Changes In Zeta Potential Research Articles

Profiling of charge characteristics and effect of pH on charge dynamics in cyprinid milt

Electrostatic properties of milt have a huge bearing on the reproductive success of externally fertilizing freshwater fish species. Considering the global significance of carp in aquaculture, we explored the charge profile of milt of ten commercially important carp species for the first time. Mean zeta potential of milt ranged from (−) 33.86 mV in Cirrhinus mrigala to (−) 56.34 mV in Systomus sarana at pH 7.0. The effect of pH on milt characteristics was studied with Labeo rohita as the model species. Zeta potential reduced significantly upon exposure to low pH (4.0) and increased at alkaline pH (10.0). Fertilization rate was significantly reduced at acidic pH. Our results indicate that changes in milt zeta potential due to acidic pH is a significant factor in reduced reproductive success of externally fertilizing freshwater fish. While low concentration of proteases were detected in milt, it remained in a stable colloidal form even after incubation for 18 h at room temperature with no significant difference in the mean zeta potential at the end of incubation. This seminal work on milt zeta potential of carp will open several avenues in aquaculture and fisheries for productivity enhancement and conservation. Study of the electrostatic properties of milt can also help explain puzzling questions of ecology, such as migratory behavior.

Development and evaluation of novel taste-masking tilmicosin microcapsules containing octenylsuccinic anhydride modified starch and maltodextrin as wall materials

Tilmicosin (TMS) is an important antibiotic in veterinary medicine, but its extreme bitter taste limits its use. In this study, TMS was encapsulated in octenyl succinic anhydride modified starch/maltodextrin (HI-CAP/MD) composite capsules with a spray drying method. The TMS microcapsules (TMS-MC) exhibited good drug loading performance with drug loading (DL) and encapsulation efficiency (EE) of 9.90 ± 0.23 % and 98.03 ± 1.56 %, respectively. There was no significant change in particle diameter and zeta potential for the emulsion and redissolved TMS-MC. These results combined with FT-IR, TGA and DSC showed the crystalline shape and chemical structure of TMS did not change during the microencapsulation. In vitro release characterization in an acidic medium (pH 1.2) and an alkaline medium (phosphate buffered solution, pH 6.8) showed that TMS-MC can be rapidly released in vitro. The bitterness evaluation implied the bitterness of TMS was masked after microencapsulation. In vitro bacterial inhibition test showed the bacterial inhibitory activity of TMS was not reduced by the microencapsulation, but was much better than that of the commercially available tylosin (TLS). Therefore, HI-CAP/MD can effectively encapsulate TMS, mask the bitter taste and maintain a good bacterial inhibitory effect, making a new drug formulation with good development prospects.

Carbon-ash separation of coal gasification fine slag by flocculation-flotation process

ABSTRACT Coal gasification slag (CGFS), which was a bulk solid waste in coal chemical industry, shows great application potential in the preparation of silica microspheres, zeolites ceramic materials, etc. However, its high residual carbon characteristics hinder to its development. Decarburization is a necessary precondition for the effective utilization of CGFS. The efficient separation of carbon or ash from CGFS remains a challenge due to its ultra-fine particle size. This work provides a novel flocculation-flotation process to achieve the complete carbon-ash separation of CGFS. The addition of anionic polyacrylamide (APAM) or polyethylene oxide (PEO) had positive effect on the flotation of CGFS, especially for APAM. With APAM dosage of 50 g/t, the ash content of carbon slag and ash slag were 59.04% and 97.11%, respectively. In this process, the zeta potential of carbon slag and ash slag decreased from −17.43 and −11.77 mV to −23.45 and −29.80 mV, respectively. The greater change of zeta potential of ash slag indicates its stronger adsorption of APAM, leading to the higher flocculation trend of ash particles than that of carbon slag. APAM has selective flocculation effect on ash slag, which contributed to reduce the mechanical entrainment during flotation, thereby achieving complete carbon-ash separation of CGFS.

