Search results for "halloysite"

MODELING OF SPIRAL HALLOYSITE NANOTUBES

2013

Functionalized halloysite nanotubes for enhanced removal of lead(II) ions from aqueous solutions

2018

In this study, environmental friendly halloysite nanotubes and their amino derivatives were used as adsorbent materials for lead(II) ions. The adsorption ability of both nanomaterials towards Pb2+ ions has been studied in NaClaq, at I = 0.1 mol L−1, in the pH range 3–6. Moreover, the effect of ionic strength on the adsorption process was evaluated at the pH of maximum efficiency of the adsorbent materials. Kinetic and equilibrium experiments were carried out by using the Differential Pulse Anodic Stripping Voltammetry (DP-ASV) technique to check the metal ion concentration in solution after contact with the two adsorbents. Different isotherm and kinetic equations were used to fit the experi…

Co-loaded cardanol/triazole-halloysite system: characterization of the supramolecular complex and evaluation of its antiproliferative activity

2014

Halloysite nanotubes modified with triazolium salts (f-HNT) were found to be promising drug carriers for biological molecules [1 ]. In this work we report data about f-HNT as carrier for cardanol, a molecule with interesting biological activity [2]. The interactio n between cardanol and f- HNT was highlighted by HPLC, FTIR spectroscopy, TGA , water contact angle measurements and SEM investigations. Release of cardanol from the system and cytotoxic e ffect of the complex f- HNT/Card on hepatocarcinoma cell lines were, also, evaluated. The obtained results put forward the use of halloysite as drug c arrier

HALLOYSITE NANOTUBES AS SUPPORT FOR METAL NANOPARTICLES FOR CATALYTIC APPLICATION

2017

Halloysite (HNT) is a natural clay that, in the last years, has shown an important increasing on various applications in different field of interesting. Chemically similar to kaolin, it shows the predominately rolled shape, to form multilayers tubes of nanometric dimensions. The different chemical composition of the inside lumen (Al-OH) surface and outside (Si-O) give to the tubes a partial negative charge outside and positive inside. In this way, it is possible to get different interactions of different molecules or systems selectivity on one or another surface. The selective functionalization, covalent or not, of the HNT lumen or outer surface, gives the possibility to the nanotubes to fu…

Protonation Constants of Halloysite Clay Nanotubes

2015

Halloysite is one of the most interesting nano-structured clay materials. It is similar to kaolin but has a hollow tubular structure that can be attributable to particular crystallization conditions. Typically, halloysite nanotubes (HNTs) are formed by 15 – 20 aluminosilicate layers, has a length of 1 ± 0.5 μm and inner and outer diameters of 1 - 30 and 30 - 50 nm, respectively [1,2]. In each layer the SiOH and the AlOH groups are disposed on the external and the internal surfaces, respectively. The particular structure of HNTs makes this kind of material very useful for different purposes in several fields. Among the various applications, worth of mention are: i) their use as additive for …

WOOD TREATMENT BASED ON HALLOYSITE/HYDROXYPROPYL CELLULOSE COMPOSITE. THERMOMECHANICAL AND POROSITY CHARACTERIZATION

2014

Materiali argillosi ibridi con potenziale attività biologica

2021

CHEMICAL MODIFICATIONS OF HALLOYSITE NANOTUBES FOR THE DEVELOPMENT OF SMART NANOMATERIALS

2015

Halloysite nanoclays (HNTs) are promising nanomaterials because of their versatile properties, such as hollow tubular morphology and tunable surface chemistry. HNTs are biocompatible, no toxic and abundantly available at low cost. Due to these characteristics HNTs are suitable for development of hybrid sustainable materials, which are perspective for wastewater remediation, green packaging and drug delivery. HNTs are quite polydisperse in size with a length of ca. 1 m, while the external diameter and the lumen range between 50-80 nm and 10-15 nm, respectively. Chemically, halloysite is composed of gibbsite octahedral sheet (Al-OH) groups on the inner surface and siloxane (Si−O−Si) groups o…

Dual drug-loaded halloysite hybrid-based glycocluster for sustained release of hydrophobic molecules

2016

A dual drug-loaded HNT–CD glycocluster delivery system based on halloysite nanotubes and carbohydrate functionalized cyclodextrin was developed by a green protocol using solvent-free microwave irradiation. The nanohybrid was employed for concurrent load and release of silibinin and curcumin. The new delivery system was characterized by means of TGA, FT-IR spectroscopy, SEM and DLS. These techniques confirm the successful loading of the two drugs in the system. SEM and DLS measurements highlighted that the nanomaterial preserves a tubular structure with an average hydrodynamic radius of ca. 200 nm. The release of the drugs from the HNT glycocluster was investigated by means of UV-vis spectro…

Site-specific halloysite functionalization by polydopamine: A new synthetic route for potential near infrared-activated delivery system

2022

Abstract Halloysite nanotubes (HNTs) represent a versatile core structure for the design of functional nanosystems of biomedical interest. However, the development of selective methodologies for the site-controlled functionalization of the nanotubes at specific sites is not an easy task. This study aims to accomplish a procedure for the site-selective/specific, “pin-point”, functionalization of HNTs with polydopamine (HNTs@PDA). This goal was achieved, at pH 6.5, by exploiting the basicity of ZnO nanoparticles anchored on the HNTs external surface (HNTs@ZnO) to induce a punctual polydopamine polymerization and coating. The morphology and the chemical composition of the nanomaterial was demo…