KOVALEN: Jurnal Riset Kimia
Not a member yet
324 research outputs found
Sort by
Aplikasi Antibakteri Nanopartikel Perak (NPAg) Hasil Biosintesis dengan Ekstrak Air Daun Kemangi: Application of Antibacterial from Silver Nanoparticles (AgNPs) Biosynthesis with Basil Leaf Extract
Get PDFNanotechnology is a technology that can be used to overcome several environmental problems. Synthesis of silver nanoparticles (AgNPs) mediated with basil leaf bioreductant with a concentration 0.5% at a temperature of 25â°C has been carried out. The result of biosynthesis of AgNPs was analyzed using a UV-Vis spectrophotometer in which the SPR band showed the maximum wavelength of 429 nm. The size of AgNPs was determined by a Particle Size Analyzer (PSA), which its size was 86.83 nm. The morphology and elemental content of AgNPs were confirmed using SEM-EDS showing that the shape of AgNPs was irregularly spherical crystals while the EDS results showed a dominant peak at 3 keV indicating silver content. AgNPs showed strong antibacterial activity against Escherechia coli and moderate against Staphylococcus aureus
Pengaruh dari Konsentrasi Elektrolit Tembaga Asetat-Asam Asetat dan Temperatur terhadap Efisiensi Arus pada Elektrodeposisi Baja Karbon Rendah dengan Tembaga: Effect of Electrolyte Concentration of Copper Acetic-Acetic Acid and Temperature on Current Efficiency in Electrodeposition of Low Carbon Steel with Copper
Get PDFOne example of an electrolysis practicum module at the Chemistry Laboratory is the plating of copper on low-carbon steel metal with cyanide as the electrolyte. This cyanide electrolyte is commonly known as Zonax Copper. Due to the dangerous cyanide content, a replacement electrolyte that is safe, cheap, and easy to obtain for student practicum scales is sought. The purpose of this study was to determine the optimum temperature and composition of copper acetate-acetic acid as indicated by the largest current efficiency value. The composition of Cu-Acetate/Acetic Acid varied 0.2/0.4; 0.4/0.6; 0.6/1.2; 0.8/1.6, and 1/2 gram/250 mL. The coating process was carried out at temperatures of 30, 40, 45, 50, and 60oC with an electrodeposition time of 10 minutes. The results show that the highest current efficiency was found in the composition (CH3COO)2Cu/CH3COOH 1gram/ 2 ml, temperature 45℃ by 93%. The effect of temperature on current efficiency is in the form of a second-order polynomial with a correlation of research results >90%. The average maximum temperature is 42.68oC and the largest current efficiency is 96% at a concentration of (CH3COO)2Cu/CH3COOH 0.6 gr/1.2 ml. The current efficiency is directly proportional to the logarithmic concentration at temperatures of 30, 40, 45, and 50oC
Identifikasi Senyawa Fraksi Larut n-Heksana Rimpang Temu Mangga (Curcuma mangga Val) Menggunakan LC-MS/MS dan Review Potensinya sebagai Antibakteri: Identification of Compounds Soluble n-Hexane Fraction of Rhizome of Temu Mangga (Curcuma mango Val) Using LC-MS/MS and Review of its Potential as Antibacterial
Get PDFPlants are like the pharmaceutical industry that provides products that have the potential as active medicinal ingredients. In order to search for compounds useful for health, the purpose of this study was to identify secondary metabolites of Curcuma mango (temu mango) growing in the experimental garden of Biopharmaca LPPM IPB and review its activity as antibacterial. Identification begins with phytochemical screening, then separation and purification by chromatographic techniques. Intersection mango simplicia was extracted with methanol, and the crude extract of methanol was partitioned with n-hexane, ethyl acetate, and methanol, respectively. The n-hexane soluble fraction was carried out by phytochemical tests, fractionation by vacuum liquid chromatography (KCV) and radial (KR), and the selected fractions was analyzed by LC-MS/MS. The results of the phytochemical test of the soluble n-hexane fraction showed a positive presence of alkaloids and terpenoids through successive tests with Mayer, Wagner, Dragendorff (alkaloid), and Lieberman-Burchard reagents. Fractionation of the n-hexane soluble fraction with KCV resulted in 9 fractions (H1-H9) and the H5 fraction showed good separation between spots in the n-hexane: ethyl acetate eluent mixture (97:3). Purification of H5 with KR obtained 7 fractions (H5.1-H5.7). Based on LC-MS/MS, the H5.2 fraction was dominated by the terpenoid group, and the results of the literature review showed the contribution of terpenoids as antibacterial compound
Delaminasi Perekat Polivinil Asetat Berbasis Air Satu Komponen untuk Aplikasi Kayu Keras Ulin dan Merbau: Delamination on Polyvinyl Acetate Water Based Adhesive One Component for Ulin and Merbau Hard Wood Working Application
