Showing posts with label Chemical Engineering. Show all posts
Showing posts with label Chemical Engineering. Show all posts

Wednesday, July 27, 2011

Isolation of Methyl Laurate from Coconut Oil as Raw Material for Fatty Alcohol Sulfate (FAS)

Rita Arbianti, Tania Surya Utami, Astri N

Abstract: Isolation of Methyl Laurate from Coconut Oil as Raw Material for Fatty Alcohol Sulfate. Methyl laurate is a raw or base material for many industries, including surfactant industries. In this research, coconut oil (VCO) is transesterified with methanol to produce methyl ester, using NaOH as the catalyst. Methyl laurate is then separated by method based on the difference in melting point. This research focuses at determining the effects of some variables in transesterification on the concentration of produced methyl laurate. The variables are temperature (40 oC, 50 oC, 60 oC, 80 oC), time of transesterification reaction (0,5 hour, 1 hour, 1,5 hours, 2 hours, 3 hours), and the percent weight of the catalyst NaOH (0,5 %, 1 %, 1,5 %, 2 %, 3 %). Research showed the concentration of methyl laurate increased, following the increased temperature, time, and percent weight of catalysts. Optimal conditions were acquired at reaction temperature of 60oC, reaction time of 2 hours, and percent weight of the catalyst NaOH of 2 %. Laurate acid conversion
to methyl laurate that yielded from optimal conditions, after the separation based on melting point, was 55,61 %.
keywords: methyl laurate, coconut oil, fatty alcohol sulfate, transesterification

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Sintesa Material Bioaktif Hydroxyapatite (HA) dengan Metode Flame Spray Pyrolysis

Nurtono, Tantular

Abstract: Hydroxy apatite (HA) particles for biomaterial for implantation of bone tissues need homogen size and high crystallinity. Submicrometer, spherical, and monodispersed HA particles have been synthesized successfully by aerosol prosess in a flame reactor. A flame burner consisted of three concentric cylindrical pipes, each for starting material solution, LPG as fuel, and air as oxidizer. Ca(NO3)2.4H2O-(NH4)2HPO4 solution was selected as starting material. Temperature distribution and particle size evolution were predicted using computational fluid dynamics (CFD). The morphology and the crystallinity of the generated particles were analyzed using scanning electron microscope (SEM) and X-R Diffraction (XRD), respectively. The generated particles were highly affected by fuel flow rate, carrier gas flow rate and heat treatment after flame process. Their crystallinities increased with increasing the fuel flow rate and increased significantly by heat treatment of 800C for 2 hours after flame process.

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Phenolic Antioxidants

Robin L. M. Cheung, BScH, MBA

Abstract: Oxygen. It’s a matter of life and death. Without oxygen most life on earth would cease to exist. But the same reactivity that makes it ideal for using sugars for energy can also backfire and damage the very cells that are using that energy. If allowed to run amok, oxygen can damage DNA, lipids, or proteins. Damage to DNA will either kill cells or turn cancerous. Damage to lipids causes damage to membranes. Damage to proteins inactivates enzymes. All of these effects result in serious disease.
Over time, evolution has developed ways to help mitigate this problem. Antioxidants are compounds that help protect cells from oxidative damage. They function by blocking the reactive compounds caused by oxygen. A quick glance at a drug store’s health food area will demonstrate the tremendous growth in popularity of antioxidants.
Although the popular press provides a lot of recommendations and superficial second-hand information about antioxidants, many of these reports misinterpret original research findings. It is only by referring to primary research journals critically that we can find the truth about antioxidants.
One particular class of antioxidants is the group of phenolic antioxidants. They are so called because they are based on phenol, an alcohol composed of a benzene ring and a hydroxyl group. These are particularly interesting because as recently as a few years ago, they were believed only to be important for flavour (Escarpa and Gonzales 2001).

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Saturday, July 23, 2011

Studi Pengaruh Proses Pencucian Garam Terhadap Komposisi Dan Stabilitas Yodium Garam Konsumsi

Nelson Saksono

Abstract: Effect of Salt Washing Process on Content and Iodium Stability of Salt. Salt washing process should increase the salt quality. It should clean the salt from sludge or clay and also reduce the impurity compound such as Mg, Ca and the reductor content. The objective of these reseach is to assess the effect of washing process on the content og hygroscopic impurities compound (Ca and Mg), and reductor content of salt. The research also investigate the water absorbing, pH, KIO3 content as function of time to obtain effect of washing process on KIO3 stability in salt. The experiment result shows that the lowest content of Mg and reductor compound 0.016 % wt and 2.65 ppm respectively which is reached at the fi ne salt washing process using 27 % wt brine. The analysis of water content indicates an increase the Ca and Mg content, causing an water absorbtion in salt , However the effect on pH the is not clear.

