Selective elimination of phenol from hydrocarbons by zeolites and silica-based adsorbents—Impact of the textural and acidic properties

• Published in: Journal of hazardous materials 2020-02, Vol.384, p.121397, Article 121397
• Main Authors: Khalil, Ibrahim, Thomas, Karine, Jabraoui, Hicham, Bazin, Philippe, Maugé, Francoise
• Format: Article
• Language: English
• Subjects: Breakthrough curves; Chemical Sciences; Phenol adsorption; Selectivity; Toluene adsorption; Zeolite acidity
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2019.121397

[Display omitted] •Phenol condensed in Y zeolite supercages but adsorbed on external silanol groups.•HY selectively adsorbed phenol in presence of toluene and linear hydrocarbon.•Easy regeneration requires low amount of acidic sites. This paper investigates the parameters that influence the selective adsorption of phenol, toxic molecule, from a semi-model biofuel mixture containing alkanes and different proportions of aromatic compounds. The adsorption capacity, selectivity and regeneration ability of different adsorbents, i.e. zeolites, silica-based solids, alumina and activated carbon, were related to their textural properties and the nature, strength or location of their acidic sites. This work demonstrates that phenol differently adsorbs in the micropores and mesopores. In the micropores of faujasites, phenol is condensed into the supercages. Otherwise, in the mesopores of the zeolite, phenol interacts with the silanol groups. On purely siliceous adsorbents, a ratio of one phenol adsorbed on one silanol group could be established. As for selectivity, the strong acidic sites of the faujasites are necessary to favor phenol adsorption compared to toluene. By contrast, the amount of strong Brønsted and Lewis acid sites limits regeneration. Hence, a compromise has to be found and the best performances were obtained using a slightly dealuminated zeolitic adsorbent presenting both micro and mesopores.