Jurnal Pendidikan Kimia
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Antibacterial Activity Test of the C-4-methoxyphenylcalix[4]resorcinarene Compound Modified by Hexadecyltrimethylammonium-Bromide against Staphylococcus aureus and Escherichia coli Bacteria
Get PDFThis study aims to determine the antibacterial activity of C-4-methoxyphenylcalix-[4]resorcinarene modified by Hexadecyltrimethylammonium-Bromide (Resorcinarene-HDTMA-Br) against Staphylococcus aureus and Escherichia coli bacteria. The study was conducted by testing the inhibition zone diameter with paper disc diffusion method. Variations in the concentration of the sample used were 10%; 15%; 20%; 25%; and 30% b/v. In this study, Dimethyl sulfoxide (DMSO) (sampel solvent) was used as a negative control and Chloramphenicol as a positive control. It was found that Resorsinarene-HDTMA-Br had higher antibacterial activity than the unmodified C-4-methoxyphenylcalix[4]resorcinarene (CMFKR) against the S. aureus bacteria. Both CMFKR and Resorcinarene-HDTMA-Br are not active against E. coli
Characterization and Antibacterial Activity Test of Hydroxyapatite (HAp) from Chicken Eggshell against Lactobacillus acidophilus Bacteria
Get PDFThe purposes of this study were to characterize Hydroxyapatite (HAp) bioceramics which synthesized from local chicken and broiler eggshell using FTIR, and to determine HAp antibacterial activity with the highest content of calcium-phosphate (HAp from broiler chicken eggshell) using paper disc method. Characterization of HAp from local chicken eggshell using FTIR showed peaks for PO43- functional group on the wavelength 1040.08, 608.46 and 568.67 cm-1; OH- functional group on the wavelength 3426.39 and 2880.46 cm-1; CO2 functional group on the wavelength 2142.91 cm-1; and CO32- functional group on the wavelength 1653.64 cm-1. Whereas broiler chicken eggshell HAp showed peaks for PO43- functional group on the wavelength 1044.40, 604.13 and 568.66 cm-1; OH- functional group on the wavelength 3419.61 and 2838.35 cm-1; CO2 functional group on the wavelength 2086.69 cm-1; and CO32- functional group on the wavelength 1653.64 cm-1. HAp antibacterial activity test against caries bacteria L. acidophilus gives the positive results either for the lowest test dose (5μg/μL) or the highest test dose (75μg/μL), which was characterized by the formation of diameter inhibitory area 22.93±0,066 and 33.08±0,031 mm (strong category of >20 mm), respectively. The characterization of HAp from local chicken and broiler chicken eggshell using FTIR confirmed the presence of HAp compounds, and the antibacterial activity test result of HAp synthesized from broiler chicken eggshell indicates a positive and strong antibacterial power
Optimization Experimental Procedure and Setup of a Guided Inquiry Laboratory Worksheet of Transesterification Reaction on Biodiesel Production
Get PDFThe aims of this research are producing an optimal experiment procedure and determining the feasibility of a guided inquiry laboratory worksheet of transesterification reaction on biodiesel production context. This research used research and development methods that composed of two stages, initial product preparation and model development (until limited testing). The data sources of this research are 20 students grade XII of science, seven chemistry teachers and three lecturers from chemistry education program of FPMIPA UPI. The instruments that used in this research are optimization and observation sheets of inquiry stages implementation, rubric of assessment students’ answer, sheets of assessment by teacher and lecturer, and student’s response questionnaires. The optimization of biodiesel production is: 12 mL of palm oil is added into erlenmeyer flask that contained boiling stone, then added by 0.12 g Potasium hidroxide in 4.5 mL methanol solution. The erlenmeyer flask then closed by rubber stopper with test tube in the middle of rubber stopper that filled with water and heated at 45oC in water bath for 5 mins by shaking the flask. The feasibility of laboratory experiment is categorized as very good. Teacher and lecturer assessment on the concept conformity, language, and the appearance of worksheet is categorized as very good. Student’s responses of laboratory activity and the worksheet are good
Cellulose Compound of Cacao Waste and Chemical Composition of Cacao Vinegar with GC-MS Method
Get PDFPotential of cacao resources at Indonesian is very dependent on the production of cacao produced by farmers and plantation availability. However, the cacao processing results are still not optimal to increase the cacao production. This is due to the disruption of pests and the number of cacao farmers over land functions for fast growing plants. Processing cacao produced cacao waste and with the use of pyrolysis technology is able to cope with the accumulation of plantation waste. This combustion results in liquid smoke of cacao (cacao vinegar) into distillate, charcoal. This study used pyrolysis temperature between 100-500 °C. The aim of this research is to analyze the cocoa waste and the results are cellulose content 17,27%, lignin 52,02% and hemicellulose 19,56%. The results of GC-MS analysis for cacao vinegar of Distric Wajo are acetic acid, n butane, methyl ester, propanoic acid, butanoic acid, cyclopenanone, 2 methyl pyridine, acetyloxy 2 propanone, butyrolactone, tetrahydro 2 furan methanol, 2,3 dimethyl 2 cyclopentene 1 on and Mequinol. The water content of the charcoal of cacao shell from Wajo district is 3.42%. The analysis results of the bound carbon content of activated charcoal of cacao shell is 54.45%. The EDS analysis for cacao shell from Wajo district resulted in C: 61.12%, O: 36.65%, Si: 0.59%, P: 1.48% and Al: 0.17%. Utilization of cocoa shell waste using pyrolysis technology can reduce carbon emissions to the environment. So that the development of everything can continue and the sustainability of forest remain sustainable.
