The pH was adjusted and the bottles were shaken in a thermostatted
shaker at 250 rpm for a known time. The two-phase
dispersions were allowed to settle for 48 h to form two clear
liquid phases: the solvent phase containing the dye and the
clear aqueous phase. Samples were drawn from aqueous phase
using 10 ml pipette for absorbance measurement of the dye to
determine dye concentration. The percentage of extraction (E)
was calculated as follows