JKPK (Jurnal Kimia dan Pendidikan Kimia)
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Measurement of Ambient Ozone Concentration using Passive Sampler
Full text linkMeasurement of ozone concentration in ambient air was carried out using the passive sampling method in Cipedes, Bandung, from 2012 – 2020. Sample analysis was done using ICS 1500 Dionex ion chromatography. The results showed a fluctuating concentration from 2012 -2020 with the highest average value in 2015 of 29.94 g/m³. The monthly pattern shows the highest ozone concentration in September and the lowest in December; this condition was related to the intensity of rainfall that can clean ozone in the atmosphere. The seasonal pattern showed in the dry season ozone concentration is relatively higher than in the rainy season. A comparison of passive and continuous sampling was made to see the performance of the passive sampler showing a similar pattern with a correlation coefficient of r = 0.48. This difference in value was related to the absorption of ozone gas in the passive sampler absorbing filter and the meteorological factors
Formulation and Antioxidant Activity of Peel Off Gel Mask from Paederia Foetida Extract
Full text linkThe peel-Off gel mask is one of the unique characteristic forms of the mask that will form an elastic transparent film layer. It can be removed without rinsing after drying and leaving no residue. The manufacture of masks using natural material is better than synthetic materials as it can cause side effects and damage the natural shape of the skin. One of the natural materials that can be used as a natural ingredient mask is the Paederia Foetida leaf. Paederia Foetida leaf contains antioxidants beneficial as the antidote to free radicals. One of the antioxidants contained in the Paederia Foetida is a flavonoid compound. The research aimed to determine the best concentration of Paederia Foetida leaf extract in the formulation of pell off gel masks with high antioxidant activity. The research method consists of preparing the sample by macerating Paederia Foetida leaf powder using ethanol. Making peel-off gel mask with variation in concentration from Paederia Foetida leaf extract of 0%, 15%, 20%, 25%, 30%. mask quality test include organoleptic test, pH, Homogeneity, stability, Drying, and dispersibility—antioxidant activity test by using DPPH with expressed as IC50 concentration. The Result of the research is that Paederia Foetida leaf extract can be formulated into a peel-off gel mask stock. The formulation of a peel-off gel mask with a concentration of Paederia Foetida leaf extract of 20% was chosen because it meets the criteria of peel-off gel mask of Indonesian Nasional Standard (It is homogeneous and stable, pH 6, spreadability 6,5 cm, and dry time 28 minutes with an IC50 of 167.74 which is a weak antioxidant)
Biosynthesis of ZnO Nanoparticles using Lime Leaf Extract (Citrus auraantifolia) for Identification of Latent Fingerprints
Full text linkFingerprints are an identification tool in forensic science because of their unique properties. Unfortunately, some of the chemicals used in fingerprint powders are toxic and pose a potential health hazard. This study was conducted to analyze the ability of ZnO nanoparticles to identify latent fingerprints. ZnO nanopowder was synthesized with lime leaf extract using the green synthesis method with double-distilled water solvent and characterized by FT-IR at a wavenumber of 4000-400 cm-1 and SEM-EDX analysis to provide information about the morphology and to detect the elemental composition nanoparticles. The average particle diameter through SEM was around 173.4 nm and formed a spherical with a rough surface with beige color. Identification of latent fingerprints using the powder dusting method on various porous surfaces (craft paper and greaseproof paper) and non-porous surfaces (glass preparations, aluminium foil, and compact disk) shows visualization with the characteristics of the ridges that look good and clear. The study showed the highest frequency of loops (47%), followed by double loops (20%), plain whorls (30%), and central pocket whorls pattern (3%) from 30 fingerprint samples consisting of 14 men and 16 women. Development identification fingerprints using TiO2 show visualization more clearly because color contrast from bright white color and detail ridges is shown better with ZnO nanopowder
