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Keywords:

  • reactive extraction;
  • annatto seed;
  • norbixin;
  • Aliquat-336

The reactive extraction of Bixa orellana seed pigment norbixin with cationic carrier Aliquat-336 (QCl) in a two phase system has been studied. A raw alkali extract of Bixa orellana pigments in 0.5% sodium hydroxide solution is used as aqueous phase and Aliquat-336 dissolved in hexane as solvent is used as the organic phase. In the aqueous alkaline phase, the pigment (bixin + norbixin) exists as sodium norbixinate in ionized form. This sodium norbixinate forms complex with QCl by an ion-exchange mechanism which is pH dependent. Re-extraction occurs via another ion-exchange reaction with H+ ion with another aqueous phase of low pH. Complexation expressed as degree of extraction increases with pH reaching almost an asymptotic whereafter tends to decrease slightly. Around 99% recovery of norbixin as its complex with Aliquat-336 was achieved at an organic phase to aqueous phase volume ratio 2:1. 98% of the norbixin-QCl complex was recovered as norbixin in aqueous solution at pH 4. The results of this investigation may be considered reasonable to believe that reactive extraction is likely to provide an attractive and alternative separation method for the recovery of norbixin. © 2011 American Institute of Chemical Engineers Environ Prog, 32: 134–138, 2013.