Search Results (2,785)

The sustainable isolation of nonamphiphilic phytochemicals remains a formidable challenge in biochemical engineering. In this study, a highly efficient and solvent free foam fractionation process was developed for recovering rosmarinic acid from botanical extracts. By systematically screening diverse biological surfactants, whey soy protein emerged as an exceptionally robust dual functional frother and nanoscale collector. Response surface methodology optimized the operational parameters to 850 mg/L protein concentration, pH 2.5, and a gas flow rate of 470 mL/min, yielding an outstanding target recovery of 93.08 percent alongside an enrichment ratio of 1.81. This macroscopic separation superiority was comprehensively elucidated at the molecular level through multiple spectroscopic techniques and computational modeling. Results confirmed a spontaneous static quenching complexation driven by synergistic noncovalent forces, predominantly hydrogen bonding, van der Waals interactions, π-stacking, and salt bridges. These interactions induced targeted conformational unfolding within the protein backbone, exposing hydrophobic domains that drastically elevated the thermodynamic affinity for the ascending gas–liquid interface. Furthermore, the concentrated product exhibited an antioxidant capacity enhancement exceeding 3.6 times compared to the crude extract, a result attributed to selective enrichment combined with the structural shielding effect provided by the protein macromolecule. Ultimately, this work provides critical mechanistic insights and establishes a scalable technological framework for the green purification of highly valuable botanical compounds. Full article

Wormlike micelles provide the structural basis for the viscoelasticity of clean fracturing fluids, yet the molecular mechanism by which calcium-containing brine regulates their growth remains insufficiently understood. In this work, all-atom molecular dynamics simulations were performed to investigate the calcium-regulated self-assembly of an EAHSB/EHAC/NaPts surfactant–counterion system. In the absence of Ca²⁺, dispersed surfactant and counterion molecules first formed small spherical aggregates, which subsequently fused into larger micelles, rod-like intermediates, and finally wormlike micelles. Increasing the local surfactant/counterion loading further promoted one-dimensional micellar growth and network-like association. When Ca²⁺ was introduced, the assembly process became slower and the final aggregate morphology shifted from elongated wormlike micelles to smaller spherical aggregates. Radial distribution functions and coordination-number analysis show that Ca²⁺ redistributes charged-group correlations within the mixed surfactant/counterion assemblies. Hydration analysis indicates enlarged polar hydration shells, whereas hydrophobic-tail hydration and gauche-defect probabilities reveal enhanced tail exposure and looser chain packing. These results demonstrate that Ca²⁺ suppresses wormlike micelle growth through coupled electrostatic redistribution, interfacial hydration, and hydrophobic-chain disorder, thereby favoring high-curvature spherical aggregates over extended wormlike networks. Full article

Aiming at the problems of low permeability, strong heterogeneity, high salinity, poor injectivity of the target reservoir, and the inability of traditional water flooding to effectively improve the oil recovery rate, a low interfacial tension and salt-resistant nano-scale particle-stabilized foam flooding system (LITF-NSF) was developed to improve the recovery rate of low-permeability oil reservoirs. Through core dynamic plugging and injectivity experiments, single/dual-tube core displacement experiments, and static imbibition oil displacement experiments, the injectivity, plugging effect, imbibition effect, oil displacement mechanism, and optimal injection parameters of the LITF-NSF foam flooding system were studied from three aspects: injection pressure, slug volume, and gas–liquid ratio. The LITF-NSF foam flooding system has good injectivity in the target reservoir, with a resistance coefficient ranging from 1.086 to 15.468; the optimal injection parameters are a constant pressure difference of 5 MPa, a gas–liquid slug volume of 0.3 PV, and a gas–liquid ratio of 2:1. Under these optimal injection parameters, the subsequent water flooding recovery rate can be increased by 29.77%; it can produce a good plugging effect on the high-permeability reservoirs of the target reservoir with a permeability difference of less than 50, and can increase the comprehensive recovery rate of heterogeneous oil reservoirs by more than 10%; the static imbibition recovery rate is 4.38% higher than that of pure water without surfactant, and has a certain permeability-enhancing oil displacement effect. The LITF-NSF foam flooding system has good adaptability to the target reservoir environment and stable foam performance, which can effectively improve the subsequent water flooding recovery rate and has a good application prospect in chemical flooding for improving the recovery rate of low-permeability oil reservoirs. Full article

