebesar 98,9. Inhibitor ekstrak daun ciplukan berpotensi sebagai inhibitor ramah lingkungan bagi Baja API 5L dilingkungan HCl 1 M.

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ABSTRACT
The ability of Physalis angulata leaves extract as green inhibitor in HCl 1 M environment has been investigated with linear polarization measurement and weight loss method. FTIR analysis was used to investigate flavonoid and antioxidant compound that plays an important role to inhibit corrosion. The free variable that has been used in this study was 10 mL, 20 mL, 30 mL, 40 mL, dan 50 mL. Physalis angulata leaves extract that contain flavonoid play role as mixed inhibitor that predominantly cathodic. This inhibitor can prevent cathasthropic damage due to aggressiveness of HCl 1 M with physisorption mechanism up to 192 hours. The concentration that showed highest efficiency 98.9 was 50 mL. It can be concluded that Physalis angulata leaves extract could be used as an alternative and environmental friendly inhibitor for API 5L in HCl 1 M environment.