Surface Charge Characteristics Research Articles

Surface charge characteristics of Gaomiaozi bentonite in high-level nuclear waste repositories

Gaomiaozi (GMZ) bentonite is an excellent backfill material for high-level nuclear waste repositories. The bentonite minerals possess a laminated structure and carry a negative charge. These surface charge characteristics play a crucial role in the development of the electric double layer at the liquid-solid interface and the adsorption of nuclear elements during the hydration process. Following the purification of GMZ bentonite, the surface electric potential of bentonite mineral colloids in suspension and compacted bentonite blocks was measured using atomic force microscopy (AFM). Additionally, the influence of various factors on its surface charge characteristics was examined, including the types of interlayer cations, ambient temperature, number of layers, and dry density. The findings reveal that at 20 °C, the surface electric potential of Na-bentonite quasicrystals averages around −225.2mV, while that of Ca-bentonite quasicrystals averages approximately −155.3mV. Additionally, the surface electric potential increases logarithmically with the number of layers. In the compacted state, its surface potential would decrease. An increase in the dry density of compacted bentonite results in a decrease in the surface electric potential. High ambient temperatures can increase the surface electric potential. The research findings offer valuable data and a theoretical foundation for predicting colloid formation, nuclear element adsorption, and swelling pressure development in bentonites used in high-level nuclear waste repositories.

Genome-Wide Identification and Characterization Thaumatin-like Protein (TLP) Genes in Wild Olive (Olea europaea var. sylvestris)

The wild olive tree (Olea europaea var. sylvestris) is the ancestor of all olive varieties, displaying remarkable adaptability to diverse climatic conditions and soil types. This iconic tree of the Mediterranean Basin stands out for its ability to withstand environmental stresses, such as water scarcity and temperature variations, playing a crucial role in the ecology, economy, and culture of the region. In this study, 42 TLP genes were characterized in the wild olive tree, distributed across 14 chromosomes and nine scaffolds. In silico analysis revealed the presence of domains associated with antifungal activity in some sequences, indicating their potential role in pathogen resistance. The structural diversity of OeTLP genes was explored through multiple alignments, conserved motifs and phenetic analysis. Correlation was observed between phenetic diversity, genetic structure, and motif patterns, suggesting different functions among OeTLP groups. Additionally, the distribution of exons and introns in the pheneticc tree provided further insights into the evolution of these genes. Comparative modeling of OeTLPs unveiled three-dimensional models with good structural quality and distinctive surface charge characteristics. This study provides a comprehensive understanding of the physicochemical, structural, and phenetic features of TLP genes in Wild Olive, contributing to knowledge about this species' response to environmental stresses and pathogens.

Surface charge characteristics in a three-electrode surface dielectric barrier discharge

The surface charge characteristics in a three-electrode surface dielectric barrier discharge (SDBD) are experimentally investigated based on the Pockels effect of an electro-optical crystal. The actuator is based on the most commonly used SDBD structure for airflow control, with an exposed electrode supplied with sinusoidal AC high voltage, a grounded encapsulated electrode and an additional exposed electrode downstream supplied with DC voltage. The ionic wind velocity and thrust can be significantly improved by increasing DC voltage although the plasma discharge characteristics are virtually unaffected. It is found that the negative charges generated by the discharge of the three-electrode structure accumulate on the dielectric surface significantly further downstream in an AC period compared to the actuator with a two-electrode structure. The negative charges in the downstream region increase as the DC voltage increases. In addition, the DC voltage affects the time required for the positive charge filaments to decay. The positive DC voltage expands the ionic acceleration zone downstream to produce a greater EHD force. The amplitude of the DC voltage affects the electric field on the dielectric surface and is therefore a key factor in the formation of the EHD force. Further research on the surface charge characteristics of a three-electrode structure has been conducted using a pulse power to drive the discharge, and the same conclusions are drawn. This work demonstrates a link between surface charge characteristics and EHD performance of a three-electrode SDBD actuator.

