The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Robert W. Field - One of the best experts on this subject based on the ideXlab platform.
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on maintaining consistency between the film model and the profile of the Concentration Polarisation Layer
Journal of Membrane Science, 2006Co-Authors: S S Vasan, Robert W. FieldAbstract:Abstract For modelling purposes, the film model with an arbitrarily assumed Concentration profile has often been used to describe Concentration Polarisation. Such arbitrary assumptions should be avoided and this can be done by estimating the boundary Layer Peclet number. For instance, the profile is often described using a power law function with exponent n, but no simple relationship has previously been given for choosing the value of n such that it is consistent with the film model. As a result, different researchers have assumed different values, such as n = 1 (linear profile), n = 1.4, or n = 2 (quadratic profile). However, n is not an independent parameter, but is solely determined by the boundary Layer Peclet number—as shown in this paper. The evolution of n with channel length is important, and its evolution with length is illustrated in this paper for pipe-flow geometry (such as tubular or hollow fibre systems).
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A Maxwell–Stefan–Gouy–Debye model of the Concentration profile of a charged solute in the Polarisation Layer
Desalination, 2006Co-Authors: Sarathi Sai Arvind Vasan, Robert W. FieldAbstract:Abstract Based on the Maxwell–Stefan equation and the Gouy–Chapman model (with the Debye–Huckel approximation), this paper gives an analytical equation to describe the Concentration profile of a charged solute in the Concentration Polarisation Layer in terms of three dimensionless numbers (the Debye number, the Nernst number, and the boundary Layer Peclet number).
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a maxwell stefan gouy debye model of the Concentration profile of a charged solute in the Polarisation Layer
Desalination, 2006Co-Authors: Sarathi Sai Arvind Vasan, Robert W. FieldAbstract:Abstract Based on the Maxwell–Stefan equation and the Gouy–Chapman model (with the Debye–Huckel approximation), this paper gives an analytical equation to describe the Concentration profile of a charged solute in the Concentration Polarisation Layer in terms of three dimensionless numbers (the Debye number, the Nernst number, and the boundary Layer Peclet number).
Sarathi Sai Arvind Vasan - One of the best experts on this subject based on the ideXlab platform.
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A Maxwell–Stefan–Gouy–Debye model of the Concentration profile of a charged solute in the Polarisation Layer
Desalination, 2006Co-Authors: Sarathi Sai Arvind Vasan, Robert W. FieldAbstract:Abstract Based on the Maxwell–Stefan equation and the Gouy–Chapman model (with the Debye–Huckel approximation), this paper gives an analytical equation to describe the Concentration profile of a charged solute in the Concentration Polarisation Layer in terms of three dimensionless numbers (the Debye number, the Nernst number, and the boundary Layer Peclet number).
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a maxwell stefan gouy debye model of the Concentration profile of a charged solute in the Polarisation Layer
Desalination, 2006Co-Authors: Sarathi Sai Arvind Vasan, Robert W. FieldAbstract:Abstract Based on the Maxwell–Stefan equation and the Gouy–Chapman model (with the Debye–Huckel approximation), this paper gives an analytical equation to describe the Concentration profile of a charged solute in the Concentration Polarisation Layer in terms of three dimensionless numbers (the Debye number, the Nernst number, and the boundary Layer Peclet number).
Semiha Arayici - One of the best experts on this subject based on the ideXlab platform.
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evaluation of fouling mechanisms in the nanofiltration of solutions with high anionic and nonionic surfactant contents using a resistance in series model
Journal of Membrane Science, 2011Co-Authors: Yasemin Kaya, Hulusi Barlas, Semiha ArayiciAbstract:Abstract The effects of feed Concentration and transmembrane pressure (TMP) on membrane fouling in the treatment of cleaning-in-place (CIP) wastewater originated from the production of liquid dishwashing detergent with a nanofiltration (NF) membrane were investigated. The resistance-in-series model was used to evaluate the flux decline caused by a gel Layer, a Concentration Polarisation Layer, and internal pore blocking in the NF membrane for CIP solutions of varying Concentration termed CIP 5, CIP 10 and CIP 20. With an increase in feed Concentration and TMP, it was observed that resistance of the gel Layer ( R g ) played a more important role in the flux decline than that of the Concentration Polarisation Layer or internal pore fouling ( R cp + in ). Considering the membrane resistance ( R m ) values, the CIP solutions containing high Concentrations of anionic and nonionic surfactants and low dye and salt Concentrations did not cause serious fouling of the NF membrane. Characterisation of the membrane surface by atomic force microscopy (AFM) and contact angle measurements also showed that the deposition of surfactant aggregates on the NF membrane surface likely played an important role in the gel Layer fouling. The NF membrane showed a rejection efficiency of over 98% for anionic surfactants, nonionic surfactant and dye in all CIP solutions. Salt rejection was not achieved in the CIP 5 solution because of the Donnan effect, whereas salt rejections were around 11–34% and 28–54% in the CIP 10 and CIP 20 solutions, respectively. The resistance-in-series model was successfully tested to evaluate the flux decline for the CIP solutions containing anionic and nonionic surfactants, dye and salt at various TMPs.
