Evaluation of fluoride removal from water by hydrotalcite-like compounds synthesized from the kaolinic clay

The present study investigates the fluoride sorption by Mg – Al – CO₃ prepared from a kaolinite as natural source of aluminium using two simple methods.Исследована сорбция фторида на Mg–Al–CO₃, полученном из каолинита как природного источника алюминия с использованием двух простых методов.Досліджена сорбція фториду на Mg–Al–CO₃, отриманому з каолініту як природного джерела алюмінію з використанням двох про- стих методів

Electrical and Dielectric Properties of Polyaniline and Polyaniline/Montmorillonite Nanocomposite Prepared by Solid Reaction Using Spectroscopy Impedance

The combination of two components with uniform distribution in nanoscale is expected to facilitate wider applications of the material. In this study, polyaniline (PAn) and polyaniline/montmorillonite (Mt) nanocomposite were prepared by solid reaction using persulfate of ammonium as oxidant. The phase composition and morphology of the nanocomposite were characterized by FTIR, UV-visible spectroscopy, X-ray diffractometer, thermal gravimetric analysis, and scanning electron microscopy. The electrical and dielectric properties were determined using spectroscopy impedance. The analysis of UV-visible and FTIR spectroscopy demonstrated that aniline chloride has been polymerized into PAn in its conducting emeraldine form. Thermogravimetric analysis suggested that PAn chains intercalated in the clay host are more thermally stable than those of free PAn prepared by solid-solid reaction. Electrical measurements were carried out using the complex impedance technique in the frequency range of 10−2 to 104 Hz at different temperatures. The ac conductivity data of different nanocomposites were analyzed as a function of frequency and temperature. It has been found that the incorporation of inorganic clay phase into polyaniline matrix has an effect on the electrical and dielectric properties of the nanomaterial

Physicochemical Characterization of Geopolymer Binders and Foams Made from Tunisian Clay

Illito-kaolinitic clay rich in hematite from south Tunisia was investigated in view of producing geopolymer materials. Geopolymers with two different densities were elaborated: cement and foam. The effects of activator concentrations on compressive strength, water absorption (durability), open porosity, and bulk density of geopolymers cement were examined, in order to assure optimal geopolymerization conditions. Geopolymer cements aged 28 days with optimum performances were achieved for 13 M of alkaline solution concentration. At these conditions, the compressive strength of prepared geopolymer reaches 27.8 MPa. The addition of silica fume to reactant geopolymer mixture induces modification of geopolymer density and decrease in the compressive strength of the final product. Geopolymer materials based on calcined Tunisian clay can be suggested as sustainable and cost-effective cement that may be applied to alternate Portland cement in many construction applications

Rheology of magnetic colloids containing clusters of particle platelets and polymer nanofibres

Magnetic hydrogels (ferrogels) are soft materials with a wide range of applications, especially in biomedicine because: (i) They can be provided with the required biocompatibility; (ii) their heterogeneous structure allows their use as scaffolds for tissue engineering; (iii) their mechanical properties can be modified by changing different design parameters or by the action of magnetic fields. These characteristics confer them unique properties for acting as patterns that mimic the architecture of biological systems. In addition, (iv) given their high porosity and aqueous content, ferrogels can be loaded with drugs and guided toward specific targets for local (non-systemic) pharmaceutical treatments. The ferrogels prepared in this work contain magnetic particles obtained by precipitation of magnetite nanoparticles onto the porous surface of bentonite platelets. Then, the particles were functionalized by adsorption of alginate molecules and dispersed in an aqueous solution of sodium alginate. Finally, the gelation was promoted by crosslinking the alginate molecules with Ca2+ ions. The viscoelastic properties of the ferrogels were measured in the absence/presence of external magnetic fields, showing that these ferrogels exhibited a strong enough magnetorheological effect. This behaviour is explained considering the field-induced strengthening of the heterogeneous (particle-polymer) network generated inside the ferrogel.This study was supported by project no. FIS2017-85954-R (Ministerio de Economía, Industria y Competitividad, MINECO, and Agencia Estatal de Investigación, AEI, Spain, cofunded by Fondo Europeo de Desarrollo Regional, FEDER, European Union)

New Trends in Clay-Based Nanohybrid Applications: Essential Oil Encapsulation Strategies to Improve Their Biological Activity

Essential oils (EOs) are used in medicinal, pharmaceutical, cosmetic, agricultural, and food industries thanks to their key properties and multiple benefits. Several techniques and embedding materials are used to nanoencapsulate EOs, in order to keep them from environmental conditions and boost their bioefficiency by controlled release. In recent years, the interest for clay nanoparticles as nanoencapsulation materials for EOs is increasing owing to their abundance in nature, low cost, inertness, and special structure. Thus, this chapter focuses on highlighting data and contributions dealing with EOs incorporation into nanoclay particles, their current applications and nanohybrid formation benefits on the stability, bioavailability, and sustained release of EOs. An overview about nanoclays used for EOs nanoencapsulation is highlighted in the beginning of this chapter followed by a brief description of EOs’ chemical composition and properties