oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Caustic Activation of Local Clays for Palm Oil Bleaching
C.A. Okwara,E.C. Osoka
Journal of Engineering and Applied Sciences , 2012,
Abstract: Local clay samples were obtained and activated for use in palm oil bleaching. The clay samples: Kaolin (from Mbano in Imo State), Bentonite (from Ohaozara in Ebonyi State) and Fuller s earth (from Bauchi in Bauchi State) were activated at 80-85°C for 35 to 40 min, using caustic soda (NaOH) at concentrations of 1M, 2M, 3M and 4M, respectively. The alkali-activated clays were then tested on palm oil of 7.68% FFA, 0.9 moisture and volatile content and 67.95 colour. The bleaching was done at about 150°C within 20 min and a Lovibond (two cell) tintometer was used to measure the extent of bleaching in terms of percentage colour reduction. The percentage colour reduction of the bleached palm oil was modelled against alkali concentration used in clay activation for the three samples. The results obtained reveal that, within the range of the experimental data, the percentage colour reduction for Kaolin and Fuller s earth can be adequately modelled using a third order polynomial with correlation coefficients of unity respectively, while that of Bentonite can be modelled using a logarithmic function with a correlation coefficient of 0.9866. Based on the models, Kaolin and Fuller s earth gave the best results when activated with 3M and 2.9M NaOH solutions respectively-giving percentage colour reductions of 76.38 and 80.69% respectively-while optimum performance for Bentonite was after activation with 1M NaOH solution, which gave 78.66% colour reduction.
Performance Evaluation of Acid Treated Clays for Palm Oil Bleaching
T.O. Salawudeen,E.O. Dada,S.O. Alagbe
Journal of Engineering and Applied Sciences , 2012,
Abstract: Palm oil bleaching using acid treated clay was investigated. Colorimeter was used to determine the colour in form of absorbance for the crude and refined palm oil. These were used to determine the percentage colour reduction. Effects of acid type, acid concentration and mass of adsorbent using Freudlich adsorption isotherms were studied. Results of the investigation revealed that HCl activated clay has relatively higher bleaching power than H2SO4 activated clay. The increase in acid concentration increases bleaching efficiency. The maximum percentage colour reduction of 94.28% was achieved in HCl activated clay at 45% acid concentration, while 89.46% colour reduction at 35% acid concentration was achieved with H2SO4 activated clay. Further increase in concentration of H2SO4 has no significant effect. The Freudlich adsorption constant n and k values for various clay samples showed that sample E has the highest bleaching power with 94.28% colour reduction, followed by sample A with 85.00% and sample B with 84.82%, samples C and D are not very effective in the activated state.
Adsorption of Palm Oil Carotene and Free Fatty Acids onto Acid Adsorption of Palm Oil Carotene and Free Fatty Acids onto Acid Activated Cameroonian Clays  [PDF]
Nde-Aga Binwie Joy,Kamga Richard,Nguetnkam Jean Pierre
Journal of Applied Sciences , 2007,
Abstract: The adsorption of carotene and free fatty acids from crude palm oil by local clay, activated with various concentrations of sulphuric acid (0.5, 1 and 2 M) was investigated. Kinetic studies of the adsorption of carotene and of free fatty acids at 65, 80 and 90°C, showed that the time required attaining adsorption equilibrium decreases as the temperature increases, regardless of the adsorbent used. Clay activated with 1 M sulphuric acid solution was the most efficient local clay for the adsorption of carotene and of free fatty acid and it compared favourably with the industrial clay used as reference. The bleaching efficiency of local clay was correlated to the surface area of the adsorbents. It was found that the Freundlich equation is applicable to the adsorption isotherms of carotene from palm oil. The Brimberg model used to determine the activation energy of the adsorption process gave the values, 82±12, 72±11, 74±11 and 37±6 kJ mol ̄1, for industrial adsorbent, 0.5, 1 and 2 M activated clays, respectively.