Fire alarm nano-coating with the controlled release of phosphorus-containing free radical for considerable flame retardant performance

The colloidal properties and surface charge characteristics of graphene oxide (GO) often lead to flocculation during the layer-by-layer (LBL) assembly. Innovatively, the charged flame retardant molecule, amino-tris(methylene phosphonic acid) (ATMP), is encapsulated within the inner cavity of halloysite nanotubes (HNTs). This integration exploits the unique structural features of HNT's inner cavity and outer wall. A composite nano-coating is constructed on the three-dimensional skeletal structure of melamine foam (MF) by assemblying GO with HNT-ATMP. This composite nano-coating exhibits both condensed-phase and gas-phase flame retardant functions. During the thermal decomposition process, phosphorus-containing radicals released from the HNTs' inner cavities enhance the flame retardancy. Moreover, the composite nano-coating demonstrates sensitive fire warning performance. A composite MF coated with 10 layers of this nano-coating emits a warning signal within 8 s fire exposure and maintains this signal without circuit failure. This study elucidates the mechanisms of flame retardancy and fire warning based on the thermal decomposition process and char layer analysis. By addressing the issue of GO flocculation during the assembly process, this research not only clarifies the underlying flame retardant and fire warning mechanisms of composite nano-coating but also proposes solutions for prolonging the duration of fire warning signals in advanced materials.

Facile Synthesis of Sodium Alginate (SA)-Based Quaternary Bio-Nanocomposite (SA@Co-Zn-Ce) for Antioxidant Activity and Photocatalytic Degradation of Reactive Red 24

This study introduces a new strategy for the environmentally friendly catalytic degradation of Reactive Red 24 (RR24) dye using sunlight. We developed a cost-effective quaternary nanocomposite by immobilizing a sodium alginate biopolymer over bioengineered Co-Zn-Ce nanoparticles, forming an SA@Co–Zn–Ce nanocomposite (where SA means sodium alginate). This composite also demonstrated an exceptional antioxidant potential of approximately 89%, attributed to the synergistic effect of sodium alginate and green-synthesized Co–Zn–Ce nanoparticles (biosynthesized using Ocimum sanctum leaf extract as a reducing agent). Scanning electron microscopy revealed grain sizes of 28.6 nm for Co–Zn–Ce NPs and 25.59 nm for SA@Co–Zn–Ce nanocomposites (NCs). X-ray diffraction showed particle sizes of 16.87 nm and 15.43 nm, respectively. Co–Zn–Ce NPs exhibited a zeta potential of 1.99 mV, whereas the sodium alginate-anchored Co–Zn–Ce showed −7.99 mV. This indicated the entrapment of negatively charged ions from sodium alginate, altering the surface charge characteristics and enhancing the photocatalytic degradation of RR24. Dynamic light scattering revealed an average particle size of approximately 81 nm for SA@Co–Zn–Ce NCs, with the larger size due to the influence of water molecules in the colloidal solution affecting hydrodynamic diameter measurement. The SA@Co–Zn–Ce NCs exhibited a CO2 adsorption capacity of 3.29 mmol/g at 25 °C and 4.76 mmol/g at 40 °C, indicating temperature-dependent variations in adsorption capabilities. The specific surface area of Co–Zn–Ce oxide NPs, measured using Brunauer–Emmett–Teller (BET) analysis, was found to be 167.346 m2/g, whereas the SA@Co–Zn–Ce oxide nanocomposite showed a surface area of 24.14 m2/g. BJH analysis revealed average pore diameters of 34.60 Å for Co–Zn–Ce oxide NPs and 9.26 Å for SA@Co–Zn–Ce oxide NCs. Although the immobilization of sodium alginate on Co–Zn–Ce oxide NPs did not increase the adsorption sites and porosity of the composite, as evidenced by the N2 adsorption–desorption isotherms, the SA@Co–Zn–Ce oxide NCs still demonstrated a high photocatalytic degradation efficiency of RR24.