The aggregation behavior of microplastics is often assumed to facilitate their removal during water treatment; however, this assumption has not been systematically evaluated for low-density polyethylene (LDPE) particles. This study aims to experimentally distinguish the effects of aggregation and dispersion on the coagulation–flocculation behavior and filterability of LDPE microplastics in the context of urban water treatment. Surface modification using two non-ionic surfactants (Tween 20 and Tween 80), combined with ultrasonic dispersion, was applied to induce controlled changes in particle aggregation behavior. Optical microscopy was used to characterize aggregation and dispersion behavior. Subsequent jar tests and filtration experiments were conducted to assess how these distinct particle states influence separation performance. Rather than presuming improved removal, the study focuses on identifying the conditions under which aggregation or dispersion governs microplastic breakthrough and filterability. By addressing process-related factors that may influence microplastic passage into treated water, the findings contribute to understanding short-term exposure risks within the urban water and health nexus. Full article

To enhance quantitativeness and interpretability in identifying the mechanisms of complex oil–mineral–surfactant systems, this paper introduces an algorithmic molecular simulation analysis approach, transforming molecular dynamics trajectory data into comparable multidimensional molecular descriptors. Specifically, based on parameters such as radial distribution functions, mean square displacement, interface concentration distribution, adsorption energy attenuation, hydrogen bond statistics, and electrostatic interactions, an algorithm analysis framework was constructed covering “trajectory data acquisition—feature descriptor extraction—interface behavior recognition—separation mechanism classification.” This framework can identify differentiated regulatory patterns of different surfactants on SARA (saturates, aromatics, resins, asphaltenes) component migration, adsorption, and desorption behavior from a large amount of dynamic simulation data, thereby improving the structural expression and mechanism discrimination capabilities of molecular simulation results. In order to clarify the component-selective microscopic mechanisms of surfactants in the separation of heavy oil from oil sands, this work employs molecular dynamics simulations to study the interactions of the non-ionic surfactant TX-100 and the biosurfactants sophorolipid and rhamnolipid with the SARA fractions of heavy oil, both in the absence and presence of calcite mineral surfaces. The results show that all three surfactants act mainly through weak long-range interactions, but with distinct mechanisms: TX-100 preferentially screens small-molecule saturates through long-chain steric hindrance and hinders the diffusion of asphaltenes; sophorolipid promotes the preferential desorption of resins via hydrogen bonding; and rhamnolipid drives the desorption of aromatics at later stages through hydrophobic–electrostatic synergy. The C001 crystal surface exhibits the strongest adsorption affinity across all systems; the mineral surface overall prolongs the diffusion equilibrium time and amplifies the above kinetic differences. This study establishes three molecular-scale mechanisms—steric hindrance sieving, hydrogen-bond-promoted desorption, and electrostatically driven desorption—and reveals the universal adsorption platform effect of the C001 crystal surface, providing a theoretical basis for the molecular design of surfactants aimed at the selective separation of heavy oil components. Full article

The development of detergent-free washing technologies has become increasingly important due to growing environmental concerns associated with synthetic surfactants. This study investigated the washing performance obtained by combining alkaline electrolyzed water (AlEW) with ultra-fine bubble (UFB) water within a two-stage washing process consisting of immersion pre-washing and alternating-flow main washing. During immersion washing, AlEW exhibited a pronounced cleaning effect, attributable to alkaline hydrolysis and saponification reactions as well as enhanced electrostatic repulsion between soils and fibers. In contrast, acidic electrolyzed water caused coagulation of proteinaceous soils and did not facilitate subsequent cleaning. When AlEW pre-washing was followed by alternating-flow washing using UFB water, a significant improvement in washing rate was obtained compared with deionized water. This enhancement was interpreted as the result of combined effects among chemical soil weakening, strong mechanical forces generated by alternating flow, and UFB-related physicochemical processes. Increasing the immersion time in AlEW further improved washing performance, demonstrating the time-dependent progression of the chemical pre-treatment. Overall, the optimal washing sequence consisted of AlEW immersion followed by UFB-assisted alternating-flow washing, which yielded the highest washing efficiency among all tested conditions. These findings highlight the potential of integrating electrolyzed water and ultra-fine bubble technologies to develop high-performance, low-environmental-load, and detergent-free washing systems suitable for developing environmentally benign washing approaches. Full article

