Study of the Contributions of Non‐Specific and Specific Interactions during Fluoxetine Adsorption onto Activated Carbons

Abstract

The adsorption of fluoxetine onto activated carbons (ACs) prepared from almond tree pruning by steam and CO 2 activation under different temperature conditions (650-9508C), was studied. In both series increasing the temperature caused an increase in the BET apparent surface area, yielding ACs with S BET up to 870 and 710 m 2 g À1 after steam and CO 2 activation, respectively. Also, a slight widening of the porosity was found in both cases. In order to modify the functionality of the ACs, two of them were impregnated with triethylenediamine (TEDA) prior to the adsorption process, which caused a decrease in the AC apparent surface mainly due to micropore blockage. The fluoxetine adsorption isotherms at 258C showed maximum adsorption capacities between 110 and 224 mg g À1 . The adsorption isotherms were analyzed using Langmuir and Freundlich models. Although the impregnation reduced the pore volume, it did not cause a decrease in the fluoxetine maximum adsorption capacity, but a modification in the adsorption mechanism was observed.

Surface Interactions during the Removal of Emerging Contaminants by Hydrochar-Based Adsorbents

“…All isotherms can be classified as L-type, according to Giles classification [22]; they present an initial rise in the low equilibrium concentration region followed by a plateau. It is noteworthy that the same pattern was obtained for fluoxetine adsorption but using activated carbons prepared by chemical activation with KOH [23] or by physical CO 2 and steam activation of almond tree pruning [24].…”

“…Finally, it has to be taken into account that under the experimental conditions used, i.e., neutral pH, both the adsorbate and adsorbent show a specific charge. Considering the speciation diagram and pka value, it can observe that fluoxetine is predominantly on its protonated form [24]. The activated samples produced by carbon dioxide activation, in general, present a more abrupt slope denoting a greater affinity at lower concentrations, while air-activated ones show a slower rise to the plateau.…”

“…Finally, it has to be taken into account that under the experimental conditions used, i.e., neutral pH, both the adsorbate and adsorbent show a specific charge. Considering the speciation diagram and pk a value, it can observe that fluoxetine is predominantly on its protonated form [24]. Regarding the ACs, the ionization of the surface functional groups and thus the electric mean charge of the material surface depend on the difference between the solution pH and the adsorbent PZC.…”

Selective silica‐based sorbent materials synthesized by molecular imprinting for adsorption of pharmaceuticals in aqueous matrices

“…300 mg/g). Lower adsorption capacities (110–224 mg/g) have been reported for activated carbons exhibiting relatively lower surface areas (710–870 m 2 /g), also in the case of fluoxetine . Nevertheless, such materials are not imprinted ones, and therefore may not be limited by pore accessibility.…”

Adsorption of fexofenadine and diphenhydramine on dehydrated and activated carbons from date palm leaflets

“…[4] Activated carbon showed a good performance in removing different pharmaceuticals such as amoxicillin, [15] sulfapyridine, tetracycline, and tylosin [16] and fluoxetine. [17] Amberlite was tested for the removal of Carbamazepine, Naproxen and Trimethoprim. [18] D001 resin was examined for the removal of miglitol anti-diabetic drug.…”