Get PDFWater-based adhesive was one of the most important media for bonding substrates to one another because of their environmental friendly character. Previously, in the application of hardwood adhesives such as Ulin and Merbau, the type of adhesive used was a two-component system. For this reason, a one-component water-based adhesive was introduced in this study. The advantage of these was environmental friendly and high durability. In this application, delamination was one of the important parameters to determine whether the adhesive used was well penetrated or not. For this reason, delamination will be the main parameter in this study. This research includes the preparation of tools and materials, manufacture of PVA (polyvinyl alcohol) solution, polymerization of polyvinyl acetate by mixing the main raw material of vinyl acetate monomer and PVOH solution using APS (ammonium persulfate) initiator. The polymerization process was carried out at 1 atm pressure and 75oC – 80oC temperature accompanied by stirring with ±500 rpm rotation rate. Final product is a homopolymer PVAc (polyvinyl acetate) with PVOH Z-210 with AAEM (acetoacetoxy ethyl methacrylate) content having an acetoxy functional group. A delamination test was carried out on the final product with a modified test based on Japanese Agricultural Standard 1152 where the product was immersed in water for 360 minutes, then placed in an oven at 40oC for 18 hours. Samples using PVOH with AAEM content have an average delamination rate of 0.67-1.67% while existing products on the market have an average delamination rate of 45.83-52.08%
Sintesis dan Karakterisasi Carbon Nanodots dengan Metode Microwave Assisted Extraction: Synthesis and Characterization of Carbon Nanodots with Microwave Assisted Extraction
Get PDFCarbon nanodots (CNDs) is one of the carbon nanoparticles that are environmentally friendly, non-toxic, and have optical properties. The aim of this study was to synthesize CNDs from ascorbic acid as a precursor using the Microwave Assisted Extraction method. method. Best results are obtained at 4 minutes of heating and 500W of power. The synthesized CNDs solution showed a blue color under 365 nm UV light. The measurement results with UV Vis spectrophotometer showed the maximum wavelength at 341.5 nm with an energy gap of 5.57 eV. The results of the Fourier transform infrared spectroscopy (FTIR) analysis show that CNDs have the -OH (hydroxyl) functional group at a wave number of 3354.61 cm-1 and C=O functional group at a wave number of 1633.09 cm-1. Characterization results using High resolution transmission electron microscopy (HRTEM) showed that CNDs were spherical in shape with a particle size range of 2.54-9.48 nm
Antioxidant Potential of Ethanol Extract from Mango Parasite (Dendrophthoe petandra) to Maintain Crude Palm Oil (CPO) Quality
Get PDFThe present study aimed to determine the effectiveness of adding natural antioxidants from ethanolic extract of mango parasite (Dendrophthoe petandra) to oxidation stability of crude palm oil (CPO) during storage. The parameters tested were levels of free fatty acid (FFA), acid values, and deterioration of bleachability index (DOBI). The antioxidant activity of D. petandra extract obtained was IC50 of 6.369 ppm. Concentrations of D. petandra extract range from 200 to 1000 ppm. Based on the results, the ethanolic extract of D. petandra was able to reduce the FFA and acid value and increase the DOBI compared to the negative control. The lowest FFA levels and acid numbers were obtained from samples with addition of 1000 ppm natural antioxidants with FFA of 4.2% and acid value of 7.4 mg KOH/g, while the DOBI value increased to 1.300
Studi Pemanfaatan Limbah Cair Ikan dan Udang sebagai Substrat dalam Produksi Listrik pada Sistem Microbial Fuel Cell (MFC): Study of Utilization of Fishery and Shrimp Wastewater as Substrate in Electricity Production in Microbial Fuel Cell (MFC) System
Get PDFMicrobial fuel cell (MFC) is a technology that utilizes bacteria in organic medium that can convert chemical energy into electrical energy. This technology can be used to treat fishery waste and shrimp waste which is rich in organic matter. This study aimed to measure the performance of the MFC system on fishery wastewater and shrimp wastewater as a means of producing bio-electricity while reducing the waste load. This study used different types of electrodes, including zinc, aluminum, copper, and carbon graphite. This technology used 0.2 M KMNO4 electrolyte solution. The research method includes three stages; production of fishery wastewater and shrimp wastewater, assembly of a dual chamber MFC bioreactor, and measurement of waste electrical energy produced. The value of electricity production with the highest average in fishery wastewater was obtained by adding electrolyte solution to the Zn/Cu electrode during 117 hours of observation were 6.86 mA with a potential difference of 1.469 V meanwhile in shrimp wastewater was obtained by adding electrolyte solution to the Al/Cu electrode were 4.38 mA with a potential difference of 1.335 V.This study can be concluded that higher electricity production is obtained from the utilization of fish wastewater using Zn/Cu electrode
