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Multiple solute ultrafiltration models in micellar enhanced ultra filtration (MEUF) have been studied, for experimental results of selective separation of Cu (II) and Co (II) with anionic surfactant, sodium dodecyl sulfate (SDS) and imino diacetic acid (IDA) as chelating agent using synthetic waste water. This model is based on mass balance analysis coupled with the filtration theory, resistance-in-series model and gel polarization model. This model is characterized by the parameters, membrane resistance R(m), membrane permeability P(m), back transport coefficient K(b), K(bi) and mass transfer coefficient k(i). These parameters are estimated by using the Levenberg-Marquardt method coupled with the Gauss-Newton algorithm. Due to cross currents caused by the superficial velocity, some solutes are removed from the membrane surface and go into the bulk known as back transport effect. Hence back transport coefficient plays significant role in explaining the extent of micellization. The simulation results show a good agreement with the experimental data of permeate quality and flux. The consideration of negligible gel thickness is suitable for dilute solutions., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Nickel and cobalt were simultaneously removed from aqueous feed using cross flow micellar enhanced ultrafiltration. Twenty kiloDalton polysulfone membrane was used and the rejection more than 99% was obtained. The effect of operating variables like inlet flow rate, inlet pressure, feed metal ions concentration, surfactant to metal ion (S/M) ratio and pH on the rejection of metal ions was investigated. Gel layer formation and concentration polarization was insignificant under the present experimental condition. Presence of salt in the aqueous feed results in drop in rejection from 99% to 88%. The distribution coefficient of solutes in the micellar phase and aqueous phase was estimated from ultrafiltration data. The loading of micelles was also estimated for both the nickel and cobalt ions which confirmed the reproducibility of the micellar enhanced ultrafiltration (MEUF) experiments.

The performance of continuous cross-flow micellar enhanced ultrafiltration (MEUF) is evaluated for the selective separation of nickel (Ni2+) and cobalt (Co2+) from the aqueous stream using anionic surfactant sodiumdodecyl sulfate (SDS) and the mixture of the anionic and nonionic surfactant (SDS+TritonX-100) with the addition of iminodiacetic acid (IDA) as a chelating agent. Operating parameters like operating time (upto 100 min), cross flow rate (100–175 mL/min.), pH of the feed solution (3-6), molar concentration ratio of the chelating agent to metals (C/M ratio, 0.5–2.5), and molar concentration ratio of the surfactant to metals (S/M ratio, 5–9) were studied to investigate the effectiveness of the process on selective separation. For the single surfactant system at all empirically selected parameters, 92% Ni2+in the permeate and 94% Co2+in the retentate was achieved whereas for the mixed surfactant system 93% Ni2+in permeate and 84% Co2+in retentate was achieved. Flux variation for single and mixed surfactant system was studied. Flux observed for the single surfactant system was 36 L/m2.h and for the mixed surfactant system was 31.5 L/m2.h. Flux measurement also indicates insignificant fouling of the membrane. [ABSTRACT FROM PUBLISHER]

A pilot plant study was carried out to evaluate the performance of continuous cross flow micellar enhanced ultrafiltration (MEUF) method for the simultaneous separation of phenol and ortho-cresol from the aqueous phase using a cationic surfactant, cetyltrimethyl ammonium bromide. The membranes used in this study are polysulfone tubular hollow fibre membrane with 6 kDa and a ceramic membrane having pore diameter 50 nm with an active layer of microporous zirconia (ZrO2) supported on α-alumina, respectively. The work includes comparing the effectiveness of membranes based on pollutants structural parameters, membrane properties and membrane modules. The characteristic parameters such as the distribution coefficient ( D), micelle binding constant ( Kp) and micelle loading ( Lm) were obtained at optimal experimental conditions. High initial rejections were observed (above 95%) for both the membranes and the permeate flux remained almost constant at 17 LMH. It was found that the polysulfone material membrane suited better for MEUF with higher and steady rejections over a period of time. High micelle leakage was observed in ceramic membrane. The energy consumption for hollow fibre polysulfone membrane was less than the ceramic membrane. © 2011 Canadian Society for Chemical Engineering [ABSTRACT FROM AUTHOR]

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The micellar enhanced ultrafiltration (MEUF) process has been used for the separation of phenol and o-cresol from aqueous solutions at room temperature (30 + 2°C) using a cationic surfactant, cetyltrimethylammonium bromide (CTAB), and polyethersulfone membrane of molecular weight cut-off 10 kDa. The effect of the cross-flow rate, the surfactant to pollutants (S/P) concentration ratio in feed, the variation of pollutants concentration in the feed keeping S/P constant, the presence of Na2SO4 and NaCl salts and mixed surfactants on the rejection of each solute and permeate flux have been studied in detail. The % rejection of phenol and o-cresol without using the surfactant observed was 24% and 41% respectively, which was increased to 60% for phenol and 80% for o-cresol at S/P ratio of 8. The effect of salts was also investigated. There was no significant effect of the cross-flow rate on the % rejection of the solutes. The effect of the membrane pore size was also investigated using 1 KDa and 30 KDa PES membranes. Characteristic parameters of MEUF such as the distribution coefficient, micelle loading, and the micelle binding were also estimated. [ABSTRACT FROM AUTHOR]

Modeling of micellar enhanced ultrafiltration (MEUF) was studied for the removal of Ni from aqueous phase by using sodium dodecyl sulphate for micellisation. Localized adsorption equilibrium model was used to predict the bound and unbound counter ions. The retentate concentration was predicted using localized adsorption equilibrium and a material balance model, and the experimental values are in close agreement with less than 1% deviations. Experimental values of the permeate flux were in close agreement with the predicted values obtained by resistances in the series model. An algorithm was developed for the prediction of the retentate concentration. [ABSTRACT FROM AUTHOR]

The micellar enhanced ultrafiltration of Ni(II) ions from the aqueous solution was studied for the dead end system using 20KD Polysulfone membrane. Dynamic behavior of the system was studied with respect to the rejection, yield, and normalized flux. The effect of feed metal ion concentration, surfactant concentration, pH, transmembrane pressure, and S/M ratio was investigated and the optimization of S/M ratio was done. The optimum S/M ratio was 10 while the critical S/M ratio was 5. The effect of monovalent salts was studied on the rejection of metal ions for the salt concentration between 10 mM to 500 mM. [ABSTRACT FROM AUTHOR]

Micellar‐Enhanced Ultrafiltration (MEUF) of the chromate anions from aqueous solutions has been studied at room temperature (28±2°C) using cationic surfactants, cetyltrimethylammonium bromide (CTAB), and cetylpyridinium chloride (CPC), micelles of which adsorb the chromate ions by electrostatic interactions. The solution is processed by ultrafiltration, using a membrane with a pore size small enough to block the passage of the micelles and the adsorbed ions. The process is highly efficient in removing the chromate ions. In the absence of other electrolytes, chromate ion rejections up to 99% were observed at optimal conditions of pH, pressure, temperature, feed chromate, and surfactant concentrations. The presence of added NaCl reduces the chromate rejection, but it was still considerable (up to 82%), even in the presence of 100 mM NaCl. The rejection rate of chromate was found to be highly dependent on the pH of the feed solution. The influence of membrane characteristics on the chromate ion removal was also studied. Various resistances like fouling resistance, concentration polarization resistance, and membrane resistance were also estimated to quantify their effects on the removal efficiency and on the flux behavior. [ABSTRACT FROM AUTHOR]