Impact of ultrasonic and heat treatments on the physicochemical properties and rennet-induced coagulation characteristics of milk from various species

This study investigates the effects of heat and ultrasonic treatments on the physicochemical parameters and rennet-induced coagulation properties of milk from a variety of species, including cow, goat, buffalo, and donkey. Milk samples were subjected to heat treatments at different temperatures (65 °C, 80 °C, 90 °C, 100 °C) and ultrasonic treatment at varying power levels (200 W, 400 W, 600 W, 800 W, 1000 W). The results revealed that changes in turbidity, particle size, zeta potential, secondary structure, and surface hydrophobicity were altered by both ultrasonic and heat treatments, as well as the kind of milk. Ultrasonic treatment of cow milk decreased α-helix content while increasing β-turn content. Under similar ultrasonic treatment, goat milk showed a considerable increase in β-sheet content, whereas β-turn and random coil contents decreased compared to control samples. Notably, the water-holding capacity of gels formed from all four types of milk increased significantly with the intensity of ultrasonic and heat treatments. The hardness of buffalo milk gels increased significantly after ultrasonic and thermal treatments, ranging from 63 °C for 30 min to 90 °C for 15 min, but the hardness of cow and goat milk gels increased in varying degrees compared to their control samples. Furthermore, gels from cow and goat milk had higher storage modulus (G’) and loss modulus (G’’) than those from buffalo and donkey milk, and changes in G’ and G’’ from the examined milk were altered by ultrasonic and heat treatments. These findings offer important insights into refining milk processing procedures to improve dairy product quality and usefulness.

Chitosan-tethered liposomes for sinapic acid delivery

Sinapic acid (SA) is a poorly water-soluble bioactive compound with numerous therapeutic applications. SA-loaded liposomes were prepared by varying soybean phosphatidylcholine (SPC) and sodium deoxycholate (SDC) ratios by the thin-layer hydration process. The formulated SA-loaded liposomes were assessed for size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE), and in vitro drug release studies. The optimized formulation SA-loaded liposomes formulation SA-L3 was further coated with chitosan. Further, chitosan coated SA-loaded liposomes (SA-L3-CS1) were estimated for surface morphology, in vitro drug release, antioxidant and cell viability studies. The optimized SA-loaded liposomes formulation exhibited particles size of 166.24 ± 6.69 nm, PDI 0.222 ± 0.020, zeta potential −12.66 ± 2.15 mV, EE of 74.33 ± 4.63 % and in vitro drug release of 87.78 ± 5.04 %. Chitosan coated SA-loaded liposomes demonstrated substantial changes in particles size (223.13 ± 14.94 nm), PDI (0.295 ± 0.021), zeta potential (19.67 ± 3.27 mV), and EE (80.79 ± 2.96 %) and prolonged drug release was observed (67.54 ± 4.40 % at 8 h). Chitosan coated SA-loaded liposomes demonstrated improved antioxidant and cell viability activities in contrast to pure SA; this could be due to the escalated solubility of SA. In conclusion, the current research revealed that chitosan coated liposomes enhance SA's antioxidant and cytotoxicity activity.

Synthesis and Kinetics of CO2-Responsive Gemini Surfactants.

