Cerium oxide for the destruction of chemical warfare agents: A comparison of synthetic routes

0458193 - ÚACH 2017 RIV NL eng J - Journal Article
Janos, P. - Henych, Jiří - Pelant, O. - Pilařová, V. - Vrtoch, L. - Kormunda, M. - Mazanec, K. - Štengl, Václav
Cerium oxide for the destruction of chemical warfare agents: A comparison of synthetic routes.
Journal of Hazardous Materials. Roč. 304, MAR (2016), s. 259-268. ISSN 0304-3894. E-ISSN 1873-3336
Institutional support: RVO:61388980
Keywords : Cerium oxide * Chemical warfare agents * Organophosphate compounds * Decontamination
Subject RIV: CA - Inorganic Chemistry
Impact factor: 6.065, year: 2016

Four different synthetic routes were used to prepare active forms of cerium oxide that are capable of destroying toxic organophosphates: a sol-gel process (via a citrate precursor), homogeneous hydrolysis and a precipitation/calcination procedure (via carbonate and oxalate precursors). The samples prepared via homogeneous hydrolysis with urea and the samples prepared via precipitation with ammonium bicarbonate (with subsequent calcination at 500 degrees C in both cases) exhibited the highest degradation efficiencies towards the extremely dangerous nerve agents soman (O-pinacolyl methylphosphonofluoridate) and VX (O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate) and the organophosphate pesticide parathion methyl. These samples were able to destroy more than 90% of the toxic compounds in less than 10 min. The high degradation efficiency of cerium oxide is related to its complex surface chemistry (presence of surface -OH groups and surface non-stoichiometry) and to its nanocrystalline nature, which promotes the formation of crystal defects on which the decomposition of organophosphates proceeds through a nucleophilic substitution mechanism that is not dissimilar to the mechanism of enzymatic hydrolysis of organic phosphates by phosphotriesterase.
Permanent Link: http://hdl.handle.net/11104/0258481