IJFAC (Indonesian Journal of Fundamental and Applied Chemistry)
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Development of the Potentiometric Method for Measurement of Cu
Get PDFPotentiometry is one of method on measuring metals based on cell potential. Measurements using potentiometry are divided into comparative cells and concentration cells. Concentration cells are measurements of a cell's potential by using two solutions with different concentrations. The aim of this study was to develop a concentration cell potentiometric method equipped with applications so measurements are easier and faster. The added application able to calculate the results of experiments so that the calculation process becomes faster and easier. Validation results give the results of the R the value of 0.9990; LoD 7.6484x10-7, LoQ 6.2103x10-7, RSD 0.64%, and recovery 98.05%. This optimum measurement was carried out at 30 oC and pH 5. The results of Cu measurements in well water obtained the result of 0.9633 ppm. Measurements using the development of this method, get good validation results and can be used on measurements similar to those in the aquatic environment. Keywords: Potentiometry, cell concentration, Copper (Cu), validation, aquatic environmen
The Light Transmittance and Electrical Conductivity Properties of Gelam Wood Carbon Nanosheet and Its Derivatives
Get PDFThe research on the preparation and characterization of transparent electrode carbon nanosheet based gelam woods bark doped with SnO2-SbO2. XRD analysis showed peaks at 2θ = 26.87°; 26.38° for carbon crystal and at 2θ = 28.59°; 34.35° for SnO; at 2θ = 51.99°; 62.20° for SbO2. SEM analysis show that the carbons have self-curling sheets that indicated defection in their surface. The carbons have self-curling sheets, which indicated that their surfaces have many defects. It assumed when exfoliation process is undergone, the layers was significantly decreased as sonication process and formed rCNSO. Diffractogram XRD of CNS, CNSO and rCNSO showed diffraction peak at 2θ= 24.3°. Oxygen functional group in CNSO might cause an increasing of interlayers distance between hexagonal networks of carbon layer. It also affect electrical resistant or the conductivity. FTIR spectrum indicate that CNSO has several absorption peaks at for –OH stretch for free water and alcohol. At 2337 cm-1 was showed a carboxylic acid peaks and C=C stretch at 1627 cm-1. There is a skeletal vibration rCNSO structure occurred at each graphene layers. The ratio of the integrated intensities (IG/ID = 0.89 for CNS, 0.85 for CNS-O, and 0.93 for rCNSO of Raman spectroscopy is significantly high. Electrical conductivity of transparent electrode ranges from 1.26 x 10-7 Scm-1 – 5.03 x 10-7Scm -1. The highest conductivity value on transparent electrode contained rCNSO.This result inferred that the usage of rCNSO can increase electrical conductivity. Therefore, the higher value of electrical conductivity can be related to the value of La. The average maximum absorption wavelength is observed at 350-530 nm which means that the transition of the electronic transition π→π* occurs in the conjugated carbons system. Electrical conductivity of transparent electrode ranges from 1.26 x 10-7 Scm-1 – 5.03 x 10-7 Scm -1. The highest conductivity value on transparent electrode contained rCNSO. The band gap values in the transparent electrode range from 2 eV - 3 eV which means they have conductor – semiconductor characters.Keywords: Nanosheet, Carbon, Electrical, Conductivity, Derivate
Performance Test of Membrane Electrode Assembly in DAFC using Mixed Methanol and Ethanol Fuel with Various Volume Comparison
Get PDFDirect Alcohol Fuel Cell (DAFC) performance is influenced by electrocatalysis reactions that occur in Membrane Electrode Assembly (MEA). In this study, MEA was made with Pt-Ru/C (anode) and Pt/C (cathode) catalysts. The results of the electrode characterization with XRD showed a carbon peak at 26.63° and Ru at 40.58°. Based on the results of Cyclic Voltammetry (CV) measurements, the Electrochemical Surface Area (ECSA) electrode value is known to be 373.601 cm2/mg. Meanwhile, the impedance value is 4.315 Ω and the electrical conductivity value is 6.61x10-4 S/cm. MEA testing using MeOH 3 M fuel produces Open Circuit Voltage (OCV) of 0.650 V. Meanwhile, MEA performance testing uses a mixture of methanol and ethanol 2 M in loading conditions obtained the best mixture of fuel composition is methanol: ethanol = 90:10 with a maximum power density of 4.34 mW/cm2 and is able to maintain the voltage at 0.649 V under conditions of 6.875 mA/cm2. The results also showed that the volume of ethanol which was too high resulted in a decrease in cell performance in the fuel mixture caused by the competition of adsorption between competing methanol and ethanol occupying the active site of the catalyst.Keywords: DAFC, fuel cell, Pt-Ru/C, ethanol, methanol, Open Circuit Voltag
Antibacterial Activity and Structure Elucidation of Salicin from Stem Bark of Salix tetrasperma ROXB.