Sunflower oil bleaching by adsorption onto acid-activated bentonite
Foletto, E. L.;Colazzo, G. C.;Volzone, C.;Porto, L. M.;
Brazilian Journal of Chemical Engineering , 2011, DOI: 10.1590/S0104-66322011000100018
Abstract: two bentonite clays with different mineralogical compositions from mendoza, argentine, were activated with h2so4 solutions of 4 and 8 n at 90oc for 3.5 hours. this treatment affected clay structural properties, as was shown by thermogravimetry, infrared spectrometry and chemical analysis. bleaching efficiency for sunflower oil was strongly dependent on the acid concentration used for clay activation. the samples have bleaching capacity comparable to that observed with a commercial adsorbent standard. the mineralogical composition of natural clays influenced the properties of the activated clays.
Clay Characterization and Optimisation of Bleaching Parameters for Palm Kernel Oil Using Alkaline Activated Clays  [PDF]
T. O. Salawudeen, A. O. Arinkoola, M. O. Jimoh, B. A. Akinwande
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2014, DOI: 10.4236/jmmce.2014.26060
Abstract: The optimum bleaching parameters (clay dose and bleaching time) for palm kernel oil were determined using alkaline activated clay locally sourced in Nigerian. Activation was carried out using NaOH and KOH. The raw and activated clay samples were characterized using XRD and XRF. Bleached oil was analyzed for % colour reduction (%CR) and percentage free fatty acid (FFA) content before and after bleaching. Alkaline activation resulted to total dissolution of Mg2+ and Ca2+ ions in the octahedral sheet. The activation also affected the tetrahedral sheet by reducing the % composition of the silica and alumina ion after the modification. The results showed that alkaline activation had significant effect on mineralogical and chemical composition of the clay samples. The optimum bleaching conditions (clay dosage and bleaching time) of 3%/weight of oil and 30 mins resulted in 33.3% CR and %FFA of 2.2. It was discovered that NaOH activated clay resulted to higher %CR while KOH activated clay shows affinity for reduced %FFA but at higher concentration of 5 M. This research has further established that alkaline activated clays are feasible alternative for acid activated clays in vegetable oil bleaching.
Using Trace Metals, Peroxide, Acid and Iodine Values to Characterize Oils Bleached Using Clays from Central and Eastern Uganda  [PDF]
Is’harq-Zubair Mukasa-Tebandeke, Pancras John Mukasa Ssebuwufu, Steven A. Nyanzi, Andreas Schumann, George W. Nyakairu, Festo Lugolobi
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.517136
Abstract: Bleaching of edible oils is known to alter the composition of oils as it removes impurities and certain food nutrients. The characteristics of bleached oil are strongly related to type bleaching medium, temperature at which bleaching is done and other factors. In this study, we compare peroxide, free fatty acid, acid and iodine values, copper and iron content of bleached and crude oils to establish the characteristics of edible oils bleached using smectite and kaolinite-rich clays. Oil industries spend large sums of money purchasing bleaching earths yet no country lacks natural clays which can be developed to bleach oils. In Uganda alone more than US$ 700,000 is spent every month yet many clay deposits are unexploited. In this study, we have documented trace metal composition, peroxide values, acid values, iodine values and free fatty acid content of bleached and unbleached cotton-seed and sunflower seed oils. The bleached oils were found to be fit for human use. Clays are either kaolinites or smectites, but the clays used to bleach edible oils are montmorillonites or bentonites. The decrease in content of iron in the bleached oils was highest for all oils bleached. The content of copper showed the smallest change. The content of copper in cotton oils decreased from 0.5 ppm to 0.15 ppm using Kajansi clay leached in 20% acid yet when Chelel clay leached under similar conditions was used decrease was from 0.5 to 0.1 ppm. The content of iron in sunflower oils bleached using Kajansi clay leached in 20% acid decreased from 1.6 to 0.2 ppm yet that bleached with Chelel clay under similar conditions decreased to 0.1 ppm. The acid values showed that the acidity in sunflower oils is largely due to oleic acid as the average value for acids is in the range close to oleic acid, cotton-seed oil corresponded to linoleic acid. The levels of free fatty acid were found to lie in range from 3.8 - 3.2 for all clays used showing no significant rise. The peroxide values of bleached oils lay between 1.2 and 0.8.
