Extração de corantes têxteis utilizando sistemas aquosos bifásicos compostos por 2-propanol e sais de sulfato

Abstract

Aqueous Two Phase Systems (ATPS) composed of 2-propanol + inorganic salt (Na2SO4/MgSO4) + water, at different temperatures T = (20, 30, 40 and 50) °C were applied in the partition studies of the textile dyes Yellow, Blue Royal and Red Dianix CC. The thermodynamic parameters of the free transfer energy (ΔGtr), enthalpy (ΔHtr) and entropy (ΔStr), respectively, were determined for dye partitioning, using the Van’t Hoff equation. The values of the partition coefficients of textile dyes Yellow, Royal Blue and Red Dianix CC, ranged from 14.21 to 1610.00, 15.15 to 994.00 and 17.32 to 311.75, respectively; and with dye extraction yields ranging from 93.17 to 99.93; 94.53 to 99.89 and 97.19 to 99.64, respectively. Based on the ΔGtr results, it was verified that the dyes partition process was thermodynamically spontaneous, in all evaluated systems. For the 2-propanol + sodium sulfate ATPS, there was a prevalence of the enthalpic contribution over the entropic contribution (ΔHtr > ΔStr), while for the 2-propanol + magnesium sulfate systems, a greater predominance of the entropic contribution was observed (ΔHtr < ΔStr). The recovery yields (Y) values obtained were above 90% for all systems.