JKPK (Jurnal Kimia dan Pendidikan Kimia)
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Effectiveness of Virtual STEM Laboratories for Enhancing High School Students' Creativity and STEM Literacy
Full text linkThe Virtual STEM Laboratory is a contextual experimental simulation learning tool that integrates science, technology, engineering, and mathematics (STEM) concepts. This study aims to investigate the Virtual STEM Laboratory's effectiveness in enhancing high school students' STEM literacy and creativity. STEM literacy is defined as the ability of a student to apply, identify, and integrate STEM concepts to solve complex problems and innovate in various areas. Meanwhile, creativity refers to the capability to generate novel and valuable ideas or solutions. The study used an experimental design with a control group to compare the effectiveness of the Virtual STEM Laboratory. In addition, students' STEM literacy and creativity were measured using posttest scores. The results showed that the experimental group had higher STEM literacy and creativity scores compared to the control group, which indicates the effectiveness of the Virtual STEM Laboratory. The study found that the Virtual STEM Laboratory improved STEM literacy as measured by the independent t-test and Kruskal Wallis test with a significance value of 0.000. This suggests that the experimental group had better STEM literacy skills than the control group. The Virtual STEM Laboratory was also found to be effective in enhancing student creativity as measured by the independent t-test with a significance value of 0.000, which implies that the experimental group generated more novel and valuable ideas than the control group. The study confirms the Virtual STEM Laboratory's effectiveness in enhancing high school students' STEM literacy and creativity. The Virtual STEM Laboratory is a valuable tool that can improve students' STEM literacy and creativity, thus contributing to their academic and professional development. Further studies can be conducted to explore the potential of the Virtual STEM Laboratory in enhancing other aspects of STEM education.Â
Use of Placuna placenta Shells as Green Adsorbent for Pb(II) Ions Sequestration from Aqueous Solution
Full text linkHeavy metal treatment is crucial to mitigate these elements' adverse environmental impacts. Among various remediation methods, adsorption stands out due to its simplicity and high efficiency. In this context, Placuna placenta shell, a biowaste, has been explored for its potential in treating wastewater contaminated with Pb(II) ions. This research was designed to assess the Placuna placenta shell's proficiency in removing Pb(II) ions from aqueous solutions. The study involved two main components: an adsorption test to evaluate the heavy metal removal capability of the Placuna placenta shel and a comprehensive characterization of the shell-based adsorbent. The adsorption experiments were conducted using a batch system, where variables such as pH levels and contact time were meticulously altered to determine their effect on the adsorption efficiency. Concurrently, the adsorbent underwent thorough characterization through Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Diffraction (XRD) analysis. The experimental findings indicated that the optimal conditions for maximum Pb(II) ion removal were achieved at a pH of 7 and a contact time of 120 minutes. The FTIR analysis of the adsorbent revealed the presence of calcium carbonate (CaCO3), a finding further substantiated by the XRD analysis results. Additionally, SEM imaging provided visual evidence of metal ion deposition on the aggregates of the adsorbent. The study demonstrated that the Placuna placenta shell exhibits promising qualities as an adsorbent for removing heavy metals from contaminated water sources. This finding highlights the potential of utilizing biowaste in environmental remediation and offers a sustainable approach to addressing heavy metal pollution
Biosynthesis of Methyl Esters from Used Cooking Oil (UCO) using Lipase Enzyme from Aspergillus oryzae on Moldy Copra