Characteristic Study of the MCM-41 Modified with Zn by Direct Synthesis
Get PDFModification of MCM-41 with zinc (Zn) by direct synthesis has been attempted. The aims of this research were (i) to show morphology of MCM-41, (ii) to know the optimal ratio of Si/Zn in MCM-41 modification, and (iii) to know crystallinity and pore diameter of MCM-41 and MCM-41 modified by Zn. Zn metal added to MCM-41 matrix by direct synthesis used zinc nitrate as precursor with ratio Si/Zn variation. Zn added by direct synthesis to get larger diameter without changing the structure of MCM-41. Characterization of material was used XRD, FTIR, TEM, and N2 adsorption. Characterization of MCM-41 with TEM show that material has spherical shape with uniform pore morphology. The result of XRD show that synthesized MCM-41 has good crystallinity with three peaks observed specific to MCM-41. Ratio of Si/Zn optimal to modification MCM-41 is Si/Zn= 100. Modified MCM-41 show decrease in crystallinity and increase pore diameter that is 35.58 Ǻ compared with MCM-41 with pore diameter 31.42 Ǻ.
Cyclic Voltammetry Study of Mediated Electrochemical Oxidation Using Platinum Wire, Pt/Co(OH)2 and Pt/Co Electrodes In Various Supporting Electrolytes
Get PDFAmoxicillin is one of β-lactam antibiotic in penicillin groups which their presence in surface water and wastewater not only affects water quality but also causes long-term adverse effects on ecosystems and human health due to their resistance to natural biodegradation. The processing of organic waste electrochemically has the advantage of cheap and efficient cost, exhaust gas that does not contain toxic and hazardous materials. We have studied the process of amoxicillin electro-oxidation mediated by a cobalt (III) ion called an electrochemical oxidation process mediated (MEO) in a voltammetry study using a platinum working electrode, Pt/Co(OH)2 and Pt/Co in various supporting electrolytes such as KNO3, NaClO4, Na2SO4 and phosphate buffer solution with concentrations 0.10 M. The results show that the amoxicillin oxidation peaks using the above-mentioned working electrode in various electrolyte solutions are in the potential range of 500-670 mV (Ag/AgCl). The presence of cobalt ions forming complex compounds with amoxicillin causes the oxidation current decreasing that indicates the presence of degradation to amoxicillin
Activity Test of Essential Lime Oil of Leaves, Twigs, and Rind against Escherichia coli and Bacillus cereus
Get PDFActivity tests of essential lime oil (Citrus hystrix DC) from its leaves, twigs, and rinds on the growth of gram-negative bacteria E. coli and gram-positive B. cereus have been conducted. Essential lime oil was obtained by steam distillation of leaves, twigs and rind for 5 h. GC-MS was used to analyze the composition of essential lime oil. Well diffusion method was used for antibacterial activities testing with concentrations of solution were 100, 300, 500 µL/mL in ethanol and microdilution method was used to determine the minimal inhibitory concentrations (MICs). The results showed that higher concentration of essential lime oil led higher minimal inhibitory in which minimal inhibitory of essential oil from rind was higher than that of leaves and twigs. MICs values of E. coli are 25, 50 and 12.5 µL/mL and of B. cereus are 6.25, 12.5 and 3.12 µL/mL of leaves, twigs and rind, respectively. Citronellal compound was found as main component of essential lime oil from leaves and twigs with value of 85.7 % and 46.4 %, respectively. In addition, sabinene (9.2%), β-pinene (21.4%), limonene (12.5%), citronellal (20.9%) and terpinene-4-ol (11.9%) were found as compounds of essential lime oil from rind
The Effectiveness of Blended Learning Oriented LKS with POGIL Strategy on High School Chemical Bond Subject
Get PDFThe rapid development of technology requires innovation in learning. One of the innovations is blended learning. The concept of blended learning is mixing of face-to-face learning model in the classroom with online learning. The blended learning will strengthen the conventional learning model conducted in the classroom through the development of education technology. Blended learning can be combined with constructivist and cooperative learning using POGIL strategy. POGIL contextual- based blended learning is suitable for chemical bonding subject because it has abstract characteristics involves atoms and electrons which are macroscopic, microscopic, and symbolic particles. The aim of this research is to create the effective student worksheet blended learning-based viewed from students pretest and posttest results. The development of model in student worksheet uses 4D models (four D models) from Thiagarajan which consists of 4 development stages: Define, Design, Develop, and Disseminate. Focus of this study was limited to the stage of develop. The data were collected using a test sheet in the form of pretest and posttest through a limited trial. The results of this research indicate that the usage of blended learning-based student worksheet is effective viewed from N-gain which was obtained as much as 86.67% of students achieving moderate criteria, 6.67% of students achieving high criteria, and 6.67% students reach low criteria
Development of Applicative-Integrative Student Worksheet Based on Scientific Approach on Reaction Rate Subject
Get PDFThis research aimed to design applicative-integrative student worksheet based on scientific approach, which was applied to the learning process by using guided inquiry learning model. The worksheet was properly assessed from three aspects. There were validity, effectivity and practicality. The approach used in this research was ADDIE approach (Analysis, Design, Development, Implementation and Evaluation) with Embedded Mixed Methods. The stages of this research were extraction of potentials and problems, designing student worksheet, validation by experts including media, subjects, and practitioners, then testing the student worksheet. The results showed that the student worksheet was appropriate based on the analysis of the data obtained. This student worksheet was feasible to be implemented in the learning process of chemistry class, particularly reaction rate subject. The result of this research showed that validity, effectivity and practicality obtained 93.9, 83.1, and 94.3%, respectively.