Search results for "Sponge"

Synergistic Activity of Silver Nanoparticles and Polyaminocyclodextrins in Nanosponge Architectures

2019

Four new composite materials, formed by silver nanoparticles embedded in polyamino-cyclodextrin nanosponge architectures, were designed exploiting the affinity of polyamino-cyclodextrins towards Ag+ ions. These materials were characterized by means of different techniques (thermogravimetry, FT-IR, solid state NMR, SEM, HR-TEM), and tested as catalysts for the reduction of nitroarenes and the oxidative coupling of anilines. The results obtained showed synergistic activity between the supramolecular binding abilities of the nanosponge matrix and the catalytic properties of the metal nanoparticle, and open the way towards the design of new composite smart nanomaterials with improved catalytic …

Antimicrobial effect of cyclodextrin-based nanodevices capable of antibiotic release

2018

FFC-NMR Relaxometric Characterization of Nanosponges for Rationalizing their Adsorption and Release abilities

Synthesis and Characterization of Halloysite-Cyclodextrin Nanosponges for Enhanced Dyes Adsorption

2017

Inorganic-organic nanosponge hybrids based on halloysite clay and organic cyclodextrin derivatives (HNT-CDs) were developed by means of microwave irradiations in solvent-free conditions. The HNT-CDs nanomaterials characterized by FT-IR, TGA, BET, TEM, SEM, DLS, and zeta-potential have showed a hyper-reticulated network which possesses both HNT and cyclodextrin peculiarities. The new HNT-CDs nanosponge hybrids were employed as nanoadsorbents, first choosing Rhodamine B as the dye model, and furthermore for the removal of some cationic and anionic dyes, under different pH values (1.0, 4.54, and 7.4). The collected results showed that the pH solution as well as the electrostatic interactions a…

Nanosponge-C3N4 composites as photocatalysts for selective partial alcohol oxidation in aqueous suspension

2023

A set of four composite materials was prepared, consisting of a nanosponge matrix based on beta-cyclodextrin in which carbon nitride was dispersed. The materials were characterized by the presence of diverse cross-linker units joining the cyclodextrin moieties, in order to vary the absorption/release abilities of the matrix. The composites were characterized and used as photocatalysts in aqueous medium under UV, visible and natural solar irradiation for the photodegradation of 4-nitrophenol, and for the selective partial oxidation of 5-hydroxymethylfurfural and veratryl alcohol to the corresponding aldehydes. The nanosponge-C3N4 composites showed higher activity than the pristine semiconduc…

Reduced graphene oxide/silver nanoparticles/β-cyclodextrin nanosponges composites with improved photocatalytic activity

2023

Significant activity improvement was achieved by associating graphene oxide-silver composite photocatalysts with cyclodextrin-based nanosponge materials, due to the synergistic effect provided by the supramolecular host abilities of the nanosponge. Three photocatalysts were prepared, fully characterized (FT-IR, ss-NMR, Raman, XRD, SEM, EDX, AFM, ICP, TGA, potentiometric titration), and tested for the oxidative photodegradation of some dyes and phenols, chosen as model organic pollutants. Compared to the unsupported photocatalyst, the nanosponge-based materials showed enhanced performances (being able to carry out the degradation even of dyes which do not react in the presence of the unsuppo…

PROPERTIES AND APPLICATIONS OF POLYAMINOCYCLODEXTRIN DERIVATIVES

Nel presente lavoro sono state prese in esame le potenziali applicazioni delle poliamminociclodestrine. In particolare, diversi derivati poliamminociclodestrinici (amCD) sono stati ottenuti utilizzando un approccio sintetico diretto, tramite reazione di sostituzione nucleofila tra la heptakis-(6-deossi)-(6-bromo)-βCD (BrβCD) e poliammine lineari. Una volta effettuata l’opportuna caratterizzazione NMR, ESI-MS e potenziometrica, sono state investigate diverse possibili utilizzazioni di tali materiali. Anzitutto, sono state valutate le capacità di dare complessi di inclusione host-guest con diversi derivati organici sia delle amCD libere che di materiali costituiti da nanospugne a base di amCD…

Evaluation of adsorption ability of Cyclodextrin-Calixarene Nanosponges towards Pb2+ ion in aqueous solution

2021

Abstract Different cyclodextrin-calixarene nanosponges (CyCaNSs) have been characterized by means of FFC-NMR relaxometry, and used as sorbents to remove Pb2+ ions from aqueous solutions. Considering that the removal treatments may involve polluted waters with different characteristics, the adsorption experiments were performed on solutions without and with the addition of background salts, under different operational conditions. The adsorption abilities and affinities of the nanosponges towards Pb2+ ions were investigated by measuring the metal ion concentration by means of Inductively Coupled Plasma Emission Spectroscopy (ICP-OES) and Differential Pulse Anodic Stripping Voltammetry (DP-ASV…

APPLICATION OF FFC-NMR TECHNIQUES FOR THE STUDY OF THE FEATURES OF NANOSPONGES

Fast-Field-Cycling (FFC) NMR relaxometry is a versatile and powerful tool for studying the microscopic dynamics of molecular systems, provided that a suitable analysis of the longitudinal relaxation kinetics and the relevant NMRD (i.e. longitudinal relaxation rate R1 vs. Larmor frequency νL) dispersion curves is performed. In particular, FFC-NMR can afford valuable information on the texture properties (average pore size, specific surface and specific pore volume) of porous materials, once they have been saturated with water. Thus, it appears a technique of choice for assessing the otherwise elusive texture properties of nanosponges (NSs). These hyper-crosslinked polymers, obtained by retic…

Nanosponge-C3N4 composites with improved photocatalytic activity for selective partial alcohol oxidation in aqueous suspension

2022

Composites of C3N4 with nanosponges based on β-cyclodextrins containing a 5% w/w of C3N4 were synthesised, physicochemicaly characterised and tested as heterogeneous photocatalysts for the degradation of 4-nitrophenol and for the partial oxidation of 5-hydroxymethyl-2-furfural and veratryl alcohol. The results outline a synergistic effect in terms of conversion and selectivity. The association of the nanosponges with the C3N4 enhances the photocatalytic activity of the semiconductor, possibly due to the local concentration effect occurring on the photocatalyst surface that would involve a concentration into the nanosponge matrix ca. 500 times larger than in the solution bulk. Composites of …