Evaluation of peanut hulls as an alternative to bleaching clays
Hassanein, M. M. M.,El- Shami, S. M.,Taha, F. S.
Grasas y Aceites , 2011, DOI: 10.3989/gya.113710
Abstract: Peanut hulls (PNH) were carbonized at different temperatures, times, and evaluated at different concentrations as an alternative to bleaching clays. Evaluation of bleached crude soybean oil with PNH was based on their delta free fatty acids, reduction in peroxide value (PV), reduction in phospholipids (PL) and bleachability. The performance of several commercially used bleaching clays was evaluated, for comparison. Mixtures were formulated including: PNH and Tonsil -N (TN), PNH and Fuller’s earth (FE) and PNH and O-passive (OP) and examined. The oxidative stability of oils was determined. Results for the investigated commercial bleaching clays revealed: TN > FE > F > TF > OP. Highest reduction in PV and PL, and highest bleachability were achieved for soybean oil bleached with 2% PNH carbonized at 500°C for 30 min (PNH”). Mixtures of PNH” with the three chosen bleaching clays indicated that 1PNH”: 2TN gave the highest bleachability. CSO was miscella bleached in hexane using PNH” and resulted in an appreciable improvement in all oil characteristics, especially in bleachability. Oxidative stability of oils was in the following order: TN > control > FE > PNH” with Induction period values of 23,1 > 6,43 > 5,73 > 2,85 h, respectively. Las cáscaras de maní (PNH) fueron carbonizadas a diferentes temperaturas y tiempos, y utilizadas a diferentes concentraciones como una alternativa a las tierras decolorantes. La evaluación de un aceite de soja decolorado con PNH se ha basado en sus ácidos grasos libres, reducción del índice de peróxidos (PV), reducción de los fosfolípidos (PL), y en la blanqueabilidad. El rendimiento de varias tierras decolorantes de uso comercial fue evaluado y comparado con el de PNH carbonizada. Las mezclas formuladas incluían: PNH y Tonsil-N (TN), PNH y tierras de Fuller (FE) y PNH y O-pasivo (OP). La estabilidad oxidativa de los aceites resultantes fue determinada. Los resultados revelaron que la efectividad de la decoloración con las tierras decolorantes investigadas fue el siguiente: TN > FE > F > TF > OP. La mayor reducción en PV y PL, y la mayor decoloración se logró para el aceite de soja blanqueado con un 2% de PHN carbonizada a 500°C durante 30 min (PNH”). Las mezclas de PHN” con las tres tierras de blanqueo elegidas indicaron que 1PHN”: 2TN dio el mayor porcentaje de decoloración. La miscela de aceite de soja crudo en hexano decolorada usando PNH” resultó mejorar apreciablemente todas las características del aceite, sobre todo la blanqueabilidad. La estabilidad oxidativa fue en el siguiente orden: TN > control > FE > PNH” con valore
DESULPHURIZATION OF LIQUID FUELS BY SELECTIVE ADSORPTION THROUGH MINERAL CLAYS AS ADSORBENTS  [cached]
M SHAKIRULLAH,W AHMAD,I AHMAD,M ISHAQ
Journal of the Chilean Chemical Society , 2012,
Abstract: Different clays collected from local sources, including Kaolinite, Montmorollinte, Palygorskite and Vermiculite have been utilized for the selective adsorption of sulphur compounds prevailing in petroleum products i.e. crude oil, kerosene and diesel oil. The desulphurization activity of the clay was compared with the charcoal, ion exchange resins and with each other. Desulphurization was performed in batch operation at different time intervals i.e 1, 3 and 6 hrs at 40 oC temperature. Out of different adsorbents used, Kaoilinte exhibited the maximum desulphurization yield of 60 %, 76 % and 64 % at 6 hrs adsorption incase of crude oil, kerosene and diesel oil respectively. All the mineral clays adsorbents were characterized by surface area, SEM and EDX analysis. The FT-IR study of the desulphurized fractions revealed that mostly high molecular weight thioles and thiophenic compounds were depleted during adsorption process.
