Jurnal Pendidikan Kimia
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The Characterization of Foam Glass Ceramic Based on Industrial Solid Waste
Get PDFAn initial characterization of the raw materials for manufacturing foam glass ceramics has been done using raw materials derived from industrial solid waste. The raw material is in the form of fly ash, a waste of coal combustion in steam power plants, stone crusher industrial waste in the form of basalt rock ash, glass bottle waste, and used aluminum smelting waste. The initial characterization was done by analyzing the chemical composition using the XRF method, identifying the crystalline phase in the raw materials using the XRD method, and morphological analysis using SEM. From the results of raw material analysis, the dominant chemical composition is SiO2, CaO, Fe2O3, and Al2O3 compounds. At the same time, the glass-ceramic foam formed has wollastonite, anorthite, and diopside crystalline phases. The pore structure formed is a closed pore
Phosphorus Analysis in Meat using UV-Vis Spectrophotometry with SnCl2 and Hydrazine Sulfate Reduction
Get PDFThis study aimed to optimize phosphorus analysis in meat using a molybdenum blue reaction involving SnCl2 and hydrazine sulfate as reducing agents to establish the most effective conditions for phosphorus detection. Meat, an essential source of nutrients like phosphorus, plays a vital role in human health, particularly bone and tooth strength. However, overconsumption of phosphorus can lead to health issues such as hyperphosphatemia, making regular monitoring of phosphorus levels in food necessary. The experiment used SnCl2 and hydrazine sulfate under varying acidic conditions to produce a stable blue complex indicative of phosphorus presence. The complex exhibited maximum absorbance in the 689–729 nm wavelength range. Validation of the method showed high linearity with R2 values of 0.9983 and 0.9984 for SnCl2 and hydrazine sulfate, respectively. The molar absorptivity for SnCl2 was 2.093 x 105 L mol-1 cm-1 and 7.92 x 104 L mol-1 cm-1 for hydrazine sulfate. Detection and quantification limits were established, and the %RSD values in each sample ranged from 1.08% to 1.93%, conforming to standard requirements. Upon analysis of meat samples, including duck, chicken, and beef, the phosphorus levels did not meet the Indonesian Nutritionist Association (PERSAGI) standards. This result emphasizes the need for regular phosphorus analysis in meat products to prevent health risks associated with excessive phosphorus intake, such as hyperphosphatemia
Effectiveness of Virtual STEM Laboratories for Enhancing High School Students' Creativity and STEM Literacy
Get PDFThe 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.
Evaluation of Color Models for Quantitative Determination of Food Dyes using Smartphone-Based Digital Image Analysis
Get PDFIn recent years, smartphones for digital image analysis (DIA) have emerged as an affordable, user-friendly, and accessible chemical and food analysis tool, particularly in colorimetry. This study aimed to compare the performance of various color models and demonstrate their usefulness in quantifying food dyes in commercial products using DIA. Images of food dye solutions at 500 Lux were captured using an OPPO F11 smartphone, and the RGB values are mathematically transformed into several color models. The results show that the normalized blue channel was the most robust color model for analyzing different food dyes using DIA. The corresponding limit of detection (LOD) and limit of quantification (LOQ) for nine food dyes studied are following: carmoisine, 3.7 and 11.3 mg/L; sunset yellow, 1.0 and 3.1 mg/L; allura red, 2.0 and 6.0 mg/L; ponceau 4R, 1.3 and 4.0 mg/L; tartrazine, 5.0 and 15.2 mg/L; fast green, 2.0 and 6.1 mg/L; brilliant blue, 1.9 and 5.7 mg/L; quinoline yellow WS, 3.3 and 9.9 mg/L and indigo carmine, 1.2 and 3.8 mg/L. These LOD and LOQ values were comparable to those obtained from UV-Vis spectroscopy measurements: carmoisine, 2.4 and 7.2 mg/L; sunset yellow: 0.9 and 2.6 mg/L; allura red, 1.4 and 4.2 mg/L; ponceau 4R, 1.9 and 5.7 mg/L; tartrazine, 0.9 and 2.7 mg/L; fast green, 1.5 and 4.4 mg/L; brilliant blue, 3.6 and 10.9 mg/L; quinoline yellow WS, 0.3 and 0.9 mg/L and indigo carmine, 4.3 and 13.0 mg/L. The DIA method was successfully applied to determine the concentrations of food dyes in three commercial samples (Samples S1-S3) containing carmoisine, tartrazine, and brilliant blue, respectively. The measured concentrations are 52.7±2.6 mg/L (S1), 105.9±5.4 mg/L (S2) and 7.9±0.5 mg/L (S3), which are in good agreement with UV-Vis spectroscopy results employing standard addition method 58.2±3.0 mg/L (S1), 106.2±1.3 mg/L (S2), 8.3±0.5mg/L (S3). Overall, this color model study demonstrates the utility of DIA method as a reliable and affordable food dye analysis tool that can potentially be used for public health and safety monitoring.
