Jurnal Pendidikan Kimia
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Study on Varied Bagasse Fiber and Epoxy Resin Compositions with Rice Bran Filler to Biocomposite Characteristics
Get PDFNatural fibers, with environmental, economic, and cost advantages, are highly sought-after for biocomposite materials. In the present study, the biocomposite samples of epoxy resin (as a matrix), bagasse fiber (as reinforcement), and rice bran (as a filler) were prepared. Tensile strength, strain, and Young's modulus will be the parameters concerning which the quality of the biocomposite can be tested. On the one hand, bagasse fiber is to be a strength enhancer in the resulting biocomposite. On the other hand, rice bran may increase the biocomposite's density. The process research comprises fiber yarn from milled bagasse, alkalized fiber with KMnO4, specimen printing process, and analysis. All the fibers were treated by soaking them in 3 grams of KMnO4 solution for 30 and 45 minutes. The fiber is drained in an oven at 50 °C for ±1.5 hours. The printed fiber onto a specimen mold was printed with a mixture of epoxy resin and rice bran (1:1 w/w) and left for one day. Variation in the fiber mass was at 3, 4, and 5 grams. The sizes of the specimens were similar to the size of the mold according to ASTM D-638 type IV. Then, the fibers were removed from the mold and tested for tensile strength, strain, and Young's modulus. The results show that the greater the fiber mass, the greater the tensile strength value. These findings indicate that the tensile strength was optimized after soaking for 45 minutes with 5-gram fiber weight, which resulted in the tensile strength of 26.32±0.25 MPa, strain of 9.65±0.14%, Young's Modulus of 3.29±0.05 MPa, and water absorption of 41.99%
Chitosan Crosslinking from Clam Shells (Cerithidea obtusa) with Tripolyphosphate for Cadmium (II) Adsorption
Get PDFThe study investigates chitosan crosslinking from clam shells (Cerithidea obtusa) with tripolyphosphate for cadmium (II) adsorption. Chitosan was prepared by deacetylating chitin using 60% NaOH and heating at 140°C for 60 minutes. Chitin was isolated from Cerithidea obtusa shells, an abundant waste in East Kalimantan. Crosslinking of chitosan with tripolyphosphate was synthesized via gelation methods, dissolving 5 g of chitosan in acetic acid and adding 0.1% tripolyphosphate as a crosslinker. The chitosan-tripolyphosphate characterization was conducted using FTIR, XRD, and SEM. FTIR spectra revealed an N-H vibration at 1635 cm−1, NH3+ deformation at 1534 cm−1, C-O stretching at 1072 cm−1, and P-O vibration at 1026.91 cm−1, indicating the presence of tripolyphosphate in chitosan. The XRD pattern showed broad peaks at 19.85° and 23.50°, characteristic of amorphous chitosan-tripolyphosphate. SEM images depicted a flat sheet without pores and a tight surface. Cadmium (II) adsorption on chitosan-tripolyphosphate at an optimum pH of 4 followed a pseudo-second-order kinetic model. It adhered to the Langmuir isotherm model, with a maximum adsorption capacity of 27.8 mg/g. The results demonstrate that chitosan crosslinked with tripolyphosphate effectively for cadmium (II) adsorption
In Silico Analysis of Antibacterial Activity of Fatty Acids in Swietenia humilis Zucc. Seed Extract Against Staphylococcus aureus sortase A enzyme
Get PDFThis study utilised molecular docking to predict the binding affinity of various fatty acids (FAs) found in Swietenia humilis to the sortase A (SrtA) protein target from Staphylococcus aureus. Binding energies, measured in kcal/mol, indicated the strength and stability of ligand-protein interactions, with lower values signifying stronger binding. The binding affinities of eight FAs as the active constituents in n-hexane extract of S. humilis and the positive control, gentamicin, were compared to assess their theoretical antibacterial activity. Palmitoleic acid exhibited the strongest binding affinity (-5.6 kcal/mol) among the FAs, suggesting the highest potential antibacterial activity, followed by linoleic, palmitic, linolenic, arachidic, tricosanoic, stearic, and oleic acids in decreasing order of affinity. Despite having weaker binding energies than gentamicin, a common gram-positive inhibitor from aminoglycoside derivative, FAs showed multiple hydrogen bonds and van der Waals interactions with key residues like ARG197, VAL168, VAL166, and ILE182, contributing to their binding stability. Palmitoleic acid formed multiple hydrogen bonds (ARG197 and GLY119) and significant van der Waals interactions, highlighting its strong theoretical binding. Stearic and oleic acids, although having higher binding energies, also formed critical hydrogen bonds, suggesting moderate potential activity. Gentamicin's single hydrogen bond suggests a highly specific binding site, which may result in high antibacterial activity despite fewer interaction points. The study indicated that FAs like palmitoleic and oleic acid show substantial potential as supplementary antibacterial agents, especially in the context of combating antibiotic resistance. This finding can pave a path for drug design and development to address the S. aureus's resistance
The conversion of bioethanol from pineapple waste to biobutanol derivatives over NiMoO4/rGo catalyst