Full text linkThe successful production of methyl esters from used cooking oil (UCO) using lipase enzymes from Aspergillus oryzae on moldy copra has been achieved. This method offers an eco-friendly substitute for crude palm oil (CPO) in generating methyl esters or biodiesel, contributing to waste reduction, economic benefits, and lowered greenhouse gas emissions for sustainable development. This study aimed to synthesize methyl esters from UCO using the Aspergillus oryzae lipase enzyme sourced from moldy copra. The enzyme was purified through ammonium sulfate fractionation and gel filtration column chromatography. Electrophoresis validated its purity, and activity was assessed through the Erdmann and Lowry method. Methyl ester synthesis involved transesterification with a UCO (1 mol): methanol (9 mol): lipase enzyme (15% v/v) ratio. The enzyme displayed notable characteristics, including 43.76 units/mg protein activity, a 41.7 kDa molecular weight, optimum pH of 8.2, temperature preference of 35°C, Km of 0.046, and a 1.926 µmol/minute Vmax. This enzyme efficiently catalyzed UCO (triolein) into methyl ester (methyl oleate), yielding 75.65%. Characterization using Fourier Transform Infrared (FTIR) revealed specific functional groups like –OH carboxylic acid, C=C alkenes, C=O esters, methyl (CH3-), and methylene (-CH2-). Gas Chromatography-Mass Spectrometry (GC-MS) analysis identified prominent compounds: methyl palmitate (12.53%), methyl vacsenate (16.44%), and, notably, methyl oleate (41.08%). This underscores the potential of Aspergillus oryzae lipase as an effective biocatalyst for UCO transesterification, yielding valuable methyl esters or biodiesel
Modification of Polyethylene Glycol and Citric Acid on Palm Fiber Waste Nanofibers on the Adsorption of Violet Crystal Dyes
Full text linkThis study developed nanofibers derived from sugar palm fiber waste, incorporating citric acid and polyethylene glycol (PEG) modifications to adsorb crystal violet (CV) dye. The synthesis process involved alkalization-acid hydrolysis and bleaching techniques. Subsequent analyses of nanofiber characteristics were conducted using Fourier-Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX). The efficacy of these modified nanofibers in adsorbing CV was quantitatively measured using an Ultraviolet-Visible (UV-Vis) spectrophotometer. The study successfully synthesized nanofibers from sugar palm fiber waste with modifications: PEG-modified nanofibers (NP 2 and NP 24) and citric acid-modified nanofibers (NS 2 and NS 24). These modifications resulted in nanofibers with a smooth, white texture. FTIR analysis of the samples (N, NP 2, NP 24, NS 2, and NS 24) revealed the presence of functional groups essential for cellulose, specifically -OH, C-H, and C-O groups. The addition of citric acid introduced a new group, C=O, albeit with very weak intensity. PEG modifications were evident from the stretching observed in the -OH groups. SEM analysis confirmed the presence of a layer on the nanofibers, attributed to citric acid (NS 2 and NS 24) and PEG (NP 2 and NP 24). XRD results indicated that the pre-and post-modification nanofibers exhibited a semi-crystalline phase. The adsorption mechanism was predominantly guided by Van der Waals electrostatic interactions between the absorbent material and the adsorbate. Intriguingly, the citric acid and PEG modifications did not significantly alter the adsorption outcomes. The adsorption capacity remained stable over time, as evidenced by measurements of 0, 15, 30, 45, 60, 90, and 120 minutes
Profiling GC-MS Ethanol Extract of Putri Malu Leaves (Mimosa pudica L.) and Its Potential as Anti Cholesterol In Vitro
Full text linkCholesterol plays a crucial role in cell building and hormone production in the body, but excessive levels can lead to various diseases. Elevated cholesterol levels increase the risk of cardiovascular diseases such as atherosclerosis. Natural remedies for high cholesterol treatment are commonly sourced from medicinal plants containing many phytochemicals. One such plant is the Putri Malu (Mimosa pudica L.) leaf. This study aims to evaluate the chemical composition of Putri Malu leaf extract and its potential anti-cholesterol effects in vitro. The extraction process used in this study was maceration, followed by GC-MS profiling analysis and the Liebermann Burchad method with UV-Vis spectrophotometry. The findings of this study revealed the presence of five chemical constituents in the extract. Among them, the second and fourth peaks had the highest abundance of acacetin at 14.08% and diosmetin at 73.79%, respectively. The ethanol extract of Putri Malu leaves demonstrated strong anti-cholesterol activity in vitro with an IC50 value of 24.8993, indicating its potential as an agent for treating hypercholesterolemia. Further research is required to evaluate this extract's efficacy in vivo and investigate its underlying mechanism of action
