JKPK (Jurnal Kimia dan Pendidikan Kimia)
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Synthesis and Photocatalytic Activity Test of Bi-TiO2 toward Humic Acid Degradation under Visible Light Irradiation
Full text linkHumic acid (HA) in water can harm humans if it is regularly used or consumed. HA causes problems in the water, such as color, taste, and the formation of metal complexes. Therefore, it is necessary to degrade HA to address these problems. In this study, HA degradation was carried out using bismuth-doped TiO2 (Bi-TiO2) as a photocatalyst. The effect of Bi-TiO2 synthesized at various Bi concentrations and calcination temperatures on HA degradation was investigated and compared to pristine TiO2. Bi-TiO2 was synthesized via the sol-gel method and characterized using X-Ray Diffraction (XRD), Diffuse Reflectance Spectroscopy UV-Visible (DRS UV-Vis), and Fourrier Transform-Infra Red (FT-IR) Spectroscopy. The XRD analysis showed that the optimum calcination temperature was 500oC, with the highest crystallinity index (62.04%) and smallest crystallite size (11.95 nm). The DRS UV-Vis analysis showed that Bi-TiO2 1.5% led to the lowest band gap of 1.59 eV (λ = 782.33 nm), indicating that the photocatalyst was active under visible light irradiation. The FT-IR analysis showed an adsorption peak from the Bi-O bond at 802.39 cm-1, which caused a shift in the Ti-O-Ti adsorption peak. The photodegradation test was conducted using a 30 mL volume of HA solution 50 ppm and a 50 mg mass of catalyst. The results showed that Bi-TiO2 1.5% exhibited the highest efficiency in degrading HA, achieving 68.54% under visible light irradiation for 180 minutes. These results suggest the potential of Bi-TiO2 as an alternative method for treating HA in peat water using visible light irradiation.Â
Meta-Analysis of the Relationship Between Learning Media in Hybrid Learning and Critical Thinking and Creativity in Science
Full text linkThe 21st-century learning paradigm is characterized by integrating technology into learning facilitating flexible and accessible learning experiences. One such model is hybrid learning, enabling education to transcend time and place with technological aid. Amidst this backdrop, it is crucial that hybrid learning provides education and fosters essential skills of the 21st century, including critical thinking and creativity. This research endeavors to establish a connection between the learning media employed in hybrid learning and the enhancement of critical thinking and creativity skills within the Science and STEM education context. The study also investigates the utilization of laboratory-based applications in chemistry instruction. Employing a meta-analysis approach with descriptive analysis methods, the researchers scrutinized 50 articles cataloged in Scopus, focusing on publications from the past decade. The meta-analysis findings unveil a significant effect size of 0.87, indicating a substantial correlation between the use of learning media and the cultivation of critical thinking skills. Moreover, the association between hybrid learning's learning media and creativity skills is evidenced by an effect size of 0.94. Consequently, it can be inferred that a substantial correlation exists between learning media in hybrid learning and the development of creativity and critical thinking abilities. The impact of laboratory-based applications and software in science education, particularly chemistry, is greatly influenced by pedagogical aspects and instructional strategies
The Impact of Online Learning in Chemistry on Student Interest, Motivation and Learning Outcomes
Full text linkUnstable network connections, including chemistry learning, often hamper the implementation of online learning during a pandemic. The study aims to investigate the effects of online learning on chemistry students' interest, motivation, learning outcomes, and the challenges faced during the implementation. The method used is a quantitative method with descriptive research. Using the proportional stratified random technique, this study determined 72 high school students (33 boys and 39 girls). In online learning, data is collected using student and teacher response questionnaires. In addition, student reactions to teacher efforts in online learning. Then, interviews with teachers and students were conducted. Questionnaires and interview guidelines were used as research instruments. Data analysis techniques were used to determine respondents' level of achievement using the percentage formula (TCR). The study's findings revealed that the average response value for learning interest was 76%, motivation was 79%, and learning outcomes were 75%. Students achieve a minimum completeness criterion score of 81% for eleventh-grade students in the science program and 89% based on the results of the chemistry test scores in online learning. The study concludes that while online learning positively impacts students' interest, motivation, and learning outcomes, there are significant barriers identified by respondents, such as a less stable internet network, for further research is expected to be able to update the data taken by researchers
