Reactive Extraction of Phenol from Aqueous Solution Using Trioctylmethylammoniumchloride and Trioctylamine in Nonane and Isoamyl alcohol

Abstract

Reactive extraction of phenol (0.053 mol kg−1) from aqueous solution is carried out using two aminic extractants, trioctylmethylammoniumchloride (TOMAC) and trioctylamine (TOA) considering four concentrations (0.023 to 0.091 mol kg−1) and dissolving them in solvents like nonane and isoamyl alcohol (IAA) at 298 K. The effects of extract type (TOMAC and TOA), their concentrations, and type of diluent on the separation efficiency of extraction have been determined. Data show that the neutral phenol molecule is more effectively extracted by TOA than TOMAC into the organic phase. Increase in the extractant concentration from 0.023 to 0.091 mol kg−1 obviously enhances the recovery of phenol (2.3 times with nonane + TOMAC or TOA; 2.97 times with IAA + TOMAC; and 4.83 times with IAA + TOA). The equilibrium extraction results are presented in terms of distribution coefficient (D), degree of extraction (%E), and loading ratio (Z). Maximum value of D (=12.25) is obtained with TOA + IAA (0.091 mol kg−1) which could extract 92.45 % of phenol from the water phase. A suitable mathematical model for the determination of equilibrium D is expressed by employing the mass action law. The equilibrium constant (KE) and the stoichiometric coefficient (n) of extraction are determined graphically. Also, the individual equilibrium constants (K11, K21, and K12) for the phenol-extractant complexes formed are estimated from the regression of the experimental values. The better extraction power of the TOA + IAA extract system is also shown from the estimated value of complexation constant (KE = 164.44). Phenol molecules form 1:1 and 2:1 and 1:1 and 1:2 solvates with nonane and IAA, respectively, with both the extractants.