Get PDFIncreasing demand for sustainable energy solutions has spurred the development of catalytic materials to convert renewable resources into value-added hydrocarbons. In this work, we investigate the feasibility of NiMoO4/rGo as an effective catalyst for converting bioethanol into renewable hydrocarbons. The surface and microstructural characteristics of rGo showed major findings like BET surface area of 26.9 m2/g with mesoporous, sufficient surface functional groups, crystalline size of 49.12 nm, and a progressive metal oxide uniform distribution on the rGo surface. The crystal morphology showed an irregular texture, suggesting strong catalytic activity. The optimal conversion was thus observed at 80°C, 90°C, and 100°C. Superior catalytic activity at 80°C afforded the resultant three major hydrocarbon-based products: 2-butanol (1.32%), isobutyl alcohol (0.89%), and 3-methyl-1-butanol (0.89%). Such products have important potential as renewable substitutes in diverse industries. Our study highlights the potential of using NiMoO4/rGo as an effective catalyst for bioethanol conversion due to its mesoporous structure, oxygen groups, and high dispersion of active metal oxide. Overall, this study renders NiMoO4/rGo a viable catalyst candidate in sustainable chemical processes and thus accelerates the application of bioethanol to manufacture precious hydrocarbon derivatives. These findings underscore the key to optimizing temperature conditions to maximize product yield and enhance the economic viability of renewable energy resources
Impacts of The POGIL Learning Model Combined With a SETS Approach on Chemical Literacy and Science Process Skills in The Context of Buffer Solutions
Get PDFThis study evaluates the impact of the Process Oriented Guided Inquiry Learning (POGIL) model combined with a Science-Technology-Society-Environment (SETS) approach on chemical literacy and science process skills within buffer solutions. Employing a quasi-experimental design with a nonequivalent control group, the research involved 71 students divided into experimental and control groups. Cluster random sampling was utilized for participant selection, and Multivariate Analysis of Variance (MANOVA) was applied to test the hypotheses. The findings reveal a significant effect of the POGIL learning model integrated with a SETS approach on simultaneously enhancing students' chemical literacy and science process skills. This outcome is substantiated by the MANOVA results, which indicate a significance level of 0.000, falling below the threshold of 0.05, thereby leading to the rejection of the null hypothesis (H0). Notably, the experimental group demonstrated significant improvements compared to the control group. Chemical literacy in the experimental group reached 79.90%, significantly higher than the 62.53% observed in the control group. Additionally, the N-gain scores for the experimental and control groups were 0.70 and 0.32, respectively, categorized as high and medium. Furthermore, the percentages of science process skills were 91.61% in the experimental group and 82.37% in the control group, both in the very good category. These results underscore the effectiveness of combining POGIL with a SETS approach in elevating chemical literacy and science process skills, suggesting this method is a potent educational tool in chemical education
Green Synthesis and Characterization of 4'-Hydroxy-4-Nitro Chalcone using Grinding Techniques
Get PDFThe challenge of developing environmentally friendly synthesis methods for biologically active compounds remains a significant focus in green chemistry. This study aimed to synthesize 4'-hydroxy-4-nitro chalcone from 4-hydroxyacetophenone and 4-nitrobenzaldehyde using a grinding technique and then characterize the synthesized compounds. The 4'-hydroxy-4-nitro chalcone was synthesized via the Claisen-Schmidt grinding method for 45 minutes at room temperature. The grinding results were extracted with chloroform. The formed crystals were tested for purity by thin-layer chromatography (TLC), and further purification was carried out by recrystallization. The synthesized chalcone was characterized using FTIR, 1H-NMR, and 13C-NMR spectroscopy. The chalcone was also tested for antibacterial activity using the disc diffusion method against Staphylococcus aureus and Escherichia coli. The results showed that 4'-hydroxy-4-nitro chalcone could be successfully synthesized from 4-hydroxyacetophenone and 4-nitrobenzaldehyde using the grinding technique, yielding orangish-white crystals with a 70.63% yield and a melting point of 173°C. Purity was confirmed by TLC, and structural characterization was achieved through FTIR, 1H-NMR and 13C-NMR spectroscopy. Antibacterial testing revealed that the synthesized chalcone produced a clear zone diameter of 9.27 mm against S. aureus and 27.88 mm against E. coli. These results indicate that the compound has relatively strong antibacterial activity against E. coli and relatively weak activity against S. aureus. This study demonstrates the effectiveness of the green synthesis method and provides valuable insights into the antibacterial properties of 4'-hydroxy-4-nitro chalcon
Particle Size Modification of Breadfruit Starch (Artocarpus altilis) into Nanoparticle Size Through Top Down Technique using Acid Hydrolysis