Electrophoresis Characterization of Nanoplastic Particle Surface Charge in Dilute Aqueous Electrolytes

Electrophoresis Characterization of Nanoplastic Particle Surface Charge in Dilute Aqueous Electrolytes

Downflow and upflow sand filtration for removing turbid particles with diverse morphological and surface-charge characteristics: Comparisons of filtered water quality and head loss distribution

Besides the physicochemical characteristics (e.g., size, structure, charge nature, etc.) of turbid particles, the filtration flow direction may affect their migration and adhesion behaviors inside the filtration unit. Unfortunately, there has been a lack of research regarding the combined effects of these above factors on filtered water quality and head loss development during filtration. In this study, different turbid particles were prepared by flocculating water samples containing kaolin and humic acid. Filtration experimental results of these flocculated waters revealed that downflow and upflow filtration modes had different durations of effective filtration under identical PAC-dosage cases, and upflow filtration led to faster increases in filtered water turbidity at the breakthrough stage compared to downflow filtration. During 180-min downflow filtration, the average size of residual turbid particles increased, but this did not occur in upflow filtration. Furthermore, differently from downflow filtration, upflow filtration had a more uniform distribution of head loss across all filter layers. The ease of backwashing differed between the two filtration modes, reflected by the different times required for reaching a relatively stable turbidity during 10-min backwashing. Lastly, based on SEM, FTIR and XPS analyses for characterizing the coagulated particle surface morphology, element composition, and functional groups, a series of conceptual models for particle removal by downflow and upflow filtrations were developed to clarify the influencing mechanisms of different turbid particles on filtration. It highlighted the advantages of upflow filtration, including improved distribution of flow resistance, better removal of larger-sized turbid particles, and enhanced pollutant-holding capacity of the filter media.

Flotation separation of hematite from quartz with dodecyl trimethyl ammonium chloride and sodium dodecyl sulfonate collector

Through a series of testing methods, including micro-flotation tests, contact angle test, ζ-potential analysis, FTIR, and XPS, the behavior and mechanism of flotation separation of hematite and quartz by mixed anionic-cationic collectors (Dodecyl Trimethyl Ammonium Chloride (DTAC) and Sodium Dodecyl Sulfonate (SDS), DS for short) were investigated. Additionally, the froth performance of the mixed collector was examined through froth stability experiments. The study revealed that the inclusion of DS collectors significantly enhanced the flotation separation efficiency of quartz-hematite, with the addition of SDS leading to a reduction in the foam viscosity of DTAC. Notably, at a pH of 7 and with a DTAC to SDS mass ratio of 2:1, the mixed collector demonstrated exceptional performance in the flotation separation of quartz and hematite, achieving a quartz recovery of 91.85 % and a hematite recovery of 11.45 %. This efficacy was corroborated by ζ-potential measurements, FT-IR analysis, and XPS analysis, which confirmed the physical adsorption of DS on the mineral surfaces. Importantly, the adsorption dynamics were found to be influenced by the different surface charge characteristics of quartz and hematite. Specifically, the higher negative charge on the surface of quartz resulted in unaffected DTAC adsorption in the presence of SDS, while on hematite surfaces, the DTAC interaction with SDS led to the partial desorption of DTAC. Consequently, the adsorption of DTAC on hematite surfaces was reduced, facilitating the selective separation of quartz and hematite.

