Chemical warfare agents; metal oxides; adsorption; simulants.

Recent Advancements On Warfare Agents/metal Oxides Surface Chemistry And Their Simulation Study

Neha Sharma and Rita Kakkar^*

Department of Chemistry, University of Delhi, Delhi 110 007, India

Adv. Mater. Lett., 2013, Current Issue, 4 (7), pp 508-521

DOI: 10.5185/amlett.2012.12493

Publication Date (Web): May 01, 2013

E-mail: rkakkar@chemistry.du.ac.in

Full Article

Abstract

Chemical warfare agents (CWA) have been used in the World Wars and in terrorist attacks, and hence there is an urgent need to find means of their decontamination. Metal oxides offer a rapid means of their disposal, since they contain reactive Lewis acid and basic sites, on which adsorption of the CWA, and subsequent hydrolysis, can take place. Destructive adsorption of CWA on metal oxides yields non-toxic products. Nanoscale metal oxides display enhanced reactive properties toward warfare agents due to their high surface area, large number of highly reactive edges, corner defect sites, unusual lattice planes and high surface to volume ratio. Both experimental and theoretical studies have established that decomposition of nerve agents is facilitated on nanoscale Al2O₃, MgO, CaO, TiO₂, ZnO and small edge and corner clay mineral fragments. Compared to sulfur mustard, nerve agents are more potent. We first briefly describe their mode of action. Many experimental and theoretical studies have been performed to study their decomposition on various metal oxide surfaces, such as MgO, CaO, Al2O₃, TiO₂, V2O₅, and clay minerals. The results of these studies are reviewed here. Photochemical degradation on TiO₂nanosurfaces has also yielded promising results. Because of the toxicity and risk involved, experimental studies have been mostly confined to the benign simulants, whereas theoretical studies have attempted to compare the real agents with their mimics. These studies establish a qualitative correlation between the G-agents and their simulant DMMP, and, hence, decomposition on metal oxide surfaces can be analyzed by observing the surface chemistry of DMMP on a wide variety of metal oxide surfaces. This review attempts to compile the literature concerning CWA and their simulants.