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şeyda şen Cagatay - One of the best experts on this subject based on the ideXlab platform.
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continuous fixed bed biosorption of reactive dyes by dried rhizopus arrhizus determination of column capacity
Journal of Hazardous Materials, 2007Co-Authors: Zumriye Aksu, şeyda şen Cagatay, Ferda GonenAbstract:Abstract A continuous fixed bed study was carried out by using dried Rhizopus arrhizus as a biosorbent for the removal of three reactive dyes; Gemacion (Procion) Red H-E7B (GR), a monoclorotriazine mono-azo type reactive dye; Gemazol Turquise Blue-G (GTB), a vinyl sulfone mono-azo type reactive dye and Gemactive (Reactive) Black HFGR (GB), a vinyl sulfone di-azo type reactive dye from aqueous solution. The effect of operating parameters such as Flow Rate and inlet dye concentration on the sorption characteristics of R. arrhizus was investigated at pH 2.0 and at 25 °C for each dye. Data confirmed that the total amount of sorbed dye decreased with increasing Flow Rate and increased with increasing inlet dye concentration for each dye. The column biosorption capacity of dried R. arrhizus was 1007.8 mg g−1 for GR dye, 823.8 mg g−1 for GTB dye and 635.7 mg g−1 for GB dye at the highest inlet dye concentration of approximately 750 mg l−1 and at the Minimum Flow Rate of 0.8 ml min−1. Thomas and Yoon–Nelson models were applied to experimental data to predict the breakthrough curves and to determine the biosorption capacity of the column for each dye useful for process design. Both models were found suitable for describing the whole dynamic behavior of the column with respect to Flow Rate and inlet dye concentration.
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investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and continuous systems
Separation and Purification Technology, 2006Co-Authors: Zumriye Aksu, şeyda şen CagatayAbstract:Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and continuous packed bed sorption systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and Flow Rate and inlet dye concentration in the continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing Flow Rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the Minimum Flow Rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to Flow Rate and inlet dye concentration.
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investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and continuous systems
Separation and Purification Technology, 2006Co-Authors: Zumriye Aksu, şeyda şen CagatayAbstract:Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and continuous packed bed sorption systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and Flow Rate and inlet dye concentration in the continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing Flow Rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the Minimum Flow Rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to Flow Rate and inlet dye concentration.
F. J. Higuera - One of the best experts on this subject based on the ideXlab platform.
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Qualitative analysis of the Minimum Flow Rate of a cone-jet of a very polar liquid
Journal of Fluid Mechanics, 2017Co-Authors: F. J. HigueraAbstract:Electrostatic atomization of a liquid of finite electrical conductivity in the so-called cone-jet regime relies on the electric shear stresses that appear in a region of the liquid surface when a meniscus of the liquid is subjected to an intense electric field. An order of magnitude analysis is used to describe the Flow induced by these stresses, which drive the liquid of the meniscus into a jet that issues from the tip of the meniscus and breaks into droplets at some distance from it. When the dielectric constant of the liquid is large, the electric shear stresses extend into the jet and cause a depression that sucks liquid from the meniscus. The induced Flow Rate is estimated and shown to represent approximately the Minimum Flow Rate at which a cone-jet can be established. It is argued that the meniscus can be stabilized by the electric field that the charge of the jet induces on it. This stabilizing mechanism weakens when the Flow Rate supplied to the meniscus decreases, and its failure may determine an alternative Minimum Flow Rate for the cone-jet regime. The instability of the jet and existing scaling laws for the size of the spray droplets are discussed.
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charge separation in the conical meniscus of an electrospray of a very polar liquid its effect on the Minimum Flow Rate
Physics of Fluids, 2009Co-Authors: F. J. HigueraAbstract:An analysis is presented of the Flow and the distribution of charge in the meniscus of an electrospray of a very polar liquid which is fed with a low Flow Rate. The shape of the meniscus is taken to be a Taylor cone. The characteristic value of the Flow Rate at which the liquid ceases to be quasineutral in a certain relaxation region of the conical meniscus under the action of the applied field is estimated, and the current/Flow Rate characteristic of the electrospray is numerically computed in these conditions. A state of complete charge separation, in which the ions that are pushed by the electric field away from the tip of the meniscus cease to reach the jet of the electrospray, is found for a finite value of the Flow Rate, and no stationary solution exists below this Flow Rate. For very polar liquids of small viscosity, this Minimum Flow Rate is of the order of the experimental Minimum for the cone-jet regime when the flux of the electric field in the jet is taken into account. The Flow induced in the meniscus by the Coulomb force in the bulk of the liquid and the electric shear stress at its surface is computed and its effect on the distribution of charge and the Minimum Flow Rate is analyzed. Estimates of the Flow and the electric current in the jet are worked out for a range of Flow Rates above the Minimum.