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Saturday, July 16, 2011

Downsized Chelating Resin-Packed Minicolumn Preconcentration For Multielement Determination Of Trace Metals by ICP-MS

Chelating resin-packed minicolumn preconcentration was used for multielement determination of trace metals in seawater by inductively coupled plasma mass spectrometry (ICP-MS). The chelating resin-packed minicolumn was constructed with two syringe filters (DISMIC 13HP and Millex-LH) and an iminodiacetate chelating resin (Chelex 100, 200-400 mesh), with which trace metals in 50 mL of original seawater sample were concentrated into 0.50 mL of 2 M nitric acid, and then 100-fold preconcentration of trace metals was achieved. Then, 0.50 mL analysis solution was subjected to the multielement determination by ICP-MS equipped with a MicroMist nebulizer for micro-sampling introduction. The preconcentration and elution parameters such as the sample-loading flow rate, the amount of 1 M ammonium acetate for elimination of matrix elements and the amount of 2 M nitric acid for eluting trace metals was optimized to obtain good recoveries and analytical detection limits for trace metals. The analytical results for V, Mn, Co, Ni, Cu, Zn, Mo, Cd, Pb, and U in three kinds of seawater certified reference materials (CRMs; CASS-3, NASS-4, and NASS-5) agreed well with their certified values. The observed values of rare earth elements (REEs) in the above seawater CRMs were also consistent with the reference values. Therefore, the compiled reference values for the concentrations of REEs in CASS-3, NASS-4, and NASS-5 were proposed based on the observed values and reference data for REEs in these CRMs.

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SYNTHESIS OF PbSe thin film by chemical bath deposition AND ITS CHARACTERIZATION USING XRD, SEM AND UV-Vis SPECTROPHOTOMETER

Lead selenide thin films were prepared by chemical bath deposition method using aqueous of lead nitrate, sodium selenate and sodium tartrate. The influence of bath temperature towards the properties of the thin films was studied. The films were characterized by X-ray diffraction, scanning electron microscopy and UV-Vis spectrophotometer. The XRD results confirmed the polycrystalline cubic structure of PbSe films. The intensity of major peak at 2ϴ=25.1° which belonged to (111) plane of PbSe, increased with bath temperature from 40 to 80 °C. The SEM micrographs showed that the most homogeneous surface and larger grain sizes could be seen for the films deposited at 80 °C as compared with other bath temperatures.

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Performance Of Hollow Fiber Membrane Gas-Liquid Contactors To Absorb CO2 Using Diethanolamine (DEA) As A Solvent

This study uses DEA solution to absorb CO2 from the gas flow through the hollow fiber membrane contactors. This study aims to evaluate the performance of hollow fiber membrane contactors to absorb CO2 gas using DEA solution as solvent through mass transfer and hydrodynamics studies. The use of DEA solution is to reduce the mass transfer resistance in the liquid phase, and on the other side, the large contact area of the membrane surface can cover the disadvantage of membrane contactors; additional mass transfer resistance in the membrane phase. During experiments, CO2 feed flows through the fiber lumens, while the 0.01 M DEA solution flows in the shell side of membrane contactors. Experimental results show that the mass transfer coefficients and fluxes of CO2 increase with an increase in both water and DEA solution flow rates. Increasing the amount of fibers in the contactors will decrease the mass transfer and fluxes at the same DEA solution flow rate. Mass transfer coefficients and CO2 fluxes using DEA solution can achieve 28,000 and 7.6 million times greater than using water as solvent, respectively. Hydrodynamics studies show that the liquid pressure drops in the contactors increase with increasing liquid flow rate and number of fibers in the contactors. The friction between water and the fibers in the contactor was more pronounced at lower velocities, and therefore, the value of the friction factor is also higher at lower velocities.

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Effects Of pH On Calcium Carbonate Precipitation Under Magnetic Field

Magnetic field effect on CaCO3 precipitation is the key parameter in evaluating the effectiveness of Anti-scale Magnetic Treatment (AMT). The purpose of this study was to investigate magnetic fields influence on CaCO3 precipitation in high and low super-saturated CaCO3 solution by varied pH CaCO3 solution using circulation flow fluid system. The observation results in the high super saturated solution (pH 8.5) showed the increase of precipited CaCO3 in magnetized solutions compared to those in non-magnetic solution during circulation process. In the low super-saturated CaCO3 solution (pH 6.4) it was found that magnetic treatment increased CaCO3 precipitation after circulation process. In high super-saturated solution, magnetic field strengthens ion interactions, which reduce precipitation during circulation process. However, in low super-saturated CaCO3 solution, magnetic field weakens hydrate ion interaction which indicated by decreasing of the conductivity of solution. It increases the precipitation of CaCO3 after the circulation of magnetization process has completed.

