JKPK (Jurnal Kimia dan Pendidikan Kimia)
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Synthesis of Core-Shell Fe3O4/C18/SiO2/[3 (2-Aminoethyl amino) propyl] Trimethoxy Silane and The Study of The Adsorption Kinetics Model of Cu2+ and Cr6+ Ions
Get PDFSynthesis of Core-Shell Fe3O4/C18/SiO2/[3 (2-Aminoetil amino) propyl] Trimethoxy silane has been conducted to study its adsorption kinetics of Cu2+ and Cr6+ ions. Fe3O4 synthesis was carried out to form cores that have magnetic properties. The aim of the coating C18/SiO2/[3(2-Aminoetilamino) propyl] trimethoxy silane was to protect these cores from physical degradation due to acids and bases, as well as the application of synthetic materials. The sono-coprecipitation method showed good results under N2 gas flow with the results of black crystals. The success of SiO2 and [3(2-Aminoethylamino) propyl coatings the transformation of the color showed Trimethoxy silane into brown and weight gain of the synthesis result. Analysis of XRD data showed that little Fe2O3 impurities were clarified by FTIR data showing the presence of amine groups from the starting material. The SEM-EDX and TEM showed a spherical shape with a core-shell system. The adsorption kinetics model was studied using two kinetics models for Cu2+ and Cr6+ ions. The results were demonstrated by the suitability of Cu adsorption to the pseudo order 1, with an adsorption rate of 0.0333 min-1, whereas for Cr corresponded to pseudo order 2 with an adsorption rate of 0.00536 gmM-1min-1
Designing Calorimeter Made from Various Wastes
Get PDFA research has been conducted which aims to design a waste-based calorimeter as an alternative to measuring heat for chemistry practicum in schools. Research products developed through the steps of design-based research comprising the steps of analysis, design, and development. The resulting product is a waste-based calorimeter equipped with an automatic stirrer. The container to store the reagent solution on the calorimeter is made of Styrofoam, paper, plastic, melamine, PVC and bamboo. Optimization tool was conducted to determine the heat capacity of the calorimeter and the enthalpy of neutralization. The highest accuracy calorimeter value between 78-97%. Bamboo calorimeter has the highest accuracy value (97%). Styrofoam calorimeter has the lowest accuracy values (78%). Based on the results of the validation and feasibility test it can be concluded that the product is declared valid and feasible
PENGEMBANGAN PERANGKAT PEMBELAJARAN KIMIA SMA KELAS XI MATERI ASAM BASA UNTUK PEMBENTUKAN KARAKTER PESERTA DIDIK
Get PDFTujuan penelitian ini adalah untuk: (1) mengembangkan perangkat pembelajaran kimia SMA kelas XI materi asam basa untuk meningkatkan hasil belajar dan pembentukan karakter peserta didik, (2) mengetahui kualitas dari perangkat pembelajaran yang dikembangkan, dan(3) mengetahui perbedaan hasil belajar dan pembentukan karakter antara peserta didik yang diajarkan menggunakan perangkat hasil pengembangan dengan yang menggunakan perangkat pembelajaran konvensional. Metode penelitian yang digunakan dalam penelitian ini adalah Research and Development (R&D) dengan mengacu pada model 4-D yang memiliki tahapan Define, Design, Develop dan Disseminate. Namun, tahapan Disseminate tidak dilaksanakan. Penelitian ini menghasilkan perangkat pembelajaran yang meliputi: silabus, rencanapelaksanaan pembelajaran, lembar kegiatan peserta didik, dan instrumen penilaian. Berdasarkan hasil penilaian oleh ahli, pendidik, dan teman sejawat, menunjukkan bahwa perangkat pembelajaran yang dikembangkan secara umum memiliki kategori “sangat baikâ€. Pembelajaran dengan menggunakan perangkat yang dikembangkan peneliti dapat membentuk karakter disiplin, tanggung jawab, kreatif, komunikatif dan teliti. Penggunaan perangkat pembelajaran hasil pengembangan juga dapat meningkatkan hasil belajar peserta didik.Berdasarkan hasil uji-t, maka terdapat perbedaan hasil belajar dan pembentukan karakter peserta didik yang diajarkan dengan perangkat hasil pengembangan dengan yang menggunakan perangkat pembelajaran konvensional
Effect Concentrations of Polyethylene Glycol in Stability Structure of Blending Polymer Cholesteryl acrylate-ITO
