Jurnal Pendidikan Kimia
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Microplastics in River Water: Raising Science Competencies and Enviromental Awarness in Secondary Education
Get PDFGuided by the PISA 2025 science framework, this study aimed to develop and validate microplastics-based chemistry teaching materials using the Four Steps Teaching Material Development (4S-TMD) model and to evaluate their impact on students’ science competencies and environmental profiles. The research employed a research-and-development (R&D) design based on the 4S-TMD stages of selection, structuring, characterization, and didactic reduction. The participants were 30 upper-secondary students (15 Grade 10 and 15 Grade 11) from Teuku Nyak Arif Fatih Bilingual School. Additional data were obtained from expert validators who reviewed the teaching materials and assessment instruments, and from microplastics identified in water samples from the Krueng Daroy River as the empirical context. The instruments comprised microplastics-based teaching materials and evaluation sheets measuring students’ science competencies and environmental profiles. Expert validation showed that the content validity ratio of the teaching materials and assessment sheets increased to acceptable values (CVR up to 1.00), indicating that all items were essential and aligned with the PISA 2025 framework. Independent-samples t-tests indicated significantly higher science competency and environmental profile scores for Grade 11 than for Grade 10 students (p < 0.05). Overall, the microplastics teaching materials developed using the 4S-TMD model were valid and showed potential effectiveness in supporting students’ ecological awareness and science competencies in line with the PISA 2025 framework
Synthesis, Characterization, and Antibacterial Activity of ZnO-CuO Nanoparticles Embedded in Chitosan and Polyvinyl Alcohol as Supporting Materials
Get PDFThe biosynthesis of bimetallic metal nanoparticles (ZnO–CuO) and their interaction with chitosan and polyvinyl alcohol (PVA) have garnered significant attention in recent years, primarily due to their promising antibacterial applications. This work proposes the bio-fabrication of ZnO–CuO nanoparticles, chitosan–PVA–ZnO–CuO nanoparticle films, and reports their physicochemical and antibacterial potential. Green betel leaves (Piper betle L.) ethanol extract was used to synthesize ZnO–CuO nanoparticles. For as-prepared bimetallic NPs, chitosan (CS), PVA, and bimetallic NPs-based films were fabricated using the casting technique. The films were investigated by Fourier Transform Infrared (FT-IR) spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and the antibacterial activity was evaluated by the agar diffusion method. FT-IR measurements showed the presence of Zn–O and Cu–O functional groups at 396 cm⁻¹ and 418 cm⁻¹ in the nanoparticles, and the films A, B, and C, these bands were observed at 394–395 cm⁻¹ (Zn–O) and 409–416 cm⁻¹ (Cu–O). Crystallite sizes of ZnO, CuO, and ZnO–CuO NPs were 4.845 nm, 54.143 nm, and 5.306 nm, respectively. SEM examination showed that the surface of the films was rough and not homogeneous. Antibacterial experiments revealed the better inhibitory activity of film C than film A and film B. The advantage of the antibacterial property was attributed to the reactive oxygen species (ROS) generated by the ZnO–CuO in collaboration with chitosan. These results indicate that chitosan/PVA film loaded with ZnO–CuO NPs holds great promise as an effective antibacterial packaging material
Total Synthesis and Molecular Docking study of Peptide AWVDY as an Anti-inflamation Agent
Get PDFBioactive peptides are known for their diverse biological functions, many of which support health and well-being. In this study, we synthesized and evaluated the anti-inflammatory potential of the peptide AWVDY, derived from oyster (Crassostrea rivularis). The synthesis was performed using the solid-phase peptide synthesis (SPPS) method, applying the Fmoc strategy on 2-chlorotrityl chloride (2-CTC) resin, and achieved a high yield of 95.83%. The resulting peptide was characterized using Time-of-Flight Mass Spectrometry (TOF-MS), which detected a peak at m/z [M+H⁺] 653.1418, consistent with the expected molecular formula C₃₂H₄₀N₆O₉. This was further validated by analytical HPLC, showing a retention time of 22.596 minutes. Molecular docking studies indicated that AWVDY binds favorably to the pro-inflammatory cytokines TNF-α and Interleukin-6, with binding affinities of -10.360, -10.430, and -8.960 kcal/mol, respectively. These findings suggest that AWVDY may act as a dual-target peptide capable of modulating inflammatory pathways, highlighting its potential as a promising candidate for the development of new anti-inflammatory therapeutics.