Get PDFBreadfruit (Artocarpus altilis) is a significant starch source, comprising up to 70.25% of its composition, and holds extensive industrial applications. However, the physicochemical properties of natural starch pose several challenges to its direct use as an industrial raw material. These challenges include high viscosity, substantial swelling power, low solubility, significant retrogradation, limited digestibility, and poor thermal stability. To address these issues, modification of the starch particle size to the nanometer scale is proposed, which is anticipated to enhance both functional and physicochemical properties. This study employs a top-down approach through 2.2 N HCl acid hydrolysis at 38°C for 24 hours. This method offers simplicity, efficiency for scale-up in industrial applications, and relatively higher stability than alternative approaches. Particle size analysis using Particle Size Analysis (PSA) revealed an average particle size of 215 nm. Fourier Transform Infrared (FT-IR) spectroscopy showed characteristic bands similar to natural starch, with slight variations in peak intensity, indicating successful acid hydrolysis and structural disruption of the molecular order. Morphological analysis revealed minimal changes in the granules' surface structure, with clumping observed due to acid hydrolysis. The resultant starch nanoparticles exhibited decreased viscosity and swelling while solubility was enhanced. Therefore, nanoparticle starch holds promising applications in food and non-food industries
Biosynthesis and Characterization of ZnO Nanoparticles with Beet Extract (Beta vulgaris L.) as Latent Fingerprint Identification
Get PDFThe uniqueness and permanence of patterns make fingerprints one of the most significant forensic tools for individual identification. The issue is that conventional fingerprint powders, frequently used today, pose serious health and environmental risks due to their use of toxic chemicals. This novel study utilizes sustainable and innovative techniques to investigate the effectiveness of beetroot fruit extract for latent fingerprint visualization. Zinc oxide (ZnO) nanopowders were synthesized using a green synthesis method, having beet fruit extract as an aqueous solvent. For applications on porous and non-porous surfaces, the fabricated ZnO was characterized using Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) analysis up to October 2023. Thirty samples were provided to perform latent fingerprint analysis. The results show that ZnO nanopowders synthesized using beet fruit extract could provide safe, non-destructive, and efficient visualization of the latent fingerprints. Of the six fingerprint patterns examined, the most common was the Plain Whorls pattern, which represented 47% of prints identified. These results highlight beet fruit extract's natural potential and efficacy as a contrast agent for imaging latent fingerprints. This clean approach can provide a novel alternative for forensic biology, characterized by low toxicity, sustainability, and high efficacy, which can lead to a safe forensic practice
Determination of Temperature, pH, Salinity, Dissolved Oxygen, TDS, TSS, and Nitrite Content in 42-Day-Old Shrimp Farming Ponds
Get PDFThis study was to determine water quality in shrimps farming through parameters temperature, pH, salinity, Dissolved Oxygen (DO), Total Suspended Solid (TSS), Total Dissolve Solid (TDS) [1,8,2]. Databases for all shrimp farms were created Water quality heavily impacts shrimp health, growth, and disease susceptibility. TDS and TSS were determined by gravimetric analysis, and nitrite was determined by UV-Vis spectrophotometry at 545 nm. Inlets, ponds and outlets were sampled to compare quality differences. The highest temperature (27.9°C) and DO (7.23 mg/L) values were found in the pond, while the inlet had the highest pH (7.54) and salinity (19 psu). TSS (0.055 mg/L) and TDS (20.460 mg/L) were highest in inlet too. The levels of nitrite at the inlet, pond and outlet were an average of 0.0073, 0.0249 and 0.0501 mg/L respectively. Nitrite in shrimp feed was 0.0535±0.0029 mg/L. The analytical parameters for the detection of quercetin were found to have excellent linearity with R² = 0.9959, precision with CV Horwitz ≤10.14%, and accuracy with 90.33–95.04%. The results showed that temperature, pH, salinity, DO, TSS, and TDS levels are suitable and that the acceptable nitrite concentration of the samples fits into the criteria for sustainable shrimp farmin
Utilization of Xylanase Enzymes Derived from Cassava in the Eco-Friendly Biobleaching of Pulp
Get PDFThe demand for paper has been increasing over time, leading to the pulp and paper industry becoming one of the largest contributors to global carbon emissions due to the chlorine-based bleaching process, particularly in Indonesia. An alternative to minimize chlorine usage involves using xylanase enzymes as part of the bleaching sequence. Xylanase can be produced from agricultural waste, including cassava residue, which contains a significant concentration of xylanase, approximately 21.3%. However, it still needs to be utilized in Indonesia. Therefore, this study aims to explore the production of xylanase enzymes from cassava residue and assess its effectiveness in the biobleaching process of pulp. The research methodology includes the production phase of xylanase enzymes by Aspergillus niger, chelating, bleaching sequence, bleaching, kappa number, and chemical saving assay. In the production of xylanase, the study determined that xylanase exhibits optimal activity under specific conditions, notably at a pH of 6 and a temperature of 60°C. Under these parameters, the enzymatic activity reached a level of 0.4986 U/mg protein. During the bleaching sequence, xylanase was used with doses of 0.3, 0.5, 0.7, 0.8, and 1 L/T pulp at 40, 45, 50, 55, 60, 65, and 70°C for 60 minutes. Following this process, bleaching was conducted at 65°C for 70 minutes, extraction at 80°C for 90 minutes, and a second bleaching phase. Subsequently, a kappa number test was performed, revealing the best kappa value at 60°C with a xylanase dose of 0.5 L/T pulp, reducing from an initial kappa number of 9 to 4.04. Additionally, under these conditions and dosage, xylanase enzymes could save approximately 23.67% in chlorine usag