Cross-flow and dead-end microfiltration of oily-water emulsions

Arnot, Tom; Field, Robert W.; Koltuniewicz, Andrzej Benedykt

doi:10.1016/s0376-7388(99)00321-x

Cited by 129 publications

(61 citation statements)

References 6 publications

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“…These values are comparable to those reported in previous work on membrane separation under externally applied pressures 3,4,6,7,39,40 . Furthermore, in intermittent stop-and-go operation, the fluxes did not decrease over a period of 100 h (Fig.…”

Section: Continuous Separation Of Oil-water Emulsionssupporting

confidence: 90%

Hygro-responsive membranes for effective oil–water separation

et al. 2012

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There is a critical need for new energy-efficient solutions to separate oil-water mixtures, especially those stabilized by surfactants. Traditional membrane-based separation technologies are energy-intensive and limited, either by fouling or by the inability of a single membrane to separate all types of oil-water mixtures. Here we report membranes with hygro-responsive surfaces, which are both superhydrophilic and superoleophobic, in air and under water. our membranes can separate, for the first time, a range of different oil-water mixtures in a singleunit operation, with >99.9% separation efficiency, by using the difference in capillary forces acting on the two phases. our separation methodology is solely gravity-driven and consequently is expected to be highly energy-efficient. We anticipate that our separation methodology will have numerous applications, including the clean-up of oil spills, wastewater treatment, fuel purification and the separation of commercially relevant emulsions.

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Section: Continuous Separation Of Oil-water Emulsionssupporting

confidence: 90%

Hygro-responsive membranes for effective oil–water separation

et al. 2012

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“…A number of publications have used the surfacerenewal concept to theoretically model cross-flow microfiltration and ultrafiltration (Koltuniewicz, 1992; Brazilian Journal of Chemical Engineering Koltuniewicz and Noworyta, 1994;Koltuniewicz and Noworyta, 1995;Constenla and Lozano, 1996;Arnot et al, 2000;Chatterjee, 2010;Sarkar et al, 2011;Hasan et al, 2013). Compared to the film and boundarylayer models of membrane filtration, the surfacerenewal model has the potential to more faithfully describe the transfer of dissolved/suspended solids due to random hydrodynamic impulses generated at the membrane surface, e.g., due to membrane roughness or by the use of spacers or turbulence promoters.…”

Section: Introductionmentioning

confidence: 99%

“…(3)] and S (rate of renewal of liquid elements at the membrane surface) were estimated by fitting the model to experimental permeate flow rate data in the CFMF of fermentation broths in laboratory-and pilot-scale units. The parameter S, which is an increasing function of the velocity of the main flow as shown empirically by Koltuniewicz (1992), Koltuniewicz and Noworyta (1994) and Koltuniewicz and Noworyta (1995), can also be looked upon as a "scouring" term, which represents the removal of deposited material from the membrane wall (Arnot et al, 2000) and which depends upon the level of flow instability. In contrast to the well-known critical-flux model of CFMF (intermediate-blocking and cake-filtration cases), the surface-renewal model of Hasan et al (2013) provides explicit expressions for the permeate flux and cake mass as functions of process time, besides indicating the influence of transmembrane pressure drop, feed concentration and liquid velocity on the permeate flux.…”

Section: Introductionmentioning

confidence: 99%

Influence of Residence-Time Distribution on a Surface-Renewal Model of Constant-Pressure Cross-Flow Microfiltration

Zhang

Chatterjee

2015

Braz. J. Chem. Eng.

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-This work examines the influence of the residence-time distribution (RTD) of surface elements on a model of cross-flow microfiltration that has been proposed recently (Hasan et al., 2013). Along with the RTD from the previous work (Case 1), two other RTD functions (Cases 2 and 3) are used to develop theoretical expressions for the permeate-flux decline and cake buildup in the filter as a function of process time. The three different RTDs correspond to three different startup conditions of the filtration process. The analytical expressions for the permeate flux, each of which contains three basic parameters (membrane resistance, specific cake resistance and rate of surface renewal), are fitted to experimental permeate flow rate data in the microfiltration of fermentation broths in laboratory-and pilot-scale units. All three expressions for the permeate flux fit the experimental data fairly well with average root-mean-square errors of 4.6% for Cases 1 and 2, and 4.2% for Case 3, respectively, which points towards the constructive nature of the model -a common feature of theoretical models used in science and engineering.

