Search results for "Halloysite"
showing 10 items of 185 documents
Halloysite nanotubes/pluronic nanocomposites for waterlogged archeological wood: thermal stability and X-ray microtomography
2020
Filling a polymer with halloysite nanotubes is considered a promising strategy to generate nanocomposites with tailored physicochemical properties. We have focused our attention on pluronic block copolymer/halloysite nanocomposites prepared by melt blending. The effect of composition on thermal stability and polymer crystallinity was investigated by thermogravimetry and differential scanning calorimetry. Electron microscopy was used to monitor the nanoparticle distribution in the polymeric matrix. The pluronic thermal stability is reduced by the clay nanoparticles. Concerning the polymer crystallinity, it is slightly decreased even if the melting temperature is lowered by halloysite. Furthe…
Halloysite Nanotubes and Metal Corrosion Inhibitors: A Computational and Experimental Study
2019
Halloysite nanotubes are widely used as a substrate for the controlled release of various types of molecules in an increasing number of applications. In this work, the interactions of halloysite silicic and aluminic surfaces with corrosion inhibitor compounds, such as benzotriazole, 8-hydroxyquinoline, 2-mercaptobenzimidazole, and 2-mercaptobenzothiazole, were investigated from a computational point of view. Two new halloysite compounds with salicylaldoxime and quinaldic acid were designed. Here we propose their synthesis, evaluate amounts of loading, and analyze the adsorption behavior.
Effect of hydraulic coefficient on membrane performance for rejection of emerging contaminants
2018
International audience; The efficient removal of Endocrine Disruptive Chemicals (EDCs) namely oxybenzone and atrazine using polysulfone (PSf) composite membranes is reported in this article. A negatively charged hydrophilic mixed matrix membrane was prepared by using Polyaniline modified halloysite nanotubes (PANi-HNT) and polysulfone. The X-ray diffraction (XRD) and attenuated total reflectance infrared (ATR-IR) technique confirm the conversion of Halloysite nanotubes to Polyaniline modified halloysite nanotubes and their presence in membrane matrix. The microvoids observable in the SEM images depict the internal structure of the membrane. Further, increasing in the water uptake and decrea…
Organic-nanoclay composite materials as removal agents for environmental decontamination
2019
Here we overview the recent advances in the fabrication of sustainable composite nanomaterials with decontamination capacity towards inorganic and organic pollutants. In this regards, we present the development of hybrid systems based on clay nanoparticles with different shapes (such as kaolinite nanosheets and halloysite nanotubes) and organic molecules (biopolymers, surfactants, cucurbituril) as efficient removal agents for both aliphatic and aromatic hydrocarbons. Due to their high specific surface area, clay nanoparticles have been successfully employed as fillers for composite membranes with excellent filtration capacity. The preparation of composite gel beads based on biopolymers (alg…
Alginate gel beads filled with halloysite nanotubes
2013
Abstract Novel hybrid gel beads with a well defined and controlled size formed by alginate biopolymer and halloysite (Hal) nanotubes were designed, prepared and characterized from the physico-chemical viewpoint. The thermogravimetry made it possible to determine the water content, the total as well as the local compositions of Hal into the gel beads. Dielectric spectroscopy evidenced that Hal reduced the fluctuation of ions. The SEM micrographs showed that the dried beads exhibit a rough surface, with pores in the micrometer range. In addition, the concentration of nanotubes was higher into the bead core at a higher overall loading. The performance of these materials was verified with the s…
Synthesis and characterization of nanomaterial based on halloysite and hectorite clay minerals covalently bridged
2021
Halloysite is an aluminosilicate clay with a predominantly hollow tubular structure (HNTs) able to act as a nanocontainer for the encapsulation of several chemicals. However, HNTs possess low affinity for metal ions in their pristine form and they need to be modified for improving their adsorption capabilities. Therefore, to overcome this issue herein we report a straightforward approach for the covalent modification of the external surface of halloysite nanotubes with hectorite clay. Compared to halloysite, hectorite possesses a lamellar structure with higher cation exchange capacity. The covalent linkage between the two clays was verified by several techniques (FTIR spectroscopy, 13C CP-M…
Dispersions of Nanoclays of Different Shapes into Aqueous and Solid Biopolymeric Matrices. Extended Physicochemical Study
2010
Dispersions of nanofillers into aqueous and solid biopolymeric matrices were studied from the physicochemical viewpoint. This work was carried out based on the idea that the combination of biopolymers, derived from renewable resources, and nanofiller, environmentally friendly, may form a new generation of nanomaterials with excellent and unique properties at low cost. To this purpose, two pectins with different degrees of methyl esterification and nanoclays like halloysite and laponite RD were selected. The thermodynamic and structural studies on the aqueous mixtures of pectin and nanoclay were able to discriminate the interactions, which control the adsorption of pectin onto the filler and…
Exploiting the Colloidal Stability and Solubilization Ability of Clay Nanotubes/Ionic Surfactant Hybrid Nanomaterials
2012
Halloysite clay nanotubes are functionalized by exploiting the different charges between the inner positive and the outer negative surfaces; accordingly, a selective adsorption is pursued by employing anionic and cationic surfactants. The obtained hybrid materials dispersed in aqueous phase are studied from the physicochemical viewpoint to investigate the colloidal stability that is a crucial parameter for applications. It is demonstrated that the adsorption of anionic surfactant into the HNTs lumen increases the net negative charge of the nanotubes enhancing the electrostatic repulsions and consequently the dispersion stability. The solubilization capability of these functionalized nanotub…
One-pot synthesis of ZnO nanoparticles supported on halloysite nanotubes for catalytic applications
2020
Abstract A versatile catalyst based on halloysite and zinc oxide (HNT@ZnO) was prepared, for the first time, starting from ZnO commercial bulk form as Zn precursor source, in a one-pot procedure. This strategy gives the possibility to obtain small ZnO nanoparticles loaded on the HNT surface without the use of inorganic salts which envisage the removal of undesired anions and therefore a calcination process at high temperature. It was found that the presence of halloysite improved the UV–vis spectral absorption ability of ZnO. The hybrid was successful used as photocatalyst for the methylorange and rhodamine B degradation. In addition, after eight consecutive cycles for the methylorange phot…
Thermal stability and flammability of polyolefin/halloysite nanotubes composites
2015
Najnowsze badania w zakresie uniepalniania poliolefin są ukierunkowane na zastosowanie dodatku nanorurek haloizytowych (HNT) jako bezhalogenowego środka zmniejszającego palność, a jednocześnie zachowującego właściwości mechaniczne osnowy. Powstająca na powierzchni płonącego nanokompozytu, zawierającego HNT, warstwa tzw. zgorzeliny ogranicza przenikanie gazów oraz ciepła i zabezpiecza materiał przed dalszym paleniem. Unikatowa struktura HNT umożliwia dodatkowo pochłanianie produktów termicznego rozkładu poliolefinowej osnowy. Na podstawie dostępnej literatury dokonano oceny wpływu różnych czynników, m.in. modyfikacji nanorurek haloizytowych i/lub dodatku kompatybilizatora i/lub doboru odpowi…