A Simple Colorimetric Detection of Bisphenol A in Exposed Drinking Bottles Using a Paper-Based Sensor
Get PDFBisphenol-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
Adsorption of Free Fatty Acids in Crude Palm Oil (Cpo) Using Chicken Egg Shells
Get PDFChicken eggshell waste can be valorized as a calcium oxide (CaO) precursor to provide a low cost and environmentally friendly adsorbent for crude palm oil (CPO) refining. This study examined how calcination temperature (800 and 850 °C), sodium bicarbonate (NaHCO3) activator concentration (3, 4, and 5%), and adsorbent mass (0.1, 0.5, and 0.9 g) affect the adsorption of free fatty acids (FFA) from CPO. Eggshell derived CaO was prepared by calcination and activation, and its phase formation was verified by X ray diffraction (XRD). Adsorbent quality after activation was assessed by iodine adsorption capacity. XRD results indicate that calcination at 850 °C produces highly crystalline CaO, while activation with 4% NaHCO3 yields the highest iodine adsorption capacity (509.83 mg g−1). Batch adsorption tests show that increasing adsorbent mass improves FFA removal, with 0.9 g identified as the optimum dose. Under this condition, FFA content decreases from 12.16% to 3.08%, corresponding to 74.70% adsorption efficiency. The treated oil meets the Indonesian standard SNI 2901 2021, which sets a maximum FFA level of 5%. Overall, chicken eggshell based CaO shows strong potential as a sustainable substitute for commercial adsorbents in CPO purification
Measuring Students' Perceptions of Constructivist Learning Environments Linked to Understanding of Rasch Modeling-Based Chemical Concepts
Get PDFThis study aims to evaluate the suitability of data obtained from the Constructivist Learning Environment Survey instrument and a multiple-choice chemistry understanding test, as well as to examine the relationship between students' perceptions of the constructivist learning environment and their understanding of chemistry concepts. A non-experimental, quantitative descriptive approach was employed, involving 519 12th-grade science students from five high schools in Gorontalo Province during the even semester of the 2024/2025 academic year. Data analysis was conducted using the Rasch model via Winsteps 3.73 software to assess instrument quality, and SPSS software to test data normality and analyze correlations. The results indicated that both instruments were valid and reliable, with person reliability of 0.81, item reliability of 0.99, and Cronbach’s Alpha exceeding 0.80—classified as excellent. A Pearson correlation analysis revealed that the calculated r value exceeded the critical value (rcount= 0.135 > rtable= 0.087), indicating a statistically significant, albeit weak, positive relationship between students’ perceptions and their chemistry understanding. The hypothesis testing results showed that the null hypothesis (H₀) was rejected and the alternative hypothesis (H₁) was accepted, confirming the existence of a relationship between students’ perceptions of constructivist learning environments and their understanding of chemistry concepts
The Effect of Additional Pineapple (Ananas comosus L. Merr.) Peel Pectin on the Characteristics of Coal Fly Ash Geopolymer
Get PDFFly ash-based geopolymer concrete is a candidate for a more sustainable material than concrete, with lower embodied energy and high early-age compressive strength properties. This work has focused on studying the use of pineapple peel pectin as an additive to enhance the compressive and split tensile strength achievable in a geopolymerization process. The compressive strength and split tensile strength were tested by physical testing, and the mineral phases, functional groups, and microstructure were analyzed by chemical analysis (XRD, FTIR, and SEM-EDX). Geopolymers containing 0%, 1%, and 2.5% pectin were fabricated. The surprising optimum was the 1% variation, which reached compressive strength of 22.13 MPa and split tensile strength of 3.18 MPa when making medium-quality concrete. XRD results of the best performing 1% sample exhibited mainly an amorphous phase, where amorphization is evident at 20–40°2θ due to broad signal peaks, a sign of successful