Chlorpheniramine recovery from aqueous solutions by emulsion liquid membranes using soy lecithin as carrier

Optimization and Prediction of Stability of Emulsified Liquid Membrane (ELM): Artificial Neural Network

In this work, the emulsified liquid membrane (ELM) extraction process was studied as a technique for separating different pollutants from an aqueous solution. The emulsified liquid membrane used consisted of Sorbitan mono-oleate (Span 80) as a surfactant with n-hexane (C6H14) as a diluent; the internal phase used was nitric acid (HNO3). The major constraint in the implementation of the extraction process by an emulsified liquid membrane (ELM) is the stability of the emulsion. However, this study focused first on controlling the stability of the emulsion by optimizing many operational factors, which have a direct impact on the stability of the membrane. Among the important parameters that cause membrane breakage, the surfactant concentration, the emulsification time, and the stirring speed were demonstrated. The optimization results obtained showed that the rupture rate (Tr) decreased until reaching a minimum value of 0.07% at 2% of weight/weight of Span 80 concentration with an emulsification time of 3 min and a stirring speed of 250 rpm. On the other hand, the volume of the inner phase leaking into the outer phase was predicted using an artificial neural network (ANN). The evaluation criteria of the ANN model in terms of statistical coefficient and RMSE error revealed very interesting results and the performance of the model since the statistical coefficients were very high and close to 1 in the four phases (R_training = 0.99724; R_validation = 0.99802; R_test = 0.99852; R_all data = 0.99772), and also, statistical errors of RMSE were minimal (RMSE_training= 0.0378; RMSE_validation = 0.0420; RMSE_test = 0.0509; RMSE_all data = 0.0406).

Three- and Multi-Phase Extraction as a Tool for the Implementation of Liquid Membrane Separation Methods in Practice

To promote the implementation of liquid membrane separations in industry, we have previously proposed extraction methods called three- and multi-phase extraction. The three-phase multi-stage extraction is carried out in a cascade of bulk liquid membrane separation stages, each comprising two interconnected (extraction and stripping) chambers. The organic liquid membrane phase recycles between the chambers within the same stage. In multi-phase extraction, each separation stage includes a scrubbing chamber, located between the extraction and stripping chambers. The three- and multi-phase multi-stage extraction technique can be realized either in a series of mixer-settler extractors or in special two- or multi-chamber extraction apparatuses, in which the convective circulation of continuous membrane phase between the chambers takes place due to the difference in emulsion density in the chambers. The results of an experimental study of the extraction of phenol from sulfuric acid solutions in the three-phase extractors with convective circulation of continuous membrane phase are presented. Butyl acetate was used as an extractant. The stripping of phenol from the organic phase was carried out with 5-12% NaOH aqueous solutions. The prospects of using three-phase extractors for wastewater treatment from phenol are shown. An increase in the efficiency of three-phase extraction can be achieved by carrying out the process in a cascade of three-phase apparatuses.

Removal of emerging contaminants by emulsion liquid membrane: perspective and challenges

Emerging contaminants (ECs) originated from different agricultural, biological, chemical, and pharmaceutical sectors have been detected in our water sources for many years. Several technologies are employed to minimise EC content in the aqueous phase, including solvent extraction processes, but there is not a solution commonly accepted yet. One of the studied alternatives is based on separation processes of emulsion liquid membrane (ELM) that benefit low solvent inventory and energy needs. However, a better understanding of the process and factors influencing the operating conditions and the emulsion stability of the extraction/stripping process is crucial to enhancing ELM's performance. This article aims to describe the applications of this technique for the EC removal and to comprehensively review the ELM properties and characteristics, phase compositions, and process parameters.

Removal of Ibuprofen at Low Concentration Using a Newly Formulated Emulsion Liquid Membrane

Ibuprofen (IBP) is a pharmaceutical product that is widely prescribed as an over-the-counter painkiller. It has been classified as a contaminant of emerging concern (CEC) that has received global attention in the search for a better wastewater separation technology. The emulsion liquid membrane (ELM) is one of the potential solutions for IBP removal from wastewater owing to its advantages, such as the ability to remove a highly soluble solute, energy efficient and tuneable formulation. To develop this ELM, a series of parameters such as stirring speed, emulsification time, organic to internal phase volume ratio (O/I), internal phase concentration, carrier concentration and surfactant concentration were studied. The extraction was carried out for 15 min stirring time and the concentration of IBP in the feed phase was determined using a UV-Vis spectrophotometer. The optimum formulation for the ELM was found at 300 rpm stirring speed, 20 min emulsification time, 3:1 of O/I, 0.1 M ammonia, NH₃ (stripping agent), 6 wt% trioctylamine, TOA (carrier) and 2 wt% sorbitan monooleate, Span 80 (non-ionic surfactant). IBP removal of 89% was achieved at the optimum parameters of ELM. The current research demonstrated that a newly formulated ELM has great potential in removing a low concentration IBP from wastewater.