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ABSTRACT: This study examined the individual and simultaneous adsorption of SO{in{itx}} (SO{in{it2}}) and NO{in{itx}} (NO-NO{in{it2}})
on activated carbon prepared from waste palm shell. The adsorption process was examined in a fixed bed reactor at low temperatures
(100\2-300\dgC). For individual adsorption without any catalytic activation, SO{in{itx}} showed good adsorption whereas NO{in{itx}}
was very much poor. In the simultaneous adsorption of SO{in{itx}} and NO{in{itx}}, SO{in{itx}} showed greater adsorption affinity
than NO{itx}. For palm shell activated carbon (PSAC) impregnated with metal catalyst (Ni and Ce) the concentration adsorbed
profile showed that the amount of SO{in{itx}} adsorbed decreased regularly, while the amount of the adsorbed NO{in{itx}} increased
irregularly. The properties of the pure and impregnated PSAC were analyzed by BET, SEM and EDX. These investigations indicated
that PSAC impregnated with metal catalyst is the determining factor in the adsorption of SO{in{itx}} and NO{in{itx}} simultaneously.
Science in China Series E Technological Sciences 04/2012; 52(1):198-203. · 1.02 Impact Factor
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ABSTRACT: Cerium (Ce) supported on palm-shell-activated carbon (PSAC) has been found to significantly increase its activity in simultaneous removal SO2 and NO from simulated flue gas. In the present study, the role of Ce on SO2 and NO removal was studied through reaction adsorption. The catalyst was characterized using BET, EDAX, and SEM. It was found that PSAC could remove SO2 only without the addition of Ce, and NO could be removed in the presence of Ce loaded over PSAC. The experimental results showed Ce10/PSAC catalyst at 100 °C yield the best breakthrough time for simultaneous removal of NO and SO2. NO removal lasted for 115 min, whereas SO2 for 165 min. As the Ce content was increased from 5 to 12%, NO conversion increased significantly, but dropped with further increase in Ce content. Higher temperatures do not encourage the simultaneous adsorption of SO2 and NO. It was found that SO2 and NO create competitive phenomenon toward the active sites of PSAC and Ce/PSAC. SO2 removal was not affected by the addition of Ce because PSAC played an important role of SO2 adsorption and Ce presences promoted the adsorption rate.
11/2009;
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ABSTRACT: This work examines the impregnated carbon-based sorbents for simultaneous removal of SO(2) and NOx from simulated flue gas. The carbon-based sorbents were prepared using palm shell activated carbon (PSAC) impregnated with several metal oxides (Ni, V, Fe and Ce). The removal of SO(2) and NOx from the simulated flue gas was investigated in a fixed-bed reactor. The results showed that PSAC impregnated with CeO(2) (PSAC-Ce) reported the highest sorption capacity among other impregnated metal oxides for the simultaneous removal of SO(2) and NOx. PSAC-Ce showed the longest breakthrough time of 165 and 115 min for SO(2) and NOx, respectively. The properties of the pure and impregnated PSAC were analyzed by BET, FTIR and XRF. The physical-chemical features of the PSAC-Ce sorbent indicated a catalytic activity in both the sorption of SO(2) and NOx. The formation of both sulfate (SO(4)(2-)) and nitrate (NO(3-)) species on spent PSAC-Ce further prove the catalytic role played by CeO(2).
Journal of hazardous materials 11/2009; 176(1-3):1093-6. · 4.14 Impact Factor
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ABSTRACT: Optimizing the production of microporous activated carbon from waste palm shell was done by applying experimental design methodology. The product, palm shell activated carbon was tested for removal of SO2 gas from flue gas. The activated carbon production was mathematically described as a function of parameters such as flow rate, activation time and activation temperature of carbonization. These parameters were modeled using response surface methodology. The experiments were carried out as a central composite design consisting of 32 experiments. Quadratic models were developed for surface area, total pore volume, and microporosity in term of micropore fraction. The models were used to obtain the optimum process condition for the production of microporous palm shell activated carbon useful for SO2 removal. The optimized palm shell activated carbon with surface area of 973 m(2)/g, total pore volume of 0.78 cc/g and micropore fraction of 70.5% showed an excellent agreement with the amount predicted by the statistical analysis. Palm shell activated carbon with higher surface area and microporosity fraction showed good adsorption affinity for SO2 removal.
Bioresource technology 11/2008; 100(4):1614-21. · 4.25 Impact Factor
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Computers & Chemical Engineering. 01/2007; 31:1187-1198.