Shi-ying Xu - One of the best experts on this subject based on the ideXlab platform.
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Hydrolysis of whey protein isolate in a tangential flow filter membrane reactor II. Characterisation for the fate of the enzyme by multivariate data analysis
Journal of Membrane Science, 2006Co-Authors: Seronei Chelulei Cheison, Zhang Wang, Shi-ying XuAbstract:Abstract The fate of Protease N (IUB 3.4.24.28, Bacillus subtilis ) enzyme was monitored while being used to hydrolyse an initial Concentration of 5% (w/v) whey protein isolate (86.98% Kjeldahl nitrogen × 6.38) continuously for 5 h at pH 7.0 and 55 °C in an enzymatic membrane reactor (EMR) fitted with a 10 kDa tangential flow filter (TFF). The retentate temperature (A: 25–55 °C), initial water permeate flux, J i (B: 1.6–18.4 mL/min) and enzyme Concentration (C: 0.5–5.5 g) were varied and optimised using response surface methodology (RSM) central composite rotatable design (CCRD). The residual enzyme activity ( A residual ), enzyme leakage ( A leakage ), enzyme loss ( A loss ), average permeate flux ( J average ) and nitrogen recovered in permeate (apparent sieving, S apparent ) were determined. A leakage was independent of enzyme Concentration but increased concomitant with increasing A and B, while both A residual and A loss decreased with increasing J i . Protease N was inhibited by WPI and hydrolysates. At 50 °C Protease N enzyme solubilised the Concentration Polarisation Layer (GPL), stabilised J average and led to higher A leakage . Principal components analysis isolated the EMR hydrodynamics due to the retentate temperature, S apparent , A leakage and J average as factors providing prominent influence in the EMR (principal components 1 and 3 which caused ca. 60% of the EMR variance) while principal component 2 (‘measure’ of Protease N enzyme property within the reactor) contributed 27.78%. The fate of the enzyme was accounted for as a balance between A residual , A leakage and A loss .
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Hydrolysis of whey protein isolate in a tangential flow filter membrane reactor: I. Characterisation of permeate flux and product recovery by multivariate data analysis
Journal of Membrane Science, 2006Co-Authors: Seronei Chelulei Cheison, Zhang Wang, Shi-ying XuAbstract:Abstract Protease N (IUB 3.4.24.28, Bacillus subtilis ) enzyme was used to continuously hydrolyse an initial 5% (w/v) whey protein isolate (86.98%, Kjeldahl nitrogen × 6.38) for 5 h at pH 7.0 and 55 °C in a 10 kDa tangential flow filter (TFF) enzymatic membrane reactor (EMR). The retentate temperature ( A : 25–55 °C), initial water permeate flux, J i ( B : 1.6–18.4 mL/min) and enzyme Concentration ( C : 0.5–5.5 g) were varied and optimised using response surface methodology (RSM) central composite rotatable design (CCRD). The residual enzyme activity ( A residual ), enzyme leakage ( A leakage ), enzyme loss ( A loss ), average permeate flux ( J average ) and nitrogen recovered in permeate (apparent sieving, S apparent ) were determined. J average decayed extensively at low retentate temperatures (25 and 30 °C), while at 50 °C the enzyme solubilised the dynamic gel Layer, stabilised J average and led to higher S apparent . J average and S apparent increased concomitantly as well as with increasing retentate temperature, J i and enzyme Concentration. Principal components analysis isolated the retentate temperature, S apparent , A leakage and J average as factors providing prominent influence in the EMR with significant contributions (ca. 60% of the EMR variance) to principal components 1 and 3 (permeate and substrate hydrodynamics property). Principal component 2 (‘measure’ of Protease N enzyme property) contributed 27.78%. Results provide evidence that when the feed temperature is suitable, high substrate solubility and low viscosity is maintained at the membrane surface and the enzyme used in the EMR solubilises and hydrolyses the Concentration Polarisation Layer (GPL) thus providing a codetergence property necessary to maintain permeate flux stability and hence high product recovery.
A G Fane - One of the best experts on this subject based on the ideXlab platform.
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quantitative measurements of the Concentration Polarisation Layer thickness in membrane filtration of oil water emulsions using nmr micro imaging
Journal of Membrane Science, 1996Co-Authors: J M Pope, A G FaneAbstract:In this paper we report measurements of the thickness of the Concentration Polarisation Layers formed during crossflow membrane filtration of an oil-water emulsion. The formation and development of the oil Polarisation Layers was visualised non-invasively using NMR chemical shift selective micro-imaging. A series of images was acquired during the transient state of the filtration, (i.e. while the Polarisation Layer was forming and the flux of filtrate was changing), prior to the establishment of steady state conditions. An estimate of the specific resistance of the Concentration Polarisation Layers was then obtained by determining the average oil Layer thicknesses and Concentration at a given time from the resulting images and measuring the corresponding (length averaged) flux of filtrate gravimetrically. After the establishment of steady state conditions, the dependence of the steady state filtrate flux on crossflow Reynolds number was found to be consistent with Brownian diffusion being the main mechanism controlling the build-up of the oil Polarisation Layers, at least under our range of operating conditions.