Charge barriers in the kidney elimination of engineered nanoparticles

The renal elimination pathway is increasingly harnessed to reduce nonspecific accumulation of engineered nanoparticles within the body and expedite their clinical applications. While the size of nanoparticles is recognized as crucial for their passive filtration through the glomerulus due to its limited pore size, the influence of nanoparticle charge on their transport and interactions within the kidneys remains largely elusive. Herein, we report that the proximal tubule and peritubular capillary, rather than the glomerulus, serve as primary charge barriers to the transport of charged nanoparticles within the kidney. Employing a series of ultrasmall, renal-clearable gold nanoparticles (AuNPs) with precisely engineered surface charge characteristics as multimodal imaging agents, we have tracked their distribution and retention across various kidney components following intravenous administration. Our results reveal that retention in the proximal tubules is governed not by the nanoparticle's zeta-potential, but by direct Coulombic interactions between the positively charged surface ligands of the AuNPs and the negatively charged microvilli of proximal tubules. However, further enhancing these interactions leads to increased binding of the positively charged AuNPs to the peritubular capillaries during the initial phase of elimination, subsequently facilitating their slow passage through the glomeruli and interaction with tubular components in a charge-selective manner. By identifying these two critical charge-dependent barriers in the renal transport of nanoparticles, our findings offer a fundamental insight for the design of renal nanomedicines tailored for selective targeting within the kidney, laying down a foundation for developing targeting renal nanomedicines for future kidney disease management in the clinics.

Amine-impregnated natural inorganic nanotubes via layer-by-layer electrostatically self-assembly approach for efficient CO2 adsorption

Developing cost-effective and high-performance solid amine adsorbents has considered as an important way to alleviate the greenhouse effect. How to precisely regulate its pore structure and surface interface characteristics, and how to cooperate to optimize the dynamic mass transfer and adsorption–desorption behavior of gas in the adsorbent are still challenging work. Herein, we demonstrated a facile and efficient approach to construct polyethyleneimine (PEI) impregnated halloysite nanotubes (HNTs) as an emerging nanocomposite for CO2 capture. Based on the natural electrostatic differences of inner and outer walls for HNTs, the hollow tubular structures of adsorbents were constructed by selective surface modification and layer-by-layer electrostatic self-assembly technology to improve the CO2 uptake capacity and cyclic stability, in which poly(sodium-p-styrene sulfonate) (PSS) and PEI were used as polyanionic and polycationic layer, respectively, to coat the inner walls of HNTs. The loading capacity of PSS-PEI composite ionic layers in HNTs and the influence of PSS polyanionic layer on PEI dispersion were specifically discussed according to the CO2 uptake capacity, adsorption heat, thermodynamics and kinetics of the adsorbents. The optimal PEI20-0.5PHNTs adsorbent exhibited a higher CO2 uptake of 0.87 mmol/g at 80 °C in the flow of 40 vol% N2/60 vol% CO2 than that of PEI20-HNTs, owing to the high amine efficiency due to the uniform dispersion of PEI in the electrostatic composite ionic layers. Furthermore, PEI20-0.5PHNTs reached 75 % of the maximum adsorption capacity at the 5th min of the adsorption process and released the most heat during adsorption at − 18.28 kJ/mol due to the presence of electrostatic composite ionic layers. PEI20-0.5PHNTs showed excellent cyclic stability with a slight loss of 7.4 %. The electrostatic self-assembled adsorbent obtained by layer-by-layer loading of PSS and PEI based on the unique surface charge characteristics of HNTs is an inspiration for the synthesis of cost-effective solid amine adsorbents for practical CO2 capture and separation.

Cashew nut shell biomass: A source for high-performance CO2/CH4 adsorption in activated carbon

This study embarks on the synthesis of activated carbon (AC) from cashew nut shells using a potassium carbonate (K2CO3) activation process, with a specific focus on its practical application in high-pressure gas adsorption. Among the synthesized samples, MCAK85 emerged as the most efficient, demonstrating a specific surface area of 1693 m2/g and total and micropore volumes of 0.839 cm3/g and 0.641 cm3/g, respectively. Importantly, this bioorganic activated carbon exhibited high sorption capacities for CO2 and CH4, with uptake values of 11.0 mmol/g and 5.5 mmol/g at 10 bar at 25°C, and a CO2/CH4 selectivity range between 9.1 and 1.8. A comprehensive range of characterization techniques were employed to analyze the structural and chemical properties of the synthesized AC, providing valuable insights into the functional groups and molecular structure. The morphology of the AC was examined using SEM, while the point of zero charge was determined to understand the surface charge characteristics. Additionally, TGA was utilized to assess the thermal stability and composition of the AC. This study underscores the potential of utilizing agricultural waste, specifically cashew nut shells, in the creation of effective materials for gas storage and purification applications. The high-pressure adsorption capacity of the produced AC, coupled with its sustainable and eco-friendly nature, underscores its suitability for environmental and industrial applications, particularly in areas focusing on greenhouse gas capture and air purification, thereby inspiring further research and development in this field.