Evaluation of Color Models for Quantitative Determination of Food Dyes using Smartphone-Based Digital Image Analysis
Full text linkIn 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.Â
Integration Method of Religious Character Values in Chemistry Learning
Full text linkScience and religion are closely related because they come from one source, namely God Almighty. Therefore, the concept of the integration of science and religion must be implemented in the form of integrating religious characters in the science learning process. This study aims to identify and inventory the learning methods used to integrate religious character values in chemistry learning. This research is conducted by reviewing the literature, both in books, journal articles and popular scientific writings, about methods of integrating religious character values in chemistry learning. The main data sources are from journal articles that discuss the integration of religious characters in chemistry learning. The journal articles that became the main data source were ten articles obtained from the Google Scholar website using the keyword "integration of religious characters in chemistry learning". The research data were analyzed descriptively and qualitatively. A critical study was also carried out on the literature to obtain the correct conclusion. According to the teacher's creativity, the study results concluded that religious character values can be integrated in chemistry learning in various ways/methods. However, in their article, the researchers did not clearly and unequivocally mention the name of the learning method used to integrate religious characters in chemistry learning. Based on this conclusion, it is recommended that other research is needed to develop a learning model that integrates religious character values in chemistry learning.Â
Removal of Pb (II) Ions from Aqueous Solution using Mahogany (Swietenia macrophylla King) Sawdust as Lowcost Adsorbent
Full text linkThis research aimed to investigate the removal efficiency of Pb (II) ions using mahogany sawdust as an adsorbent. Several experiments were carried out to get the results. The batch adsorption method was used. The parameters studied were pH and contact time. The pH variation used was 2, 3, 4, 5, and 6. Contact time variation used was 5, 10, 15, 30, 60, 90, 120 and 150 minutes. To evaluate the isotherm model of the adsorption, the metal concentration variation used was 10, 25, 50, 100, 150, and 200 mg/L. To evaluate kinetics adsorption, pseudo-first-order and pseudo-second-order models were used. The characterization of the adsorbent was carried out by determining pHPZC, FTIR analysis, and SEM analysis. The adsorbent had a pHPZC of 5.63. FTIR spectra showed that the adsorbent had -OH functional group that could bind to Pb (II) ions. SEM analysis showed that the surface morphology of the adsorbent supported the removal of Pb (II) ions. In this work, pH 6 provided the highest removal of Pb (II) ions, while the contact time which provided the highest removal of Pb (II) ions was 30 minutes. The removal of Pb (II) ions followed the Freundlich adsorption isotherm, while the adsorption kinetics followed pseudo-second-order model.Â
Study of BOD, COD and TSS Removal in Batik Industry Wastewater using Electrocoagulation Method
Full text linkCentral Java, especially Pekalongan, is one of the largest batik centres with a high amount of batik waste and has the potential to pollute the environment. Wastewater treatment using the electrocoagulation method as an alternative to environmental pollution prevention in Pekalongan Regency. This study determined the effect of stress and resistance time on decreasing COD, BOD and TSS levels in batik wastewater. The analysis performed on the samples included BOD (Biological Oxygen Demand), COD (Chemical Oxygen Demand), TSS (total suspended solids), and pH. Voltage variations of 12, 24, and 30 volts and holding times of 90, 120, 150, and 180 minutes were applied. A pair of aluminium metals (Al-Al) was used with a thickness of 0.1 cm, an area of 12x14 cm, and a volume of 2500 ml. The results showed that the voltage and contact time decreased the amount of COD, BOD and TSS. In addition, the results showed that the electrocoagulation method at a voltage of 30 volts and a contact time of 180 minutes could reduce COD levels by 75.78%, TSS levels by 93.9%, and BOD levels by 83.75%
