Langmuir最新文献

A coal tar pitch-based porous carbon adsorbent (CPA) was synthesized through a straightforward method involving the heating of a mixture of KOH and coal tar pitch (CTP). This CPA exhibited a high surface area of 1811.2 m² g^-1 and a large pore volume of 0.94 cm³ g^-1 when prepared with a CTP to KOH mass ratio of 1:4 at 800 °C. Parameters such as the heating temperature and activator dose were optimized to enhance the adsorption efficiency. The prepared CPA was extensively characterized by SEM, XRD, FTIR, and BET measurements. Notably, CPA presented a distinct adsorption performance for Orange G (OG), achieving a maximum adsorption capability of 449.7 mg g^-1. Kinetic studies indicated that the adsorption process followed the pseudo-second-order model, while the adsorption isotherm data demonstrated that both chemical and physical interactions favored OG adsorption. Thermodynamic analysis revealed that the adsorption of OG on CPA was spontaneous and exothermic and increased the entropy. Density functional theory (DFT) calculations provided insights into the adsorption mechanism, highlighting electrostatic interactions, hydrogen bonds, and π-π interactions as the dominant processes governing OG adsorption onto the adsorbent.

Biofouling can cause severe infections, device malfunctions, and failures in diagnostics and therapeutics. Proteins such as bovine serum albumin (BSA) have recently been used as coatings to resist biofouling because they combine surface anchoring and antifouling properties. However, their antifouling effectiveness will significantly deteriorate in complex biofluids with high salinity, limiting their practical applications. In this work, we developed a zwitterion-conjugated protein with enhanced antifouling capability by grafting zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) onto BSA protein via a click reaction. This conjugated protein can easily anchor on various substrates, both inorganic and organic, and exhibits efficient and broad-spectrum fouling resistance to metabolites, proteins, and complex biofluids. Even in the complex fetal bovine serum with higher salinity, the BSA@MPC coating can also maintain 99% fouling resistance robustly, over 6-fold superior to native BSA-coated surfaces in antifouling capability. Direct surface forces measurement reveals that such outstanding antifouling properties of conjugated protein BSA@MPC could be attributed to the stable hydration layer on its surface and the steric repulsion from the antipolyelectrolyte behavior of zwitterionic MPC polymer in the high-salinity environment. Our findings advance the development of protein-based functional materials and provide valuable insights for designing novel antifouling surfaces for marine, food, and bioengineering applications.

Constructing alternating donor-acceptor (D-A) units within g-C₃N₄ represents an effective strategy for enhancing photocatalytic performance through improved charge carrier separation while concurrently addressing energy shortages and facilitating wastewater remediation. Here, a series of D-A-type conjugated photocatalysts (CNBTC-X) are prepared using g-C₃N₄ as an acceptor unit and different masses of 5-bromo-2-thiophenecarboxaldehyde (BTC) as a donor unit by a one-step thermal polymerization. CNBTC-50 presents higher photocatalytic properties for CO₂ reduction coupled with tetracycline (TC) removal than those of g-C₃N₄, CNBTC-10, CNBTC-30, and CNBTC-70. The introduction of the unique electron-donor-acceptor structure effectively drives the separation and transfer of photoinduced carriers while reducing the internal carrier transfer hindrance. Photocatalytic experiments reveal that the CNBTC-50 photocatalyst achieves up to 94.6% TC removal under visible light irradiation conditions. Compared with that of the pristine g-C₃N₄, the photocatalytic degradation reaction rate constant of CNBTC-50 is significantly increased by about 3.87 times. The study examines the influence of various reaction parameters on degradation activity, including catalyst concentration, pH, and TC concentration. Additionally, LC-MS is utilized to perform a comprehensive analysis of the intermediates and pathways involved in TC degradation. Furthermore, CNBTC-50 demonstrates remarkable photocatalytic CO₂ reduction activity, achieving rates of 20.83 μmol g^-1 h^-1 (CO) and 9.36 μmol g^-1 h^-1 (CH₄), which are 10.68 and 5.98 times more efficient than those of g-C₃N₄, respectively. This work aims to offer valuable guidance for the rational design of nonmetal D-A-structured catalysts and effectively integrates reaction systems to couple CO₂ reduction with antibiotic removal.