Abstract 3198: An analysis of breast cancer membrane lipid-modified nanoliposomes for enhanced targeting of triple-negative breast cancer

Abstract Background: Every breast cancer diagnosis is unique in its own way. Triple-negative breast cancer (TNBC), has a highly aggressive phenotype characterized by a rapid growth rate profile, increased risk of metastasis and recurrence. TNBC is devoid of epidermal growth factor receptor 2, estrogen, and progesterone receptors. All three are commonly present in other forms of breast cancer disease. The aim of this study was to develop a cell membrane lipid-extracted nanoliposomes (CLENs) for selective targeting compared to conventional nanoliposomal varieties. An additional objective was to investigate the role of microenvironment on targeting using cell model of TNBC, and representations of non-target tissue environments for comparison. Method: Lipid extracts (LE) obtained from 4T1, a murine mammary carcinoma cell line from a BALB/cfC3H mouse was used to formulate the CLENs (cell membrane lipid-extracted nanoliposomes) with different ratios of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), a phospholipid used in most conventional drug delivery liposomes. Different lipid compositions and ratios were employed to evaluate cellular uptake in target, non-target and off-target cells. The target cell line, 4T1, off-target and non-target cell populations included CRL-2089, normal breast fibroblasts, SKBR3 a (human breast cancer), and A549 a (lung cancer) cell lines. Other studies involved determination of molecular charge and zeta potential of various nanoliposomal preparations and corresponding fluorescence studies in vitro. Results: The physicochemical properties of CLENs such as particle size and surface charge characteristics were vital when assessing benefit of the lipid-based preparations. The size of the CLENs typically ranged between 130 - 165 nm and zeta potential values were negatively-charged. The inclusion of 70 mol% of LE in preparation of 4T1-CLENs demonstrated increased cellular uptake and binding by the 4T1 target cells compared to the control DOPC (100%). The highest degree of selectivity was observed in early cell binding events, and with studies involving more extended incubation time points under different experimental conditions. Off-target cells demonstrated reduced uptake by comparison. Overall, 4T1-CLENs was most efficient when applied against intended target 4T1 cells, when compared to relevant control cell populations. In conclusion, studies performed to date suggest the notion that lipid extracts derived from TNBC improves targeting. Citation Format: Christiana Ayertey, Parmida Amid, Mohammed H. Almozain, Robert B. Campbell. An analysis of breast cancer membrane lipid-modified nanoliposomes for enhanced targeting of triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3198.

Natural and synthetic plagioclases: Surface charge characterization and sorption of trivalent lanthanides (Eu) and actinides (Am, Cm)

