14 results on '"Sarti, Elena"'
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2. COMPETITIVE ADSORPTION OF ORGANIC POLLUTANTS AND LIGNIN DERIVATIVES PHENOLIC COMPOUNDS ON HYDROPHOBIC ZEOLITES
- Author
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Sarti, Elena, Pasti, Luisa, Martucci, Annalisa, Bagatin, R., and Cavazzini, Alberto
- Subjects
organic pollutants ,adsorption ,organic pollutants, water remediation, zeolites, adsorption, lignin derivatives phenolic compounds ,zeolites ,water remediation ,lignin derivatives phenolic compounds ,NO - Published
- 2015
3. Adsorption properties of particles for environmental applications
- Author
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Sarti, Elena
- Subjects
emerging contaminants ,adsorption ,zeolites ,Settore CHIM/01 - Chimica Analitica ,water remediation ,CHIM/01 Chimica analitica ,mesoporous materials - Abstract
The contaminants of emerging concerns (CECs) are defined by the United States Geological Survey (USGS) as: “any synthetic or naturally occurring chemical or any microorganism that is not commonly monitored in the environment but has the potential to enter the environment and cause known or suspected adverse ecological and/or human health effects.” In other words, CECs are any substances that can be suspected to cause harm. Basically, they are substances used in human activities every day for all kinds of purposes. Because they are so numerous, ubiquitous and chemically different, they are frequently divided into categories that describe their purpose, use or other characteristics. Some common categories are: pharmaceuticals, personal care products, agricultural runoff (pesticides, pathogens and fertilizers), fuel-based-compounds, chlorinated solvents, flame retardants (perfluorinatedalkyl compounds), plasticizers, dyes and endocrine disruptors. CECs are continuously entering water sources throughout the world because of their widespread use. Conventional wastewater and recycled water treatments are only partially effective in their removal or degradation, so they are discharged into the environment with treated wastewater effluent, recycled water and wastewater plant sludge. Other sources of CECs include industrial wastewater effluents, untreated wastewater from manufacturing facilities, landfill leachates, effluents from poultry farms and animal feeding facilities where veterinary drugs may be used. Effects of CECs on human and ecosystem health are largely unknown and relatively little is known about the ways they travel through the environment or how they may be transformed or degraded during their residence time in the environment. Some studies have shown that even very low exposure to certain CECs can have impacts on biological systems. CECs are generally present at very low concentration in natural waters. Therefore, it is important on one hand to develop analytical methods able to detect these molecules in accurate way to better evaluate their impact on the environment, and on the other hand to enhance the efficiency of water remediation technologies in order to decrease their potential adverse effects on biota. Several methods have been reported to be suitable for both of these purposes; sorption based technologies were demonstrated to be efficient and economical methods both for the enrichment of trace pollutants and for their removal from water. Among the large number of inorganic adsorbents, zeolites were proven to be efficient in removing organic compounds from environmental matrixes. Recently, mesoporous silica materials have also received increasing interest because their properties (high surface area, high pore volume, controlled pore size) make them promising as adsorbents in contaminant removal processes. Moreover, due to the thermal and chemical stability of these siliceous adsorbents, they can be considered environmentally compatible. The aim of the present work is to study the adsorption properties of microporous (Beta, ZSM-5, Y and ferrierite zeolites) and mesoporous (MCM-41 and HMS) siliceous materials towards various organic compounds in aqueous solutions. This investigation has the dual purpose of evaluating the application of the selected adsorbents both in remediation technologies of natural waters and as medium for solid phase extraction systems of pre-concentration. For what concerns the studied contaminants, four compounds (ketoprofen, hydrochlorothiazide, atenolol, erythromycin) have been selected as members of CECs. These four drugs belong to different therapeutic classes and have been detected in natural waters of several countries because they are not efficiently removed by conventional wastewaters treatments plants. Moreover they are characterized by different physico-chemical properties as molecular dimensions, acid/base