Effects of process factors on performances of liquid membrane-based transfer of indole-3-acetic acid.

The paper has aimed at studying the transfer of indole 3-acetic acid (IAA) from a feed aqueous solution to a stripping aqueous solution of NaOH using a chloroform bulk liquid membrane and trioctylamine (TOA) as a ligand (L). Initial molar concentrations of IAA in the feed phase, cIAA,F0 (10-4-10-3 kmol/m3), of TOA in the membrane phase, cL,M0 (10-2 and 10-1 kmol/m3), and of NaOH in the stripping phase, cNaOH,S0 (10-2 and 1 kmol/m3), were selected as process factors. Their effects on the final values of IAA concentration in the feed phase (cIAA,Ff) and stripping solution (cIAA,Sf), extraction efficiency (EF), distribution coefficient (KD), and recovery efficiency (ER) were quantified using multiple regression equations. Regression coefficients were determined from experimental data, i.e., cIAA,Ff,ex = 0.02-1 × 10-4 kmol/m3, cIAA,Sf,ex = 0.22-2.58 × 10-3 kmol/m3, EF,ex = 90.0-97.9%, KD,ex = 9.0-46.6, and ER,ex = 66.5-94.2%. It was found that cIAA,F0 had the most significant positive effect on cIAA,Ff and cIAA,Sf, whereas cNaOH,S0 had a major positive effect on EF, KD, and ER. A deterministic model based on mass transfer of IAA was developed and its parameters, i.e., mass transfer coefficient of IAA-L complex in the liquid membrane (0.82-11.5 × 10-7 m/s) and extraction constant (1033.9-1779.7 m3/kmol), were regressed from experimental data. The effect of cL,M0 on both parameters was significant.

Analytical Applications of Transport Through Bulk Liquid Membranes.

This review discusses the results of research in the use of bulk liquid membranes in separation processes and preconcentration for analytical purposes. It includes some theoretical aspects, definitions, types of liquid membranes, and transport mechanism, as well as advantages of using liquid membranes in laboratory studies. These concepts are necessary to understand fundamental principles of liquid membrane transport. Due to the multiple advantages of liquid membranes several studies present analytical applications of the transport through liquid membranes in separation or preconcentration processes of metallic cations and some organic compounds, such as phenol and phenolic derivatives, organic acids, amino acids, carbohydrates, and drugs. This review presents coupled techniques such as separation through the liquid membrane coupled with flow injection analysis.