Nanomaterials have shown great potential for enhanced oil recovery in low-permeability reservoirs because of their excellent interfacial regulation capability. However, their stability and interfacial activity are challenged under extreme reservoir conditions. In this work, a silica nanofluid composed of SiO₂ nanoparticles and the zwitterionic surfactant lauramidopropyl hydroxy sulfobetaine (LHSB) was prepared, and its interfacial regulation characteristics and enhanced oil recovery mechanisms were systematically investigated. The results show that the introduction of LHSB effectively improves the dispersion stability of silica nanoparticles, and the prepared nanofluid maintains good stability at temperatures up to 120 °C and salinities up to 6 wt%. The silica nanofluid exhibits excellent interfacial activity and wettability alteration capability, reducing the oil–water interfacial tension to 0.57 mN/m and decreasing the static water contact angle on the rock surface from 112° to 37°. Meanwhile, the nanofluid significantly reduces flow resistance in porous media, achieving a flow resistance reduction rate of 20%. Oil displacement experiments indicate that injection volume, injection slug number, and shut-in time all have significant effects on oil recovery performance. The optimal operating condition was determined to be 1 PV single-slug injection followed by a 12 h shut-in period, under which the oil recovery during subsequent waterflooding reached 27%. We expect that this study will provide valuable insights into nanofluid formulation design, support the efficient development of low-permeability reservoirs, and offer a theoretical basis and technical guidance for field applications. Full article

Transdermal drug delivery offers several advantages over conventional routes. However, its use is limited by the low permeability of the stratum corneum. This limitation is especially significant in the case of hydrophilic drugs such as caffeine. This study explored microemulsion systems to enhance the transdermal delivery of caffeine (CF) using chemical penetration enhancers as cosurfactants. Kolliphor^® PS80 (PS80), Kolliphor^® RH40 (RH40), Kolliphor^® PS20 (PS20), and Kollicream^® OD (OD) were evaluated as cosurfactants for the first time in microemulsion formulations consisting of water, oil, and a fixed surfactant-to-cosurfactant ratio of 4:1 (w/w), with 14% of each cosurfactant incorporated. CF skin permeation from microemulsions was assessed via in vitro permeation studies using Franz diffusion cells and human cadaver skin. The results showed that OD-based microemulsions achieved approximately 3-fold higher CF skin permeation compared with the control formulation and 1.4–1.6-fold higher permeation compared with formulations containing PS80, RH40, and PS20. Furthermore, CF solubility in the four cosurfactants followed the order: PS20 > RH40 > PS80 > OD. These findings indicate that PS20 provides the highest solubility for CF among the tested cosurfactants. The results also included visual evaluations. No significant changes in appearance or physical properties were observed during the 10-month study. All samples remained clear and stable throughout the testing period. This study uniquely highlights the critical role of cosurfactant selection in optimizing microemulsion-based transdermal delivery systems. This work addresses a previously unexplored aspect, namely, the effect of cosurfactants with different physicochemical properties on the skin permeation of caffeine. The findings provide valuable insight into developing more effective transdermal and topical drug delivery systems. Full article

This work investigates the effect of specific electrolytes (NaCl, KCl, MgCl₂, and CaCl₂) on bubble coalescence and the stability of the resulting foam caps in aqueous sodium dodecyl sulfate (SDS) solutions. At low concentrations, we observe that all electrolytes studied exhibited a similar effect on bubble coalescence, driven primarily by the electrostatic screening of the repulsion between bubbles. However, a distinct divergence in behavior emerges at higher concentrations: KCl and CaCl₂ destabilize the foam, while NaCl and MgCl₂ act as foam boosters. By applying Pitzer’s theory and the concept of cohesive pressure, we propose that foam stability is governed by the hydration compatibility between the surfactant head groups and the salt ions. We describe a mechanism in which the “cohesive pressure” of the water matrix determines the efficiency of the SDS adsorption layer. Specifically, strong kosmotropic ions (e.g., Mg²⁺) preserve the hydration shell of the sulfate head groups, thereby preventing film collapse, whereas ions with lower dehydration energy (e.g., Ca²⁺) are proposed to facilitate the formation of contact ion pairs, thereby promoting rapid coalescence. Full article