The environmental fate of radiotoxic actinides may be controlled by their interactions with feldspars. Here, the sorption of trivalent minor actinides (Am, Cm) and their rare earth analog Eu onto synthetic pure Ca-feldspar (anorthite) and natural plagioclases of different Ca contents is investigated, covering ranges of [M3+] (52 nM–10 μM), solid-liquid ratios (1–3 g/L), pH (3–9), and ionic strengths (0.01–0.1 M NaCl) under both ambient and CO2-free conditions. As a first step to understand the uptake behavior of the heavy metals, the hitherto unknown surface charge and (de-)protonation reaction of Ca-feldspars is characterized. The zeta potential shows an unusual increase and charge reversal between pH 4 and 7 , which becomes more pronounced with increasing amounts of Ca in the crystal lattice and is likely connected to adsorption and/or surface precipitation of dissolved Al3+. Streaming potential measurements yield (de)protonation constants for anorthite surface sites of log K- = −6.94 ± 0.38 and log K+ = +6.84 ± 0.38. Batch sorption data shows strong immobilization of M3+ by plagioclases at mildly acidic and basic pH. Time-resolved laser fluorescence spectroscopy using Cm indicates the formation of an inner-sphere complex and its two hydrolyzed forms. The complex reactivity of dissolved Al3+ at the plagioclase-water interface severely complicated the development of a surface complexation model, emphasizing the need for additional research in this area. Our study highlights the importance of molecular-level studies to understand surface reactions and uncover unknown processes, which may have significant impact on the transport of (radiotoxic) contaminants in the geosphere.

The change of coordination environments induced by vacancy defects in hematite leads to a contrasting difference between cation Pb(II) and oxyanion As(V) immobilization

Hematite is an iron oxide commonly found in terrestrial environments and plays an essential role in controlling the migration of heavy metal(loid)s in groundwater and sediments. Although defects were shown to exist both in naturally occurring and laboratory-synthesized hematite, their influences on the immobilization of heavy metal(loid)s remain poorly understood. In this study, hematite samples with tunable vacancy defect concentrations were synthesized to evaluate their adsorption capacities for the cation Pb(II) and for the oxyanion As(V). The defects in hematite were characterized using XRD, TEM-EDS mapping, position annihilation lifetime spectroscopy, and XAS. The surface charge characteristics in defective hematite were investigated using zeta potential measurements. We found that Fe vacancies were the primary defect type in the hematite structure. Batch experiments confirmed that Fe vacancies in hematite promoted As(V) adsorption, while they decreased Pb(II) adsorption. The reason for the opposite effects of Fe vacancies on Pb(II) and As(V) immobilization was investigated using DFT calculations and EXAFS analysis. The results revealed that Fe vacancies altered As–Fe coordination from a monodentate to a bidentate complex and increased the length of the Pb–Fe bond on the hematite surface, thereby leading to an increase in As(V) bonding strength, while decreasing Pb(II) adsorption affinity. In addition, the zeta potential analysis demonstrated that the presence of Fe vacancies led to an increase in the isoelectric point (IEP) of hematite samples, which therefore decreased the attraction for the cation Pb(II) and increased the attraction for the oxyanion As(V). The combination of these two effects caused by defects contributed to the contrasting difference between cation Pb(II) and oxyanion As(V) immobilization by defective hematite. Our study therefore provides new insights into the migration and fate of toxic heavy metal(loid)s controlled by iron minerals.

Construction of fully coated polypyrrole oxygen-barrier film based on MXene nanosheets for high reliability capacitive deionization

MXene has emerged as a promising capacitive deionization (CDI) faradic material for the advantages of excellent hydrophilicity, outstanding specific capacitance, and highly reversible ions intercalation/de-intercalation. However, its practical applications are severely restricted by the bottleneck problems of severe self-stacking and susceptibility to be oxidized by dissolved oxygen in aqueous solution. Herein, polypyrrole (PPy) oxygen-barrier film was fabricated and fully coated on the surface of MXene by the in-situ polymerization method to construct the composite electrode of PPy@MXene. In this unique architecture, the PPy oxygen-barrier film both enhances the antioxidant properties of MXene and weakens the strong interfacial interactions between MXene nanosheets to reduce the self-aggregation. Meanwhile, by doping different ions (Cl– and dodecyl benzene sulfonate, DBS–), PPy films were provided with excellent conductivity, abundant hole sites, and good ion exchange properties, which significantly promoted the charge priority adsorption capability of PPy-Cl@MXene and PPy-DBS@MXene electrodes. Consequently, compared with MXene//MXene cell, the PPy-Cl@MXene//PPy-DBS@MXene CDI cell presents dominant deionization capacity (55 mg g−1) and outstanding cycling stability (3 % degradation after 40 cycles). Most importantly, the morphology, structure and surface charge characteristics of the electrodes after long-term desalination confirmed that the MXene with fully coated PPy film was not destroyed by dissolved oxygen and maintained good structural integrity, which is conducive to improving the reliability of the MXene-based electrodes in CDI. Additionally, ion doped PPy@MXene electrodes highlight preferential adsorption to divalent cations. The work proposes a new strategy to advance the practical application of MXene by simultaneously solving its self-stacking and oxidative degradation issues.

