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Jurnal Akademika Kimia
Published by Universitas Tadulako
ISSN : 24775185     EISSN : 23026030     DOI : -
Core Subject : Science, Education,
Chemistry Education
Jurnal Akademika Kimia is an electronic open-access journal that aims to publish the latest research results in the area of chemistry education and pure chemistry from academicians, professionals, and other practitioners at all levels of chemistry education. The journal coverage includes the following: current trends of professional chemistry education, educational technology, teacher education, educational science, learning assessment, learning models and development of learning materials, as well as pure chemistry including organic chemistry, inorganic chemistry, analytical chemistry, physical chemistry, biochemistry and other chemistry fields such as environmental chemistry, that emphasis on a broad description of the general methods and processes for the synthesis, modification, and characterization of chemical materials.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 213 Documents
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Atmospheric Corrosion Inhibition of Steel Using Tea Leaf Extract in the Coastal Environment of Air Tawar, Padang Kurniawan, Niko; Saputra, Sabrizal; Dinalia, Dinalia; Yerimadesi, Yerimadesi; safitri, sauli
Jurnal Akademika Kimia Vol. 14 No. 2 (2025)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2025.v14.i2.pp123-131

Abstract

This study evaluates the effectiveness of tea leaf extract as a corrosion inhibitor for steel under real coastal atmospheric exposure. The novelty of this work lies in its direct assessment of a plant-derived inhibitor in an open-air marine environment, a setting that has not been adequately addressed in previous studies, which have largely focused on controlled aqueous systems. In addition, this study employs mature tea leaves, an abundant agricultural byproduct with naturally high tannin content, processed through a simple, solvent-free extraction method, thereby offering a sustainable route for green inhibitor development. The extract was obtained from mature tea leaves through aqueous boiling, and its tannin content was quantified using UV–Vis spectrophotometry. ASSAB 760 steel specimens were coated by immersion in tea extract at varying concentrations and soaking durations, followed by natural exposure in a coastal environment for 1 to 30 days. Corrosion behavior was evaluated using the weight loss method. The results showed that mature tea leaves contained the highest tannin concentration (29530.95 ppm), supporting their selection for inhibitor application. The optimum extract concentration was identified as 11000 ppm with a 5-hour immersion time. Under these conditions, treated steel exhibited a substantially lower corrosion rate (7.78 × 10⁻⁵ g/cm²/day) compared to untreated steel (1.66 × 10⁻⁴ g/cm²/day), corresponding to a maximum inhibition efficiency of 84.71%. The inhibition mechanism is attributed to the formation of a stable Fe³⁺–tannin chelate complex that adsorbs onto the steel surface, forming a protective film that restricts the ingress of aggressive chloride-rich moisture in the coastal atmosphere. Overall, the findings demonstrate the practical viability of mature tea leaf extract as an effective and environmentally benign atmospheric corrosion inhibitor, providing field-relevant insight into sustainable protection strategies for marine-exposed steel infrastructure.
A Study Compares The Effectiveness of Hydrochloric and Sulfuric Acids in Hydrolyzing Jackfruit Seeds into Bioethanol Ginting, Elfrida; Simatupang, Lisnawaty; Sembiring, Jhony H.
Jurnal Akademika Kimia Vol. 14 No. 3 (2025)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2025.v14.i3.pp174-180

Abstract

North Sumatera Province, known for its jackfruit production, presents an opportunity to explore jackfruit seeds as a viable bioethanol feedstock. The province’s diverse agricultural commodities generate substantial agricultural waste, currently primarily used as fertilizer. This research aims to diversify waste utilization by focusing on jackfruit, a prominent commodity in North Sumatera, and its potential as a bioethanol feedstock. Given the scarcity of fossil fuels, exploring renewable energy sources, such as bioethanol derived from agricultural waste, is crucial. Identifying accessible sources within regions is vital. Converting jackfruit seed starch into bioethanol requires hydrolysis. This paper compares hydrochloric and sulfuric acid for bioethanol production. Qualitative testing confirmed the presence of bioethanol from both acids. The density of bioethanol produced using hydrochloric acid was 0.825 g/mL, 3.4% higher than the Indonesian standard value. Similarly, the density of bioethanol produced using sulfuric acid was 0.894 g/mL, 12% higher than the standard value. The viscosity of bioethanol produced using hydrochloric acid was 1.02 cp, 12% lower than the standard value. In contrast, bioethanol produced using sulfuric acid had a viscosity of 1.04 cp, 11% lower than the standard value. FTIR spectra of bioethanol treated with hydrochloric acid showed five prominent peaks: 3339.88 cm-1 (OH), 2953.35 cm-1 (-CH), 1643.79 cm-1 (-C-C), 1450.75 cm-1 (-CH3), and 1014.17 cm-1 (-CO). FTIR spectra of bioethanol treated with sulfuric acid showed only two major peaks at 3339.46 cm-1 and 1635.42 cm-1, both corresponding to -OH and -CH. The NMR spectra show three distinct peaks. In ethanol’s proton NMR spectrum, the first doublet at 1.71 and 1.61 ppm is the methyl group protons. The second peak at 2.02 ppm is the hydroxyl group proton. The third doublet at 3.59–3.62 ppm is the methylene group protons. All methods indicate that hydrochloric acid is a more effective hydrolytic agent than sulfuric acid.
Effectiveness of Problem-Based Learning with Dr Stone Animation on Grade XI Students’ Acid-Base Learning Outcomes Jannah, Miftahul; Tiwow, Vanny M. A.; Abram, Paulus H.; Nurmayanti, Yuli
Jurnal Akademika Kimia Vol. 14 No. 3 (2025)
Publisher : Universitas Tadulako

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22487/j24775185.2025.v14.i3.pp181-186

Abstract

The background of this research is low student performance in the topic and the need for an innovative, interactive, and contextual learning approach. This study aims to examine the effectiveness of the Problem-Based Learning (PBL) model using Dr Stone's animation media on students' learning outcomes in the acid-base topic for Grade XI students at SMA Negeri 1 Sirenja. The problem addressed in this research relates to how to improve student learning outcomes and engagement through the integration of contextual and technology-based media. The research employed a pre-experimental design with a one-group pre-test and post-test on a single experimental class consisting of 30 students. The instruments used included Lesson Plans (RPP), Student Worksheets (LKPD), Dr Stone animation media, and a multiple-choice learning outcome test consisting of 15 validated questions, reviewed and approved by expert validators. The validation results showed that all instruments were valid and appropriate for use. Student learning outcomes were analysed using the N-Gain score to measure the improvement after learning. The average N-Gain score was 0.7331 (73.31%), placing it in the moderately effective category. The average difference between pre-test and post-test scores was 37.10 points, indicating a significant improvement in student learning outcomes. Most students experienced substantial learning gains after participating in problem-based learning supported by animation media. This study demonstrates that combining the Problem-Based Learning (PBL) model with Dr Stone's animation media effectively improves student learning outcomes. Furthermore, this study supports the learning process by incorporating a contextual and interactive approach that fosters students’ motivation, deepens their conceptual understanding, and promotes active involvement in chemistry lessons. It also offers valuable guidance for teachers on applying technology-integrated, student-centred teaching strategies in science education.

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