Browsing by Author "Rosales, Emilio"
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- Continuous adsorption studies of pharmaceuticals in multicomponent mixtures by agroforestry biocharPublication . Puga, Antón; Moreira, Manuela M.; Pazos, Marta; Figueiredo, Sónia; Sanromán, M. Ángeles; Delerue-Matos, Cristina; Rosales, EmilioIn this study, the adsorption of a multicomponent mixture of active pharmaceutical compounds, such as Venlafaxine (VLX), Trazodone (TRZ) and Fluoxetine (FLX), was studied in a biochar fixed-bed column. The selection of appropriate biochar (eucalyptus, grapevine cane and holm tree biochar) as an adsorbent was carried out through batch assays. An insight into the adsorption mechanism and its correlation with the chosen biochars was performed, showing that electron donor/acceptor interaction is the main mechanism involved. Equilibrium and kinetic batch adsorption experiments were performed and the results demonstrated that eucalyptus biochar was the most viable option for the removal of the pollutants, individually and combined. Column adsorption experiments were performed and Thomas, Yoon-Nelson and Yan models were adjusted to the breakthrough curves. This multicomponent system exhibited a synergetic behavior for TRZ and an antagonist for VLX and FLX, when compared to the single and multicomponent systems previously evaluated in batch assays. The treatment of real wastewaters, spiked with pollutants, has demonstrated the removal efficiency of multicomponent mixtures. Finally, the adsorbent regeneration by elution in different solutions was also investigated and methanol proved to be the most effective eluent for the column regeneration
- Electro-Fenton degradation of a ternary pharmaceutical mixture and its application in the regeneration of spent biocharPublication . Puga, Antón; Moreira, Manuela M.; Figueiredo, Sónia A.; Delerue-Matos, Cristina; Pazos, Marta; Rosales, Emilio; Sanromán, M. ÁngelesThis study proposed an integrated valorisation system, by combining adsorption and electro-Fenton processes for fast and effective micropollutant remediation of a complex pharmaceutical mixture. The pharmaceuticals venlafaxine, fluoxetine and trazodone, commonly detected in the environment (river water and sediment), were selected in this study as target pollutants. Initially, the electro-Fenton degradation process of the ternary mixture was optimised. For this, a Box-Behnken experimental design was used and the degradation of each pollutant, as a response function, was evaluated using three key operational process parameters (iron concentration, current intensity and solution pH). The pharmaceutical mixture was removed by total adsorption onto the biochar, the regeneration of which was then carried out under the optimal electro-Fenton conditions (0.24 mA, 0.33 mM Fe2+ and pH 3.2). In addition, different options in relation to the presence of iron were considered: i) iron dissolved in aqueous solution; ii) iron supported on the biochar; iii) no addition of iron (“self-cleaning”). The results confirmed that the natural content of iron in the biochar was enough to catalyse the electro-Fenton regeneration. The adsorption-electro-Fenton regeneration process was repeated over several cycles with no reduction in the efficiency of either process. Finally, this combination (adsorption and electro-Fenton process) was tested using an aqueous matrix from a wastewater treatment plant.