Surfactants are hailed as "industrial monosodium glutamate", and are widely used as emulsifiers, demulsifiers, water treatment agents, etc., in the petroleum industry. However, due to the unidirectivity of conventional surfactants, the difficulty in demulsifying petroleum emulsions generated after emulsification with such surfactants increases sharply. Therefore, it is of great significance and application value to design and develop a novel switchable surfactant for oil exploitation. In this study, a CO2-switchable Gemini surfactant of N,N'-dimethyl-N,N'-didodecyl butylene diamine (DMDBA) was synthesized from 1, 4-dibromobutane, dodecylamine, formic acid, and formaldehyde. Then, the synthesized surfactant was structurally characterized by infrared (IR) spectroscopy, hydrogen nuclear magnetic resonance (1H NMR) spectroscopy, and electrospray ionization mass spectrometry (ESI-MS); the changes in conductivity and Zeta potential of DMDBA before and after CO2/N2 injection were also studied. The results show that DMDBA had a good CO2 response and cycle reversibility. The critical micelle concentration (CMC) of cationic surfactant obtained from DMDBA by injecting CO2 was 1.45 × 10-4 mol/L, the surface tension at CMC was 33.4 mN·m-1, and the contact angle with paraffin was less than 90°, indicating that it had a good surface activity and wettability. In addition, the kinetic law of the process of producing surfactant by injecting CO2 was studied, and it was found that the process was a second-order reaction. The influence of temperature and gas velocity on the reaction dynamics was explored. The calculated values from the equation were in good agreement with the measured values, with a correlation coefficient greater than 0.9950. The activation energy measured during the formation of surfactant was Ea = 91.16 kJ/mol.

Encapsulation of lemongrass essential oil by bilayer liposomes based on pectin, gum Arabic, and carrageenan: Characterization and application in chicken meat preservation.

The volatile characteristics of lemongrass essential oil (LO) have seriously hindered its further application, and encapsulation it with multilayer modified liposomes may be an effective strategy to improve this dilemma. This study selected chitosan (CH) and three anionic polymers, pectin (P) / gum arabic (GA) / carrageenan (C), as the first and second coating polymers to modify nano liposomes (NL) by layer-by-layer electrostatic deposition, obtaining three bilayer liposomes, P-CH-NL, GA-CH-NL, and C-CH-NL as high-quality stabilized carriers of LO. The bilayer liposomes showed a dense membrane structure ranging from 110 to 150nm uniformly, with good antioxidant properties. All bilayer liposomes had good stability during 28-day storage at 4°C, while C-CH-NL performed relatively better inferred by smaller changes of size, PDI and Zeta potential. The total volatile base nitrogen (TVB-N) values of fresh chicken meat and a total number of bacterial colonies (TBC) experiments showed that GA-CH-NL and C-CH-NL could better retard the increase of volatile salt base nitrogen. All bilayer liposomes could delay the time for the total bacterial count to exceed 6 log CFU/g (from 7days to 10 / 12days). Therefore, the bilayer liposomes P-CH-NL, GA-CH-NL, and C-CH-NL may be promising natural preservatives for food products.

Development of biocompatible lipid-polymer hybrid nanoparticles for enhanced oral absorption of posaconazole: A mechanistic in vitro and in silico assessment

The current research focuses on the development of lipid-polymer hybrid nanoparticles (LPHNs) designed to enhance the solubility and bioavailability of posaconazole (PCZ). PCZ, an antifungal drug, faces challenges due to its poor water solubility, resulting in inconsistent absorption and limited bioavailability. LPHNs composed of stearic acid and poly-δ-decalactone (PDL) were successfully fabricated and characterized. The optimized formulation (P-LPHN4) exhibited a particle size of 104.0 nm, negative zeta potential (−38.9 mV), high drug loading (19.5 %), and efficient encapsulation (82.6 %). In vitro release studies demonstrated sustained drug release over 18 h, with P-LPHN4 displaying the highest drug release (92 %). Stability studies revealed good physical stability over 45 days with no significant changes in particle size, zeta potential, and PDI. In silico simulations using GastroPlus® predicted significantly improved intestinal absorption and systemic exposure for P-LPHN4 compared to the pure drug suspension in a simulated rat model. The model predicted a higher peak plasma concentration (Cmax) for P-LPHN4 (∼0.012 μg/mL) compared to the PCZ suspension (∼0.0058 μg/mL). The model identified the duodenum and jejunum as primary absorption sites for both formulations, with P-LPHNs showing significantly higher overall absorption (84.5 %) compared to the suspension (47.5 %). Simulation results revealed a dose-dependent increase in both Cmax and AUC with increasing oral P-LPHN4 dose, while Tmax remained unaffected. In conclusion, the developed posaconazole-loaded lipid-polymer hybrid nanoparticles (P-LPHN4) showed promising results in terms of enhanced drug release, stability, and bioavailability.

