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, c(IAA,F0) (10(–4)–10(–3 )kmol/m(3)), of TOA in the membrane phase, c(L,M0) (10(–2) and 10(–1) kmol/m(3)), and of NaOH in the stripping phase, c(NaOH,S0) (10(–2) and 1 kmol/m(3)), were selected as process factors. Their effects on the final values of IAA concentration in the feed phase (c(IAA,Ff)) and stripping solution (c(IAA,Sf)), extraction efficiency (E(F)), distribution coefficient (K(D)), and recovery efficiency (E(R)) were quantified using multiple regression equations. Regression coefficients were determined from experimental data, i.e., c(IAA,Ff,ex) = 0.02–1 × 10(–4) kmol/m(3), c(IAA,Sf,ex) = 0.22–2.58 × 10(–3) kmol/m(3), E(F,ex) = 90.0–97.9%, K(D,ex) = 9.0–46.6, and E(R,ex) = 66.5–94.2%. It was found that c(IAA,F0) had the most significant positive effect on c(IAA,Ff) and c(IAA,Sf), whereas c(NaOH,S0) had a major positive effect on E(F), K(D), and E(R). 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 m(3)/kmol), were regressed from experimental data. The effect of c(L,M0) on both parameters was significant.