Get PDFPolymer ChoAcry/ITO was added glycol is one of the material polymer liquid crystal modifications. In general polymer liquid crystal cholesteryl acrylate was made for many application usage in optoelectronics materials. This research want to study effect Polyethylene Glycol (PEG) in polymer choAcry/ITO for stability structure of blending choAcry/ITO. PEG 0.006 was added to mixed cholesteryl acrylate with ITO. Polymerizations that doing using UV curing photopolymerizations. Characterizations group functions using Fourier Transformed Infra Red (FTIR) and Nuclear Magnetic Resonance (NMR). Effect concentrations of PEG in PolyChoAcry-ITO shown from FTIR spectrum, shown not different. Peak in spectrum showed are C=C and C-H aliphatic, C=C aromatic, C-O ester, and para-benzene. Based on data FTIR that PE-b-PEG not change structures. Therefore, diffractogram of XRD, showed added ITO and PEG can be affect phisycal and chemistry properties of polymer cholestryl acrylate. This data showed PEG changed structures of polymer. Polyethilene glycol spreading into polymer cholesteryl acrylate. In the literatures told that PEG can be conjunctionc between that monomer or polymer cholesteryl acrylate-ITO
Preparation of Silver-Chitosan Nanocomposites Colloidal and Film as Antibacteri Material
Get PDFColloidal nanocomposites silver-chitosan have been made. Silver nanoparticles were produced by chemical reduction methods assisted microwave irradiation using chitosan from crab shells as a reducing agent and stabilizer, AgNO3 as a precursor and NaOH as an accelerator. This study investigated AgNO3 concentration toward localized surface plasmon resonance (LSPR) phenomenon of nanocomposites colloidal. The size and shape of the silver nanoparticles were confirmed by TEM. Furthermore, the stability of the storage was observed for twelve weeks. Colloidal and film nanocomposites silver- chitosan have been made by casting method by drying at room temperature. After that, the film characterization was carried out, including swelling with gravimetry methods and surface morphology using scanning electron microscopy (SEM). Diffusion methods tested colloid antibacterial activity and silver-chitosan nanocomposite film’s against E. Coli and S. Aureus. The results showed that the formation of silver nanoparticles was identified by the LSPR absorption band's appearance at 413-419 nm. The increasing of AgNO3 concentration increased the intensity of the LSPR absorption band. Silver nanoparticles with sizes of about 3-9 nm are spherical. The silver nanoparticles were stable at 12 weeks of storage. The higher AgNO3 concentration tends to increase the swelling of the film. The surface of the silver-chitosan nanocomposite film’s was rougher than that of the chitosan film. The higher the silver nanoparticle concentration, the higher the colloid and film antibacterial activity against E. Coli and S. Aureus
Potential of Water Extract of The White Frangipani (Plumeria acuminate) and Hibiscus (Hibiscus tiliaceus) Leaves Powder as Textile Natural Dyes
Get PDFSynthetic dyes have a high environmental impact, especially on waters. The use of natural dyes for textiles provides new hope for ecological improvement. This article is to find out the yield of water extract of white frangipani (Plumeria acuminate) and hibiscus (Hibiscus tiliaceus) leaves-powder, as well as to find out whether the water extracts have potential as textile natural dyes. Natural dyes must have a good quality of fastness. For this reason, the color fastness tests for washing with a launder meter and colorfastness against rubbing with a crock meter are performed. Colorfastness is assessed by comparing color changes to washing with grayscale and color changes due to staining on fabric with staining scale. The rubbing test is carried out on the wet and dry cloth. Cotton and polyester fabrics are samples that will be colored. Fixers used to bind dyes are Al2(SO4)3, CaCO3, and FeSO4.H2O. The results show that the water extraction of hibiscus and white frangipani leaves powder gave a yield of 11% (w/w) and 27 % (w/w), respectively. The test of colorfastness against washing showed that both water extract of the white frangipani dan hibiscus leaves has a pretty good average quality in staining scale but less in grayscale. The test against rubbing shows that the type of fixer used affects the quality of the colorfastness, but in general, the water extract of white frangipani leaves gives better quality as a potential of natural dye than hibiscus leave