Orientation of Antibody Modified and Reacted on Carboxy-Functionalized Polystyrene Particle Revealed by Zeta Potential Measurement.

The comprehensive understanding of the orientation of antibodies on a solid surface is crucial for affinity-based sensing mechanisms. In this study, we demonstrated that the orientation of primary antibodies modified on carboxy-functionalized polystyrene (PS) particles can be analyzed using zeta potential behavior at different pH based on the combined Gouy-Chapman-Stern model and the acid dissociation of carboxy groups and antibodies. We observed that at low surface concentrations of the primary antibody, a side-on orientation was predominant. However, at higher concentrations (approximately 30000 antibodies per PS particle), the orientation shifted to an end-on type due to steric hindrance. Furthermore, the reaction mechanism of the secondary antibody exhibited pH-dependent behavior. At pH > 7, the zeta potential changes were attributed to the antibody-antibody reaction, whereas at pH < 7, adsorption of secondary antibody onto the PS particle was observed, leading to a change in the orientation of the primary antibody modified on the PS particle to an end-on type. The change in zeta potential due to secondary antibody binding indicated a detection limit of 37000 antibodies per PS particle. As a result, we revealed that the analysis of zeta potential behavior enables the evaluation of antibody orientation and the detection of zeptomole order antibodies. This study represents the first demonstration of this capability. We anticipate that the present concept and results will broaden the quantitative application of zeta potential measurements and have significant implications for research areas, including physical chemistry and analytical chemistry.

Participation of strong charge-assisted hydrogen bonds in interactions of dissolved organic matter represented by Suwannee River Humic Acid

Terrestrial dissolved organic matter (DOM) plays critical roles in many biotic and abiotic environmental reactions as well as in water treatment. Its structure is therefore of great interest. We examined dissolved Suwannee River Humic Acid (HA) to probe the potential participation of exceptionally strong, negative charge-assisted hydrogen bonds, (−)CAHB, in DOM cohesion and interaction with small weak acids using high performance size exclusion chromatography (HPSEC), transmission electron microscopy, zeta-pH curves, and pH drift experiments. The results support a previously proposed two-tier state of aggregation, in which tightly-knit primary particles (≤ ∼10 kDa) form larger secondary aggregates (up to micrometer in size). Evidence for (−)CAHB is gained through zeta potential changes and pH drift experiments. The primary particles interact with (−)CAHB-capable solutes (simple carboxylic acids and phosphate) but not (−)CAHB-incapable solutes. We identified disruption of intra-segmental and inter-molecular (−)CAHB leading to swelling and disaggregation, as well as formation of nouveau (−)CAHB with free groups on HA. The effects were solute-concentration dependent and greater at pH 5 than pH 6, consistent with CAHB theory. Phosphate induced the greatest shifts in the HPSEC molecular size distribution curves. The shifts were unaffected by prior stripping of innate polyvalent metals. We conclude that the (−)CAHB contributes to the cohesion of DOM, affecting its size and charge, and provides a means by which weak acid pollutants, nutrients, and natural compounds can interact with DOM. Such interactions have implications for the behavior of DOM in the environment, the fate and transport of anthropogenic pollutants, and the roles DOM play in water treatment technologies.