Highly Selective and Sensitive Determination of Hg(II) Ions Using Ion Selective Electrodes (ISE) Coated with the BEC4ND1 Ionophore as Membranes
Full text linkThe research on the highly selective and sensitive determination of Hg(II) ions using ion-selective electrodes (ISE) coated with the BEC4ND1 ionophore as a membrane has been successfully carried out. ISE was designed using the membrane composition of the [(BEC4ND1 ionophore : PTCPB : DOS : PVC) (3 : 2 : 60 : 35 % w/w)]. The ESI-BEC4ND1 ionophore has good characteristics where it shows a sensitivity value of 29.933 mV/decade in the Hg(II) ion concentration range of 10-9 - 10-1 M with a limit of detection (LoD) of 10-7 M. The response time obtained is in the range of 4 - 8 minutes with a relative standard deviation (RSD) of 0.548. The ESI-BEC4ND1 ionophore also shows the average value of selectivity coefficient (Kij) < 1. These results indicate that the presence of Zn(II), Cd(II), and Pb(II) ions as interfering ions in the analyte solution does not affect the performance of the ESI-BEC4ND1 ionophore in detecting Hg(II) ions. The ESI-BEC4ND1 ionophore that has been developed shows good selectivity, sensitivity, stability, and reproducibility, so the ESI-BEC4ND1 ionophore is promising to be used as a Hg(II) ion detector in the environment
Photocatalytic Degradation of Methylene Blue using Fe2O3-TiO2/Kaolinite under Visible Light Illumination
Full text linkCombining 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
Analysis of Students’ Critical Thinking Skills by Applying Flipped Classroom Learning Model using Powtoon Application on The Topic of Salt Hydrolysis
Full text linkThis study aims to determine students' critical thinking skills by applying flipped classrooms using the Powtoon application on the topic of salt hydrolysis. This study, which included 36 participants—15 men and 21 women—used a descriptive methodology and was carried out at one of Jakarta's public high schools. The instrument used was an observation sheet to observe the flipped classroom model’s learning process, critical thinking skills tests, reflective journals, and depth interviews. The flipped classroom method entails four steps: pre-class by studying independently and providing stimuli. In-class by fostering critical thinking; and post-class by evaluating. Combining asynchronous and synchronous activities was the process. Students learn independently during the pre-class stage by answering pre-learning questions and watching videos. During the class phase, Zoom meetings are used for synchronous learning to discuss salt hydrolysis applications in particular contexts. Discussion assignments on the salt hydrolysis case help students learn asynchronously after class. The study results showed that the flipped classroom using the Powtoon application can be an alternative for distance learning and can influence the students’ critical thinking at a very good level. It also helps them be more active and critical in learning, like exchanging opinions with others and doing assignments on the topic of salt hydrolysis
Synthesis of PMCA (P-Methoxy Cinnamic Acid) using Perkin Reaction and Its Activity as Photo Protective and Antifungal Agent
Full text linkThis study aimed to synthesize p-methoxy cinnamic acid through the Perkin reaction and to determine its activity as a photoprotective and antifungal agent against Candida albicans. The PMCA compound was synthesized by reacting p-methoxy benzaldehyde with acetic anhydride using a sodium acetate catalyst in a sonicator at 50oC for 60 minutes. The synthesized was a white precipitate with a % yield of 2.09% and a melting point of 172-175oC. ATR-FTIR identified this compound with several functional groups, C=O, OH carboxylic acid, para-substituted benzene, and C=C. Analysis by GC-MS showed a single peak at a retention time of 11.710 minutes with m/z 178. Characterization of this compound by 1H-NMR spectrometry showed several chemical shifts showing the presence of OH groups of carboxylic acids, C=C groups, aromatic benzene groups, and methoxy. The results of this characterization indicated that the synthesis product was PMCA. The antioxidant activity of PMCA using the DPPH radical gave IC50 at a concentration of 352.6138 ppm. In vitro sunscreen activity against PMCA compounds provided high protection at a concentration of 30 ppm with SPF 32,505. The antifungal activity against Candida albicans showed inhibition zones of 0.257cm± 0.044, 1.397cm± 0.093, and 1.533cm± 0.111, respectively at concentrations of 5%, 10%, and 15%. The PMCA compounds can be synthesized through the Perkin reaction assisted by ultrasonic waves and can potentially be photoprotective and antifungal agents