behaviour, hydrophobicity, ecc. Perfluorooctanoic acid (PFOA) was selected because, due to its high water-solubility, it has been frequently found in aquatic environment; moreover it is extremely persistent and toxic. The selected organic pollutants were toluene and methyl-tert-butyl ether (MTBE): they were chosen as representative of BTEX (benzene, toluene, ethylbenzene, xylene) and fuel oxygenate compounds, respectively. Because of its high water solubility and hence high bioavailability, MTBE belongs to the class of emerging contaminants too. In this thesis, chromatographic, thermogravimetric and diffractometric techniques were employed to study the adsorption process in order to: 1) investigate the adsorptive properties of the siliceous materials; 2) characterise their structures after the adsorption of the selected contaminants; 3) localise the organic species in the zeolites channel systems; 4) probe the interactions between organic molecules and framework oxygen atoms; 5) characterize the kinetic of the adsorption process. In particular, the thermodynamics and kinetics of the adsorption process of contaminants on hydrophobic zeolites were studied by using complementary techniques: chromatography and thermogravimetry. Chromatography was mainly used to measure the adsorption isotherms of the studied compounds. The adsorption isotherm is useful for representing the capacity of a zeolite for adsorbing organics from water, and in providing description of the functional dependence of capacity on the concentration of pollutants. Experimental determination of the isotherm allows for evaluating the feasibility of adsorption for treatment, in selecting a zeolite and in estimating adsorbent dosage requirements. Moreover, from isotherm parameters it is possible to evaluate the adsorption energy distribution of the process. The abovementioned techniques were also employed to investigate the kinetics of the adsorption. Kinetics deals with changes in chemical properties in time and is concerned especially with rates of changes: hence it plays a fundamental role in determine the proper contact time for the removal of pollutant components from wastewater. To investigate the adsorption mechanism, diffraction techniques were employed to localize the organic adsorbed into the zeolite structure. The information gathered by this last investigation – in cooperation with the Earth Science Department UNIFE - allow to define the interactions between organic molecules and zeolite framework. The experimental data revealed that the amount of the organic pollutant embedded inside the framework was influenced by the lattice structure, the hydrophobicity (SiO2/Al2O3 ratio: SAR) and the thermal treatments of the adsorbent. For mesoporous silica materials, an important role is also played by the procedure of template removal (thermal treatment or solvent extraction). Both hydrophobic and electrostatic interactions were demonstrated to contribute to the adsorption process: in fact, hydrophobicity and dissociation constant of the solute strongly affect the adsorption. In many cases the selected molecule was proved to be adsorbed inside the framework of the siliceous materials. Generally, it was also proved that the adsorption process was very fast in all the studied zeolites towards several classes of pollutants. Also the adsorption kinetic of PFOA on mesoporous silica materials was satisfying if compared with literature data dealing with other types of adsorbents. To investigate the possible competition of natural organic matter towards contaminants adsorption, the effect of two lignin-derived phenolic monomers (caffeic acid and parahydroxybenzaldheyde) with molecular dimensions comparable to those of the pores of the adsorbent material on the adsorption properties of zeolites was considered. This last part of the work of thesis is a fraction of a wider project whose purpose is to study the interaction and mobility of groundwater pollutants adsorbed in zeolite pores in order to improve the efficiency of permeable reactive barriers. This project involves Ferrara, Bologna and Piemonte Orientale Universities with the financial and scientific support of ENI Research Center of San Donato Milanese. The results revealed that zeolites are selective adsorbents for organic pollutants. In fact, it was demonstrated that toluene is preferentially and almost exclusively adsorbed from mixtures of toluene and humic acid monomers in aqueous solutions. In conclusion, favourable adsorption kinetics along with the effective and selective adsorption of contaminants into zeolites and mesoporous siliceous materials make these cheap and environmentally-friendly materials a tool with interesting applications for the removal or enrichment of organic pollutants from contaminated waters.