(Invited) Changes in Electric Double-Layer Structures Under Localized Surface Plasmon Excitation

For the visible light energy conversion, the localized surface plasmon resonance (LSPR), which is the collective oscillations of free electrons, should be promising. With the excitation of LSPR, the highly localized electric field generates in the vicinity of metal nanostructures. It is interesting that various unique photo-response properties, such as chemical reactions or molecular excitations, can be observed due to the enhancement of light-matter interaction.[1] To understand and control such mediated chemical reactions or electrochemical reactions, the precise understanding about the electrified interfaces of plasmonic nanostructures should be required.Especially in the electrochemical system, the electric double layer is formed due to the difference in electrochemical potential between the metal interface and solution. The study of the surface potential is important for the design of chemical reactions because the surface potential at the liquid-solid interface is dependent on the physical properties of the systems. The zeta potential which is the potential of the slipping surface near the Stern layer of the diffusion layer could provide such information. From this point of view, in this study, we investigated the electric double-layer structures through the examination of the zeta potential under LSPR excitation condition. To obtain the zeta potential, we have performed the streaming potential method using Au nanoisland structures under visible light illuminations to excite the LSPR. It was interesting that the zeta potential was drastically changes under the visible light illumination conditions. This zeta potential change indicates the changes in the electric double layer structures through the excitation of LSPR. Through the investigations of incident wavelength dependence or the substrate dependences, the effects for the LSPR excitations on the electric double layer structure have been revealed. The present work would provide the fundamental knowledge about the effect on the LSPR excitation at solid-liquid interfaces.[1] H. Minamimoto et al., Acc. Chem. Res., 2022, 55(6), 809.

A food for elders with dysphagia: Effect of sodium alginate with different viscosities on the gel properties of antarctic krill composite shrimp surimi

This study investigated the effects of sodium alginate (SA) with different viscosities on the physicochemical properties and structure of composite shrimp surimi gels made from Antarctic krill and Litopenaeus vannamei. Changes in texture, rheology, water status, thermal stability, chemical bonding, zeta potential, and microstructures of the gels were analyzed to explore their feasibility as food products for individuals with dysphagia. The addition of SA addition increased the chewiness, absolute value of zeta potential, WHC, and thermal stability of the composite shrimp surimi gels. Concurrently, it decreased the gel strength and the content of chemical bonds, such as ionic and hydrogen bonds, with these changes being more significant at higher SA viscosities. The water distribution analysis showed that increasing SA viscosity increased the content of immobilized water within the gels and stabilized the water. From the perspective of zeta potential and microstructure, higher SA viscosities significantly increased the absolute value of zeta potential, enhanced the electrostatic repulsion and spatial potential resistance, and resulted in larger microstructural gaps, which improved the moisture-trapping capacity and WHC of the gels. The microstructure was more homogeneous and continuous at an SA viscosity of 800 mPa s. International Dysphagia Dietary Standardization Initiative (IDDIS) testing showed that gels with added SA can be classified into Tier 6 dysphagia diets. These findings provide insights for developing nutritious dysphagia-suitable foods for elders.

Probing the effect of protein corona on SERS signals: insights from melamine detection in milk matrix

Matrix effects limit the application of surface-enhanced Raman scattering (SERS) technology in the field of food safety. This study elucidated it from the perspective of protein corona by employing a model system for melamine SERS detection in milk. Compared with the melamine standard solution, higher detection limits (1 mg/L and 10 mg/L) are observed in milk matrix. The melamine signal exhibits an 80% reduction in whey protein solution, suggesting that protein has a significant impact on SERS signals. The changes in particle size, zeta potential and UV–vis spectra indicate the AuNPs interact with whey protein. Forming protein corona inhibits the melamine-induced AuNPs aggregation, reducing the number of ‘hot spot’ and the adsorption of melamine on AuNPs (from 0.28 mg/L to 0.07 mg/L), which may be responsible for signal loss. The found matrix effect from protein corona provides new insights for developing strategies about reducing matrix effect in SERS application.