Ion Concentration-Dependent Surface Charge Density Inside a Nanopore.

Surface charges shape the electrical double layer (EDL) structure at solid-liquid interfaces, critically influencing the performance of energy storage and micro/nanofluidic devices. However, accurately measuring surface charge density in nanoconfined spaces continues to be a challenge. Here, we introduce a methodology via solid-state nanopores that can investigate the dependence of surface charge density on salt concentrations and nanopore diameters. Measurements, complemented by a theoretical model, reveal that the surface charge density decreases as both the salt concentration in bulk solutions and the nanopore sizes are reduced. Notably, when the salt concentration in the bulk solution drops below 10-3 M, protons dominate ion conductance in a nanopore, resulting in a constant surface charge density. This study introduces an effective approach to surface charge characterization and may serve in the design of electrokinetically driven nanofluidic systems.

Lithium-Modified TiO2 Surface by Anodization for Enhanced Protein Adsorption and Cell Adhesion.

Promoting osseointegration is an essential step in improving implant success rates. Lithium has gradually gained popularity for promoting alkaline phosphatase activity and osteogenic gene expression in osteoblasts. The incorporation of lithium into a titanium surface has been reported to change its surface charge, thereby enhancing its biocompatibility. In this study, we applied anodization as a novel approach to immobilizing Li on a titanium surface and evaluated the changes in its surface characteristics. The objective of this study was to determine the effect of Li treatment of titanium on typical proteins, such as albumin, laminin, and fibronectin, in terms of their adsorption level as well as on the attachment of osteoblast cells. Titanium disks were acid-etched by 66 wt % H2SO4 at 120 °C for 90 s and set as the control group. The etched samples were placed in contact with an anode, while a platinum bar served as the counter electrode. Both electrodes were mounted on a custom electrochemical cell filled with 1 M LiCl. The samples were anodized at constant voltages of 1, 3, and 9 V. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) results showed no significant differences in the topography. However, the ζ potentials of the 3 V group were higher than those of the control group at a physiological pH of 7.4. Interestingly, the adsorption level of the extracellular matrix protein was mostly enhanced on the 3 V-anodized surface. The number of attached cells on the Li-anodized surfaces increased. The localization of vinculin at the tips of the stretching cytoplasmic projections was observed more frequently in the osteoblasts on the 3 V-anodized surface. Although the optimal concentration or voltage for Li application should be investigated further, this study suggests that anodization could be an effective method to immobilize lithium ions on a titanium surface and that modifying the surface charge characteristics enables a direct protein-to-material interaction with enhanced biological adhesion.

The Influence of Thermal Aging on the Surface Trap Characteristics and Surface Flashover of Epoxy Resin

