ARTÍCULO
Simultaneous removal of metronidazole and Pb(II) from aqueous solution onto bifunctional activated carbons
Sonia Judith Segovia-Sandoval1 & Erika Padilla-Ortega2 & Francisco Carrasco-Marín3 & María Selene Berber-Mendoza1 &
Raúl Ocampo-Pérez2
Environmental Science and Pollution Research
https://doi.org/10.1007/s11356-019-05857-w, 2019.
ABSTRACT:
In this work, it was analyzed the behavior of three commercial activated carbons with different textural and chemical properties to adsorb individually metronidazole and lead ions from aqueous solution. Afterwards, the activated carbons were modified with citric acid to remove both compounds simultaneously. Both sets of activated carbons were characterized chemically and texturally. XPS analysis was performed to corroborate the adsorption mechanism of lead on the surface of the carbons. Finally, the intraparticle diffusion of both adsorbates was elucidated by the application of diffusional model in three dimensions. The results evidenced that adsorption mechanismforMNZ and Pb(II) is independent, the adsorption forMNZ is governed by ?–? dispersive interactions, whereas Pb(II) adsorption is mainly controlled by electrostatic interactions. The binary adsorption equilibrium shows that the adsorption of MNZ is independent from the concentration of Pb(II), whereas the adsorption of Pb(II) is affected by the presence ofMNZ at low concentrations (0.1mmol L?1), but it remains almost constant at concentrations ofMNZ between 0.1 and 1.5 mmol L?1. Finally, the mass transport of MNZ was faster than Pb(II) from the solution to the external surface of activated carbon and the mass flux of MNZ inside the particle was superior to the mass flux of Pb(II). Lastly, there might be an obstruction phenomenon with MNZ impeding Pb(II) to reach the active sites placed into the carbon’s microporosity structure.