geolypolimerization. Geopolymerization was also confirmed by FTIR analysis through the presence of Si–O–Si and Si–O–Al asymmetric stretching vibration peaks at 1018.41 cm−1, illustrating the inclusion of pectin observed by the C–H stretches in the range 2900–2300 cm−1 and the carboxyl group stretch at 1635.64 cm−1. The microstructure of the quality concrete 1% formulation was characterized by a tight, perfect structure as seen through SEM images, while the 0% and 2.5% mixes had more porous and cracked structures. These results suggest that 1% pectin incorporation improves geopolymer mechanical performance without adversely affecting structure, merits for further mechanical properties, and long-term stability
The Effect of Coagulant Particle Size, Coagulant and Flocculant Dose on Remazol Yellow Dye Removal Effectiveness
Get PDFTextile 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
Improving electrochemical sensor performance for detection of 3-MCPD based on moleculary imprinted polymer-Nd2O3-Graphene
Get PDFPalm oil is a key raw material in the food industry with significant strategic value. However, during the refining and deodorization processes, it can produce 3-monochloropropane-1,2-diol (3-MCPD), a compound known to be carcinogenic. Therefore, a detection method with high selectivity and sensitivity is essential. In this study, an electrochemical sensor based on molecularly imprinted polymers (MIPs) was developed and integrated with neodymium oxide–graphene (Nd₂O₃/Gr) nanocomposites. Characterization techniques such as Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Scanning Electron Microscopy (SEM) confirmed the successful fabrication and favorable morphology of the MIPs–Nd₂O₃/Gr composites. The sensor’s performance was evaluated using Differential Pulse Voltammetry (DPV) and cyclic voltammetry methods. The incorporation of Nd₂O₃ and graphene significantly enhanced the sensor’s ability to detect 3-MCPD, demonstrating excellent linearity (R² = 0.9932) across a wide concentration range. Moreover, pH was found to play a critical role in low-concentration detection, influencing the sensor’s response. These findings indicate that the MIPs–Nd₂O₃/Gr sensor offers high selectivity and sensitivity, making it a promising candidate for monitoring 3-MCPD levels in food products and enhancing food safety control
Analysis of Nitrogen Dioxide as Air Pollutant in Office, Industrial, Residential, and Transportation Areas in Lampung Province
Get PDFMonitoring air quality can be undertaken in industrial areas, residential areas, offices, and transportation hubs to maintain public health and sustainable environmental practices in Lampung Province. The province suffers unique challenges, including a mix of emission sources (industrial activities, vehicular traffic, and domestic operations). Industrial zones have high levels of nitrogen dioxide (NO₂) due to manufacturing, transportation hubs have increased NO₂ due to vehicle emissions, and residential regions provide background pollution from household pollutants. Such complex spires must be addressed to achieve acceptable levels of air quality. This research aimed to analyze NO₂ concentrations on four stations in 15 districts of Lampung Province using the Air Pollution Index Values (ISP - Indeks Standar Pencemaran Udara). To assess the coupling relationship between the NO₂ concentrations and seasonal variations over 2 years, Statistical Analysis of Variance (ANOVA) was analyzed. The results showed that NO₂ levels had higher concentrations along transportation routes but were still safe and non-hazardous according to Regulation No. 41 of 1999. The average NO₂ concentrations in the districts were also below the regulatory threshold, reflecting good air quality management in the region. The ANOVA analysis results with the Anderson-Darling test show p-values of 0.322 (rainy season) and 0.258 (dry season), both above the 0.05 significance level. These results imply that the data follows a normal distribution and that there are no significant differences between the districts' average NO₂ concentrations by season. The study highlights the necessity of continued surveillance and targeted interventions to address air quality issues in Lampung Province