JKPK (Jurnal Kimia dan Pendidikan Kimia)
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222 research outputs found
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A Simple Colorimetric Detection of Bisphenol A in Exposed Drinking Bottles Using a Paper-Based Sensor
Full text linkBisphenol-A (BPA) is a chemical widely used in the production of polycarbonate plastics and epoxy resins, commonly found in bottled water containers. BPA migration into drinking water can occur due to variations in pH and temperature during storage, posing potential health risks with prolonged exposure. This study focuses on the development of a rapid and accurate colorimetric paper sensor for BPA detection. The sensor employs a chromogenic reagent that selectively reacts with BPA, resulting in a visible color change from yellow to dark red. Experimental results demonstrated that the sensor exhibits high sensitivity, with a limit of detection (LOD) of approximately 0.29 mmol L⁻¹. Validation using water samples from plastic bottles exposed to environmental conditions confirmed the sensor’s capability to effectively identify BPA leaching. Additionally, the sensor showed excellent stability, indicated by a relative standard deviation (%RSD) of 0.62%, and high accuracy, with recovery values ranging from 100.87% to 107.39%. These findings suggest that the developed colorimetric paper sensor is a promising tool for on-site monitoring of BPA contamination in drinking water, providing a simple, fast, and cost-effective alternative to conventional analytical methods
A Portable Laboratory Kit for Student Self-Learning on Factors That Affect Reactions
Full text linkIn chemistry practicums, students can enhance their scientific thinking skills and develop scientific attitudes. However, in some underprivileged schools, particularly during the COVID-19 pandemic, practicum activities were restricted due to the unavailability of laboratory tools and materials. To address this issue, a portable laboratory kit was developed to support practical learning experiences. This study aims to develop a portable laboratory tool model, integrating the Predict-Observe-Explain (POE) approach, to improve students' learning outcomes on reaction rates. This research employs a mixed-methods approach with an embedded experimental model, utilizing a one-group pretest-posttest design. The portable laboratory kit includes hands-on tools and materials, student worksheets, and teacher guides aligned with POE learning syntax. Three experts conducted validation and implementation involving 24 high school students. A novelty of this study lies in the practical worksheet design, which follows the POE learning syntax and fosters intertextual relationships across macroscopic, submicroscopic, and symbolic representations. The findings reveal a significant difference between pretest and posttest scores regarding students' understanding of factors affecting reaction rates. Specifically, the number of students who demonstrated complete understanding after the intervention was: nine for the effect of structure on reaction rate, 13 for the effect of ionization energy on reaction rate, and 20 for the effect of surface area on reaction rate. Regarding catalysts, 15 students fully understood the effect of a homogeneous catalyst, and 18 students understood the effect of a heterogeneous catalyst. Interviews with teachers and students further indicated that students found the approach novel, motivating them to engage more deeply. Additionally, many students expressed feeling particularly challenged during the prediction stage of the POE learning process
Characterization of SiO₂/C Composites from Bamboo Leaves and Graphite for Lithium-Ion Battery Anode
Full text linkSilicon dioxide (SiO₂) is a key component found in various biomass materials, including bamboo leaves. This study aims to synthesize SiO₂/C composites using bamboo leaves as the silica source and graphite as the carbon source, targeting their application as anode materials in lithium-ion batteries (LIBs). Silica particles were first prepared using the sol-gel method and characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM). The SiO₂/C composite was synthesized through a solid-state reaction by mixing SiO₂ and graphite in varying SiO₂ weight percentages of 0%, 5%, 20%, and 100%, followed by calcination at 500 °C for 30 minutes under argon atmosphere. The morphology and composition of the resulting composites were analyzed using SEM-EDX. These composites were then employed as anode materials in LIBs, paired with a nickel manganese cobalt oxide (NMC) cathode. Electrochemical performance was assessed using a battery analyzer, and charge-discharge cycle (CDC) data were obtained. The addition of carbon significantly improved the electrochemical performance. Specifically, the composite with 100% SiO₂ showed a low capacity of 9.88 mAh/g, while those with 5% and 20% SiO₂ demonstrated significantly enhanced specific capacities of 97.35 mAh/g and 129.34 mAh/g, respectively, after five cycles
Eco-Friendly Revolution in Fingerprint Detection: Synthesis of Zno Nanoparticles Using Durian (Durio Zibethinus) Peel Extract Pakpak Bharat
