In the last decade, it was demonstrated that domestic wastewaters contain a variety of organic contaminants such as pharmaceuticals and personal care products. Most of these compounds undergo both incomplete removal in wastewater treatment plants and slow natural degradation, consequently they are found in surface waters receiving effluent from treatment plants [1]. Pharmaceuticals can also be found in surface waters due to their veterinary use, in such cases they enter the environment via manure dispersion and animal excretion onto soils [2]. Studies on conventional biological drinking-water treatment processes such as biofiltration have shown that they are largely ineffective in removing pharmaceuticals [3]. In literature, several works focused on advantages of zeolites as adsorbents, such as high selectivity, rapid kinetics, reduced interference from salt and humic substances [4], excellent resistance to chemical, biological, mechanical and thermal stress [5-7 and references therein]. Even if zeolites are more expensive with respect to other adsorbents, they offer the possibility to be regenerated without loss of performances at relatively low temperatures [8-10]. In this work, the removal of three different pharmaceuticals (atenolol C14H22N2O3, ketoprofen C16H14O3, diclofenac C14H11Cl2NO2) from water by high-silica organophilic zeolite Y (with a SiO2/Al2O3 ratio equal to 200) will be investigated. All selected drugs differ in chemical properties and molecular dimensions and are ubiquitous contaminants in the sewage waters, while not being effectively removed by conventional activated sludge treatment and membrane bioreactors (MBRs). Despite the large effort devoted to these studies, up to now, a limited number of investigations on drugs-loaded zeolites have been carried out by X-ray or neutron diffraction to obtain the location and population of atoms sites [4-7, 9-10]. The present study is designed to determine the contribution of hydrogen bonding, hydration and dynamics to the thermostability of selected pharmaceuticals adsorbed onto zeolites from water. Neutron diffraction has been shown to be a powerful technique for locating light atoms even at medium resolution. By using the deuterated forms of the target pharmaceuticals almost all accessible labile H atoms (i.e., most of those in O-H and N-H groups) will been replaced by D atoms thus increasing the overall scattering power of the crystal for neutrons and cancelling the negative scattering density of H atoms which tends to reduce the positive density of other atoms. Additionally, deuteration also reduces the incoherent scattering from hydrogen in the sample as well as the background scattering thus increasing the diffraction signal. Finally, the extent of H/D exchange in the OH/COOH groups, as determined in neutron Fourier maps, directly reflects local dynamics in the drugs structure. This experimental technique has already been used by our group to determine the population and location of hydroxyls in deuterated and calcined D-ferrierite [11-12], mordenite [13] and heulandite [14] and very recently zeolite L (proposal 5-22-744 ) by using the data collected at D2B beamline (ILL, Grenoble). The aim of this proposal is to determine the number and location of adsorbed-drugs sites in zeolite Y, the synthetic counterpart of natural faujasite, via powder neutron diffraction. Zeolite Y is a large pore material which crystallizes in the cubic space group Fd-3m, with a lattice constant ranging from about 24.2 to 25.1 A, depending on the framework aluminium concentration, cations, and state of hydration. The pore structure is characterized by approximately 12A diameter cages, linked through access windows ( 7.0A×7.1A in diameter) and thus permitting quite large molecules to enter, making this structure potentially useful in the adsorption of thedrugs under study. The sample to be used in this project is a synthetic commercial zeolite Y (code HSZ-390HUA) with a 200 SiO2/Al2O3 (mol/mol) ratio, purchased in its protonated form from the Tosoh Corporation (Japan). We plan to collect three samples of zeolite Y powders (Atenolol-Y, diclofenac-Y and ketoprofen-YL, respectively). In particular, all samples will be obtained by the ion exchanging the as-synthesized form with deuterated drugs in aqueous solution for ≈140 h at room temperature and then washed with D2O. All samples will be packed in our laboratory in an argon-flushed glove-bag into a vanadium container sealed with a rubber gasket to ensure humidity-free transport to the neutron source. Powder diffraction data will be preferentially collected