Modification of Polyethylene Glycol and Citric Acid on Palm Fiber Waste Nanofibers on the Adsorption of Violet Crystal Dyes
Get PDFThis 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
The Effects of Instagram Media with Inquiry on Critical Thinking Skills in The Topic Reaction Rates
Get PDFIn the 21st century, social media has emerged as a potential educational tool to enhance learning outcomes and critical thinking skills. To explore this, a study assessed whether Instagram, employed as a learning media for inquiry-based chemistry learning, influences students' critical thinking abilities. The research adopted a quasi-experimental design, utilizing a pretest-posttest nonequivalent control group approach in eleventh-grade science classes across Senior High Schools in Surakarta. The research focused on reaction rates due to its abstract nature and visualization challenges. Random sampling was employed to select 72 students aged 16 to 18, divided into experimental and control groups. The research instrument encompassed 24 questions in pretest and posttest formats, comprising multiple-choice and essay-type questions. N-Gain analysis revealed a noteworthy increase in learning outcomes within the experimental group, registering a value of 0.79, surpassing the control group's value of 0.69. This underscores Instagram's efficacy as a learning tool, outperforming conventional teaching methods. Regarding critical thinking skills, the experimental group displayed the highest competence in indicators such as explanation, self-regulation, evaluation, analysis, and conclusion. The study establishes that when integrated into chemistry education with an inquiry-based model, Instagram positively impacts students' critical thinking skills, specifically about reaction rates. This research contributes novel insights into the application of Instagram for chemistry education and pioneers the examination of critical thinking skills within this context, enriching the domain of chemistry learning
The Synthesis and Physicochemical Characterization of Hydroxyapatite (HAp) from Local Duck Egg Shells
Get PDFHydroxyapatite (HAp) Biocheramics was the main component of remineralisation agent to the hard tissues; it is commonly synthesized from compounds rich with calcium. One of the compounds recommended as a HAp source was eggshells. This study aimed to synthesize the HAp from local duck eggshells containing Calcium 0,8631 ± 0,0015g/g and Phosphor 0,3118 ± 0,0016g/g. The synthesis process of HAp by Base Precipitation methods showed rendement 85,06 ± 1,0135%. The Physicochemical characterization to the HAp showed the Calcium contains 0,4760 ± 0,0027g/g; Phosphor 0,0897 ± 0,0023g/g; Porosity 82,0106 ± 0,4484%; Biodegradability 5,3506 ± 0,0295%; and Swelling ability 5,7678 ± 0,1897%. The results concluded that the local duck egg shells were recommended as HAp sources. Based on characterisation results, the HAp made from it was potentially applied as a remineralization agent
Photocatalytic Degradation of Methylene Blue using Fe2O3-TiO2/Kaolinite under Visible Light Illumination
Get PDFCombining TiO2 and a semiconductor with a smaller band gap, such as Fe2O3, to form a heterojunction composite can increase its photocatalytic activity. In this work, the Fe2O3-TiO2/kaolinite composites were successfully synthesized by ultrasonic-assisted coprecipitation using titanium-tetraisopropoxide (TTIP) dan Fe (NO3)3.9H2O as precursors. Using kaolinite as a matrix also increases the photocatalyst’s surface area. The obtained Fe2O3-TiO2/kaolinite composites were characterized. The crystal phase was characterized using X-Ray Diffraction and resulted in anatase with a crystallite size average of 9,7 nm. Fourier Transform Infrared Spectrophotometer (FTIR) shows the peak at a wavenumber 574-1210 cm−1 ascribed TiO2 and Fe2O3 incorporated into kaolinite. The Optical properties show the absorption edge of Fe2O3-TiO2/kaolinite is redshift toward the visible light region. The result showed that the photocatalytic activity of Fe2O3-TiO2/kaolinite composites with heterostructure was more active than the corresponding Fe2O3 or pure TiO2 in the degradation of methylene blue under visible light illumination, which can degrade 83% for 180 minutes. Fe2O3 and kaolinite cause its synergistic effect as supporting materials. Furthermore, it indicates that the recombination of photo hole and photoelectron charge pair can be minimized. The Fe2O3-TiO2/kaolinite composite is a promising photocatalyst to degrade organic pollutants for wastewater treatment
Development of Guided Inquiry-Based Electronic Modules and Its Effects on Students' Chemical Literacy
Get PDFOne effort to present abstract concepts is the use of learning media. Electronic can provide opportunities for students to learn independently without relying on them. This study aims to determine the feasibility and practicality of guided inquiry-based electronic modules, the difference in students’ chemical literacy abilities in each class, and the effectiveness of learning using guided inquiry-based electronic modules on students’ chemical literacy. This research is a 4D development model consisting of Define, Design, Develop, and Disseminate. This study was conducted at Senior High School 1 Tembilahan Hulu, and the participants were 60 high school students and five chemical teachers, and two validators– data collection in questionnaires and tests. This study used a quasi-experimental method and a post-test-only control group design. The data analysis technique in this research is a descriptive statistical analysis technique of percentages. The results showed that the feasibility of the product assessed by validators showed that the guided inquiry-based electronic module was proper to use in this research. The practicality of the chemistry teacher assessment shows a very good category, the chemical literacy of students who use guided inquiry-based electronic modules in learning is better than students who do not use guided inquiry-based electronic modules in learning. The effectiveness test showed that learning using an electronic module based on guided inquiry scored 0.74 in the medium category
Effectiveness of The Guided Inquiry-Based Flipped Classroom Learning System on Buffer Solution Materials on Students’ Learning Outcomes
Get PDFThis study aims to reveal the effectiveness of the Guided Inquiry-based Flipped Classroom learning System on the buffer solution material on student learning outcomes. This research was conducted with a non-equivalent control group design using a sample of 72 students divided into a control group and an experimental group. The instrument used in this study was a test of students learning outcomes in the form of a written test for student assessment. The test is carried out by giving pretest (Pretest) and posttest (Posttest) questions that have adjusted to the learning objectives. Based on the study's results, the N-Gain Value found in the experimental class was higher than in the control class, with values of 0.82 and 0.70 respectively. From the results of the t-test using the Microsoft Excel application, tcount is 2.47, and the ttable with a significance level of 0.05 is 1.99, so tcount value is greater than ttablevalue. So can be concluded that using the flipped classroom learning system based on guided inquiry on buffer materials effective improves student learning outcome