In the flotation process, there is galvanic corrosion between sulfide mineral particles, which increases the difficulty of separation between minerals. Therefore, the selection of suitable reagents to weaken this corrosion is of great significance. In this article, macromolecular organic reagent sodium lignosulfonate (SLC) was used to weaken the galvanic corrosion between galena and pyrite. Meanwhile, the effect of SLC on the mineral flotation behavior was studied, and the mechanism of SLC was further studied through ion dissolution tests, contact angle tests, infrared spectrum tests, and density functional theory (DFT) calculation. The adsorption of SLC on the mineral electrode increased the charge transfer resistance on the surface of the mineral electrode and hindered the resistance transfer; therefore, it could weaken the galvanic corrosion between galena and pyrite. SLC could selectively depress pyrite at low alkalinity. CaOH⁺ promoted the adsorption of SLC on the pyrite surface. When the pH of the slurry was adjusted by lime, SLC was more easily adsorbed on the pyrite surface, which hindered the adsorption of the collector on the surface of pyrite.

Palm leaves serve as a traditional recording medium and are widespread in south and southeast Asia, and they have a long history. However, they are sensitive to environmental fluctuations, especially moisture, which may severely affect their conservation status. In this research, the moisture absorption behaviors of palm leaves in different states, including raw, treated, naturally aged, and artificially aged ones, were investigated by intelligent gravimetric analysis (IGA) and water retention value (WRV) to analyze their moisture absorption characteristics. Mathematical model was employed to fit and analyze their water adsorption curves, aiming to explore the content and distribution of the adsorbed water in monolayered and multilayered. Then, the chemical and physical properties of different palm leaves were studied by chemical composition analysis, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM), and low-field nuclear magnetic resonance (low-field NMR), and the relationship between moisture absorption characteristics and their chemical composition and physical structures was analyzed. The results demonstrated that both treatment and aging processes could have a noticeable impact on the moisture absorption of palm leaves, as evidenced by reduced equilibrium moisture content (EMC) at high relative humidity (RH), decreased multilayer water adsorption content, and slightly increased monolayer water adsorption content. Besides, palm leaves exhibit a lower rate of moisture adsorption, at ∼30-50% RH, which facilitates their long-term conservation. The results of chemical and physical analyses revealed that the reduced content of hydrophilic groups was the primary reason for a decrease in palm leaves moisture absorption. Additionally, the fiber structure changes of palm leaves caused by treatment or aging may have different influences on their moisture adsorption, especially the content of monolayer adsorbed water.

Enrichment of metal particles in lubricating oil is a crucial pretreatment for wear debris analyses in applications of condition-based machinery maintenance. Current techniques using physical filter cleaning and magnetic attachment to enrich metal particles have limitations in terms of efficiency and selectivity. This work presents an innovative acoustic manipulation chip for efficiently enriching metallic particles from lubricating oil. The platform utilizes the hybrid acoustic forces to perform high throughput particle enrichment in microchannels, even in an intensive flow environment. Regarding the viscosity effect of lubricating oil, the temperature dependence upon the particle enrichment is explored, and the figure of merit is employed to quantify the enrichment performance from the captured microscopic images. Experimental results demonstrate the proposed platform shows great nonselectivity for enriching both magnetic and nonmagnetic particles. This method opens a new door for developing automatic filter-free pretreatment tools to perform efficient particle enrichment in lubricating oil, which have great potential in many application scenarios, such as advanced wear debris analyses, oil quality monitoring, etc.

Low alloy steel faces localized corrosion issues in service environments, primarily due to pitting corrosion induced by inclusions. Conventional protective measures cannot significantly improve the corrosion resistance of the steel. In this study, an effective industrial approach was proposed to enhance the corrosion resistance of low alloy steels. Cerium (Ce) was added during the refining process to modify inclusions and alter the mechanism of inclusion-induced localized corrosion, thereby improving the substrate's ability to inhibit pitting corrosion. The effect of Ce treatment on the cleanliness of molten steel was investigated, and a kinetic model of inclusion evolution was established based on thermodynamic calculations. The pitting corrosion induced by CaS·C₁₂A₇ and CeAlO₃ inclusions was studied through immersion experiments over different durations. The degree of corrosion after being soaked for 20 min was significantly different. The size and depth of pitting pits induced by CeAlO₃ inclusions were much smaller than those induced by CaS·C₁₂A₇ inclusions. The electron back scatter diffraction tests confirmed that CaS·C₁₂A₇ inclusions exhibited a higher corrosion sensitivity compared to CeAlO₃, thus promoting the initiation of pitting. Electrochemical tests demonstrated a positive shift in the corrosion potential and a reduction in current density. This implies that CeAlO₃ inclusions can significantly inhibit pitting occurrences. Based on the dissolution behaviors of CaS·C₁₂A₇ and CeAlO₃ inclusions, a kinetic model was established to describe the initiation and propagation of pitting induced by these inclusions.