1H and 13C NMR Study of Oligosuccinimide Prepared by Thermal Condensation and Evaluation of Its Scale Inhibition
Full text linkThe presence of scale is a serious problem in the petroleum industry, and some efforts should be made to control scale formation. Oligosuccinimide (OSI) is an oligomer with several repeating units of succinimide. The structure of the OSI main chain and end groups has never been comprehensively analyzed. Meanwhile, OSI is potentially a scale inhibitor due to chelating properties, high polarity, and high solubility. This study investigates the molecular structure of oligosuccinimide, focusing on the main chain and end groups. Synthesis was carried out by thermal condensation between maleic anhydride and ammonium carbonate using a 1H and 13C NMR spectroscope equipped with Distortionless Enhancement by Polarization Transfer 135, Heteronuclear Multiple Quantum Coherence, and Single Quantum Coherence. The NMR analysis results detected the presence of the main chain and several synthesized OSI end groups, such as the amino, succinimide, and maleimide end groups. However, the dicarboxylic acid end group and other irregular structures, as in polysuccinimide (various synthesis methods), were not identified. It confirmed that our thermal condensation method produced OSI with less irregular structures than previous methods. Evaluation of OSI as CaCO3 and CaSO4 scales inhibitor showed reasonably good performance in very small concentrations. The inhibition efficiency was 73.20% for the CaCO3 scale with 10 mg.L-1 and 55.29% for the CaSO4 scale with 10 mg.L-1 inhibitor concentration. Analysis of thermal stability informed OSI has good thermal stability because it started to be degraded at 353.38 °C
Comparison Study of Ionic Gelation and SNEDDs Method in the Preparation of Cocoa Peel Extract Nanoparticles as Antibacterial Against Klebsiella pneumonia
Full text linkCocoa peel is the primary waste from chocolate production. It contains flavonoids that can inhibit the growth of Klebsiella pneumonia which causes chronic bronchitis. This study aims to obtain cocoa peel extract nanoparticles for antibacterial caused by K. pneumonia. The isolation of flavonoids was done using the maceration method in 96% ethanol. Phytochemical and Thin Layer Chromatography (TLC) analyses have been used to identify the active compounds contained in the extract. Flavonoid levels have been investigated using UV-Visible spectrophotometry. The preparation of nanoparticles from cocoa peel used ionic gelation and Self-Nano Emulsifying Drug Delivery System (SNEDDS). The nanoparticle obtained has been analyzed for particle size and polydisperse index. In vitro test was carried out to determine the antibacterial activity of K. pneumonia. Identification of active compounds using a UV-Visible spectrophotometer showed that cocoa peel extract contained flavonoids of 6.33%. Nanoparticle preparations using the SNEDDS method were more optimal than the ionic gelation method, with particle sizes 135.2 nm (4%), 156.1 nm (12%), and 235.3 (20%). Based on the in vitro test, nanoparticles from cocoa peel extract were able to inhibit the growth of K. pneumonia
The Adsorption Performance and Characterization of Activated Charcoal of Bone Char Against Acid Orange 7
Full text linkThe use of Acid Orange 7, a synthetic dye, in the textile industry harms the environment because it is carcinogenic. This research aims to remove the Acid Orange 7 dye dissolved in the water. This study used cow bone charcoal as an alternative adsorbent made by the carbonization method. In addition, the batch adsorption method was applied in the bleaching process of the synthetic dye waste, Acid Orange 7. Several tests, such as SEM, EDX, BET, XRD, and FTIR, were carried out to determine the characteristics and ability of activated charcoal from cow bones as an adsorbent for acid Orange 7 dye waste. Other organic adsorbents, such as graphene oxide and activated carbon, were used to compare the results. Bone char adsorption Acid Orange 7 62.2% efficiently. The adsorption efficiency of activated carbon is 79.8%, while graphene oxide has an adsorption rate of 89.4%. The findings revealed that bone char could be used to cure synthetic dye waste, Acid Orange 7, as an alternative. Additional treatmentÂ