z Catalysis Physico–chemical Properties, Biological and Environmental Impact of Nb–saponites Catalysts for the Oxidative Degradation of Chemical Warfare Agents Daniele Costenaro, [a] Chiara Bisio,* [a, b] Fabio Carniato, [a] Sergey L. Safronyuk, [c] Tatyana V. Kramar, [c] Marina V. Taran, [d] Mykola F. Starodub, [d] Andrey M. Katsev, [c] and Matteo Guidotti* [b] Niobium-containing saponite clays are active catalysts, under mild ambient conditions and in the presence of aqueous hydrogen peroxide, in the oxidative abatement of sulfur- containing blister chemical warfare agent simulants, such as (2- chloroethyl)ethyl sulfide. Over a Nb-saponite solid, a complete, selective and safe abatement of the chemical agent was attained within 8 h. The biological and environmental impact of the Nb-containing nanostructured clays used as decontami- nation solids was assessed by specific rapid biotoxicity tests on bioluminescent bacteria and vegetable plants. No negative impact on the strain of luminescent bacteria was evidenced in terms of acute and chronic toxicity. No adverse effects have been observed on vegetable plants in terms of germination, vigour and induction of chlorophyll fluorescence either. Introduction The destruction and the abatement of stockpiles of highly toxic chemical warfare agents (CWA) are typically based on drastic degradation methods, such as thermal destruction and hydrol- ysis reactions relying on the use of concentrated alkaline solutions and/or total oxidation processes using strong stoi- chiometric oxidants, mainly containing active chlorine sour- ces. [1] These approaches, even though they proved to be effective and safe for operators and technical personnel, may pose non-negligible problems in terms of high costs (especially when high temperatures are employed for the degradation) and of environmental impact, due to the use of large amounts of over-stoichiometric strong reactants to force the complete conversion of the hazardous reactant. [2] Currently, a growing attention is being paid to detoxification techniques based on residue-free inexpensive decontaminants. [3] Similarly, the use of heterogeneous catalysis and nanostructured solids can be a valid alternative strategy, in order to reduce the amount of reactants involved in the abatement reaction and to speed up the global process. [4, 5] Layered solids, such as phyllosilicate clays and, in particular, saponite materials, can be considered good candidates for the abatement, removal and decontamination of CWAs. Advan- tages such as high robustness, enhanced adsorption capabil- ities, good chemical versatility and very low production costs make these solids promising catalysts for the removal and destruction of hazardous CWAs. In this aim, a new class of heterogeneous catalysts able to promote the selective oxidation of toxic organosulfur CWAs and, in particular, of bis-(2-chloroethyl)sulfide (commonly known as sulfur mustard or yperite: the blistering chemical weapon used first on the battlefields of World War I), into non- noxious products was proposed by some of us. [6] A Nb(V)- containing saponite clay (Nb-SAP) was identified as an effective solid catalyst for the CWA oxidative abatement of the hazard- ous sulfide in the presence of aqueous hydrogen peroxide (aq. 30 %) under extremely mild conditions. Thanks to this system, it is possible to circumvent the use of active chlorine-based oxidants, whose addition to the decontamination formulations is to be gradually replaced by more eco-friendly alternatives. [1, 6] Niobium(V) centers have shown so far promising perform- ances in oxidation catalysis, especially in the presence of hydrogen peroxide as oxidant, thanks to the combined action of oxidation [7, 8] and acid properties. [9] Analogously, polyoxonio- bate species showed a unique basic character successfully exploited in the hydrolytic degradation of sarin and soman CWAs as well as other nerve and blister agent simulants. [10] In Nb(V)-layered saponite materials, niobium sites are able to trigger the selective oxidation of organic sulfides into sulfoxides, prevent their over-oxidation into sulfones (the [a] Dr. D. Costenaro, Dr. C. Bisio, Dr. F. Carniato Nano-SiSTeMI Interdisciplinary Centre University of Eastern Piedmont “A. Avogadro” Viale T. Michel 11, 15121, Alessandria, (Italy) E-mail: chiara.bisio@uniupo.it [b] Dr. C. Bisio, Dr. M. Guidotti Institute of Molecular Sciences and Technology - ISTM National Research Council - CNR via C. Golgi 19, 20144, Milano, (Italy) E-mail: m.guidotti@istm.cnr.it [c] S. L. Safronyuk, T. V. Kramar, Prof. A. M. Katsev Medical Academy V.I. Vernadsky Crimean Federal University boulevard Lenina 5/7, 295006, Simferopol [d] Dr. M. V. Taran, Prof. M.F. Starodub National University of Life and Environmental Sciences of Ukraine Heroyiv Oborony 15, Kyiv-03041, (Ukraine) Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/slct.201700042 Full Papers DOI: 10.1002/slct.201700042 1812 ChemistrySelect 2017, 2, 1812 – 1819  2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim