Ammonia removal using activated carbons: effect of the surface chemistry in dry and moist conditions


Autoria(s): Gonçalves, Maraisa; Sánchez García, Laura; Jardim, Erika de Oliveira; Silvestre-Albero, Joaquín; Rodríguez Reinoso, Francisco
Contribuinte(s)

Universidad de Alicante. Departamento de Química Inorgánica

Universidad de Alicante. Instituto Universitario de Materiales

Materiales Avanzados

Data(s)

28/05/2012

28/05/2012

03/11/2011

Resumo

The effect of surface chemistry (nature and amount of oxygen groups) in the removal of ammonia was studied using a modified resin-based activated carbon. NH3 breakthrough column experiments show that the modification of the original activated carbon with nitric acid, that is, the incorporation of oxygen surface groups, highly improves the adsorption behavior at room temperature. Apparently, there is a linear relationship between the total adsorption capacity and the amount of the more acidic and less stable oxygen surface groups. Similar experiments using moist air clearly show that the effect of humidity highly depends on the surface chemistry of the carbon used. Moisture highly improves the adsorption behavior for samples with a low concentration of oxygen functionalities, probably due to the preferential adsorption of ammonia via dissolution into water. On the contrary, moisture exhibits a small effect on samples with a rich surface chemistry due to the preferential adsorption pathway via Brønsted and Lewis acid centers from the carbon surface. FTIR analyses of the exhausted oxidized samples confirm both the formation of NH4+ species interacting with the Brønsted acid sites, together with the presence of NH3 species coordinated, through the lone pair electron, to Lewis acid sites on the graphene layers.

Financial support from MEC(projectMAT2007- 61734 FEDER) and Generalitat Valenciana (PROMETEO/2009/002). The European Commission is also acknowledged (project FRESP CA, contract 218138). J.S.-A. acknowledges support from MEC, GV, and UA (RyC2137/06).

Identificador

GONÇALVES, Maraisa, et al. “Ammonia removal using activated carbons: effect of the surface chemistry in dry and moist conditions”. Environmental Science &Technology. Vol. 45, No. 24 (2011). ISSN 0013-936X, pp. 10605-10610

0013-936X (Print)

1520-5851 (Online)

http://hdl.handle.net/10045/22587

10.1021/es203093v

Idioma(s)

eng

Publicador

American Chemical Society

Relação

http://dx.doi.org/10.1021/es203093v

info:eu-repo/grantAgreement/EC/FP7/218138

Direitos

Copyright © 2011 American Chemical Society

info:eu-repo/semantics/restrictedAccess

Palavras-Chave #Activated carbons #Ammonia removal #Surface chemistry #Química Inorgánica
Tipo

info:eu-repo/semantics/article