Surface charge accumulation of epoxy resin is easy to cause surface flashover under DC voltage, and thermal aging is an important factor affecting surface charge and trapping characteristics. In this paper, the electron and hole trap characteristics of epoxy resin were studied by changing the polarity and amplitude of charging voltage. Then, the influence of thermal aging on the trap energy level distribution of epoxy resin is researched by conducting the thermal aging experiment, based on which the influence of the energy level distribution of electron trap on the negative DC flashover characteristics is furtherly studied. Experimental results show that the energy level of electron trap and hole trap on the surface of epoxy resin ranges from 0.70 eV to 0.96 eV, the peak energy level of hole trap is slightly higher than that of electron trap. The maximum of the density of trapped charge in the electron trap and hole trap is 1.98 × 1020eV−1·m−3 and 1.82 × 1020eV−1·m−3 respectively. The energy level of traps on the surface of epoxy resin generally shows a deepening trend after thermal aging. The peak energy level of electron trap increases from 0.84 eV to 0.98 eV after 29 d of thermal aging, which is due to the product containing strongly polar group produced by thermal aging. The results of flashover testing shows that the flashover voltage first increases and then decreases with the extension of thermal aging time. With the extension of aging time from 7 d to 29 d, the flashover voltage decreases by about 11.2%, the change of flashover voltage is related to the change of trap energy level distribution on the surface of dielectric. This paper can provide theoretical and experimental basis for the insulation design of epoxy resin applied in electric equipment.

Revolutionizing goat milk gels: A central composite design approach for synthesizing ascorbic acid-functionalized iron oxide nanoparticles decorated alginate-chitosan nanoparticles fortified smart gels

Goat milk gels (GMGs) are popular food due to their high water content, low-calorie density, appealing taste, texture enhancers, stability, and satiety-enhancing characteristics, making them ideal for achieving food security and zero hunger. The GMGs were optimized using the central composite design matrix of response surface methodology using goat milk powder (35–55 g), whole milk powder (10–25 g), and potato powder (10–15 g) as independent variables. In contrast, complex modulus, flow stress, and forward extrudability were chosen as dependent variables. The maximum value of complex modulus 33670.9 N, good flow stress 7863.6 N, and good extrudability 65.32 N was achieved under optimal conditions. The optimized goat milk gel was fortified with ascorbic acid-coated iron oxide nanoparticle (magnetic nature) decorated alginate-chitosan nanoparticles (AA-MNP@CANPs), making it nutritionally rich in an economically feasible way—the decorated AA-MNP@CANPs characterized for size, shape, crystallinity, surface charge, and optical characteristics. Finally, the optimized fortified smart GMGs were further characterized via Scanning electron microscopy, Rheology, Texture profile analysis, Fourier transforms infrared (FTIR), and X-Ray Diffraction (XRD). The fortified smart GMGs carry more nutritional diversity, targeted iron delivery, and the fundamental sustainability development goal of food security.

Utilization of organoclay amended bentonite for hydraulic barrier applications under adverse electrolyte environment

Inorganic ions such as sodium and calcium are often found in industrial leachates, municipal solid waste leachates and deep geological repositories, which can significantly impact the geotechnical properties of hydraulic barrier materials. Researchers have suggested the utilization of organoclays as landfill liner amendments, especially when the liner is in contact with organic contaminants. This study focuses on the impact of inorganic salts (NaCl and CaCl2) on the geotechnical properties, such as consistency limits, swelling, and hydraulic conductivity of organoclay-amended bentonite (BOC) liners. Different concentrations of salt solutions (0, 0.1 N and 1 N) were selected for the execution of Atterberg limits, free swell tests, and oedometer tests. The surface charge characteristics of bentonite and organoclay were attained with the aid of zeta potential measurements. The variation in the surface topographies of soil samples at different electrolyte conditions was analyzed with the help of scanning electron microscope images. The addition of organoclays significantly reduced bentonite's swelling characteristics and liquid limit due to the unique hydrophobic and organophilic attributes of organoclay but increased the hydraulic conductivity. However, the influence of inorganic salts on the geotechnical parameters of organoclay-amended bentonites showed less variance than that of bentonite. Also, no soil samples exceeded the limiting hydraulic conductivity criteria required for landfill liners, i.e. 1 × 10−9 m/s. Hence, organoclay-amended bentonites could potentially be utilized for hydraulic barrier applications even in an electrolytic environment without compromising the hydraulic conductivity criteria.