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A Simple Technique For Surface Area Determination Through Supercritical Co2 Adsorption

The measurement of specific surface area of porous materials has long been important in physical sciences and is currently growing in importance in applied and environmental science. Numerous systems have been developed for surface area measurement by gas adsorption. Commercial systems are available which can measure a wide range of absolute surface area with relative ease. However, their cost is often prohibitive. In this study, an inexpensive apparatus for surface area measurement has been set up to be used for measuring supercritical adsorption of CO2. The Ono-Kondo Lattice model was used to represent the adsorption isotherm and to determine the surface area. The results of surface area determination using CO2 adsorption combined with OK model have been compared to the numbers obtained from nitrogen BET method. For surface area determination of zeolites and activated carbons, the new method give reasonable agreement results (within 10% deviation) compared to the results obtained from nitrogen BET method. In addition, the new method also gives more reasonable results for surface area determination of coals. As known, the nitrogen BET method gives almost zero of coals' surface area. This might due to the characteristic of the coals' structure that might be change (the pores are closed) during the cooling process in nitrogen BET method. Moreover, the new method can also be used to determine the surface area of porous materials using CO2 adsorption data at various temperatures without sacrificing their accuracy.

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Effect Of Diafiltration On Preparation Of Fermented Mung Beans Concentrate As Probiotic Savory Flavor Through Ultrafiltration Membrane

Diafiltration by means of the ultrafiltration system of probiotic fermented Mung beans (Phaseolus radiatus L.) concentrate has been performed to reduce or eliminate salts and smaller impurities than the nominal cut-off of the membrane of 20,000 nominal weight cut-off (NWCO). These processes have been conducted as an attempt in order to get a probiotic product with organoleptic acceptability, composition, and the optimal total lactic acid bacteria (LAB) counts because the presence of salts will affect on the viability of LAB and the cell lysis of LAB and limit its utility in food products. Concentrate of probiotic mung beans was prepared through fermentation of LAB using inoculum of LAB consisting of Lactobacillus bulgaricus and Streptococcus thermophylus (1 : 1) on fermented mung beans extract inoculated by inoculum of Rhizopus–C1 in rice substrates at salt condition. Ultrafiltration and diafiltration modes have been carried out at flow rate of 8.77 Liter/minute, room temperature and the pressure of 5 bar (0 to 79.7 minutes) and 7 bar (0-154.5 minutes) with the ratio of the volume of pure water to the volume of initial feed (number of diavolume, Nd) of 0, 0.25, 0.5, 0.75, 1.0 and 1.25, respectively. The experiment results based on total LAB counts as a probiotic product show that a high Nd can reduce the salt content but increase the total LAB counts. Nd of 1.0 results reduce the salt content which is equal to retentate, permeate, and the optimal total LAB counts. Ultrafiltration and diafiltration modes at the pressure of 7 bar and Nd of 1.0 give a retentate with total solid of 6.1355%, salt of 1.3515% and remove 86.15% of the salt from probiotic fermented mung beans concentrate and total LAB counts of 10.73 log cycles. Meanwhile, the permeate obtained at this condition results in flux value of 10.83 Liter/m2.hour with contents of total solid of 6.8199%, salt of 1.325% and total LAB counts of 5.49 log cycles.

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An Empirical Model For Build-Up Of Sodium And Calcium Ions In Small Scale Reverse Osmosis

A simple models for predicting build-up of solute on membrane surface were formulated in this paper. The experiments were conducted with secondary effluent, groundwater and simulated feed water in small-scale of RO with capacity of 2000 L/d. Feed water used in the experiments contained varying concentrations of sodium, calcium, combined sodium and calcium. In order to study the effect of sodium and calcium ions on membrane performance, experiments with ground water and secondary effluent wastewater were also performed. Build-up of salts on the membrane surface was calculated by measuring concentrations of sodium and calcium ions in feed water permeate and reject streams using Atomic Absorption Spectrophotometer (AAS). Multiple linear regression of natural logarithmic transformation was used to develop the model based on four main parameters that affect the build-up of solute in a small scale of RO namely applied pressure, permeate flux, membrane resistance, and feed concentration. Experimental data obtained in a small scale RO unit were used to develop the empirical model. The predicted values of theoretical build-up of sodium and calcium on membrane surface were found in agreement with experimental data. The deviation in the prediction of build-up of sodium and calcium were found to be 1.4 to 10.47 % and 1.12 to 4.46%, respectively.

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