Emulsion-mediated self-assembly of nanoparticles at liquid–liquid interfaces has been established, yet its particle adsorption kinetics remain largely unexplored. In this study, we investigate particle adsorption during this process by sonicating Au colloids with an oil phase. Unlike a planar water–oil interface, which poses a finite sorption energy barrier, the curved interfaces of droplets substantially lower this barrier, thereby switching the adsorption regime from kinetic control to diffusion control. In this scenario, sonication generates emulsions with a huge total water–oil interfacial area, may accelerate mass transport (acting as an agitator), and may also activate particles to overcome the residual (if any) barrier, all of which synergistically enhance particle adsorption. Furthermore, optical observations could reveal that the droplet surfaces are sparsely decorated with particle aggregates, leaving ample free area for further unimpeded adsorption, and coalescence of particle-laden droplets continuously releases particles to the planar water–oil interface, where they form a compact film. Our results might highlight effective means to enhance particle adsorption for subsequent interfacial assembly of nanoparticles.
Steel rolling oily sludge (SROS) is a highly emulsified, high-viscosity hazardous waste, whose apparent viscosity is governed by its oil–water interfacial structure. To clarify the role of the oil phase, model water-in-oil (W/O) and oil-in-water (O/W) emulsions were prepared using oleic acid and palmitic acid, and their rheological behaviors were systematically investigated via steady-state rheometry, optical and polarized-light microscopy, and quantitative droplet-size analysis. The results revealed that pure oleic acid behaved as a Newtonian fluid, whereas the W/O emulsions exhibited pronounced shear-thinning and yield stress due to the hydrogen-bonding network among water droplets. The O/W emulsions showed nearly Newtonian behavior at low oil content, but their viscosity increased sharply upon phase inversion to W/O. Furthermore, palmitic acid significantly enhanced the viscosity and yield stress of both systems. Droplet-size statistics showed that a moderate amount of palmitic acid minimized droplet size and polydispersity, whereas excess palmitic acid enlarged the droplets. Polarized-light microscopy and macroscopic observations confirmed that this viscosity jump was driven by the precipitation of excess palmitic acid, which formed a rigid crystalline network at room temperature. These findings elucidate the viscosity mechanism of SROS and provide a theoretical basis for improving its flowability and resource utilization.
Hafnium oxide is a benchmark material for advanced dielectric, optical, and radiation-resistant technologies; however, its functional behavior is critically governed by its microstructural state and defect landscape. Here, hafnium oxide particles synthesized via non-hydrothermal nanoprecipitation (NPN) and hydrothermal processing (NPH) were investigated to elucidate how synthesis-driven structural consolidation influences thermal stability, morphological features, and electronic structure. A comprehensive multi-technique approach combining X-ray diffraction, dynamic light scattering, electron microscopy, semi-quantitative EDS, thermal analysis (TGA/DSC), and UV-Vis spectroscopy was employed. The non-hydrothermally synthesized material (NPN) exhibits a highly disordered amorphous network characterized by an elevated optical band gap (∼5.5eV), pronounced sub-gap defect states, and an extended Urbach absorption tail. In contrast, hydrothermal processing (NPH) promotes local dehydroxylation and crystal phase consolidation, yielding a stable framework where structural ordering narrows the optical gap to 5.0eV and restores a well-defined fundamental absorption edge. These findings demonstrate that tailored synthesis pathways enable precise tuning of the structural, chemical, and electronic properties of hafnium oxide, providing a clear roadmap for engineering materials optimized either for defect-driven functional applications or for high-stability dielectric devices.
Engineered low-salinity water (LSW) injection was investigated as an environmentally favorable enhanced oil recovery strategy for heavy oil in Berea sandstone. A Taguchi L9 design was used to formulate nine brines (861–4483 ppm total dissolved solids) with systematically varied Na+, Ca2+, Mg2+, and SO42− concentrations and to evaluate their effects on interfacial tension (IFT), wettability, zeta potential, and oil recovery. Among the nine engineered low-salinity brines, BR6 (2877 ppm) yielded the lowest IFT, whereas BR8 (4059 ppm) yielded a contact angle of 20°, compared with 38° for FW. Contact angles were measured after brine exposure and provided comparisons among the tested brine conditions. Zeta potential became increasingly negative as salinity decreased, suggesting stronger electrostatic repulsion at the rock–brine interface and conditions favorable for wettability modification. Optimization of the ionic composition yielded an engineered brine (OPT) predicted by Taguchi design analysis and experimentally validated. In microcosm tests, OPT and BR6 achieved oil recoveries of 53.8% and 51.6%, respectively; corresponding packed-column recoveries were 38.8% and 42.0%. Moreover, tertiary BR6 injection after formation-water flooding recovered an additional 12.2% of the original oil in place. Overall, the results suggested that engineered LSW performance is governed by ionic composition rather than salinity reduction alone.
The complex mineral composition and heterogeneous intergrowth characteristics of copper–tin polymetallic sulfide ores make it difficult to obtain an appropriate particle-size distribution and sufficient mineral liberation during grinding, which can affect subsequent separation. This study investigated the effects of sodium tripolyphosphate (STPP) as a grinding aid on a copper–tin polymetallic sulfide ore from the Datun Plant in Gejiu, Yunnan, China. Grinding and separation tests, together with mineralogical and surface characterization using MapsMin, SEM-EDS, zeta-potential and contact-angle measurements, and DLVO/EDLVO calculations, were conducted to evaluate the effects of STPP on grinding and subsequent separation. The grinding results showed that, compared with the lime-only condition (0.10 wt% lime), the addition of 0.025 wt% STPP increased the proportion of the target size fraction (−0.15 + 0.019 mm) by 1.76%, without a marked increase in the fine fraction (−0.019 mm) or the coarse fraction (+0.15 mm). Compared with the lime-only condition, the addition of 0.025 wt% STPP increased the grade and recovery of the copper flotation concentrate by 0.20% and 3.54%, respectively, and those of the cassiterite gravity concentrate by 0.44% and 14.31%, respectively. The overall Sn recovery of the combined gravity separation and flotation process increased from 92.58% under the lime-only condition to 93.56% with the addition of 0.025 wt% STPP, but decreased to 92.39% when the STPP dosage was increased to 0.050 wt%. Automated mineralogical analysis showed that STPP addition increased the complete liberation degrees of cassiterite and bornite, while varying degrees of improvement were also observed for other major minerals. With the addition of 0.025 wt% STPP, the maximum particle size decreased from 820.95 to 495.30 μm, and D90 decreased from 374 to 237 μm relative to the lime-only condition. Surface characterization and DLVO/EDLVO analysis indicated that STPP altered mineral surface properties and interparticle interactions, which may have contributed to the observed changes in particle-size distribution and mineral liberation.