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“…The surface-renewal concept has been used to theoretically model cross-flow microfiltration and ultrafiltration by a number of workers (Koltuniewicz, 1992;Koltuniewicz and Noworyta, 1994;Koltuniewicz and Noworyta, 1995;Constenla and Lozano, 1996;Arnot et al, 2000;Chatterjee, 2010;Sarkar et al, 2011;Hasan et al, 2013, Zhang andChatterjee, 2014). In contrast to the film and boundary-layer models of cross-flow membrane filtration, the surface-renewal model has the potential to more realistically describe the transfer of dissolved/suspended solids due to Dean vortices mentioned above, and also due to random hydrodynamic impulses generated at the membraneliquid interface, e.g., due to membrane roughness or by the use of spacers or turbulence promoters.…”

Section: Introductionmentioning

confidence: 99%

“…The values of these parameters were estimated by fitting the model to experimental permeate flow rate data in the CFMF of fermentation broths in laboratory-and pilot-scale units (Hasan et al, 2013). The parameter S increases with velocity of the main flow (Koltuniewicz, 1992;Koltuniewicz and Noworyta, 1994;Koltuniewicz and Noworyta, 1995), and can be thought of as a "scouring" term that represents the removal of deposited material from the membrane wall (Arnot et al, 2000), and which depends on the level of flow instability. From dimensional considerations, Hasan et al (2013) proposed a correlation for S as a function of the diameter of the membrane channel, axial flow velocity, relative roughness of the membrane wall, and viscosity and density of the feed suspension.…”

Section: Introductionmentioning

confidence: 99%

Application of a Surface-Renewal Model to Permeate-Flux Data for Constantpressure Cross-Flow Microfiltration With Dean Vortices

Idan

Chatterjee

2015

Braz. J. Chem. Eng.

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-The introduction of flow instabilities into a microfiltration process can dramatically change several elements such as the surface-renewal rate, permeate flux, specific cake resistance, and cake buildup on the membrane in a positive way. A recently developed surface-renewal model for constant-pressure, cross-flow microfiltration (Hasan et al., 2013) is applied to the permeate-flux data reported by Mallubhotla and Belfort (1997), one set of which included flow instabilities (Dean vortices) while the other set did not. The surfacerenewal model has two forms ─ the complete model and an approximate model. For the complete model, the introduction of vortices leads to a 53% increase in the surface-renewal rate, which increases the limiting (i.e., steady-state) permeate flux by 30%, decreases the specific cake resistance by 14.5% and decreases the limiting cake mass by 15.5% compared to operation without vortices. For the approximate model, a 50% increase in the value of surface renewal rate is shown due to vortices, which increases the limiting permeate flux by 30%, decreases the specific cake resistance by 10.5% and decreases the limiting cake mass by 13.7%. The cake-filtration version of the critical-flux model of microfiltration (Field et al., 1995) is also compared against the experimental permeate-flux data of Mallubhotla and Belfort (1997). Although this model can represent the data, the quality of its fit is inferior compared to that of the surface-renewal model.

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Cross-flow and dead-end microfiltration of oily-water emulsions

Cited by 129 publications

References 6 publications

Hygro-responsive membranes for effective oil–water separation

Hygro-responsive membranes for effective oil–water separation

Influence of Residence-Time Distribution on a Surface-Renewal Model of Constant-Pressure Cross-Flow Microfiltration

Application of a Surface-Renewal Model to Permeate-Flux Data for Constantpressure Cross-Flow Microfiltration With Dean Vortices

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