Among the small-sized organic components of natural waters, the so-called humic monomers (building blocks of humic substances) can affect the efficiency of wastewater treatment plants (WWTPs) based on adsorption processes, due to their dimension comparable to those of the sorbent pores. Recently, the environmental antibiotic spreading is of concern because of the antibiotic-resistance development. Several studies report about the occurrence in surface waters and WWTPs/hospital effluents of sulfonamides, a top-selling class of antibiotics systematically used as growth promoters and to treat/prevent bacterial infections, owing to their anionic nature. Adsorption on high silica (HS) zeolites has been proposed as an efficient technique to remove high amount of sulfonamides with a favourable kinetics in model studies but no information is available about the effect of humic monomers on their efficiency [Ref]. Here the adsorption/desorption of sulfamethoxazole (SMX) sulfonamide on a HS zeolite Y was investigated in the presence of two humic monomers: vanillin (VNL) and caffeic acid (CA). VNL competed with SMX for the zeolite adsorption sites, conversely to what observed for CA, according to their solubility and pKa values. As SMX-VNL co-adsorption was revealed, FTIR spectroscopy combined to Rietveld analysis of XRPD data allowed to define the guest-guest interactions inside the zeolite pores. DFT calculations in vacuo confirmed the stabilization of the complex (see figure) with respect to the isolated compounds. Finally, both thermal treatment and solvent extraction succeeded in the regeneration of the exhausted zeolite. [Ref] Leardini et al., Martucci et al., 2014 Min. Mag.; Blasioli et al., 2014 J. Coll .Interface Sci.; Braschi et al., 2013 RSC-Advances; Martucci et al. 2013 Micropor. Mesopor. Mat.; Braschi et al., 2010 Langmuir; Braschi et al., 2010 J. Hazard. Mat. Research co-funded by the Italian Ministry of Education, University, and Research (2008 BL2NWK)
Adsorption selectivity of veterinary sulfonamide antibiotics and humic monomers by zeolite Y and regeneration studies: A zeolite-based WWTP technology against antibiotic resistance
MARTUCCI, Annalisa
2015
Abstract
Among the small-sized organic components of natural waters, the so-called humic monomers (building blocks of humic substances) can affect the efficiency of wastewater treatment plants (WWTPs) based on adsorption processes, due to their dimension comparable to those of the sorbent pores. Recently, the environmental antibiotic spreading is of concern because of the antibiotic-resistance development. Several studies report about the occurrence in surface waters and WWTPs/hospital effluents of sulfonamides, a top-selling class of antibiotics systematically used as growth promoters and to treat/prevent bacterial infections, owing to their anionic nature. Adsorption on high silica (HS) zeolites has been proposed as an efficient technique to remove high amount of sulfonamides with a favourable kinetics in model studies but no information is available about the effect of humic monomers on their efficiency [Ref]. Here the adsorption/desorption of sulfamethoxazole (SMX) sulfonamide on a HS zeolite Y was investigated in the presence of two humic monomers: vanillin (VNL) and caffeic acid (CA). VNL competed with SMX for the zeolite adsorption sites, conversely to what observed for CA, according to their solubility and pKa values. As SMX-VNL co-adsorption was revealed, FTIR spectroscopy combined to Rietveld analysis of XRPD data allowed to define the guest-guest interactions inside the zeolite pores. DFT calculations in vacuo confirmed the stabilization of the complex (see figure) with respect to the isolated compounds. Finally, both thermal treatment and solvent extraction succeeded in the regeneration of the exhausted zeolite. [Ref] Leardini et al., Martucci et al., 2014 Min. Mag.; Blasioli et al., 2014 J. Coll .Interface Sci.; Braschi et al., 2013 RSC-Advances; Martucci et al. 2013 Micropor. Mesopor. Mat.; Braschi et al., 2010 Langmuir; Braschi et al., 2010 J. Hazard. Mat. Research co-funded by the Italian Ministry of Education, University, and Research (2008 BL2NWK)I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
