Avaliação do processo de extração de fenilalanina com Adogen 464 pela técnica de membranas líquidas sufartantes.

Abstract

In this work, the process efficiency of surfactant liquid membranes applied to phenylalanine extraction from synthetic aqueous solutions was evaluated. A study of the effects of relevant parameters on the system behavior was carried out in order to establish appropriateconditions of extraction. The aim was to use these conditions as an experimental basis to perform posterior researches for production of a dietetic formulation containing low levels of phenylalanine, as a dietetic supplement for phenylketonurics. The experimental work wasseparated in batch runs of emulsification and permeation. From the emulsification experiments, the individual and coupled effects of surfactant, carrier and modifier concentrations upon the coalescence time of the primary emulsion could be evaluated. In the permeation study, several parameters that could affect the technique performance on theamino acid extraction were investigated. These variables were the following: surfactant and carrier concentrations, time of permeation, stirring speed, membrane phase/inner phase volumetric ratio, feed phase/ primary emulsion volumetric ratio and KCl concentration inthe inner phase. Finally, the influence of the use of recycled membranes on the separation process was investigated. The results of the emulsification experiments showed that the surfactant affects the membrane stability, as expected, and that it can act like a modifieragent, improving the amine solubilization in the organic phase of low polarity. Further, it was observed that the carrier is also able to stabilize the primary emulsion in systems without the presence of the modifier. The results obtained from the permeation experiments indicated that the system presented better extraction conditions when the studied operational variables were set at the following conditions: [ECA 4360] = 2% w/w; [Adogen 464] = 2% w/w; time of permeation = 5 minutes; stirring speed = 120 rpm; FM/FI ratio = 2:1; FE/EP ratio = 3:1, e [KCl]FI = 2,0 M. Under these conditions, 75% of the solute could be extracted from the feed phase, associated with a swelling percentage of 60% and an inner phase phenylalanine concentration 4,5 times greater than the initial one on the feed phase. The experiments carried out with recycled membranes indicated that these could be reused with 45% reduction in the Phe extraction capacity when compared to fresh membrane phase. The spent membrane phases were reused two subsequent extraction cycles, presenting similar performances in both cycles.