Get PDFSalix tetrasperma Roxb. (Family Salicacaeae) is a plant that used as traditional medicine for anti-inflammatory, analgesic, reduces fever, and itching medicine. In this study was carried out extraction, isolation, structure elucidation of salicin from Salix tetrasperma Roxb. stem bark and it’s antibacterial activity. The extraction method was used the maceration method by n-hexane, ethyl acetate, and methanol solvents. Isolation of compound from ethyl acetate extract of Salix tetrasperma Roxb. stem bark using chromatography methods and obtained white solid (15 mg). The structure was elucidated using spectroscopic analysis, including Ultraviolet (UV), Infrared (IR), Nuclear Magnetic Resonance (NMR) and comparative literature, identified as salicin compound with molecule formula C13H18O7. Antibacterial activity was evaluated against Escherichia coli and Staphylococcus aureus bacteria using disk diffusion method. This compound has a great an antibacterial activity against Staphylococcus aureus bacteria with clear zone diameter of 10.2 ± 0.3 mm. This shows that the Salix tetrasperma Roxb. stem bark has great potential as a source of antibacterial compoun
Acid Resistance Test of Probiotic Isolated from Silage Forage Swamp on In Vitro Digestive Tract
Get PDFAntibiotics are commonly used in poultry ration, and afterward these drug residues may persist in foods. There is an alternative source of antibiotics in poultry rations, one of which is using probiotics. Probiotics are living microorganisms capable of reaching the gastrointestinal tract and benefiting health, leaving no residue in the body. Probiotics can be originated from bacteria such as lactic acid bacteria (LAB) which produced lactic acid and antimicrobial components. LAB must be able to live in the digestive system with various pH condition. pH resistance testing of LAB was performed by introducing diluted bacteria into several buffer solutions with different pH and a predetermined incubation time, then was grown in MRS agar medium. This study was conducted to determine the resistance of LAB isolates as probiotics from silage forage swamp at different pH distributed in vitro digestant. The design used was a complete randomized design consist of 3 treatments and 3 replications. The treatments were using isolate of Kumpai Tembaga silage (P1), isolate of 50% Kumpai Tembaga silage and 50% Kemon Air silage (P2), and isolate of Kemon Air silage (P3). The results showed that all isolates used were lactic acid bacteria, and the treatment significantly affected the value of LAB resistance test against low pH and high pH. Isolate from Kumpai Tembaga silage (P1) is a lactic acid bacterium with higher ability to survive in pH of in vitro digestive system
Studies on the Controlled Release of Drugs from Magnetic Nanobiocomposites
Get PDFMagnetic nanocomposites are a class of smart materials that have attracted recent interest as drug delivery systems or as medical implants. In this study, meltable nanobiocomposites (NBC) composed of biocompatible dextran fatty acid ester and magnetic nanoparticles (MNPs) melting close to human body temperature were prepared and loaded with Rhodamine B (RhB) or green fluorescent protein (GFP) as model drugs to evaluate their potential use as drug delivery system. The release of the model drugs from the magnetic NBC investigated under the influence of a high frequent alternating magnetic field (AMF, 20 kA/m at 400 kHz) showed that on-demand release is realized applying the external AMF. The NBC showed a long-term stability (28 d) of the incorporated iron oxide particles after incubation in artificial body fluids. This work reveals the potential of the NBC as a drug carrier
The Effect of H-USY Catalyst in Catalytic Cracking of Waste Cooking Oil to Produce Biofuel