- Published
- 2014
4. Hydrophobic zeolites as adsorbent media for pre-concentration of emerging contaminants in aqueous dilute solutions
- Author
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Sarti, Elena, Bosi, Valentina, Martucci, Annalisa, and Pasti, Luisa
- Subjects
emerging contaminants ,water pollution ,adsorption ,zeolites, adsorption, emerging contaminants, water pollution, solid phase extraction ,solid phase extraction ,zeolites ,NO - Published
- 2014
5. High Silica Zeolites for the Removal of Polar Organic Contaminants from Water
- Author
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Bosi, Valentina, Sarti, Elena, Pasti, Luisa, and Martucci, Annalisa
- Subjects
emerging contaminants ,adsorption ,adsorption, zeolites, emerging contaminants ,zeolites ,NO - Published
- 2014
6. Adsorbimento di acido perfluoroottanoico su materiali mesoporosi
- Author
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Pasti, Luisa, Sarti, Elena, Nassi, Marianna, Bosi, Valentina, and Martucci, Annalisa
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Mesoporous silica ,perfluorinated ,adsorption - Published
- 2013
7. Water contaminants adsorption onto micro and mesoporous materials
- Author
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Sarti, Elena, Pasti, Luisa, Martucci, Annalisa, and Bagatin, R.
- Subjects
ZEOLITES ,Mesoporous silica ,water remediation ,adsorption - Published
- 2013
8. ADSORPTION OF SELECTED PHARMACEUTICALS BY ZEOLITES
- Author
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Sarti, Elena, Pasti, Luisa, Martucci, Annalisa, Cavazzini, Alberto, and Dondi, Francesco
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Zeolite ,Pharmaceuticals ,Adsorption - Published
- 2012
9. Adsorption of pharmaceuticals into beta zeolites
- Author
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Pasti, Luisa, Martucci, Annalisa, Nassi, Marianna, and Sarti, Elena
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Beta zeolite ,adsorption ,pharmaceutical - Published
- 2011
10. Adsorption of pharmaceuticals from water by zeolites
- Author
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Sarti, Elena, Pasti, Luisa, Martucci, Annalisa, and Dondi, Francesco
- Subjects
Pharmaceuticals ,Wastewater treatment ,Adsorption ,emergent contaminants - Published
- 2011
11. ADSORPTION OF PHARMACEUTICALS FROM WATER
- Author
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Sarti, Elena, Pasti, Luisa, Martucci, Annalisa, and Dondi, F.
- Subjects
adsorption ,emergent contaminants - Published
- 2011
12. Effect of Silica Alumina Ratio and Thermal Treatment of Beta Zeolites on the Adsorption of Toluene from Aqueous Solutions.
- Author
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Sarti, Elena, Chenet, Tatiana, Pasti, Luisa, Cavazzini, Alberto, Rodeghero, Elisa, and Martucci, Annalisa
- Subjects
- *
ALUMINUM oxide , *SILICA , *ZEOLITES , *TOLUENE , *AQUEOUS solutions - Abstract
The adsorption of toluene from aqueous solutions onto hydrophobic zeolites was studied by combining chromatographic, thermal and structural techniques. Three beta zeolites (notated BEAs, since they belong to BEA framework type), with different SiO2/Al2O3 ratios (i.e., 25, 38 and 360), before and after calcination, were tested as adsorbents of toluene from aqueous media. This was performed by measuring the adsorbed quantities of toluene onto zeolites in a wide concentration range of solute. The adsorption data were fitted with isotherms whose models are based on surface heterogeneity of the adsorbent, according to the defective structure of beta zeolites. The thermal treatment considerably increases the adsorption of toluene, in the low concentration range, on all BEAs, probably due to surface and structural modifications induced by calcination. Among the calcined BEAs, the most hydrophobic zeolite (i.e., that with SiO2/Al2O3 ratio of 360) showed the highest binding constant, probably due to its high affinity for an organophilic solute such as toluene. The high sorption capacity was confirmed by thermogravimetric analyses on BEAs, before and after saturation with toluene. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
