The removal of pesticide residues from wool wax by solvent extraction

Abstract

A range of suitable solvents for the removal of dieldrin and diazinon residues from wool wax by solvent-solvent extraction was evaluated. Extraction of a 10% solution of wool wax in hexane with N,N-dimethylformamide was shown to be the most effective. These solvents were then used to measure the partition coefficients of 36 organochlorine, organophosphorus, and pyrethroid pesticides that have the potential to be found in wool wax. Repeated batchwise extraction of a raw wool wax, which had been spiked to produce typical pesticide residue levels, yielded a high-quality wax in which all pesticide residues had been reduced to below detectable levels. The treated wool wax was lighter in color with a lower acid number and a lower free alcohol content and had excellent water absorption characteristics. All detergents associated with the recovery of wool wax from an aqueous scour were also removed.