Removal of Lead(II) from Aqueous Solution Using Triton X-114 in the Presence of Alanine or Phenylalanine as Biodegradable System

Abstract

Abstract The Cloud Point Extraction (CPE) of Pb(II) ion, using Triton X-114/ alanine and Triton X-114/phenyalanine as biodegradable systems, was carried out. The experimental results are expressed by four responses to surfactant concentration, amino acid concentration and temperature variations: extent of solute extraction (E), remaining solute (Xm,w) and surfactant (Xt,w) concentrations in dilute phase and volume fraction of coacervate (}C) at equilibrium. An empirical smoothing method was used, where the results were represented on three dimensional plots using the Box-Behnken design (BBD) and the response surface methodology (RSM). High extraction efficiencies (94% with alanine and 98% with phenylalanine) are reached in optimal conditions. Thereby, solute concentration reduction in the dilute phase is about 4 and 12 times with alanine and phenylalanine, respectively. The pH effect is also studied. Finally, the possibility of recycling the surfactant/amino acid system by pH change is proved.