Nanocrystalline Metal Oxides as Destructive Adsorbents for Organophosphorus Compounds at Ambient Temperatures

Abstract

Nanocrystals of magnesium oxide react with organophosphorus compounds at room temperature by dissociative chemisorption, which we term “destructive adsorption”. This process involves cleavage of PO and PF bonds (but not PC bonds) and immobilization of the resultant molecular fragments. These ultrafine powders have unusual crystalline shapes and possess high surface concentrations of reactive edge/corner and defect sites, and thereby display higher surface reactivity, normalized for surface area, than typical polycrystalline material. This high surface reactivity coupled with high surface area allows their use for effective decontamination of chemical warfare agents and related toxic substances. Herein data is presented for paraoxon, diisopropylfluorophosphate (DFP), and (CH3CH2O)2P(O)CH2SC6H5 (DEPTMP). Solid‐state NMR and IR spectroscopy indicate that all OR and F groups dissociate; this leaves bound PO4, F, and OR groups for paraoxon, DFP, and DEPTMP, respectively. For paraoxon, it was shown that one monolayer reacts. For DEPTMP, the OR groups dissociate, but not the PCH2SC6H5 group. The nanocrystalline MgO reacts much faster and in higher capacity than typical activated carbon samples, which physisorb but do not destructively adsorb these phosphorous compounds.

Multifunctional ZnO/Nylon 6 nanofiber mats by an electrospinning–electrospraying hybrid process for use in protective applications

“…Rajagopalan et al [19] proposed a destructive adsorption mechanism in which paraoxon is catalyzed by a metal oxide, which leads to the breakage of P-O bonds. Figure 7 shows the possible detoxification reaction of paraoxon by a ZnO/nylon nanofiber.…”

Optical and structural properties of Mn doped MgO powders synthesized by Sol-gel process

“…is an interesting basic oxide that has many applications in several areas such as: catalysis, adsorption, synthesis of refractory ceramics [1][2][3][4], nano electronics, optoelectronics and sensing devices [5], superconductor products [6]. A large number of techniques were commonly used for the preparation of MgO powders, such as sol-gel method [7], thermal evaporation [8], flame spray pyrolysis [9], combustion aerosol synthesis [10], chemical vapor deposition [11], hydrothermal [12], and surfactant methods [13].…”

Adsorption of Cadmium (Ii) Ions by Polyacrylonitrile-Based Activated Carbon Nanofibers/Magnesium Oxide as Its Adsorbents

“…The obtained results revealed that both ACNFs and ACNFs/MgO has good adsorption capacity and effective for the removal of heavy metals from wastewater. Moreover, previous studies have shown that MgO was one of the good adsorbent with high SSA and the incorporation between ACNFs and MgO has proven to be good adsorbent [22] for Cd removal. Based on the results obtained, it can be said that both ACNFs and ACNFs/MgO can be good adsorbent for Cd removal.…”