la9b00835_si_001.pdf (1.36 MB)
CeO2‑Decorated α‑MnO2 Nanotubes: A Highly Efficient and Regenerable Sorbent for Elemental Mercury Removal from Natural Gas
journal contribution
posted on 2019-05-27, 00:00 authored by Anastasios Chalkidis, Deshetti Jampaiah, Mohamad Hassan Amin, Patrick G. Hartley, Ylias M. Sabri, Suresh K. BhargavaCeO2 nanoparticle-decorated
α-MnO2 nanotubes
(NTs) were prepared and tested for elemental mercury (Hg0) vapor removal in simulated natural gas mixtures at ambient conditions.
The composition which had the largest surface area and a relative
Ce/Mn atomic weight ratio of around 35% exhibited a maximum Hg0 uptake capacity exceeding 20 mg·g–1 (2 wt %), as determined from measurements of mercury breakthrough
which corresponded to 99.5% Hg0 removal efficiency over
96 h of exposure. This represents a significant improvement in the
activity of pure metal oxides. Most importantly, the composite nanosorbent
was repeatedly regenerated at 350 °C and retained the 0.5% Hg0 breakthrough threshold. It was projected to be able to sustain
20 regeneration cycles, with the presence of acid gases, CO2, and H2S, not affecting its performance. This result
is particularly important, considering that pure CeO2 manifests
rather poor activity for Hg0 removal at ambient conditions,
and hence, a synergistic effect in the composite nanomaterial was
observed. This possibly results from the addition of facile oxygen
vacancy formation at α-MnO2 NTs and the increased
amount of surface-adsorbed oxygen species.