Influence of Upwelling in the Southern Waters of Java on CO2 Concentration in Kototabang, Agam District West
Get PDFAbsorption of atmospheric CO2 by the sea through two processes, namely solubility pumps and biological pumps. This study aims to determine the effect of upwelling in the southern waters of Java on atmospheric CO2 concentrations in Kototabang. The data used are in situ CO2 concentration, sea surface temperature and chlorophyll-a concentration from 2004-2016. The method used was descriptive analysis. The results showed that upwelling that occurred during JJA-SON caused a decrease in sea surface temperature to 26.8 °C and 27.1 °C respectively, as well as an increase chlorophyll-a concentration to 2.03 mg/m3 and 2.19 mg/m3. In both seasons CO2 concentration in Kototabang dropped to 385.8 ppm and 385.4 ppm. Meanwhile, when there was no upwelling during DJF-MAM, sea surface temperatures rose to 28.8 °C and 29.0 °C, and chlorophyll-a concentration dropped to 0.32 mg/m3 and 0.54 mg/m3. CO2 concentration in DJF and MAM increased to 386.3 ppm and 386.5 ppm. Based on these results it is known that when upwelling occurs, CO2 concentration decrease and vice versa
Misconceptions of High School Students in Salt Hydrolysis Topic Using a Three-Tier Diagnostic Test (TTDT)
Get PDFThis study aims to find out whether high school students in Surakarta have misconceptions in salt hydrolysis material and to find out which concept is the most misconception experienced by high school students in Surakarta in salt hydrolysis material. This study used a descriptive approach. Data collection techniques using data triangulation technique from the results of the Three-Tier Diagnostic Test (TTDT), formative tests, and interviews. The sample used in this study was determined using a purposive sampling technique. Based on the research conducted, high school students in Surakarta experienced misconceptions in salt hydrolysis material as much as 36.75%, 35.94% Scientific knowledge, 15.63% lack of knowledge, and 10.90% error. Most misconceptions experienced by high school students in Surakarta on salt hydrolysis material occur in sub concepts: a) conclude the acid-base properties shown from salt solutions (49.91%), b) calculate the pH of the salt solution (39.15), c) analyze the reaction salt hydrolysis (37.21%), d) analyze the concept of hydrolysis that occurs in solution (35.98), e) determine the types of hydrolysis of salt (21.87%)
Determination of Chlorine on Brewed Robusta Coffee (Coffea canephora var. Robusta) with V60 Method
Get PDFOne of the manual brewing techniques is the pour-over V60 method. It uses a filter paper, which is suspected of containing chlorine as a paper bleaching agent that will dissolve in coffee. Health problems that can be caused by consuming chlorine-containing beverages in the long term can cause directly disease related to liver, bladder, intestinal cancers, arteriosclerosis, high blood pressure, pneumonia, bronchitis, dyspnea, and allergies. This study aims to determine the chlorine content of brewed robusta coffee using the brew V60 method. The chlorine test with the colour reaction method and the precipitation test as qualitative analysis to determine chlorine levels is an argentometric titration with the Mohr method. This research shows that all three samples of filter paper and coffee with V60 brewing method contain chlorine. The titration result shows that chlorine levels in filter paper brand A are 81.9 mg/L, brand B 49.9 mg/L, and brand C 69.9 mg/L. Levels of chlorine in V60 brewed coffee brand A are 44.6 mg/L, brand B 21.9 mg/L, and brand C 28.6 mg/L. This research concludes that the chlorine content in filter paper and V60 coffee brewing beverages on brand A, brand B, and brand C is unqualified according to WHO regulation about chlorine qualification for clean drinking water, which is 5 mg/L