Oligoelectrolyte-mediated, pH-triggered release of hydrophobic drugs from non-responsive micelles: Influence of oligo(2-vinyl pyridine)-loading on drug-loading, release and cytotoxicity

pH-responsive polymeric micelles have been extensively studied for nanomedicine and take advantage of pH differentials in tissues for the delivery of large doses of cytotoxic drugs at specific target sites. Despite significant advances in this area, there is a lack of versatile and adaptable strategies to render micelles pH-responsive that could be widely applied to different payloads and applications. To address this deficiency, we introduce the concept of oligoelectrolyte-mediated, pH-triggered release of hydrophobic drugs from non-responsive polymeric micelles as a highly effective approach with broad scope. Herein, we investigate the influence of the oligoelectrolyte, oligo(2-vinyl pyridine) (OVP), loading and polymer molecular weight on the pH-sensitivity, drug loading/release and cytotoxicity of poly(ethylene glycol-b-ε-caprolactone) (PEG-b-PCL) micelles using copolymers with either short or long hydrophobic blocks (PEG4PCL4 and PEG10PCL10, respectively). The micelles were characterized as a function of pH (7.4 to 3.5). Dynamic light scattering (DLS) revealed narrow particle size distributions (PSDs) for both the blank and OVP-loaded micelles at pH 7.4. While OVP encapsulation resulted in an increase in the hydrodynamic diameter (Dh) (cf. blank micelles), a decrease in the pH below 6.5 led to a decrease in the Dh consistent with the ionization and release of OVP and core collapse, which were further supported by proton nuclear magnetic resonance (1H NMR) spectroscopy and UV–visible (UV–vis) spectrophotometry. The change in zeta potential (ζ) with pH for the OVP-loaded PEG4PCL4 and PEG10PCL10 micelles was different, suggesting that the location/distribution of OVP in the micelles is influenced by the polymer molecular weight. In general, co-encapsulation of drugs (doxorubicin (DOX), gossypol (GP), paclitaxel (PX) or 7-ethyl-10-hydroxycamptothecin (SN38)) and OVP in the micelles proceeded efficiently with high encapsulation efficiency percentages (EE%). In vitro release studies revealed the rapid, pH-triggered release of drugs from OVP-loaded PEG10PCL10 micelles within hours, with higher OVP loadings providing faster and more complete release. In comparison, no triggered release was observed for the OVP-loaded PEG4PCL4 micelles, implying a strong molecular weight dependency. In metabolic assays the drug- and OVP-loaded PEG10PCL10 micelles were found to result in significant enhancement of the cytotoxicity compared to drug-loaded micelles (no OVP) or other controls. Importantly, micelles with low OVP loadings were found to be nearly as effective as those with high OVP loadings. These results provide key insights into the tunability of the oligoelectrolyte-mediated approach for the effective formulation of pH-responsive micelles and pH-triggered drug release.

Nano-emulsification of Osmanthus essential oil: Characterizations, stability and molecular interactions explaining antibacterial activity

The practical usage of Osmanthus essential oil (OEO) in foods is limited due to its poor solubility in water, higher volatility, and instability. This research aimed to prepare OEO nano-emulsion (OEO-NE) by high-pressure homogenization technique and characterize its nano-form (particle size, zeta potential, structure, FTIR, and thermodynamic stability). The antibacterial activity of OEO was researched using network pharmacology and molecular docking. Furthermore, the antibacterial and antioxidant activities of OEO-NE and OEO were researched. The OEO-NE exhibited long-term storage stability compared to the OEO, with particle size changing to 40.90 nm ∼ 68.09 nm and zeta potential changing to −38.37 mV ∼ −35 mV over 31 storage days at 4 °C and 25 °C. Dihydro-β-ionone and linalool oxide showed better binding affinity for S. aureus TyrRS than E. coli 24 kDa. In addition, nano-emulsification effectively stabilizes the antibacterial and antioxidant activity of OEO. Therefore, OEO-NE is an effective strategy to enhance stability and bioavailability.

