2 research outputs found
Carbon Textiles Modified with Copper-Based Reactive Adsorbents as Efficient Media for Detoxification of Chemical Warfare Agents
Carbon
textile swatch was oxidized and impregnated with copper hydroxynitrate.
A subsample was then further heated at 280 °C to form copper
oxide. The swatches preserved their integrity through the treatments.
As final products, they exhibited remarkable detoxification properties
for the nerve agent surrogate dimethyl chlorophosphate (DMCP). Based
on the amount of reactive copper phases deposited on the fibers, their
adsorption capacities were higher than those of the bulk powders.
After 1 day exposure to DMCP (1:1 weight ratio adsorbent/DMCP), 99%
of the initial amount of DMCP was eliminated. A synergistic effect
of the composite components was clearly seen. GC-MS results showed
that the main surface reaction product was chloromethane. Its formation
indicated hydrolysis as a detoxification path. Surface analyses showed
phosphate bonding to the fibers and formation of copper chloride.
The appearance of the latter species results in a clear textile color
change, which suggests the application of these fabrics not only as
catalytic protection agents but also as sensors of nerve agents
Role of Surface Chemistry and Morphology in the Reactive Adsorption of H<sub>2</sub>S on Iron (Hydr)Oxide/Graphite Oxide Composites
Composites
of magnetite and two-line ferrihydrite with graphite oxide (GO) were synthesized
and tested as hydrogen sulfide adsorbents. Exhausted and initial composites
were characterized by the adsorption of nitrogen, X-ray diffraction,
potentiometric titration, thermal analysis, and FTIR. The addition
of GO increased the surface area of the composites due to the formation
of new micropores. The extent of the increase depended on the nature
of the iron (hydr)oxide and the content of GO. The addition of GO
did not considerably change the crystal structure but increased the
number of acidic functional groups. While for the magnetite composites
an increase in the H<sub>2</sub>S adsorption capacity after GO addition
was found, the opposite effect was recorded for the ferrihydrite composites.
That increase in the adsorption capacity was linked to the affinity
of the composites to adsorb water in mesopores of specific sizes in
which the reaction with basic surface groups takes place. Elemental
sulfur and ferric and ferrous sulfates were detected on the surface
of the exhausted samples. A redox reactive adsorption mechanism is
proposed to govern the retention of hydrogen sulfide on the surface
of the composites. The incorporation of GO enhances the chemical retention
of H<sub>2</sub>S due to the incorporation of OH reactive groups and
an increase in surface heterogeneity