Zumriye Aksu - One of the best experts on this subject based on the ideXlab platform.
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continuous fixed bed biosorption of reactive dyes by dried rhizopus arrhizus determination of column capacity
Journal of Hazardous Materials, 2007Co-Authors: Zumriye Aksu, şeyda şen Cagatay, Ferda GonenAbstract:Abstract A continuous fixed bed study was carried out by using dried Rhizopus arrhizus as a biosorbent for the removal of three reactive dyes; Gemacion (Procion) Red H-E7B (GR), a monoclorotriazine mono-azo type reactive dye; Gemazol Turquise Blue-G (GTB), a vinyl sulfone mono-azo type reactive dye and Gemactive (Reactive) Black HFGR (GB), a vinyl sulfone di-azo type reactive dye from aqueous solution. The effect of operating parameters such as Flow Rate and inlet dye concentration on the sorption characteristics of R. arrhizus was investigated at pH 2.0 and at 25 °C for each dye. Data confirmed that the total amount of sorbed dye decreased with increasing Flow Rate and increased with increasing inlet dye concentration for each dye. The column biosorption capacity of dried R. arrhizus was 1007.8 mg g−1 for GR dye, 823.8 mg g−1 for GTB dye and 635.7 mg g−1 for GB dye at the highest inlet dye concentration of approximately 750 mg l−1 and at the Minimum Flow Rate of 0.8 ml min−1. Thomas and Yoon–Nelson models were applied to experimental data to predict the breakthrough curves and to determine the biosorption capacity of the column for each dye useful for process design. Both models were found suitable for describing the whole dynamic behavior of the column with respect to Flow Rate and inlet dye concentration.
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investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and continuous systems
Separation and Purification Technology, 2006Co-Authors: Zumriye Aksu, şeyda şen CagatayAbstract:Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and continuous packed bed sorption systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and Flow Rate and inlet dye concentration in the continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing Flow Rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the Minimum Flow Rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to Flow Rate and inlet dye concentration.
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investigation of biosorption of gemazol turquise blue g reactive dye by dried rhizopus arrhizus in batch and continuous systems
Separation and Purification Technology, 2006Co-Authors: Zumriye Aksu, şeyda şen CagatayAbstract:Abstract Gemazol Turquise Blue-G, a vinyl sulfone mono-azo type reactive dye, containing copper-phtlalocyanine as cromofor group, was removed from its aqueous solution in batch and continuous packed bed sorption systems by using dried Rhizopus arrhizus as a biosorbent. Operating variables studied were temperature, initial pH, initial dye concentration and sorbent dosage in the batch stirred system and Flow Rate and inlet dye concentration in the continuous packed bed. In the batch system, the fungal biomass exhibited the highest dye uptake as 773.0 mg g−1 at 45 °C, at an initial pH value of 2.0, at an initial dye concentration of 812.6 mg l−1 for a biomass dosage of 0.5 g l−1. The Freundlich, Langmuir and Redlich–Peterson adsorption models were used for the mathematical description of the biosorption equilibrium and isotherm constants were evaluated at different temperatures. Equilibrium data fitted well the Langmuir model in the studied concentration (100–800 mg l−1) and temperature (25–45 °C) ranges. Sorption data were fitted to pseudo first-order, pseudo second-order and saturation type kinetic models assuming that the external mas transfer limitations in the system can be neglected. The dye uptake process was found to follow pseudo second-order and saturation type kinetics. The thermodynamic parameters calculated showed that the adsorption process is feasible and has an endothermic character. The effect of operating parameters on the sorption characteristics of R. arrhizus in the continuous packed bed was investigated at pH 2.0 and at 25 °C. Data confirmed that the total amount of sorbed dye and column sorption capacity decreased with increasing Flow Rate and increased with increasing inlet dye concentration. The maximum column biosorption capacity of dried R. arrhizus cells was 823.8 mg g−1 at the highest inlet dye concentration of 776.3 mg l−1 at the Minimum Flow Rate of 0.8 ml min−1. Thomas model was applied to experimental column data to determine the characteristic parameters of column useful for process design and to predict the breakthrough curves. The model was found suitable for describing the whole part of dynamic behavior of the column with respect to Flow Rate and inlet dye concentration.
Marco Magnani - One of the best experts on this subject based on the ideXlab platform.