Get PDFThe crisis in petroleum is caused by the diminishing supply of petroleum resources from nature. This phenomenon encourages researchers to continue to look for processes and methods to produce energy from other resources. One of these ways is to produce energy that can be utilized from waste, including converting waste cooking oil into biofuel. This method not only could provide a source of renewable energy, but also help resolve the issue of household waste. The process used to produce biofuel from waste cooking oil is by catalytic cracking, where waste cooking oil after pretreatment is converted into biofuel in the flow reactor with H-USY catalyst. In this research, the reaction temperatures used are 400 °C, 450 °C, 500 °C and 550 °C and reaction times are 30, 45 and 60 minutes with the mass ratio of the amount of waste cooking oil to the amount of catalyst used is 40:1 (w/w). The highest yield of liquid biofuel product was obtained at 60.98%. The use of H-USY catalyst shows that the distribution of components contained in biofuel are 28.02% of diesel products (C17 -C20), 23.96% of gasoline (C6 –C12) and 7.78% of Heavy oil (C20 >) in catalytic cracking of waste cooking oil with a reaction time of 45 minutes at a temperature of 450 °C
Pyrolysis of Vacuum Residue By Thermal and Catalytic Cracking Using Active Alumina Catalyst
Get PDFVacuum Residue as feedstock derived from Pertamina Refinery Unit III was cracked in a fixed batch reactor under thermal and catalytic with single stage pyrolysis process using active alumina oxide (Al2O3) as a catalyst. The catalytic pyrolysis process carried out at a temperature 450°C in the presence of a varied catalyst to feed ratio 0.5-2.5 w/w% and varied of reaction times 5-30 minutes. While the thermal process performed under same operating conditions without presence the catalyst. The effect of alumina catalyst ratio on quantity and quality of yield product, the effect of operating conditions (reaction times) on yield distribution has been investigated. As a result, the cracked products are liquid, gas and coke residue. The yield of liquid products was dominant, the highest catalyst ratio showed the highest yield of the liquid product reached 63.1 wt% and the lowest yield of coke residue by 24.75 wt%. The highest yield of gas by 23.9 wt% was found at minimum catalyst used by 0.5 wt
The Characteristic of Coal Oil From Catalytic Coal Gasification
Get PDFIn this work, the catalytic gasification process of coal was studied at different operating temperatures and catalyst weights. The purpose of this study was to study the characteristics of coal oil produced through the gasification process using Nickel Molybdenum (NiMo) catalyst. The effect of adding NiMo catalyst with variations in weight of 0%, 5%, 10% and 15% for different gasification temperatures (375 – 385 °C, 430 – 440 °C, and 475 – 485 °C) were studied on coal with a calorific value of 6,400 kcal/kg. The process was done in fluidized bed reactor under atmospheric pressure and an air flow rate of 2 liters/minute was flow for 60 minutes. The results showed that NiMo is effective as a catalyst in the gasification of coal at 430 – 440 °C, the addition of 15% weight of catalysts produced coal oil with a yield of 9.35% and the composition of hydrocarbon consists of 59.75% of aromatics, 26.42% of aliphatics, and 7.34% of phenolics. Compared to coal oil without catalyst give a yield of 6.56% with 57.33% of aromatics, 17.44% of aliphatics, and 16.03% of phenolics. This showing that NiMo catalysts have a high selectivity to increase aromatic and aliphatic hydrocarbons in coal oil
Breakdown of Water-in-Oil Emulsion on Pyrolysis Bio-Oil
Get PDFThe pyrolysis bio-oil which has been studied by many researchers has typically contained a high amount of water, around 20-30%. In this research, the effective bio-oil purification using chemical demulsification method has been studied to reduce the amount of water by breaking down the water-in-oil emulsion on pyrolysis bio-oil. A various dosage of chemical demulsifier (100 ppm, 150 ppm, 200 ppm, and 250 ppm) has been added into the pyrolysis bio-oil and the water separation over time also been observed. The temperature of bio-oil (30, 40, 50, 60, and 70 °C) was also studied as a factor that could have a significant effect on the demulsification process of pyrolysis bio-oil. After the injection of 250 ppm of demulsifier at 30 °C, the water separation reached a maximum of 72% in 60 minutes and could reduce the water content from 25% to 8.5%. At the temperature of 60oC and 250 ppm of demulsifier, the water separation reached a maximum of 96% in 35 minutes, and successfully reduced the water content from 25% to 1.3%. Finally, it has been concluded that this bio-crude purification using chemical demulsification method could be applied to effectively reduce the amount of water from pyrolysis bio-oil product