Analysis of the effect of internal phase leakage on liquid membrane separations

Abstract

A general physical model of a typical batch extraction system employing liquid surfactant membranes is developed. The model takes into account the continuous-phase resistance and the interfacial resistance along with permeation through a composite emulsion globule. It also quantifies the loss in extraction efficiencies by leakage of the encapsulated phase due to membrane breakage. The physical model is easily adapted to apply to the case of transport facilitation wherein the solute is reacted in the internal phase to yield products incapable of permeating through the membrane phase. Experimental data on o-chlorophenol extraction are satisfactorily correlated with the model.

Unsteady-state modeling and analysis for liquid surfactant membrane hydrocarbon separation processes

“…The effect of extraction factor and Biot number on the theoretically predicted fractional solute extraction calculated from eq 9 over a range of Fourier numbers up to 0.5 is shown in at Biot numbers and extraction factors exceeding 1000 a unique fractional extraction vs Fourier number curve exists. Such a unique curve at high Bi has also been reported by Borwanker et al (1988) in modeling phenol separations by W/O/W liquid membranes. The experimental data on batch liquid membrane permeation are reported in Table I.…”

“…In the latter case the separation is based on some type of facilitated transport mechanism either through chemical reaction of solute with reagent in the internal phase as in phenol/ammonia (Lee and Chan, 1990) removal from wastewater or through use of carriers in membrane phase as in recovery of metal ions. The diffusional mass transfer in such systems is complicated by chemical reaction, and the complex mathematical models that have been built up generally require numerical solutions (Bunge and Noble, 1984; Borwanker et al, 1988). Such complications are not present in liquid membrane hydrocarbon separations where separation is based simply on differences in solubility and/or diffusivity of the permeating component in the aqueous membrane phase.…”

Encapsulation Using Hyperbranched Polymers: From Research and Technologies to Emerging Applications

“…Membrane-based techniques such as reverse osmosis are most-often employed for applications that require ultrapure solutions . Innovation in membrane-based technologies has led to the development of emulsion liquid membranes (ELMs), among others. − Although ELMs are commercialized, technical challenges in separating 1−10 μm droplets still remain. − As an alternative to ELM, several micellar-based approaches have been discussed in the literature. For example, extraction with the help of nanosponges that are based on cyclodextrins have been investigated .…”

Swelling phenomena of emulsion liquid membranes with dithio‐DEHPA as carrier

“…Break-up of the emulsion leads to leakage of the internal phase into the external phase and the efficiency of the process is consequently decreased. The rate of break-up is usually a function of the surfactant concentration in the membrane and the agitation speed [16]. Strong agitation increases the possibility of membrane rupture and it is often neces-sary to use moderate agitation.…”