13. Influence of caffeic acid on the adsorption of toluene onto an organophilic zeolite.
- Author
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Chenet, Tatiana, Sarti, Elena, Costa, Valentina, Cavazzini, Alberto, Rodeghero, Elisa, Beltrami, Giada, Felletti, Simona, Pasti, Luisa, and Martucci, Annalisa
- Subjects
CAFFEIC acid ,ADSORPTION (Chemistry) ,HYDROXYL group ,MOLECULAR weights ,BINARY mixtures ,TOLUENE - Abstract
• Caffeic Acid adsorption onto ZSM-5 depends on pH. • Caffeic Acid is incorporated into the zeolite framework. • The hydroxyl group of caffeic acid interacts with the framework oxygen atoms. • Competitive adsorption on ZSM-5 follows the order Toluene > Caffeic Acid. Wastewaters and polluted natural water can contain a large variety of organic substances deriving from both natural and anthropogenic sources. Hydrophobic zeolites have great potential for the removal of different organic substances and among them aromatic, chlorinated, and oxygenated compounds. In this work the influence of caffeic acid - an allelochemical representing low molecular weight natural organic matter - on the adsorption of toluene in aqueous matrix has been investigated. To accomplish this task, the adsorption of caffeic acid on ZSM-5 has been studied. Differently from toluene, whose adsorption is not significantly influenced by pH, the uptake of caffeic acid onto zeolite strongly depends on pH, the maximum saturation capacity (46 mg g
−1 ) was obtained at pH 4, corresponding to the nonionized form of caffeic acids. Additionally, caffeic acid interacts with zeolite framework and water molecule as suggested from the shift in the apparent dissociation constant evaluated from adsorption data and confirmed by structural investigation. Competitive adsorption of binary mixture of toluene and caffeic acid in a wide concentration range shows that ZSM-5 is a selective adsorbent for Toluene, and when caffeic acid is present at high concentration (100 mg L−1 ) the adsorbed quantity of toluene from solution is reduced of less than 15 %. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
14. High-Silica Zeolites as Sorbent Media for Adsorption and Pre-Concentration of Pharmaceuticals in Aqueous Solutions.
- Author
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Sarti, Elena, Chenet, Tatiana, Stevanin, Claudia, Costa, Valentina, Cavazzini, Alberto, Catani, Martina, Martucci, Annalisa, Precisvalle, Nicola, Beltrami, Giada, Pasti, Luisa, and Valencia, Susana
- Subjects
- *
ZEOLITES , *AQUEOUS solutions , *SEWAGE disposal plants , *HYDROCHLOROTHIAZIDE , *SORBENTS , *ADSORPTION (Chemistry) , *ZEOLITE Y - Abstract
The present work focused on the use of high-silica commercial zeolites as sorbent media for pharmaceuticals in an aqueous matrix. As drug probes, ketoprofen, hydrochlorothiazide, and atenolol were selected, because of their occurrence in surface waters and effluents from wastewater treatment plants. Pharmaceuticals adsorption was evaluated for two Faujasite topology zeolites with Silica/Alumina Ratio 30 and 200. The selected zeolites were demonstrated to be efficient sorbents towards all investigated pharmaceuticals, thanks to their high saturation capacities (from 12 to 32% w/w) and binding constants. These results were corroborated by thermal and structural analyses, which revealed that adsorption occurred inside zeolite's porosities, causing lattice modifications. Finally, zeolites have been tested as a pre-concentration media in the dispersive-solid phase extraction procedure. Recoveries higher than 95% were gained for ketoprofen and hydrochlorothiazide and approximately 85% for atenolol, at conditions that promoted the dissolution of the neutral solute into a phase mainly organic. The results were obtained by using a short contact time (5 min) and reduced volume of extraction (500 µL), without halogenated solvents. These appealing features make the proposed procedure a cost and time saving method for sample enrichment as well as for the regeneration of exhausted sorbent, rather than the more energetically expensive thermal treatment. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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