Assessment of the process of cottonseed oil bleaching in hexane
Megahed, Ola A.
Grasas y Aceites , 2002,
Abstract: This work has been initiated to assess the feasibility of bleaching cottonseed oil in miscella as a processing step next to alkali refining in miscella. Alkali refining of cottonseed oil in miscella has several advantages over conventional refining technologies with respect to oil quality, oil losses and process cost. Therefore, the process efficiency of the bleaching of cottonseed oil in presence of hexane (at a volumetric ratio of 1:1), has been studied and compared to that without solvent. The process efficiency has been evaluated according to the decolourization capacity, the oil losses on spent earth, the filtration rate of the oil from the clay and the acidity of the bleached oil as well as its peroxide content. The bleaching in presence of hexane was carried out at 25 oC whereas that by conventional bleaching at 110 oC. Different clay loads were used in each of the two bleaching techniques and the colour indices of the oils before and after bleaching determined in each case. The results were used to predict Freundlich adsorption equations for the oil pigments in both cases. These equations were then used to predict the colour of the oils obtained by bleaching of refined oils of different grades. The results have shown that oil decolourization is more efficient in presence of solvent when the starting oil is of an acceptable grade and the reverse is true for low grade oils. Also, the possibility of oil oxidation during bleaching is less in presence of solvent. Moreover, the bleaching in miscella has proved two other additional advantages over conventional bleaching. The filtration of oil from clay is much faster in miscella bleaching and the oil losses on spent earth is lower. This will be reflected on the overall process economy. Este trabajo ha sido iniciado para evaluar la viabilidad de la decoloración del aceite de semilla de algodón en miscela como un paso de procesado próximo a la refinación alcalina en miscela. La refinación alcalina de aceite de semilla de algodón en miscela tiene varias ventajas sobre las tecnologías de refinación convencionales con respecto a la calidad del aceite, pérdida de aceite y coste del proceso. Por tanto, la eficacia del proceso de decoloración de aceite de semilla de algodón en presencia de hexano (a una relación volumétrica 1:1), ha sido estudiada y comparada a aquella sin solvente. La eficacia del proceso ha sido evaluada de acuerdo con la capacidad de decoloración, las pérdidas de aceite en tierras agotadas, la velocidad de filtración del aceite de la tierra decolorante y la acidez del aceite decolorado así c
Adsorption of herbicide triclopyr on homoionic clays
Liu Weiping,Alba Pusino,Fang Zhuo,Carlo Gessa
环境科学学报(英文版) , 1995,
Abstract: The adsorption of the herbicide triclopyr on homoionic Fe3+ , Al3+ , Cu2+ , K+ and Na+ exchanged montmorillonite samples was investigated and the adsorption isotherm was described by the Fre-undlich equation. The adsorption capacity decreased in the order Fe3+ , Al3+ , Cu2+) , Ca2+ , K+ and Na+-clays. The triclopyr adsorption from chloroform solution was also studied by analytical, spectroscopic, and X- ray powder diffraction techniques. IR results suggested that the adsorption involved the formation of hydrogen bonds with water molecules in the interlayer and might have involved both the protonation of the pyridinenitrogen atom, due to a proton transfer from the acid metal - bound water , and also the formation of directbounds between the carboxylate groups and the exchange cations. The pesticide forming complexes with interlayer cations in montmorillite in soils might be extractable by solvents and was therefore releaed into the environment.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.