Χρύση νανοϋλικών ZnO για την απομάκρυνση βαρεών μετάλλων από υδατικά διαλύματα

Βόλλα, Ελένη-Μαρία; Volla, Eleni-Maria

dc.contributor.author	Βόλλα, Ελένη-Μαρία	el
dc.contributor.author	Volla, Eleni-Maria	en
dc.date.accessioned	2024-08-30T09:49:53Z
dc.date.available	2024-08-30T09:49:53Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/60067
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.27763
dc.rights	Default License
dc.subject	Nανοσωματίδια ZnO	el
dc.subject	Οργανικοί Ρύποι	el
dc.subject	Βαρεά Μέταλλα	el
dc.subject	Ιόντα Cu2+	el
dc.subject	Προσρόφηση	el
dc.subject	ZnO nanoparticles	en
dc.subject	Organic Pollutants	en
dc.subject	Heavy Metals	en
dc.subject	Cu2+ Ions	en
dc.subject	Adsorption	en
dc.title	Χρύση νανοϋλικών ZnO για την απομάκρυνση βαρεών μετάλλων από υδατικά διαλύματα	el
dc.title	Use of ZnO nanomaterials for the removal of heavy metals from aqueous solutions	en
heal.type	bachelorThesis
heal.classification	Nanoparticles	en
heal.classification	Νανοσωματίδια	el
heal.language	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2024-02
heal.abstract	Contemporary technological and industrial advancements have led to increased reliance on chemicals for product innovation, leading to heightened contamination of water sources by traditional pollutants (organic dyes, heavy metals) and disease-causing microorganisms. Wastewater treatment processes now reveal “emerging pollutants”, including pharmaceuticals, endocrine disruptors, and agricultural chemicals. While some are benign, certain emerging pollutants can harm diverse organisms. Researchers seek cost-effective water purification methods that completely degrade pollutants without generating harmful by-products. Semiconductor-based photocatalytic degradation, particularly using zinc oxide (ZnO), is a promising strategy ensuring water purification and supporting wastewater treatment. In the present study, ZnO nanoparticles were synthesized using a facile precipitation method based on an optimization of the experimental conditions for the ZnO nanoparticles’ synthesis that has been already conducted on a previous study of our team utilizing the Taguchi approach. More specifically, the optimal conditions were achieved using zinc acetate dihydrate as the Zn precursor at a concentration equal to 0.3 M, sodium hydroxide as the precipitating agent (1.5 M), methanol as the solvent (the pH value of the solvent was equal to 13), a temperature during the synthetic procedure of 70 °C, 600 °C as calcination temperature, a 90 min stirring time, and 700 rpm as the stirring speed. The utilized ZnO nanoparticles were synthesized based on the aforementioned conditions and thoroughly characterized. The obtained results indicated a pure hexagonal wurtzite phase, coupled with increased crystallinity (79.83 %) and a relatively small crystallite size (3.29 nm), as well as an enhanced specific surface area (32 m2 /g) and an energy band gap equal to 3.37 eV. Initially, the efficiency of the prepared ZnO nanoparticles was examined towards the photocatalytic degradation of an organic dye (Rhodamine B-RhB) under UV light irradiation. The as-prepared ZnO nanoparticles achieved 100 % degradation of the RhB dye within 90 min under UV light irradiation, while the pseudo-first-order reaction kinetics provided a realistic description of the photocatalytic degradation of rhodamine B given the calculated R2 values (0.989). Additionally, based on the acquired experimental results, ●OH radicals were found to be the major reactive oxygen species involved in rhodamine B’s photocatalytic degradation. Finally, after the ZnO nanoparticles were reused five times, they indicated negligible (≈7 %) photodegradation efficiency decrease towards the examined organic compound. Moreover, the performance of ZnO nanoparticles as an adsorbent for removal of heavy metal (Cu2+) ions from aqueous solutions was successfully evaluated. The adsorption data showed better fit at pH=6 to Freundlich isotherm model. Applicability of pseudo-second order (PSO) kinetic model specified the chemisorption process. Thermodynamic parameters confirmed that the removal of Cu2+ ions was an endothermic process. The maximum adsorption efficacy Cu2+ [xiii] ions based on monolayer adsorption was found to be 643 mg/L. Besides, used ZnO nanoparticles could be efficiently reused for at least three times after treatment with NaOH. The high uptake capacity for Cu2+ ions coupled with the good reusability, render the as-prepared ZnO nanoparticles a potentially attractive adsorbent material for heavy metal removal applications.	en
heal.advisorName	Παυλάτου, Ευαγγελία Α.	el
heal.committeeMemberName	Καραντώνης, Αντώνης	el
heal.committeeMemberName	Βουγιούκα, Σταματίνα	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Χημικών Μηχανικών. Τομέας Χημικών Επιστημών (I). Εργαστήριο Γενικής Χημείας	el
heal.academicPublisherID	ntua
heal.numberOfPages	95 σ.	el
heal.fullTextAvailability	false