Low‐intensity continuous ultrasound effect on proliferation and morphology of fibroblast cells

AbstractRecently, the use of ultrasound (US) for triggering drug release to specific tissues was explored, but its direct effects on cells have not been thoroughly understood. For this reason, this study aimed to investigate the impact of US powers and US irradiation times on fibroblast cells (NIH‐3T3). The results showed that the diverse US settings had varying effects on cell proliferation and distribution in the polystyrene culture dish. Interestingly, at 10 W, 43 kHz with changing exposed time up to 30 min either stimulated or inhibited fibroblast cell growth after 24 and 72 h of cultivation compared to the control sample in the absence of US, while longer US exposure time led to a moderate reduction in cell quantity. Moreover, higher US levels of 20 and 30 W could cause an aggregation of cells and sublethal damage to the cells. Importantly, the morphology of fibroblast was changed from stellate‐shape to round‐shape under greater US powers. Elevated US power also influenced interactions between proteins and lipids, affecting the atomic and molecular charges, leading to changes in both zeta potential and pH of the dispensed cell solution.

Interaction, Surface Activity, and Application of Mixed Systems of Alcohol Ether Sulfate Anionic Surfactants with Multiple Ethylene Oxide Groups and Gemini Quaternary Ammonium Surfactant.

The surface activities and application properties for the mixtures of cationic surfactants tetramethylene-1,4-bis[N,N-bis(hydroxypropyl)-hexa/decyloxypropylammonium] bromide (GC10-P) and tetramethylene-1,4-bis[N,N-bis(hydroxyethyl)-hexa/decyloxypropylammonium] bromide (GC10-E) and anionic surfactant isomeric sodium fatty alcohol ether sulfates (iso-AE9S) were investigated using both the tensiometry and the conductometry. The interaction parameters and thermodynamic micellization parameters of GC10-P/iso-AE9S and GC10-E/iso-AE9S mixtures were evaluated by Clint-Rubingh and Motomura theoretical models. When the mole fraction of α1 for GC10-P/iso-AE9S mixed system was 0.2, the critical micelle concentration (CMC) reached a minimum of 1.61 × 10-4 mol/L, and the minimum critical micelle concentration of the GC10-E/iso-AE9S mixed system is 2.67 × 10-5 mol/L at α1 = 0.6. The CMC value of the mixed system is 1-2 orders of magnitude lower than that of any single component. The results indicate that the synergistic effects of the investigated mixed systems (evaluated by βm) are in order of GC10-P/iso-AE9S < GC10-E/iso-AE9S, with maximum βm values of -17.98 and -9.78, respectively. The change in zeta potential indicates that the poly(ethylene oxide) chain has weakened the charge density of the hydrophilic headgroup of the anionic surfactant. The interfacial tension at the oil-water interface in the mixed system of anionic/cationic surfactants is lower than that of any single component, exhibiting a higher interfacial activity. The mixed system exhibits a decreased contact angle and superior wetting ability over any single component, and it also enhances foam performance, emulsification performance, and degreasing performance.

Electrophoretic deposition of ceramic coatings from modified suspensions of microsized powders of doped BaCeO3 and BaCeO3–BaZrO3 proton-conducting electrolytes

