Using self-foaming dispenser, wet aqueous foams were prepared from isoviscous solutions of sodium lauryl sulfate (SLS) with chemically distinct polymer stabilizers. Contribution of coalescence and Ostwald ripening to the foam decay was examined from photos and video data. The bubble coarsening was estimated by dispersion analysis using the Lifshitz–Slezov–Wagner equation. Water-soluble polymers were selected from typical thickeners and suspending agents. Xanthan gum, hydroxyethyl cellulose, polyacrylamide, cross-linked sodium polyacrylate, cross-linked and hydrophobically modified (meth)acrylate copolymers were tried as foam stabilizers. By the same way, xanthan gum and submicron bentonite particles were used as foam stabilizers. Stability of the foams containing mentioned polymers as well as xanthan plus bentonite studied by the photographs and dispersion analysis. The polymers characterize by their efficacy to stabilize the wet foam. Possible reasons for poor stabilization of the foam containing cross-linked polyacrylates, both hydrophilic and hydrophobically modified, are given. The behavior of polymer-containing foams and joint stabilizing action of xanthan and bentonite are explained by variations in the structure of foam films. Graphical Abstract

During the development of the disposal concept in a crystalline massif of the Russian Federation, a question arose regarding the selection of the most suitable types of bentonite for a buffer layer. Data on the composition, structure, surface, and adsorption properties of four promising deposits have been obtained. The correlations between genesis and specific surface area (SSA) revealed in this study indicate that bentonites of volcanogenic-sedimentary origin have lower SSA in comparison with those of sedimentary and hydrothermal origin. The main contribution to the charge of the 2:1 layer is made by isomorphic substitutions in the tetrahedral sheet, which directly affects the sorption properties of bentonites. The influence of smectite structure on adsorption properties have been described. In particular, the dependencies between the layer charge and cation exchange capacity (CEC) have been analyzed. At the same time, the research indicates that, unlike the CEC, the specific surface area of a deposit is determined by its geological history. Special attention is being paid to refining methodological approaches for deriving crystal chemical formulae of smectites, which will be needed in the future for modelling changes in bentonite over a long-term perspective.

Data have been presented on the dispersity, drainage, and rheological properties of aqueous foams stabilized with acylamidopropyl betaine (cocaamidopropyl betaine) and containing a polysaccharide,...

This study reports on the development of nanocomposites utilizing a mineral inhibitor and a micronutrient filler. The objective was to produce a slow release fertilizer, with zinc sulfate as the filler and halloysite nanotubes as the inhibitor. The study seeks to chemically activate the intercalation of zinc into the macro-, meso-, and micropores of the halloysite nanotubes to enhance their performance. As a result, we obtained three nanocomposites in zinc sulfate solution with concentrations of 2%, 20%, and 40%, respectively, which we named Hly-7Å-Zn2, Hly-7Å-Zn20, and Hly-7Å-Zn40. We investigated the encapsulation of zinc sulfate in halloysite nanotubes using X-ray diffraction analysis, transmission electron spectroscopy, infrared spectroscopy (FTIR), and scanning electron microscopy with an energy-dispersive spectrometer. No significant changes were observed in the initial mineral parameters when exposed to a zinc solution with a concentration of 2 mol%. It was proven that zinc was weakly intercalated in the micropore space of the halloysite through the increase in its interlayer distance from 7.2 to 7.4. With an increase in the concentration of the reacted solution, the average diameter of the nanotubes increased from 96 nm to 129 nm, indicating that the macropore space of the nanotubes, also known as the “site”, was filled. The activated nanocomposites exhibit a maximum fixed content of adsorbed zinc on the nanotube surface of 1.4 wt%. The TEM images reveal an opaque appearance in the middle section of the nanotubes. S SEM images revealed strong adhesion of halloysite nanotubes to plant tissues. This property guarantees prolonged retention of the fertilizer on the plant surface and its resistance to leaching through irrigation or rainwater. Surface spraying of halloysite nanotubes offers accurate delivery of zinc to plants and prevents soil and groundwater contamination, rendering this fertilizer ecologically sound. The suggested approach of activating halloysite with a zinc solution appears to be a possible route forward, with potential for the production of tailored fertilizers in the days ahead.