Full text linkFingerprints are a reliable means of forensic identification because ridge patterns are unique and permanent. Conventional fingerprint powders, however, may contain hazardous ingredients that pose health and environmental risks. This study synthesized zinc oxide (ZnO) nanoparticles via a green route using durian peel (Durio zibethinus) extract and evaluated their potential as an eco-friendly latent fingerprint developer. ZnO nanoparticles were characterized by FTIR to identify functional groups, SEM to examine morphology and particle size, and EDX to verify elemental composition. The biosynthesized ZnO showed semi-spherical to granular particles with sizes of 40–90 nm and no severe agglomeration. FTIR indicated hydroxyl and carbonyl groups from durian peel biomolecules, suggesting their role as reducing and stabilizing agents. EDX confirmed dominant Zn (72.5%) and O (15.2%) signals, supporting high purity ZnO formation. Latent fingerprint development was tested using prints from 40 respondents on porous surfaces (black cardboard and oil paper) and nonporous surfaces (microscope slide, aluminum foil, and compact disc). The ZnO nanopowder produced clear ridge patterns and higher contrast on nonporous substrates, while conventional powders tended to leave residues and may require less safe reagents. These results indicate that durian peel derived ZnO nanoparticles are a promising, economical, and environmentally friendly alternative for latent fingerprint visualization and provide added value for agricultural waste utilization in forensic applications
Development and Evaluation of Articulate Storyline-Based Interactive Media: Integration of Socio-Scientific Issues in Hydrocarbon Learning to Enhance Students’ Critical Thinking Skills
Full text linkCritical thinking enables students to make informed decisions, resist misinformation, and construct deeper disciplinary understanding, yet it remains underdeveloped in many classrooms. This study developed and evaluated an interactive hydrocarbon learning medium created with Articulate Storyline and integrating socioscientific issues (SSI) within the ADDIE framework (Analysis, Design, Development, Implementation, Evaluation). The research was conducted at an Islamic boarding school in Banjarmasin with 61 students (individual try-outs: n = 5; small-group trials: n = 10). Instruments—questionnaires, observation sheets, and tests—were aligned to Facione’s six critical-thinking indicators and used to assess validity, practicality, and effectiveness. Content and media validity were high (expert ratings: 0.89 and 0.88), internal consistency was acceptable (Cronbach’s alpha = 0.86), and practicality was rated very good (mean = 4.59). Effectiveness analyses showed substantial learning gains (normalized gain, n-gain = 0.77 and 0.78) and statistically significant pre- to post-improvements (paired t-tests, p < 0.001), indicating the medium effectively enhances students’ critical thinking in chemistry. Limitations include the focus on a single topic (hydrocarbons), a single site with a modest sample, and no assessment of other skills or long-term retention. Within these bounds, the media demonstrate strong quality and practical classroom value, supporting teachers to design engaging, student-centered instruction that cultivates deeper thinking
In Silico Pharmacokinetic and Microbiota-Integrated Profiling of Resveratrol Analogs
Full text linkResveratrol, a polyphenolic compound, possesses extensive biological activities; however, its use in clinical applications is restricted due to its poor bioavailability and rapid metabolism. In the present work, resveratrol and 14 of its structural analogs were screened by a combined in silico methodology. The methodology integrated density functional theory (DFT) calculations, quantitative structure–activity relationship (QSAR) modeling, physiologically based pharmacokinetic (PBPK) simulations, and microbiota-associated interaction considerations. Molecular descriptors were generated from optimized geometries at the DFT level of theory to predict permeability and metabolic characteristics. PBPK modelling was used to simulate the distribution of compounds in different physiological states. In contrast, bioinformatics analysis was used to support the gene expression modulation and the response of the microbial community to the analog structure. Several analogs predicted permeability and metabolic stability significantly better than native resveratrol. Furthermore, some compounds exhibited good associations with gut microbiota and metabolic pathways that may have regulatory functions. The results indicate that certain resveratrol analogs are potential drug candidates for further in vitro and in vivo studies. Furthermore, we report a full computational framework to aid the discovery of rational bioavailable polyphenol-related drugs
GC-MS and ADMET Profiling of Bruguiera gymnorrhiza Mangrove Leaf Extract Origin Sulawesi with Antioxidant Properties
