Produksi Hidrogen Dari Reaksi Aluminium Dan Larutan Alkali Konsentrasi Rendah Pada Temperatur Dan Tekanan Sub-Kritis

Christanto, Raphael (2025) Produksi Hidrogen Dari Reaksi Aluminium Dan Larutan Alkali Konsentrasi Rendah Pada Temperatur Dan Tekanan Sub-Kritis. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Peningkatan konsumsi energi global mendorong pengembangan sumber energi terbarukan, salah satunya hidrogen dari reaksi aluminium dan air. Penelitian ini mengkaji produksi hidrogen dalam kondisi subkritis—ketika air berada di bawah titik didih—yang berpotensi meningkatkan aktivitas ionik dan laju reaksi. Reaksi dilakukan menggunakan aluminium foil 1XXX (0,5 gram) dan larutan NaOH dengan konsentrasi 0,03; 0,045; dan 0,06 M pada temperatur 120, 140, dan 160 °C, serta tekanan 1, 7, 10, dan 13 bar. Variasi gas penambah tekanan meliputi oksigen, nitrogen, dan argon, dengan dan tanpa penggunaan kasa logam untuk memperbesar eksposur aluminium terhadap air. Analisis dilakukan dengan menghitung yield hidrogen berdasarkan hukum gas ideal, mengukur pH sebelum dan sesudah reaksi, serta karakterisasi morfologi dan fasa padat menggunakan dokumentasi visual dan X-ray diffraction (XRD). Hasil menunjukkan bahwa tekanan optimum untuk produksi hidrogen berada pada rentang ≤ 7 bar. Penggunaan gas oksigen pada tekanan tinggi lebih disarankan karena mampu menurunkan energi aktivasi dan menghasilkan struktur aluminium dengan luas pori terbesar. Penambahan konsentrasi NaOH meningkatkan yield secara konsisten, sementara kasa logam memperbesar area reaksi. Penurunan yield pada tekanan tinggi dikaitkan dengan pasivasi, ditunjukkan melalui ΔG pembentukan Al₂O₃ yang semakin negatif dan hasil XRD yang tidak menunjukkan terbentuknya produk reaksi. Sebaliknya, pada tekanan rendah, pembentukan AlO(OH) lebih termodinamika-menguntungkan. Kondisi 160 °C dan 1 bar menghasilkan yield rendah akibat air berada dalam keadaan vapor-density, yang dapat diidentifikasi secara akurat menggunakan pendekatan persamaan keadaan.
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The growing global energy demand has driven the development of renewable energy sources, one of which is hydrogen production via the reaction of aluminum and water. This
study investigates hydrogen generation under subcritical conditions—where water is maintained below its boiling point—potentially enhancing ionic activity and reaction kinetics.
The reaction was conducted using 1XXX series commercial aluminum foil (0.5 grams) and NaOH solutions with concentrations of 0.03, 0.045, and 0.06 M at temperatures of 120, 140, and 160 °C, and pressures of 1, 7, 10, and 13 bar. Pressurizing gases included oxygen, nitrogen, and argon, applied both with and without metal mesh to increase aluminum’s exposure to water. Analyses were performed by calculating hydrogen yield based on the ideal gas law, measuring pH before and after the reaction, and characterizing surface morphology and solid-phase
composition using visual documentation and X-ray diffraction (XRD). Results show that the optimal pressure for hydrogen production lies at or below 7 bar. At higher pressures, oxygen is the most effective pressurizing gas due to its ability to lower activation energy and promote
porous aluminum structures with the largest surface area. Increasing NaOH concentration consistently enhanced hydrogen yield, and the use of metal mesh effectively increased the
reactive surface. Yield reduction at high pressures is attributed to passivation, indicated by increasingly negative Gibbs free energy (ΔG) for Al₂O₃ formation and the absence of reaction products in XRD analysis. In contrast, AlO(OH) formation is thermodynamically more favorable at lower pressures. At 160 °C and 1 bar, hydrogen yield declined due to water entering the vapor-density region, which can be accurately predicted using equation of state.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Energi Aktivasi, Hidrogen, Pasivasi, Reaksi Aluminium-Air, Subkritis, Activation energy, Aluminum–water reaction, Hydrogen, Passivation, Subcritical
Subjects:	Q Science > QC Physics > QC111 Density and specific gravity Q Science > QC Physics > QC 611.97.T46 Temperature effects. Including transition temperature Q Science > QD Chemistry > QD1 Oxidation-reduction reaction. Q Science > QD Chemistry > QD502 Chemical kinetics Q Science > QD Chemistry > QD79.T38 Thermal analysis
Divisions:	Faculty of Industrial Technology and Systems Engineering (INDSYS) > Physics Engineering > 30201-(S1) Undergraduate Thesis
Depositing User:	Raphael Christanto
Date Deposited:	25 Jul 2025 05:49
Last Modified:	25 Jul 2025 05:49
URI:	http://repository.its.ac.id/id/eprint/121377

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