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Kayıt Tarihi: 2021-13-Ocak
Aktif Durum: Pasif
Gönderilenler: 30
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| Gönderen: 2021-23-Ocak Saat 09:56 | Kayıtlı IP
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Activated carbons of various origins (bituminous coal,
wood, coconut shells,pellets.com/">activated carbon pellets aquarium and
peat) were studied as adsorbents of hydrogen sulfide.
Before the experiments the surface of the adsorbents was
characterized by using the sorption of nitrogen, Boehm
and potentiometric titrations, thermal analysis, and
FTIR. The adsorbents were chosen to differ in their
surface areas, pore volumes, and surface acidities. To
broaden the spectrum of surface acidity, carbons were
oxidized by using nitric acid and ammonium persulfate.
After hydrogen sulfide adsorption the species present on
the surface were analyzed using thermal analysis, ion
chromatography, and elemental analysis. The H(2)S
breakthrough capacity tests showed that the performances
of different carbons differ significantly. For a good
performance of carbons as hydrogen sulfide adsorbents a
proper combination of surface chemistry of carbon and
porosity is needed. It was demonstrated that a more
acidic environment promotes the formation of sulfur
oxides and sulfuric acid despite yielding small H(2)S
removal capacities. On the other hand, a basic
environment favors the formation of elemental sulfur
(sulfur radicals) and yields high capacities. The
presence of a sufficient amount of water preadsorbed on
the carbon surface to facilitate dissociation also plays
an important role in the process of H(2)S
adsorption/oxidation. The results showed that there is a
critical value in carbon surface acidity, which when
exceeded results in a negligible hydrogen sulfide
breakthrough capacity. This is consistent with the
mechanism of H(2)S adsorption on unmodified carbons,
where the rate-limiting step is the reaction of adsorbed
hydrogen sulfide ion with dissociatively adsorbed oxygen.
When the acidity is expressed as pH, its value should be
higher than 5 to ensure the effective removal of hydrogen
sulfide from the gas phase.
https://coco
nutactivatedcarbon.com Study of carbon regeneration
using water washing and heat treatment showed that the
adsorbents can be regenerated to about 40% of their
initial capacity.
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Konu: Activated carbons of various origins
