NanoContraChem: from the design to the development of nanostructured clays and oxides for the catalytic decontamination of chemical warfare agents

The degradation of highly hazardous chemical and biological warfare agents (CWAs and BWAs) relies typically on the use of strong oxidants with high environmental impact (based on active chlorine-based formulations) or on thermal abatement under harsh conditions. Two main new classes of chlorine-free catalytically active sorbent solids, able to promote the oxidative sorption and degradation of toxic organosulfur and organophophorus CWAs into non-noxious products as well as the detoxication of BWAs have been studied and developed. Transition metal-containing phyllosilicate clays were identified as catalysts for the oxidative abatement of CWA and BWAs in the presence of in situ produced hydrogen peroxide, as an oxidant. The materials proved to be bifunctional catalytic-sorbent solids, able to enhance the oxidising capability of H2O2 [1] and to show a marked acid character. Analogously, metal oxide materials with different chemical compositions and textural morphology and porosity were prepared and tested under mild decontamination conditions [2,3]. The performance of clay materials (Nb-saponite and Fe-montmorillonite) and inorganic oxides (Nb2O5, TiO2, ?-Al2O3 and WO3) was evaluated at room temperature in the oxidative degradation of (2-chloroethyl)ethyl sulfide (CEES) and dimethyl(methylphosphonate) (DMMP), simulants of blistering and nerve CWAs, respectively, with solid oxidants able to release in situ H2O2. The impact on living microorganisms was then evaluated by biotoxicity tests on bioluminescent bacteria (Photobacterium leiognathi Sh1) [4]. The toxicological effect on the environment was also assessed with specific tests on vegetable plants (Phaseolus vulgaris).