The production of polymeric nanoparticles using microfluidic systems holds great potential for controlled drug delivery applications. In this study, the effects of flow parameters and surfactant properties on the characteristics of PLGA (Poly (lactic-co-glycolic acid)) nanoparticles were systematically investigated. First, the total flow rate (TFR) and flow rate ratio (FRR) were optimized to ensure stable droplet formation. Subsequently, the effects of different surfactant types (anionic, cationic, and nonionic) and their varying concentrations were evaluated. Using the selected parameters, capsaicin-loaded PLGA nanoparticles were successfully produced. The particles were prepared using a microfluidic platform, and the organic phase was subsequently removed via solvent evaporation. The resulting formulations were comprehensively characterized in terms of particle size, polydispersity index (PDI), zeta potential, and encapsulation efficiency (%EE). Additionally, the in vitro release profiles and cytotoxicity of capsaicin-loaded nanoparticles were evaluated. This study aimed to elucidate the decisive role of surfactant parameters in the microfluidic production of PLGA nanoparticles and to contribute to the development of optimized and reproducible formulations. Full article

Endodontic irrigant solutions act as crucial pretreatment conditioning agents in dentin biomimetic remineralization, preparing the collagen scaffold for calcium phosphate infiltration and subsequent tooth structure reconstruction. In this study, root dentin discs were exposed for 10 min to five irrigant solutions: sodium hypochlorite (NaClO, 3%), EDTA (17%), citric acid (CA, 10%), chlorhexidine (CHX, 2%), and an innovative experimental formulation containing citric acid (7%) and surfactants. Samples were then aged in Hank’s Balanced Salt Solution (HBSS) at 37 °C for three months to simulate long-term clinical conditions. Physicochemical modifications of the collagen and apatite phases were assessed at each experimental stage using ATR-FTIR spectroscopy, with the A_CaP/A_{Amide I} and A₈₇₀/A_CaP absorbance ratios as markers of the degree of mineralization and apatite carbonate content, respectively. Results indicated that CHX- and EDTA-treated dentin exhibited the highest remineralization after ageing, while NaClO impeded remineralization due to collagen degradation. The experimental irrigant produced the most pronounced demineralization, followed by CA; however, it also facilitated significant remineralization, attributed to citrate–collagen binding and surfactant-enhanced apatite nucleation. NaClO selectively degraded collagen and increased apatite crystallinity; CA inhibited apatite nucleation through adsorbed citrate ions, and CHX and EDTA induced minimal alterations. These findings provide molecular-level evidence linking short-term irrigant effects to the long-term potential for dentin biomineralization, with direct implications for irrigant selection in regenerative endodontic protocols. It should be noted that this study was conducted on dentin discs obtained from a single tooth; all findings should therefore be regarded as preliminary and require confirmation in studies with larger, biologically independent sample sizes. Full article

Cod liver oil is a rich source of polyunsaturated fatty acids (PUFAs) but is highly susceptible to oxidative degradation, limiting its use in topical formulations. This study aimed to develop stable cod liver oil nanoemulsions for topical application and to evaluated the influence of surfactant ratio (lecithin/PEG-15 hydroxystearate: 2.5:1 and 1:1, w/w), emulsification method (ultrasonication or high-pressure homogenization), and vitamin E acetate supplementation on their physicochemical properties and oxidative stability. Eight nanoemulsions were characterized in terms of droplet size, polydispersity, ζ-potential, vitamin E acetate encapsulation efficiency, oxidative stability, film-forming capacity and cytocompatibility. Among the investigated formulations, F4 (2.5:1 lecithin/PEG-15 hydroxystearate, high-pressure homogenization, with vitamin E acetate) exhibited the most favorable characteristics, including a mean droplet size of 67.95 nm, ζ-potential of −63.12 mV and vitamin E acetate encapsulation efficiency of 32.59%. The formulation demonstrated good physicochemical stability under thermal, mechanical and photostability testing, improved oxidative stability, transient film-forming behavior with an initial occlusive effect, and no cytotoxicity toward human dermal fibroblasts. These findings indicate that nanoemulsion performance depends on the combined influence of formulation composition and processing conditions, with F4 representing a promising topical carrier for cod liver oil intended for interaction with the stratum corneum. Full article