A Bibliometric Analysis of Publications on Systems Thinking in Chemistry Education using Vosviewer,
Full text linkThis study utilizes a bibliometric approach along with computational mapping analysis. This study employs a bibliometric approach, complemented by computational mapping using VOSviewer, to explore systems thinking research in chemistry education. The primary goal is to identify key research themes and trends in this field. The initial step involved searching for articles with keywords like "systems thinking" and "chemistry education" using the Publish or Perish software and Google Scholar database. This yielded 922 articles, which were carefully selected based on specific criteria. The comprehensive analysis included co-authorship, co-citation, co-occurrence, cluster, and content analysis using VOSviewer. The quantitative analysis highlights the significance of publications related to systems thinking in chemistry education and broader educational contexts. Over the past decade, prominent themes emerged, including sustainability education, design thinking, outcomes assessment, critical systems, climate change, and more. Qualitative insights further emphasize the relevance of understanding systems thinking in chemistry education, influencing pedagogical approaches and research initiatives. This research aims to provide valuable insights for researchers, educators, and practitioners in the chemistry education field. This study offers a roadmap for future developments by delineating prevalent themes and trends. Understanding the challenges and opportunities in systems thinking research within chemistry education can contribute to enhancing teaching methods and shaping research agendas. This analysis provides a comprehensive overview of the evolving landscape of systems thinking in chemistry educatio
Optimization of Nitration of 3-Hydroxypyrazine-2-Carboxamide to 3-Hydroxy-6-Nitropyrazine-2-Carboxamide
Full text linkThis study focuses on optimizing the synthesis of 3-hydroxy-6-nitropyrazine-2-carboxamide, a critical intermediate in producing various pyrazine-based pharmaceuticals. The compound is synthesized through the nitration of 3-hydroxypyrazine-2-carboxamide, employing sulfuric acid (H2SO4) and potassium nitrate (KNO3) as reagents. The research aimed to refine the synthesis process to enhance yield purity for pharmaceutical applications. The optimization entailed adjusting the reagents' composition and solvents, specifically the ratio of substrate to KNO3, the volume of H2SO4 used per gram of substrate, and the temperatures for both the reaction and product precipitation. Optimal results were observed at a substrate-to-KNO3 ratio of 1:2, with 12 mL of H2SO4 per gram of substrate. The reaction temperature was set at 50°, and precipitation occurred effectively at 0°C. This optimized method significantly improved the yield and purity of the compound. The process demonstrated excellent repeatability, with yields ranging from 77% to 80%, a considerable increase from the 48% yield reported in previous studies. The molecular structure of the synthesized compound was confirmed through comprehensive spectroscopic analyses, including 1H NMR, 13C NMR, and High-Resolution Electrospray Ionization Time-of-Flight Mass Spectrometry (HRESI-TOF-MS). This research represents a significant advancement in synthesizing 3-hydroxy-6-nitropyrazine-2-carboxamide, offering a more efficient and reliable method for producing this key pharmaceutical intermediate. The improved synthesis process ensures higher yields and maintains the purity required for pharmaceutical applications, thereby contributing to the efficient development of pyrazine-based drug compounds
Anti-Dandruff Shampoo Formulation from Rambutan Leaf Extract (Nephelium lappaceum L.) as Antifungal Malassezia furfur