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ABSTRACT: High performance sorbents for flue gas desulfurization can be synthesized by hydration of coal fly ash, calcium sulfate, and calcium oxide. In general, higher desulfurization activity correlates with higher sorbent surface area. Consequently, a major aim in sorbent synthesis is to maximize the sorbent surface area by optimizing the hydration conditions. This work presents an integrated modeling and optimization approach to sorbent synthesis based on statistical experimental design and two artificial intelligence techniques: neural network and genetic algorithm. In the first step of the approach, the main and interactive effects of three hydration variables on sorbent surface area were evaluated using a full factorial design. The hydration variables of interest to this study were hydration time, amount of coal fly ash, and amount of calcium sulfate and the levels investigated were 4-32 h, 5-15 g, and 0-12 g, respectively. In the second step, a neural network was used to model the relationship between the three hydration variables and the sorbent surface area. A genetic algorithm was used in the last step to optimize the input space of the resulting neural network model. According to this integrated modeling and optimization approach, an optimum sorbent surface area of 62.2m(2)g(-1) could be obtained by mixing 13.1g of coal fly ash and 5.5 g of calcium sulfate in a hydration process containing 100ml of water and 5 g of calcium oxide for a fixed hydration time of 10 h.
Chemosphere 02/2006; 62(1):89-96. · 3.21 Impact Factor
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ABSTRACT: Optimizing the production of microporous activated carbon from waste palm shell was done by applying experimental design methodology. The product, palm shell activated carbon was tested for removal of SO2 gas from flue gas. The activated carbon production was mathematically described as a function of parameters such as flow rate, activation time and activation temperature of carbonization. These parameters were modeled using response surface methodology. The experiments were carried out as a central composite design consisting of 32 experiments. Quadratic models were developed for surface area, total pore volume, and microporosity in term of micropore fraction. The models were used to obtain the optimum process condition for the production of microporous palm shell activated carbon useful for SO2 removal. The optimized palm shell activated carbon with surface area of 973 m2/g, total pore volume of 0.78 cc/g and micropore fraction of 70.5% showed an excellent agreement with the amount predicted by the statistical analysis. Palm shell activated carbon with higher surface area and microporosity fraction showed good adsorption affinity for SO2 removal.
Bioresource Technology.
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ABSTRACT: A hybrid silica gel-‘succinic acid-zinc acetate’ catalyst (SG-SAZnA) was synthesized for the esterification of palmitic acid with isopropanol. The scanning electron microscope (SEM) and X-ray diffraction (XRD) studies indicated the presence of a crystalline compound formed by the interaction of the surface succinic acid fragment and zinc acetate. The high thermal stability and catalytic activity of SG-SAZnA catalyst excluded the possibility of breaking of the bond between SA and the silica gel surface. The SG-SAZnA catalyst was mildly acidic, its surface area and average pore size were in the range of mesopores. The kinetics of the esterification of palmitic acid and isopropanol catalyzed by SG-SAZnA catalyst was studied in a stirred batch reactor for the synthesis of isopropyl palmitate. The effects of stirrer speed, reaction temperature, feed molar ratio, catalyst loading and reusability of the catalyst were evaluated. The SG-SAZnA catalyst activity was found to be higher compared to the hybrid silica gel–zinc acetate material (SG-ZnA) for the esterification reaction. The catalyst showed a long life and could be reused for various catalytic cycles without deactivation. The experimental reaction rates were correlated using different rate models. These models include the pseudo-homogeneous, Eley–Rideal and Langmuir Hinshelwood Hougen Watson models. The Langmuir Hinshelwood Hougen Watson (LHHW) model fitted the experimental kinetic data well over a wide range of operating conditions. The reaction parameters obtained from LHHW model were useful for the design of a catalytic distillation column for the production of isopropyl palmitate.
Applied Catalysis A: General. 297(1):8-17.
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ABSTRACT: Fatty acid esterification is increasingly realized as a reactive distillation (RD) process because of its formation being affected by the chemical equilibrium. The reactive distillation column performance for the production of isopropyl palmitate by esterification of the palmitic acid with isopropanol has been studied in the present research. The reaction was catalyzed in the presence of zinc acetate supported on functionalized silica gel catalyst. The process parameters such as total feed flow rate, reboiler temperature, palmitic acid feed composition, palmitic acid feed temperature, molar ratio of isopropanol feed to palmitic acid feed and reflux ratio were studied experimentally in the catalytic distillation column. Two types of models were used for the simulation of catalytic distillation column. These were (a) equilibrium stage model and (b) rate-based model. The predictions from the rate-based model matched with the experimental results qualitatively and quantitatively. The simulation study was also carried out to determine the effects of other important parameters and design factors such as the column pressure, distillate to feed ratio, feed location, catalyst weight, height of reactive zone and height of separation zones. A technically optimized RD process for the production of isopropyl palmitate has been proposed on the basis of the experimental and simulated data.
Computers & Chemical Engineering.