at the D2B beamline, with satisfactory counting statistics in order to allow full Rietveld refinements of all datasets. The powder data will be processed using the GSAS package. The location of extraframework species will be carried out by a combination of least squares and Difference Fourier map techniques. To achieve these results high resolution at high-q is mandatory to obtain powder diffraction data for accurate Rietveld refinement. The proposed D2B instrument will dramatically expand the knowledge of drugs adsorption on zeolites, allowing large chemical complexes and a range of pharmaceuticals to be studied. References [1] Martucci, A., Braschi, I., Marchese, L., & Quartieri, S. (2014) Mineral. Mag., 78(5), 1115. [2] Figueroa R.A., Leonard A., MacKay A.A. (2004) Environ. Sci. Technol. 38, 476. [3] Ternes T.A., Meisenheimer M., McDowell D., Sacher F., Brauch H.J., Haist- Gulde B., Preuss G., Wilme U., Zulei-Seibert N. (2002) Environ. Sci. Technol. 36, 3855. [4] Braschi I., Martucci A., Blasioli S., Mzini L. L., Ciavatta C., & Cossi M. (2016) Chemosphere, 155, 444. [5] Martucci A., Pasti L., Marchetti N., Cavazzini A., Dondi F., Alberti A. (2012) Micro. Meso. Mater. 148, 174. [6] Pasti L., Sarti E., Cavazzini A., Marchetti N., Dondi F., Martucci, A. (2013) J. Sep. Sci. 36, 1604.[7] Braschi I., Blasioli S., Gigli L., Gessa C.E., Alberti A., Martucci A. (2010) J. Hazard. Mater. 17, 218. [8] Rodeghero E., Martucci A., Cruciani G., Bagatin R., Sarti E., Bosi V., Pasti L. (2016) Catal. Today 227, 118. [9] Martucci A., Rodeghero E., Pasti L., Bosi V., Cruciani G. (2015) Micro. Meso. Mater. 215, 175. [10] Braschi I., Blasioli S., Buscaroli E., Montecchio D., & Martucci A. (2016). J. Env. Sciences, 43, 302. [11] Martucci A., Alberti A., Cruciani G., Radaelli P., Ciambelli P., Rapacciuolo M., (1999) Micro. Meso. Mater., 30, 95. [12] Alberti A. and Martucci A. (2010) J. Phys. Chem. C 114, 7767. [13] Martucci A., Cruciani G., Alberti A., Ritter C., Ciambelli P., Rapacciuolo M., (2000) Micro. Meso. Mater. 35–36, 405. [14] Martucci A., Parodi I., Simoncic P., Armbruster T., Alberti A. (2009), Micro. Meso. Mater. 123, 15.
Location of pharmaceuticals adsorbed from water on Y organophilic zeolite by neutron powder diffraction
Annalisa Martucci
Primo
Project Administration
;Giada BeltramiUltimo
Methodology
;Luisa PastiSecondo
Methodology
;Elisa RodegheroPenultimo
Data Curation
2017
Abstract
In the last decade, it was demonstrated that domestic wastewaters contain a variety of organic contaminants such as pharmaceuticals and personal care products. Most of these compounds undergo both incomplete removal in wastewater treatment plants and slow natural degradation, consequently they are found in surface waters receiving effluent from treatment plants [1]. Pharmaceuticals can also be found in surface waters due to their veterinary use, in such cases they enter the environment via manure dispersion and animal excretion onto soils [2]. Studies on conventional biological drinking-water treatment processes such as biofiltration have shown that they are largely ineffective in removing pharmaceuticals [3]. In literature, several works focused on advantages of zeolites as adsorbents, such as high selectivity, rapid kinetics, reduced interference from salt and humic substances [4], excellent resistance to chemical, biological, mechanical and thermal stress [5-7 and references therein]. Even if zeolites are more expensive with respect to other adsorbents, they offer the possibility to be regenerated without loss of performances at relatively low temperatures [8-10]. In this work, the removal of three different pharmaceuticals (atenolol C14H22N2O3, ketoprofen C16H14O3, diclofenac C14H11Cl2NO2) from water by high-silica organophilic zeolite Y (with a SiO2/Al2O3 ratio equal to 200) will be investigated. All selected drugs differ in chemical properties and molecular dimensions and are ubiquitous contaminants in the sewage waters, while not being effectively removed by conventional activated sludge treatment and membrane bioreactors (MBRs). Despite the large effort devoted to these studies, up to now, a limited number of investigations on drugs-loaded zeolites have been carried out by X-ray or neutron diffraction to obtain the location and population of atoms sites [4-7, 9-10]. The present study is designed to determine the contribution of hydrogen bonding, hydration and dynamics to the thermostability of selected pharmaceuticals adsorbed onto zeolites from water. Neutron diffraction has been shown to be a powerful technique for locating light atoms even at medium