Bicarbonate-activated hydrogen peroxide and efficient decontamination of toxic sulfur mustard and nerve gas simulants

Abstract

¹³C NMR spectra showed that peroxymonocarbonate (HCO₄^-) was generated in the NaHCO₃-activated H₂O₂ solution and pH was a key factor in its production. A cycle for the bicarbonate anion was proposed as HCO₃^-→HCO₃ → (CO₂)₂*→CO₂(aq)→HCO₄^- (H₂CO₄)→HCO₃^- (HCO₃) basing on the results of NMR, electron paramagnetic resonance, chemiluminescence analysis. In this cycle, (CO₂)₂* was the key intermediate and (CO₂)₂*→2CO₂+hv was the rate controlling step. Thioanisole and paraoxon, the simulants of sulfur mustard gas and nerve gas, respectively, were efficiently decontaminated by the NaHCO₃-activated H₂O₂ solution. While HCO₄^- was the primary oxidant for the oxidation of thioanisole, O₂^- generated during the decomposition of HCO₄^- or H₂O₂ led to the secondary oxidation of the sulfide. Paraoxon was degraded in the NaHCO₃-activated H₂O₂ solution via nucleophilic substitution by OOH^- and OH^-, and the degradation rate increased exponentially with increasing pH. Alkali metal ions had a catalytic effect on the degradation of paraoxon. Mustard gas and soman degraded efficiently into nontoxic products in NaHCO₃-activated H₂O₂. A pH range of 9-10 was found to be optimum for the broad-spectrum decontamination of chemical warfare agents and other eco-toxicants using NaHCO₃-activated H₂O₂.

Keywords: Bicarbonate-activated H(2)O(2); Chemical warfare agent; Decontamination; Paraoxon; Thioanisole.