Full text linkMangrove plants, particularly Bruguiera gymnorrhiza, are recognized as sources of bioactive compounds. This study analyzed the chemical profiles, safety, and antioxidant activity of B. gymnorrhiza leaf extract origin Sulawesi, a biodiversity-rich Wallacean region. Research on B. gymnorrhiza leaves from Sulawesi remains scarce. GC-MS analysis identified inositol, fatty acid, ester, and terpenoid derivatives as major chemical profiles related to stress tolerance and remedial properties. ADMET predictions showed good intestinal absorption but suggested potential hepatotoxicity at high doses. Brine shrimp lethality tests revealed low acute toxicity with an LD₅₀ of 873.381 µg/mL, supporting in silico findings. The extract exhibited strong antioxidant activity (IC₅₀ 49.78 µg/mL), comparable to Vitamin E, and higher than reports from other regions. These results indicate that Sulawesi mangroves store valuable chemical compounds and serve as environmental health indicators. Combining chemical profiling, computational prediction, and experimental validation highlights their pharmaceutical potential while emphasizing the need for careful dose optimization and ecological monitoring. This study reinforces the importance of conserving Wallacean biodiversity and offers a foundation for safe, natural antioxidant commercialization. Future work should assess in vivo effectiveness, long-term toxicity, and the ecological impacts of pollutant immobilization in mangrove ecosystems
Green Synthesis of Silver Nanoparticles using Lemongrass Leaf (Cymbopogon citratus) Extract as a Reductant for Novel Colorimetric Mercury(II) Detection
Full text linkMercury(II) contamination in water poses serious risks to human health, requiring rapid detection. This study develops a fast colorimetric sensor based on silver nanoparticles (AgNPs) synthesized using lemongrass (Cymbopogon citratus) leaf extract as a green reducing agent. Synthesis conditions were optimized, the AgNPs were characterized, and analytical performance was validated using standard parameters. Sensor responses were monitored by UV Vis spectroscopy through changes in the surface plasmon resonance (SPR) band and quantified from absorbance variations. The optimum synthesis produced a reddish brown AgNP colloid at 45 minutes, 3 mM AgNO3, and 10% lemongrass extract. The nanoparticles showed a maximum absorption at 432 nm and an average size of 150.8 nm. Validation results indicate excellent selectivity for Hg2+ and a pronounced change in the overall SPR signal at 600 ppm Hg2+. The method was linear over 0 to 0.8 ppm Hg2+ with R2 = 0.9988 (y = 0.04x + 0.0722). The limits of detection and quantification were 3.681 × 10^-9 ppm and 1.115 × 10^-8 ppm, respectively. Molar absorptivity reached 10.84 × 10^3 L mol^-1 cm^-1 at 416 nm. These results demonstrate that lemongrass mediated AgNPs provide a simple, rapid, and sensitive platform for mercury detection in water
The Effect of Coagulant Particle Size, Coagulant and Flocculant Dose on Remazol Yellow Dye Removal Effectiveness
Full text linkTextile dye effluents are hazardous because many residual dyes are persistent, toxic, and potentially carcinogenic. This study assessed an environmentally friendly coagulation flocculation route to remove Remazol Yellow, an azo dye used in the batik industry in South Sulawesi, by substituting synthetic reagents with papaya (Carica papaya) seeds as a coagulant and Aloe vera gel as a flocculant. FTIR confirmed hydroxyl, carboxyl, and amine groups in papaya seeds, while Aloe vera gel was dominated by polysaccharide and carboxylate features. Jar tests were performed at room temperature using an initial dye concentration of 30 mg L−1. Coagulation was conducted for 5 min at 950 rpm, followed by flocculation for 30 min at 125 rpm and sedimentation for 30 min. Residual dye was measured by UV Vis spectrophotometry at 417 nm. Operational variables were optimized, including coagulant particle size (30 to 100 mesh), papaya seed dose (10 to 50 mg L−1), and Aloe vera gel dose (10 to 60 g L−1). The optimum particle size was 70 mesh, giving 60.4 percent removal. The optimum papaya seed dose was 20 mg L−1 with 83.5 percent removal, and the optimum Aloe vera gel dose was 50 g L−1, achieving 97.4 percent removal. These results demonstrate the potential of papaya seeds and Aloe vera gel as effective and sustainable materials for batik dye wastewater treatment
Safer and Sustainable Co-precipitation Synthesis of NCA (LiNi0.80Co0.15Al0.05O2) Cathodes: Eliminating Ammonia in Favor of NaOH for pH Control
Full text linkDeveloping safer and more sustainable synthesis routes for lithium ion battery cathodes is important for both environmental practice and laboratory education. This study reports an ammonia free oxalate coprecipitation route to synthesize LiNi0.80Co0.15Al0.05O2 (NCA), in which ammonia as the usual pH controller was fully replaced by sodium hydroxide (NaOH). NaOH dosage was varied at 20 g, 40 g, 60 g, and 80 g to control precipitation, precursor quality, and the properties of the final cathode after calcination and sintering. X ray diffraction confirmed formation of a layered α NaFeO2 type structure with R3m symmetry for all samples without detectable secondary phases. The 40 g NaOH condition showed the best structural ordering, reflected by a relatively high I(003)/I(104) intensity ratio associated with reduced cation mixing. Fourier transform infrared spectra verified oxalate ligand decomposition during thermal treatment and the appearance of metal oxygen lattice vibrations consistent with NCA formation. Scanning electron microscopy revealed that the 40 g NaOH sample produced more uniform particles with a narrower size distribution than other variants. Based on these results, the 40 g NaOH sample was selected for electrochemical evaluation and delivered an initial discharge capacity of about 110 mAh/g at 0.1 C in a full cell configuration. Overall, NaOH is demonstrated as an effective and safer substitute for ammonia in oxalate coprecipitation, enabling greener NCA synthesis protocols for research and teaching