resolution. By using the deuterated forms of the target pharmaceuticals almost all accessible labile H atoms (i.e., most of those in O-H and N-H groups) will been replaced by D atoms thus increasing the overall scattering power of the crystal for neutrons and cancelling the negative scattering density of H atoms which tends to reduce the positive density of other atoms. Additionally, deuteration also reduces the incoherent scattering from hydrogen in the sample as well as the background scattering thus increasing the diffraction signal. Finally, the extent of H/D exchange in the OH/COOH groups, as determined in neutron Fourier maps, directly reflects local dynamics in the drugs structure. This experimental technique has already been used by our group to determine the population and location of hydroxyls in deuterated and calcined D-ferrierite [11-12], mordenite [13] and heulandite [14] and very recently zeolite L (proposal 5-22-744 ) by using the data collected at D2B beamline (ILL, Grenoble). The aim of this proposal is to determine the number and location of adsorbed-drugs sites in zeolite Y, the synthetic counterpart of natural faujasite, via powder neutron diffraction. Zeolite Y is a large pore material which crystallizes in the cubic space group Fd-3m, with a lattice constant ranging from about 24.2 to 25.1 A, depending on the framework aluminium concentration, cations, and state of hydration. The pore structure is characterized by approximately 12A diameter cages, linked through access windows ( 7.0A×7.1A in diameter) and thus permitting quite large molecules to enter, making this structure potentially useful in the adsorption of thedrugs under study. The sample to be used in this project is a synthetic commercial zeolite Y (code HSZ-390HUA) with a 200 SiO2/Al2O3 (mol/mol) ratio, purchased in its protonated form from the Tosoh Corporation (Japan). We plan to collect three samples of zeolite Y powders (Atenolol-Y, diclofenac-Y and ketoprofen-YL, respectively). In particular, all samples will be obtained by the ion exchanging the as-synthesized form with deuterated drugs in aqueous solution for ≈140 h at room temperature and then washed with D2O. All samples will be packed in our laboratory in an argon-flushed glove-bag into a vanadium container sealed with a rubber gasket to ensure humidity-free transport to the neutron source. Powder diffraction data will be preferentially collected at the D2B beamline, with satisfactory counting statistics in order to allow full Rietveld refinements of all datasets. The powder data will be processed using the GSAS package. The location of extraframework species will be carried out by a combination of least squares and Difference Fourier map techniques. To achieve these results high resolution at high-q is mandatory to obtain powder diffraction data for accurate Rietveld refinement. The proposed D2B instrument will dramatically expand the knowledge of drugs adsorption on zeolites, allowing large chemical complexes and a range of pharmaceuticals to be studied. References [1] Martucci, A., Braschi, I., Marchese, L., & Quartieri, S. (2014) Mineral. Mag., 78(5), 1115. [2] Figueroa R.A., Leonard A., MacKay A.A. (2004) Environ. Sci. Technol. 38, 476. [3] Ternes T.A., Meisenheimer M., McDowell D., Sacher F., Brauch H.J., Haist- Gulde B., Preuss G., Wilme U., Zulei-Seibert N. (2002) Environ. Sci. Technol. 36, 3855. [4] Braschi I., Martucci A., Blasioli S., Mzini L. L., Ciavatta C., & Cossi M. (2016) Chemosphere, 155, 444. [5] Martucci A., Pasti L., Marchetti N., Cavazzini A., Dondi F., Alberti A. (2012) Micro. Meso. Mater. 148, 174. [6] Pasti L., Sarti E., Cavazzini A., Marchetti N., Dondi F., Martucci, A. (2013) J. Sep. Sci. 36, 1604.[7] Braschi I., Blasioli S., Gigli L., Gessa C.E., Alberti A., Martucci A. (2010) J. Hazard. Mater. 17, 218. [8] Rodeghero E., Martucci A., Cruciani G., Bagatin R., Sarti E., Bosi V., Pasti L. (2016) Catal. Today 227, 118. [9] Martucci A., Rodeghero E., Pasti L., Bosi V., Cruciani G. (2015) Micro. Meso. Mater. 215, 175. [10] Braschi I., Blasioli S., Buscaroli E., Montecchio D., & Martucci A. (2016). J. Env. Sciences, 43, 302. [11] Martucci A., Alberti A., Cruciani G., Radaelli P., Ciambelli P., Rapacciuolo M., (1999) Micro. Meso. Mater., 30, 95. [12] Alberti A. and Martucci A. (2010) J. Phys. Chem. C 114, 7767. [13] Martucci A., Cruciani G., Alberti A., Ritter C., Ciambelli P., Rapacciuolo M., (2000) Micro. Meso. Mater. 35–36, 405. [14] Martucci A., Parodi I., Simoncic P., Armbruster T., Alberti A. (2009), Micro. Meso. Mater. 123, 15.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