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the Minimum Flow Rate of electrosprays in the cone jet mode
Journal of Fluid Mechanics, 2019Co-Authors: Manuel Gamerocastano, Marco MagnaniAbstract:Stable electrospraying in the cone-jet mode is restricted to Flow Rates above a Minimum, and understanding the physics of this constraint is important to improve this atomization technique. We study this problem by measuring the Minimum Flow Rate of electrosprays of tributyl phosphate and propylene carbonate at varying electrical conductivity (all other physical properties such as the density , surface tension and viscosity are kept constant and equal to those of the pure liquids), and through the analysis of numerical solutions. The experiments show that the dimensionless Minimum Flow Rate is a function of both the dielectric constant of the liquid and its Reynolds number, . This result is unexpected in the light of existing theories which, for the conditions investigated, predict a Minimum Flow Rate that depends only on and/or is marginally affected by . The experimental dependency on the Reynolds number requires the viscous stress to be a factor in the determination of the Minimum Flow Rate. However, the numerical solutions suggest that a balance of opposing forces including the fixing viscous stress, which at decreasing Flow Rates may lower the acceleration of the Flow to the point of making it unstable, is unlikely to be the cause. An alternative mechanism is the significant viscous dissipation taking place in the transition from cone to jet, and which at low Flow Rates cannot be supplied by the work done by the tangential electric stress in the same area. Instead, mechanical energy injected into the system farther downstream must be transferred upstream where dissipation predominantly takes place. This mechanism is supported by the balance between the energy dissipated and the work done by the electric stress in the transition from cone to jet, which yields a relationship between the Minimum Flow Rate, the Reynolds number and the dielectric constant that compares well with experiments.
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the Minimum Flow Rate of electrosprays in the cone jet mode
Journal of Fluid Mechanics, 2019Co-Authors: Manuel Gamerocastano, Marco MagnaniAbstract:Stable electrospraying in the cone-jet mode is restricted to Flow Rates above a Minimum, and understanding the physics of this constraint is important to improve this atomization technique. We study this problem by measuring the Minimum Flow Rate of electrosprays of tributyl phosphate and propylene carbonate at varying electrical conductivity . The experimental dependency on the Reynolds number requires the viscous stress to be a factor in the determination of the Minimum Flow Rate. However, the numerical solutions suggest that a balance of opposing forces including the fixing viscous stress, which at decreasing Flow Rates may lower the acceleration of the Flow to the point of making it unstable, is unlikely to be the cause. An alternative mechanism is the significant viscous dissipation taking place in the transition from cone to jet, and which at low Flow Rates cannot be supplied by the work done by the tangential electric stress in the same area. Instead, mechanical energy injected into the system farther downstream must be transferred upstream where dissipation predominantly takes place. This mechanism is supported by the balance between the energy dissipated and the work done by the electric stress in the transition from cone to jet, which yields a relationship between the Minimum Flow Rate, the Reynolds number and the dielectric constant that compares well with experiments.
Alfonso M Ganancalvo - One of the best experts on this subject based on the ideXlab platform.
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the Minimum or natural Rate of Flow and droplet size ejected by taylor cone jets physical symmetries and scaling laws
New Journal of Physics, 2013Co-Authors: Alfonso M Ganancalvo, N Rebollomunoz, J M MontaneroAbstract:We aim to establish the scaling laws for both the Minimum Rate of Flow attainable in the steady cone-jet mode of electrospray, and the size of the resulting droplets in that limit. Use is made of a small body of literature on Taylor cone-jets reporting precise measurements of the transported electric current and droplet size as a function of the liquid properties and Flow Rate. The projection of the data onto an appropriate non-dimensional parameter space maps a region bounded by the Minimum Rate of Flow attainable in the steady state. To explain these experimental results, we propose a theoretical model based on the generalized concept of physical symmetry, stemming from the system time invariance (steadiness). A group of symmetries rising at the cone- to-jet geometrical transition determines the scaling for the Minimum Flow Rate and related variables. If the Flow Rate is decreased below that Minimum value, those symmetries break down, which leads to dripping. We find that the system exhibits two instability mechanisms depending on the nature of the forces arising against the Flow: one dominated by viscosity and the other by the liquid polarity. In the former case, full charge relaxation is guaranteed down to the Minimum Flow Rate, while in the latter the instability condition becomes equivalent to
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jetting dripping transition of a liquid jet in a lower viscosity co Flowing immiscible liquid the Minimum Flow Rate in Flow focusing
Journal of Fluid Mechanics, 2006Co-Authors: Alfonso M GanancalvoAbstract:We study the jetting-dripping (J-D) transition of a Flow-focused viscous liquid jet surrounded by a co-Flowing immiscible, lower viscosity liquid. A theoretical model describing wave propagation in open cylindrical Flows has been adapted to our problem and further expanded to incorpoRate spatio-temporal stability considerations (global modes). The J-D transition sets the Minimum liquid Flow Rate issuing as a steady jet and breaking up into droplets whose size is commensuRate with the jet diameter. At the onset of dripping, droplets become considerably larger than jetting droplets, under comparable Flow parameters. A linear theory accounting for convective and absolute instability is provided, along with a detailed interpretation of the parametrical space, under realistic viscosity and density restrictions. The experimental part sums up a collection of laboratory data illustrating the J-D transition with good agreement with the theory.