Cloud Point Extraction and Spectrophotometric Studies for the Extraction of Nigrosin and Aniline Blue Dyes using Mixed Micelles of TBAB and Triton X-114

Abstract

The extractions of two anionic dyes viz. nigrosin and aniline blue by cloud point extraction method using mixed micelles of tetrabutylammonium bromide (TBAB) and Triton X-114 were conducted. To get the greatest extraction efficiency, pH of the solution, surfactant concentration, concentration of electrolyte, equilibrium temperature and time were optimized. A linear calibration curve in the range of 0.567-9.07 mg/L (nigrosin) and 0.982-19.645 mg/L (aniline blue) was obtained. Limit of detection were found to be 2.45 ng/L and 2.008 ng/L for nigrosin and aniline blue dyes, respectively. Thermodynamic parameters were also calculated to establish the feasibility of the process. This method was then used to determine the dyes in tap and sea water samples. The extraction efficiency was explained in terms of dye surfactant interaction as shown by observed spectral changes between anionic dye and cationic surfactant followed by solubilization of the complex in non-ionic surfactant.