Full text linkA shampoo is a product that is used to maintain hair. The most common hair problem is dandruff. A microorganism that causes dandruff is Malassezia furfur. Malassezia furfur is the causative microorganism that infects the skin and scalp into dandruff. This fungus can grow quickly if the head has excess oil glands. Rambutan leaf extract contains secondary metabolites that can inhibit fungal growth. Alkaloids can inhibit the growth of fungi because fungi can grow well at a pH of 3,8 – 5,6. Flavonoids and tannins can cause damage to cell membrane proteins, causing changes in membrane permeability and fungal cell membrane lysis. Saponins can break down fungal cells. A shampoo formulation from Rambutan leaf extract sets it apart from other anti-dandruff shampoos because its herbal composition is safe and increases bioavailability benefits. The method used is laboratory experimental. This research procedure is making rambutan leaf extract using a rotary evaporator, making shampoo by compounding the formulation components, growing test mushrooms on PDA media, making test mushroom suspensions, and conducting the research and data collection. The result showed that shampoo from rambutan leaf extract has an inhibition zone diameter of 0.3 cm to 0.6 cm had a moderate growth inhibition response. The results of the antifungal activity test showed that the rambutan leaf extract shampoo concentration of 10%, 15% and 30% can inhibit the growth of fungi with the best inhibitory concentration at 30% in a strong category
Synthesis of Dibenzalacetone using Sonochemistry and Its Antibacterial Activity Against Escherichia coli
Full text linkThe synthesis of dibenzalacetone, a ketone compound with potential antibacterial properties, especially against Escherichia coli, has typically involved time-consuming methods. This study adopts sonochemistry, an increasingly popular technique recognized for its efficiency and quick yield. The aim is to synthesize dibenzalacetone using the sonochemical method and evaluate its antibacterial efficacy against E. coli. The synthesis process includes a cross-aldol condensation reaction between acetone and benzaldehyde, catalyzed by NaOH, conducted in an ultrasonic bath at 35 °C for 1-5 minutes. The optimal synthesis condition, achieved in 4 minutes, resulted in a 76.56% yield of dibenzalacetone, characterized as a bright yellow solid with a melting point of 111-114°C. Techniques such as FT-IR, GC-MS, 1H-NMR, and 13C-NMR spectrometry were employed for structural characterization. The FTIR analysis revealed various functional groups, including C=O ketone, C=C aromatic, and C-H aromatic. GC-MS data confirmed the molecular weight of dibenzalacetone at m/z 234.1. Furthermore, 1H-NMR and 13C-NMR analyses provided detailed insights into the compound's chemical shifts and structural groups, affirming the successful synthesis of dibenzalacetone. The antibacterial activity of dibenzalacetone against E. coli was tested at concentrations ranging from 5% to 20%. Notably, at a 15% concentration, dibenzalacetone exhibited antibacterial activity comparable to amoxicillin. These findings suggest that dibenzalacetone, efficiently synthesized via sonochemistry, not only achieves a high yield but also has potential as an antibacterial agent against E. coli. This research highlights the efficacy of sonochemistry for the rapid and effective synthesis of compounds with significant medical applications
Analysis Thin Film Polymer Composite of Polymethyl Metacrylate-Reactive Mesogen Diacrylate and its Conductivity Properties
Full text linkThis study aimed to investigate the impact of temperature during the UV curing process on the formation of a thin film polymer composite composed of polymethyl methacrylate-reactive mesogen diacrylate. The thin film polymer composite was successfully synthesized using the UV curing method, and the reactive mesogen diacrylate employed in this study was RM 82. Methyl methacrylate and RM 82 were polymerized through UV curing with photopolymerization additions using Benzoyl Peroxide as the initiator. The photopolymerization process was performed at various temperatures of 125℃, 150℃, and 200℃ for 5 minutes. The thin film photopolymerized at 125℃ and 150℃ exhibited greater transparency than the thin film photopolymerized at 200℃. The FTIR results indicated the breakdown of the vinyl group and the triple bond. The FTIR spectrum displayed successful polymerization, with peak wave numbers of 1147 cm-1 and 1221 cm-1 for PMMA in the presence of C-O-C in the ester and a peak at 1465 cm-1. The SEM results demonstrated that the thin film photopolymerized at 200℃ had become distorted. The XRD results revealed that the thin films of all variations were semi-crystalline. Meanwhile, the conductivity test revealed that the thin film photopolymerized at 125℃ had a conductivity value of 2.095 x 10-12 S, while the photopolymerized thin film at 150℃ had a conductivity of 2.14 x 10-12 S. Hence, the addition of reactive mesogen RM82 by 50% may increase the conductivity value of the thin film, making it a potential material for applications as a thin film polymer composite of PMMA-RM 82