Thermal–gas–chemical treatment (TGCT) using activated aluminum alloys is a promising near-wellbore stimulation method for high-viscosity oil reservoirs, combining localized heat generation, hydrogen release, pressure increase, and chemical activation of the treated zone. This study evaluates the potential of TGCT for the Karazhanbas field using laboratory core flooding experiments and reservoir-scale scenario analysis. Experiments were conducted on unconsolidated core models saturated with high-viscosity oil. Treatment with activated aluminum alloy and formation water generated up to 2600 mL of gas but did not increase oil displacement efficiency. In contrast, the system containing activated aluminum alloy, 3 wt.% HCl, and 2 wt.% surfactant intensified the reaction, promoted gas–liquid foam formation, increased electrical resistivity to 5000 Ω·m, and improved oil displacement efficiency from 0.37 to 0.61. The additional oil recovery reached 16.8 mL, corresponding to a relative increase of approximately 65%. Reservoir-scale scenario calculations showed a heterogeneous production response, with maximum oil production rate increases ranging from 0.03 to 3.27 m³/day, depending on well conditions. The results indicate that TGCT efficiency is controlled by the combined thermal, gas, and chemical effects rather than gas generation alone. Field-scale implementation requires the calibration of the treatment radius, effect duration, temperature response, gas saturation, permeability alteration, and well-specific reservoir conditions. Full article

The growing demand for safe and minimally processed fresh fruits and vegetables has highlighted the need for effective and environmentally friendly decontamination methods. Conventional washing techniques often fail to remove pesticide residues and microbial contaminants efficiently, while chemical disinfectants raise concerns related to toxicity and sustainability. In this context, natural surfactants and fermentation-derived solutions have emerged as promising alternatives. This critical review presents aspects regarding recent advances in the use of plant-based and microbial surfactants, for the decontamination of fresh products, with highlights on their mechanisms of action, ranging from enhanced removal of hydrophobic residues to disruption of microbial bio-films. Also, particular attention is given to the potential of combining surfactants with bioactive compounds obtained through fermentation processes, as well as to the valorization of agro-industrial waste as sustainable raw materials. The impact of these treatments will contribute to the improvement of product quality, safety, and environmental compatibility. Finally, current challenges related to scalability, standardization, and regulatory aspects are outlined, highlighting the need for further research to support the transition from laboratory studies to real-world applications. Full article

Camellia japonica L., an East Asian species with extensive ethnobotanical use, is a rich source of bioactive metabolites including polyphenols, saponins, terpenoids, sterols, and fatty acids. These compounds have attracted significant attention in cosmetic research due to increasing demand for natural, multifunctional ingredients with antioxidant, anti-inflammatory, antimicrobial, moisturizing, and skin-brightening properties. This review summarizes the major classes of Camellia metabolites, their chemical characteristics, and mechanisms of action. Terpenoids and polyphenols, including phenolic acids, flavonoids, and tannins, exhibit potent antioxidant and anti-aging properties. Camellia saponins serve as mild natural surfactants for gentle skin cleansing, while phytosterols, amino acids, proteins, and seed fatty acids synergistically reconstruct the epidermal barrier and maintain cutaneous hydration. This review further addresses the current applications of these Camellia-derived bioactives in ameliorating photo-aging, hyperpigmentation, skin inflammation, and barrier dysfunction. Despite significant progress, key challenges persist, including incomplete understanding of biosynthetic regulation, suboptimal extraction methods, limited study of synergistic effects, and insufficient human safety data. Future studies should employ omics technologies and green extraction approaches to elucidate biosynthetic pathways, validate efficacy, and promote sustainable utilization of Camellia resources in cosmetics, pharmaceuticals, and related industries. Full article