Alginate hydrogels are frequently used in 3D bioprinting and tissue repair and regeneration. Establishing the structure-property-performance correlation of these materials would benefit significantly from high-resolution structural characterization in aqueous environments from the molecular level to continuum. This study overcomes technical challenges and enables high-resolution atomic force microscopy (AFM) imaging of hydrated alginate hydrogels in aqueous media. By combining a new sample preparation protocol with extremely gentle tapping mode AFM imaging, we characterized the morphology and regional mechanical properties of the hydrated alginate. Upon cross-linking, basic units of these hydrogel materials consist of egg-box dimers, which assemble into long fibrils. These fibrils congregate and pile up, forming a sponge-like structure, whose pore size and distribution depend on the cross-linking conditions. At the exterior, surface tension impacts the piling of fibrils, leading to stripe-like features. These structural features contribute to local, regional, and macroscopic mechanics. The outcome provides new insights into its structural characteristics from nanometers to tens of micrometers, i.e., at the dimensions pertaining to biomaterial and hydrogel-cell interactions. Collectively, the results advance our knowledge of the structure and mechanics from the nanometer to continuum, facilitating advanced applications in hydrogel biomaterials.

Ferroptosis has been recognized as an iron-based nonapoptotic-regulated cell death process. In the quest of resisting the unyielding vehemence of triple-negative breast cancer (TNBC), herein we have showcased the ferroptosis-inducing heteroleptic [LIr_cRu], [LIr_cIr_h], and [LIr_cRe] complexes, enabling them to selectively target "sialic acid", an overexpressed cancer cell-surface marker. The open-circuit potential (OCP) measurements in live cancer cells revealed the specific interaction between TNBC and the complexes, whereas control experiments with normal cells did not exhibit such interactions. GSH depletion, GPx4 inhibition, NADH/NADPH oxidation, lipid peroxidation, COX-2 activation, and Nrf2 inactivation were meticulously investigated upon treatment with these complexes to establish a strong basis for ferroptosis. Among all complexes, the complex [LIr_cIr_h] (IC₅₀ = 25 ± 2.17 μM) has been well-documented as a potent ferroptosis inducer, which unveils the sturdy interaction with sialic acid possessing the highest binding constant (K_b = 0.71 × 10⁵ M^-1, ΔG = -279345.8026 kcal/mol) along with the highest serum albumin binding affinity (K_HSA = 0.67 × 10⁶ M^-1) and significant DNA intercalation (K_b = 0.56 × 10⁵ M^-1, K_app = 1.06 × 10⁶ M^-1, and C₅₀ of intercalation is 76.56 μM), displaying the decreased current intensity in differential pulse voltammetry (DPV). Moreover, the complex [LIr_cIr_h] exhibited mitochondrial dysfunction and membrane damage (diminished MMP, ΔΨ_m) through the production of copious reactive oxygen species (ROS) in MDA-MB-231 cells upon considerable accumulation in mitochondria (Pearson's coefficient = 0.842). The analysis of the field emission scanning electron microscopy (FE-SEM) image has marked the vivid membrane damage induced by the complex [LIr_cIr_h], exhibiting ablaze evidence for the destruction of TNBC cells through ferroptosis.

Although chirality is critical for molecular properties and functions, experimental quantification of chirality is lacking. Herein, we performed cyclic voltammetry (CV) under polarized magnetic fields to provide a unified scale to quantify and compare DNA chirality. We observed the largest electron spin polarization in DNA structures with opposite chiral senses, which is consistent with the effect of chiral-induced spin selectivity (CISS). Spin polarization is weaker among DNA topologies of the same chiral arrangement, with DNA triplexes exhibiting the strongest CISS. Within DNA duplexes, spin polarization is further reduced depending on the sequence, with fewer guanine-cytosine (GC) pairs displaying a weaker CISS likely due to localized variations in chirality. Surprisingly, spin polarization is vectorial along the DNA duplex while presenting the smallest variation when the transportation directions of electrons become opposite. The four factors, chiral sense, topology, sequence, and directionality of electron transportation, delineate hierarchical contributions to molecular chirality, with profound implications ranging from spintronics to molecular recognitions.