The structural stability of barrier layers is critical for the long-term effectiveness of landfill remediation projects, although leachate pumping and organic contamination can cause structural degradation, reduce remediation performance, and increase the risk of pollutant release. The objectives of this study were to determine the consolidation–rebound mechanisms of sand–bentonite mixtures through standardized tests and to analyze deformation under diesel contamination using multi-scale approaches, including pore-structure characterization, particle-size distribution, cation exchange capacity, and oil-blocking effects. The results revealed that uncontaminated soil (0.0 wt.% diesel) exhibited non-linear compression behavior, with an initial decrease and a subsequent increase with increasing sand content; when the consolidation pressure exceeded 400 kPa, the compression rate decreased markedly. The compression deformation of the contaminated soil increased and was positively correlated with the sand and diesel contents, with accelerated deformation at >4.0 wt.% diesel. The rebound capacity decreased under combined sand–diesel effects. Microstructural analysis indicated that initial compression was controlled by inter-aggregate pores, whereas mid- to late-stage compression was influenced by intra-aggregate pore evolution and particle breakage. Increased diesel content shifted aggregate breakage from single/secondary to tertiary patterns, altering later compression behavior. Coupled hydration reduction and enhanced oil-blocking suppressed rebound significantly, worsening with increasing diesel content. Technical–economic analysis revealed that pure bentonite (0% sand) was optimal under uncontaminated conditions and that a 10% sand mixture was best under contaminated conditions. The sand–bentonite barrier exhibited amplified consolidation–rebound deformation and reduced stability with increasing sand and diesel contents, providing a theoretical basis for long-term landfill remediation assessment.

Improving the thermal and rheological limitations of traditional natural hydrogels remains a key challenge for their medical use. Inorganic and organic elements were combined synergistically to develop natural hydrogels, and subsequently subjected to comprehensive thermal and rheological analysis for potential applications in physical medical treatments. The primary objective of this study was to optimize the technological, biopharmaceutical, and therapeutic properties of these innovative hydrogels, constituted by an inorganic framework of clay particles entrapping organic components from peat extracts. The hydrogels underwent thorough mineralogical and chemical characterization, confirming the pharmaceutical-grade quality of the clay component, which was predominantly composed of montmorillonite and saponite. Rheological evaluations revealed non-Newtonian viscoplastic behavior, with viscosity and thixotropy increasing significantly with higher clay concentrations and prolonged swelling durations. Thermal analyses demonstrated that the hydrogels possess adequate heat-transfer capabilities, ensuring effective maintenance of skin temperature during therapeutic application. Elemental analysis and cation exchange capacity determinations highlighted the substantial water retention and ion exchange properties of the hydrogels, contributing to their stability and functional performance. The integration of organic and inorganic constituents enhanced synergistically the mechanical strength, thermal stability, and therapeutic efficacy of the hydrogels. These advancements position the formulated hydrogels as promising candidates for innovative applications in physical medical treatments, offering enhanced mechanical and thermal properties essential for effective therapeutic outcomes.

One of the challenges in measuring the adsorption of metal cations is that they may form metal hydroxide compounds at certain pH ranges. This becomes problematic when adsorption is quantified in terms of measuring a decrease in metal ions in solution, because metal hydroxy complexes are removed from solution through precipitation, leading to erroneously high determinations of adsorption. Within this context, the present study aimed to analyze the pH-dependent adsorption behavior of Ni2+ ions onto sepiolite, a naturally occurring magnesium silicate clay mineral, while simultaneously accounting for the precipitation of nickel compounds during the process. For this purpose, zeta potential, ion exchange capacity, and the adsorption behavior of 2.5×10–3 mol L–1 nickel (II) sulfate hexahydrate onto relatively high-quality sepiolite were investigated. Kinetic studies and thermodynamic assessments were delineated to enhance the understanding of adsorption isotherms, both for future research and practical applications in environmental remediation. The results showed that the adsorption of Ni2+ ions onto sepiolite before the onset of precipitation is governed by an ion exchange process involving the release of Mg2+ ions from the sepiolite matrix and the uptake of Ni2+ ions from the solution. Above the threshold of pH ~8 where Ni-hydroxide complexes begin to form, ~97% of nickel ions were present in the forms of NiOH+, Ni(OH)2, and Ni(OH)3–. Isotherms for total Ni2+ removal were constructed to distinguish true adsorption from precipitation phenomena. The calculated and experimental values for true adsorption were found to be in good agreement.