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RISS 인기검색어
- 검색키워드
- 저자 : M. Rajeswari (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
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Continuous Biosorption of Cadmium by Moringa olefera in a Packed Column
M. Rajeswari,Pushpa Agrawal,S. Pavithra, Priya,G. R. Sandhya,G. M. Pavithra 한국생물공학회 2013 Biotechnology and Bioprocess Engineering Vol.18 No.2
The biosorption of Cd(II) by Moringa oleifera using a batch system and a continuous up flow mode in a fixed bed column was studied. Batch adsorption experiments were performed as a function of pH, biosorbent dose, contact time, volume of the solution, and initial metal concentration. The adsorption isotherms obtained fitted well into the Freundlich and Langmuir isotherms. The dynamic removal of cadmium by powdered seed of the Moringa oleifera was studied in a packed column. The effect of bed height (4 and 8 cm) and flow rate (2 and 5mL/min) on biosorption process was investigated and the experimental breakthrough curves were obtained. Results showed that by increasing the bed height and decreasing the flow rate, the breakthrough and exhaustion times increased. The break-through time was considered as a measure of the column performance. The maximum break-through time of 320 min was achieved at the operating condition of 2 mL/min influent flow rate and bed height of 8 cm.
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Binder burnout and sintering kinetic study of alumina ceramics shaped using methylcellulose
K. Rajeswari,S. Chaitanya,P. Biswas,M. Buchi Suresh,Y.S. Rao,Roy Johnson 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.1
Ceramic components are generally processed by the techniques such as compaction, extrusion, injection molding, casting etc., and the selection of forming method is generally based on the complexity of the shapes. Additives such as binders, plasticizers, surfactants and lubricants, which are generally organic in nature, play a significant role to ensure the flowability of the mass which is critical in shaping of ceramics. Alumina (α-Al2O3) powder was subjected to torque rheometric studies to identify Critical Volume Binder Concentrations (CBVC) corresponding to specific processing regimes. An initial torque value of 3-4Nm for compaction followed by 6-7N-m for extrusion and 2-3N-m for casting regimes were observed. Viscosities of the pre-mixes prepared by the addition of methyl cellulose (C6H7O2 (OH)x(OCH3)y, (where x = 1.0-1.5 and y = 2-1.45) as a binder were also found to exhibit a similar trend in viscosity, corresponding to CBVC torque values and are shaped into green specimens. Green strength of the standard specimens (45 × 4 × 3 mm) was estimated through 3-point bend tests and exhibited a good correlation with the binder content. Binder burnout characteristics were also elucidated by TG/DSC technique and activation energy estimated is 75-110 kJ/mol for the thermal degradation of methylcellulose binder. Activation energy of 883 ± 45 kJ/mol was estimated through kinetic analysis of sintering by the construction of the Master Sintering Curves (MSC).
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Synthesis of Acetins from Glycerol using Lipase from Wheat Extract
Pradima J,Rajeswari. M. Kulkarni,Archna Narula,Sravanthi Veluturla,Rakshith R,Nawal Rabia Nizar 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.4
New technology-driven biocatalysts are revolutionizing the biochemical industries. With maximum utilization of renewable feedstock, biocatalysts have been the basis for a major breakthrough. Lipases are the most widely established catalysts used for hydrolysis, esterification and transesterification reactions. In this research, a biochemical process that combines extraction of lipase enzyme from germinated wheat seeds and its application to valorize glycerol to acetins by esterification is presented. Acetins are among highly rated, value-added products derived from glycerol. The favorable conditions for the enzymatic conversion of glycerol were observed as glycerol to acetic acid molar ratio (1:5), reaction temperature (40 o C) and the amount of enzyme (20% v/v). 65.93% of glycerol conversion was achieved for duration of 15 h with the use of tert-butanol solvent. This method proposes to explore the viability of a biological route to convert glycerol derived from biodiesel industry to acetins with further streamlining.
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( Pradima J Britto ),( Rajeswari M Kulkarni ),( Archna Narula ),( Sunaina Poonacha ),( Rakshita Honnatagi ),( Sneha Shivanathan ),( Waasif Wahab ) 한국화학공학회 2022 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.60 No.1
Biodiesel production has attracted attention as a sustainable source of fuel and is a competitive alternate to diesel engines. The glycerol that is produced as a by-product is generally discarded as waste and can be converted to green chemicals such as acetins to increase bio-diesel profitability. Acetins find application in fuel, food, pharmaceutical and leather industries. Batch experiments and analysis have been previously conducted for synthesis of acetins using glycerol esterification reaction aided by sulfated metal oxide catalysts (SO<sub>4</sub> <sup>2-</sup>/CeO<sub>2</sub>-ZrO<sub>2</sub>). The aim of this study was to optimize process parameters: effects of mole ratio of reactants (glycerol and acetic acid), catalyst concentration and reaction temperature to maximize glycerol conversion/acetin selectivity. The optimum conditions for this reaction were determined using response surface methodology (RSM) designed as per a five-level-three-factor central composite design (CCD). Statistica software 10 was used to analyze the experimental data obtained. The optimized conditions obtained were molar ratio - 1:12, catalyst concentration - 6 wt.% and temperature -90 ℃. A packed bed reactor was fabricated and column studies were performed using the optimized conditions. The breakthrough curve was analyzed.
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Veluturla, Sravanthi,Narula, Archna,Rao, D. Subba,Indraja., S,Kulkarni, Rajeswari. M. The Korean Institute of Chemical Engineers 2018 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.56 No.4
An increase in the global production of biodiesel has resulted in the newfound significance of its byproduct, glycerol. The synthesis of acetins is an economical avenue to enhance the value of glycerol derived from biodiesel. WE developed an eco-friendly process for the synthesis of fuel additives from glycerol using a mixed oxide $SO{_4}^{2-}/CeO_2-Al_2O_3$ as catalyst. The $CeO_2-Al_2O_3$ mixed oxide was synthesized by the combustion method and then sulfated. The characterization of the catalyst was by means of XRD, BET, FTIR, and SEM. The influence of temperature, mole ratio and catalyst loading on yield and selectivity of the acetins was studied for the esterification of glycerol. The reaction rate constants ($k_1$, $k_2$ and $k_3$) were estimated using optimization method in MAT lab, and the activation energies ($E_1$, $E_2$ and $E_3$) were determined by the Arrhenius equation. Furthermore, a kinetic model was developed.
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