Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
8 results
Search Results
Item Liquid-liquid equilibrium of poly(ethylene glycol) 4000 + diammonium hydrogen phosphate + water at different temperatures(2008) Amaresh, S.P.; Murugesan, S.; Iyyaswami, I.; Murugesan, T.Liquid-liquid equilibrium for an aqueous two-phase system containing poly(ethylene glycol) 4000 + diammonium hydrogen phosphate + water was studied at four different temperatures of (25, 30, 35, and 45)°C. The binodal curve was fitted to three different empirical equations relating the concentrations of PEG 4000 and diammonium hydrogen phosphate, and the coefficients were estimated for the respective temperatures for all three equations. The effective excluded volume values were obtained from the binodal model for the present system, and salting-out ability of the salt was discussed. Tie line compositions were correlated using the Othmer-Tobias and Bancroft equations, and the parameters are also reported. Further, the experimental binodal data of the poly(ethylene glycol) 4000 + diammonium hydrogen phosphate + water system were compared to poly(ethylene glycol) 6000 + diammonium hydrogen phosphate + water for (25, 35, and 45)°C. © 2008 American Chemical Society.Item Densities and viscosities of poly(ethylene glycol) 4000 + diammonium hydrogen phosphate + water systems(2009) Iyyaswami, I.; Murugesan, S.; Amaresh, S.P.; Govindarajan, R.; Murugesan, T.The densities and viscosities of binary and ternary solutions of the poly(ethylene glycol) 4000 (PEG4000) + diammonium hydrogen phosphate + water system were determined at different temperatures [(298.15, 303.15, 308.15, 313.15, and 318.15) K]. The measured density and viscosity data of all the binary and ternary systems were fitted to available empirical correlations, for the corresponding temperatures. The density data show a linear variation with mass fraction of the polymer for all temperatures. The viscosity data of all the solutions were correlated as a function of their mass fraction, using a nonlinear equation, for the five different temperatures covered in the present work. Densities and viscosities of PEG4000 - diammonium hydrogen phosphate two-phase systems have been measured at (298.15, 303.15, 308.15, 313.15, and 318.15) K. The tie line lengths (TLL) of the aqueous two-phase systems have also been estimated, and the effect of the physical properties on the TLL is also reported. © 2009 American Chemical Society.Item Liquid-liquid equilibrium of poly(ethylene glycol) 6000 + triammonium citrate + water systems at different temperatures(2009) Iyyaswami, I.; Murugesan, S.; Govindarajan, R.; Amaresh, S.P.; Murugesan, T.Liquid - liquid equilibrium for an aqueous two-phase system containing poly(ethylene glycol) 6000 + triammonium citrate + water was studied at five different temperatures, (25, 30, 35, 40, and 45) °C. The binodal curve was fitted to an empirical equation relating the concentrations of PEG 6000 and triammonium citrate, and the coefficients were estimated for the respective temperatures. The effective excluded volume values were obtained from the binodal data. Tie line compositions were estimated and correlated using Othmer - Tobias and Bancroft equations, and the parameters are reported. © 2009 American Chemical Society.Item Densities and viscosities of polyethylene glycol 6000 + triammonium citrate + water systems(2009) Iyyaswami, I.; Govindarajan, R.; Amaresh, S.P.; Murugesan, T.The densities and viscosities of binary and ternary solutions of the aqueous two-phase systems created by the polyethylene glycol 6000 + triammonium citrate + water system were measured at different temperatures [(25, 30, 35, 40, and 45) °C] and correlated with empirical equations. The density data were compared with those available in the literature. The density data show a linear variation with the mass fraction of the polymer for all temperatures. The density and viscosity of the top and bottom phases were also measured and reported. © 2009 American Chemical Society.Item Liquid-liquid equilibrium of poly(ethylene glycol) 2000 + diammonium hydrogen citrate + water system at different temperatures(2011) Iyyaswami, I.; Srikanth, C.K.; Sindhu, N.Phase diagrams and liquid-liquid equilibrium (LLE) data of the aqueous poly(ethylene glycol) (PEG-2000) + diammonium hydrogen citrate system (aqueous two-phase system) has been determined experimentally at (298.15, 303.15, 308.15, 313.15, and 318.15) K. The effects of temperature on the binodal curve and tie-lines have been studied. The binodal curve was fitted to an empirical equation relating the concentrations of PEG 2000 and diammonium hydrogen citrate, and the coefficients were estimated for the respective temperatures. Tie line compositions were estimated and correlated using Othmer-Tobias and Bancroft equations, and the parameters are reported. The effect of temperature on the phase-forming ability in the investigated system has been studied based on a salting-out coefficient; obtained from fitting the binodal data to a Setschenow-type equation for each temperature. The effective excluded volume values were also calculated from the binodal data. © 2011 American Chemical Society.Item Densities and viscosities of binary and ternary mixtures and aqueous two-phase system of poly(ethylene glycol) 2000 + diammonium hydrogen citrate + water at different temperatures(2012) Kalaivani, S.; Srikanth, C.K.; Iyyaswami, I.The densities and viscosities of aqueous solutions of poly(ethylene glycol) (PEG-2000) and diammonium hydrogen citrate were determined for mass fractions from 0.05 to 0.5 at different temperatures of (298.15, 303.15, 308.15, 313.15, and 318.15) K. The density data show a linear variation with mass fraction of the polymer and salt for all temperatures. The viscosity data of PEG 2000 and diammonium hydrogen citrate solutions were correlated as a function of mass fraction, using a nonlinear equation, for the five different temperatures covered in the present work. Densities and viscosities of PEG-diammonium hydrogen citrate two-phase systems have also been measured at (298.15, 303.15, 308.15, 313.15, and 318.15) K and are correlated with composition. The tie-line lengths (TLL) of the aqueous two-phase systems have also been estimated. © 2012 American Chemical Society.Item Partitioning studies of glutaminase in polyethylene glycol and salt-based aqueous two-phase systems(2013) Bolar, S.; Belur, P.D.; Iyyaswami, I.The partitioning behavior of glutaminase produced from Zygosaccharomyces rouxii in polyethylene glycol (PEG)-salt aqueous two-phase systems (ATPSs) was investigated. ATPSs comprising of different PEG-salts were considered. Binodal data and tie lines generated for the selected systems were analyzed and correlated with Othmer-Tobias and Bancroft equations. Effects of salt type, PEG molecular weight, concentrations of phase components, and tie line length on enzyme partitioning were evaluated. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Item Partitioning studies of ?-lactalbumin in environmental friendly poly (ethylene glycol) - Citrate salt aqueous two phase systems(2013) Kalaivani, S.; Iyyaswami, I.Aqueous two-phase systems (ATPS) formed by polymer and salt have been utilized to enrich the desired biomolecule into one of the phase with higher yield and purity. The eco-friendly, biodegradable poly ethylene glycol (PEG) and different citrate salts were chosen as ATPS phase components to investigate the partitioning behavior of ?-lactalbumin (?-La). System factors and process parameters such as type and concentration of salt, molecular weight and concentration of PEG, pH, temperature and the effect of additives were studied and the results are discussed in detail. PEG 1000-tri-potassium citrate system yields high partition coefficient of 20 with a better yield of 98 % in the top phase. The addition of NaCl as an additive and acidic pH lowers the yield of ?-La in the top phase. Influence of phase volume ratio (V r) on partitioning was studied and found that the partition coefficient remains almost constant along the tie line. High yield was achieved at a V r of 3.5 at the tie line length of 50.63 (%, w/w). © 2013 Springer-Verlag Berlin Heidelberg.