Destruction of PCDDs and PCDFs. A convenient method using alkali-metal hydroxide in 1,3-dimethyl-2-imidazolidinone (DMI)

Complete and easy-to-use chemical destruction of PCDDs and PCDFs (10–12,000 ppb), which were extracted from urban incineration fly-ash, was achieved by employing an improved alkali-metal hydroxide method in a novel aprodc polar solvent DMI (1,3-dimethyl2-imidazolidinone), a commercially available highly inert solvent under strongly basic conditions. The destruction reagent can be easily prepared by dissolving 0.5 g NaOH or KOH in 10 cm3 DMI, to which was added a hexane solution (1 cm3) of PCDDs and PCDDs (initial concentration > 30 ppm) extracted from fly-ash (30 g). Warming the solution at 90°C for 0.5 h, in the absence or presence (5%) of water, realized the highly efficient destruction (>99.99%) of the hazardous organohalogen compounds.