Adsorption Of Metal Lead (Pb) In Batik Industrial Wastewater Using Cellulose-Based Adsorbent: Literature Review
No full textThis literature review aims to determine the characteristics of the batik industrial wastewater, the type of adsorbent activation method most widely used to adsorb lead (Pb) in the batik industry wastewater, and the correlation between the source of cellulose and parameters on the adsorption ability of lead metal (Pb) with variations in adsorbent mass, pH and contact time in batik industrial wastewater. This literature review was carried out in 7 steps: exploring topics, searching, storing, and organizing information, selecting the required information, expanding the search, analyzing, and evaluating. Information and present the results. This literature review shows that Batik industrial wastewater contains BOD, COD, TSS, and heavy metals. The literature review obtained that the BOD and COD values came from the batik industrial wastewater of Jetis Sidoharjo with a value of 1775.5 mg/L and 16654.80 mg/L, the largest TSS value came from the batik industrial wastewater Gedhog with a value of 449 mg/L. The largest metal content of lead came from the batik industrial wastewater of Wiradesa, with a value of 7.654 mg/L. The most widely used activation method for treating adsorbents is the chemical activation method with strong acids such as HCl, HNO3, and H2SO4. There is a correlation between the source of cellulose and parameters in the adsorption of lead metal in batik industry wastewater. Different sources of cellulose and parameters resulted in different adsorption capacities. Based on the literature review, the highest percentage of cellulose was found in sawn teak (60%), corn cobs (41%), rice straw (37.71%), rice husks (34%), and kapok seeds (21.83%). Maximum adsorption lies in the adsorbent with a mass of 0.1 – 1g, pH 5-7, and 30-45 minutes contact time.Â
Conventional and Microwave-Assisted Synthesis of 4’-Bromochalchone Utilizing 4-Bromoacetophenone and Benzaldehyde as Starting Material in Alkaline Condition
Full text linkThis study focuses on synthesizing 4’-bromochalcone through conventional and irradiation microwave methods to determine each method's time efficiency and yield. 4-Bromoacetophenone was treated with benzaldehyde in the presence of a base. Conventionally, the reaction mixture was stirred at room temperature. While in the microwave irradiation method, the reaction mixture was irradiated at a power of 140 watts. The compound was identified, including the melting point and physicochemical properties. The structure of the compound was confirmed by infrared, 1H- and 13C-nuclear magnetic resonance, and mass spectroscopy spectral data. The results showed that 4’-bromochalcone had been successfully synthesized using conventional and microwave irradiation methods in a good yield (94.61%±0.6793 and 89.39%±0.6418, consecutively). The structure assignment based on infrared, 1H- and 13C-nuclear magnetic resonance, and mass spectroscopy spectral data revealed that the synthesized product was 4’-bromochalcone. Synthesis of 4’-bromochalchone using microwave irradiation could be done in a shorter time than the conventional method.Â
Molecular Docking of Shallot (Allium ascalonicum) Active Compounds to Lanosterol Enzym 14-Alpha Demethylase and Squalene Monooxygenase for Antifungi Potential Activity
Full text linkShallots (Allium ascalonicum) are one of the important horticultural export commodities in Indonesia, but the productivity of shallots has decreased due to the attack of pathogenic fungi. This study was aimed to determine the potential of active shallot compounds as ligands for inhibiting the activity of the enzyme lanosterol 14-alpha demethylase (ID: 4LXJ) and squalene monooxygenase (ID: 6C6R) enzymes which play an important role in the biosynthesis of ergosterol or fungal cell membranes. The molecular docking used the Autodock Vina (PyRx) program, an analysis of molecule interaction used PyMol, and Discovery Studio 2019 to analyze the types of bonds between molecules. Thirty-nine ligands from shallot compounds are docked to the anti-fungal target protein. The results showed ascalonicoside A1, ascalonicoside A2, ascalonicoside B, quercetin, isorhamnetin, quercetin di glucoside, quercetin tri glucoside, ethyl palmitate and benzyl salicylate have the potential to be anti-fungal to the enzyme lanosterol 14-alpha demethylase and squalene monooxygenase enzyme that responds to the synthesis of fungi cell wall. These ligand compounds bind to the target protein's amino acid residues with hydrogen and hydrophobic bonds. This research showed that shallot was the potential to be replicated as an anti-fungus for many purposes