Analisis Kandungan Merkuri (Hg) pada Badan Air, Sedimen dan Biota yang Terdampak Aktivitas Pertambangan Emas di Kabupaten Parigi Moutong: Analysis of Mercury (Hg) Content in Water Bodies, Sediments, and Biota Affected by Gold Mining Activities in Parigi Moutong District
Get PDFParigi Moutong District is one of the regencies in Central Sulawesi province with the highest number of illegal mining activities. Unlicensed mining activities generally use mercury as an extracting agent and gold processing waste is generally disposed of in rivers or other water bodies. The purpose of this study was to analyze the levels of heavy metal mercury (Hg) in water bodies, sediments, and marine biota in gold mining areas in Parigi Moutong District. The sampling method was carried out by random sampling method, while the analysis of mercury content in samples of river water, sediment, and biota was carried out using atomic absorption spectroscopy (AAS). From the results of the study, it was found that mercury levels in water and sediment samples were still below the quality standard value which were 0.001 mg/Kg and 0.13 mg/Kg, respectively, while the mercury levels in all biota samples had exceeded the quality standard values ​(0.03 mg/Kg). This indicates that mercury has accumulated in the food chain in the water near the mine site
Potensi Ekstrak Batang Kayu Gempol (Nauclea orientalis L.) dalam Menghambat Pertumbuhan Bakteri: Potency of Gempol (Nauclea orientalis L.) Stem Extracts to Inhibiting Bacterial Growth
Get PDFThe study of the potential of Gempol wood stem extract (Nauclea orientalis L.) with three solvent polarities has been exercised to determine the extract with a certain polarity and the smallest concentration that can inhibit the growth of bacteria Staphylococcus aureus and Escherichia coil. Extraction is performed using the maceration method with n-hexane, ethyl acetate, and ethanol as solvents. Furthermore, the potency in inhibiting the growth of bacteria was observed by the diffusion method with a range of extract concentrations from the largest to the smallest. The extract's ability to inhibit bacterial growth in the time range of up to 24 hours was measured using the turbidimetric method. The results showed that ethyl acetate and ethanol extracts were able to inhibit the growth of both bacteria in a wide concentration range (100 %– 5%), although n-hexane extracts showed the highest percentage in inhibiting both bacteria (15.27 mm and 16.89 mm, respectively). Turbidimetric assays showed the extract was stronger in inhibiting S. aureus compared to E. coli in the logarithmic phase range of 12 hours. This study showed that semipolar and polar extracts can inhibit the growth of bacteria with a wider concentration range compared to non-polar extracts despite having a higher inhibition capability
Verifikasi Metode Pengujian Kadar Nitrit dalam Air Limbah Secara Spektrofotometri UV-Visibel: Verification of a UV-Visible Spectrophotometry Method for Analysis of Nitrite Levels in Wastewater
Get PDFWastewater is the residue from a business and or activity in the form of liquid. One of the chemical compounds that cause pollution is nitrite. The nitrite level in wastewater is a key parameter in determining water quality because of its toxicity. The standard method for nitrite analysis refers to SNI 06-6989.9-2004 using sulfanilic acid and N-(1-naphthyl)-ethylenediamine dihydrochloride (NED) reagents. Linearity, instrument detection limit (LDI) and quantification detection limit (LOQ), precision, accuracy, and calculation of measurement uncertainty estimation are some of the verification parameters that were tested. The regression curve's results showed that the correlation value (r) = 0.9998, the instrument detection limit value of 0.0014 mg/L, the quantitation limit value of 0.0035 mg/L, the precision value (%SBR) of 1.30 percent, the accuracy value is in the range (90-100)% and the relative uncertainty of 5.88 %. The verification results suggested that the UV-Visible spectrophotometer-based nitrite test technique in wastewater had passed the acceptance requirements and may be utilized for routine laboratory analysis