Noble metal-based sorbents: A way to avoid new waste after mercury removal

[Display omitted] •New regenerable noble metal-based sorbents were developed for mercury removal.•Efficiencies of 100 % can be achieved without generating new Hg-containing toxic waste.•The Hg-Ag amalgamation process differs from the Hg-Au one.•The presence of SO2 traces poisons the sorbent with Ag...

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Published inJournal of hazardous materials Vol. 400; p. 123168
Main Authors Antuña-Nieto, Cristina, Rodríguez, Elena, Lopez-Anton, Maria Antonia, García, Roberto, Martínez-Tarazona, M. Rosa
Format Journal Article
LanguageEnglish
Published Netherlands Elsevier B.V 05.12.2020
Subjects
Clean energy
Gold
Mercury waste
Regenerable sorbent
Silver
Gold
Silver
Regenerable sorbent
Clean energy
Mercury waste
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Summary:[Display omitted] •New regenerable noble metal-based sorbents were developed for mercury removal.•Efficiencies of 100 % can be achieved without generating new Hg-containing toxic waste.•The Hg-Ag amalgamation process differs from the Hg-Au one.•The presence of SO2 traces poisons the sorbent with Ag and not with Au.•Ag and Au regenerable sorbents would be environmentally competitive. The development of technologies to control mercury emissions is now a legal requirement imposed by recent international agreements. The use of regenerable sorbents is consistent with this requirement as it allows mercury to be captured from industrial gases without generating new mercury-containing toxic waste. Because regenerable sorbents based on noble metals are often questioned due to the heavy investment they entail, this study assesses the viability of their use in terms of efficiency and cost. Its primary aim is to develop new regenerable sorbents based on an activated carbon support impregnated with Ag in order to compare their cost and behavior in a CO2 enriched gas stream with that of similar materials containing Au. Mercury retention efficiencies of 100 % can be achieved over several adsorption-desorption cycles depending on the type of noble metal used, particle size and impurities in the gas atmosphere. The results suggest that the Hg-Ag amalgamation process differs from the Hg-Au one, in that they show different kinetics of adsorption and temperatures of desorption. The Ag and Au regenerable sorbents developed in this study would be competitive given the environmental and health benefits they offer compared to the single-use activated carbons employed until now at industrial scale.
ISSN:0304-3894
1873-3336
DOI:10.1016/j.jhazmat.2020.123168