Two-Stage Decontamination of Organophosphorus Compounds on Sensitive Equipment Materials

Decontamination of sensitive equipment materials contaminated by organophosphorus (OP) compounds by a two-stage process was evaluated. The process involved extraction of OP from contaminated materials with methanol (first stage), followed by decomposition of OP by heterogeneous catalytic methanolysis (second stage). In a series of tests diazinon, malathion, paraoxon, parathion, and other organophosphorus pesticides were spiked onto sensitive equipment materials and extracted with methanol after a presented contact time. After extraction, the lowest quantity of residue was found for diazinon, while parathion was the most persistent. High-impact polystyrene (HI-PS) retained 10-fold or more mass of OP than other tested materials. The surface of the HI-PS was deteriorated after contacting with OP due to a plasticizing effect. A longer contact time with HI-PS and lower polarity factor of OP resulted in higher residual amounts of OP after extraction. In the second stage of the process, diazinon and paraoxon wer...