This work investigates the influence of molecular iodine introduced as a charging agent into the suspensions based on the BaCe0.8Sm0.19Cu0·01O3 (BCSCuO), BaCe0·5Zr0·3Y0.1Yb0.1O3-δ (BCZYYbO) and BaCe0.89Gd0.1Cu0·01O3-δ (BCGCuO) proton-conducting electrolytes at concentrations up to 1.0 g/L on their electrokinetic properties. The peculiarities of changes in zeta potential, pH, conductivity of the suspensions, the thickness and morphology of the coatings depending on the amount of iodine added are determined. It has been established that when the iodine concentration increases to 1 g/L, the electrical charge of the particles and the sign of the zeta potential undergo a reversal. Additionally, there is a natural decrease in the pH value towards the acidic side and a corresponding increase in the suspension conductivity. The research has demonstrated that in the suspension with a high iodine content (1 g/L), cathodic and anodic deposition can occur simultaneously under electrophoretic deposition (EPD) conditions at low voltage values (below 8 V). However, as the voltage increases, only cathodic deposition occurs. Therefore, the impact of altering the type of the EPD is threshold in nature relative to the magnitude of the EPD voltage. It has been shown that in order to practically implement EPD of ceramic coatings from modified suspensions of microsized powders of doped BaCeO3 and BaCeO3–BaZrO3 proton-conducting electrolytes, it is necessary to select a small amount of added iodine (0.1–0.2 g/L) to initiate a stable deposition process and to ensure continuity and uniformity of the coatings. This article discusses possible mechanisms of zeta potential inversion, electrophoretic mobility, and the EPD nature under conditions of high concentrations of iodide ions in the suspension bulk. The experiments have demonstrated the viability of the EPD process for the formation of a uniform BCSCuO coating (∼10 μm) on a supporting NiO–BCSCuO anode substrate using an iodine-modified suspension. This coating was subsequently sintered into a dense ceramic film at 1450 °C. In addition to the fundamental significance, the study results have implications for the practical use to improve and simplify the thin-film SOFC technology.

Unraveling the Impact of Ethylenediaminetetraacetic Acid Chelating Agents on the Oil Recovery Processes: An Insight into Its Role in Fluid-Fluid and Rock-Fluid Interactions.

In recent years, chelating agents have garnered increasing attention due to their unique capabilities in addressing challenges associated with chemically enhanced oil recovery materials. Most previous studies have primarily focused on examining the influence of chelating agents on rock-fluid interactions. However, their effects on fluid-fluid interactions, specifically on interfacial tension (IFT) characteristics under various conditions, remain relatively unknown. This study investigates the effect of crucial reservoir parameters on the performance of ethylenediaminetetraacetic acid (EDTA) chelating agents in the IFT between crude oil and brine. Furthermore, the study evaluated the impact of varying concentrations of this agent on rock wettability alteration, zeta potential, and spontaneous imbibition. The results illustrated that introducing EDTA at high concentration into seawater (SW) solution reduced the IFT by 85%. Additionally, while higher pH levels contributed to IFT reduction due to increased hydroxyl ions, excessive salinity levels resulted in elevated IFT. Raising the temperature from 30 to 75 °C further decreased the IFT, changing the IFT for optimal EDTA concentration from 20.43 to 2.56 mN/m (∼88% reduction). The changes in zeta potential and contact angle measurements indicated that solutions of 5 and 7 wt % EDTA shifted rock wettability from oil-wet to strongly water-wet, resulting in the wettability alteration index of 1.01 and 1.02, respectively. Inductively coupled plasma analysis, on the other hand, revealed substantial chelation of metal ions from both the solution and rock when EDTA was added to the rock/SW system. This resulted in a significant increase in Ca2+ ions and a decrease in Mg2+ ions, attributed to the multi-ion exchange phenomenon.

Development of quantitative structure activity relationships (QSARs) for predicting the aggregation of TiO2 nanoparticles under favorable conditions

This study developed multi-linear regression (MLR) quantitative structure-activity relationships (QSARs) to predict n-TiO2 aggregation in the presence of high concentrations of representative emerging organic contaminants (EOCs), which presented favorable conditions to interaction with n-TiO2. The largest diameter change (Δ 517 nm at 0 h and Δ 1164 nm at 12 h) of n-TiO2 was observed by estrone, while the smallest diameter change (Δ −114 nm at 0 h and – 4 nm at 12 h) was observed by lincomycin during experimental periods. In addition, the zeta potential changes of n-TiO2 were observed that the biggest changes were observed by 17β-estradiol (−1.3 mV) and alachlor (−10.02 mV) at 0 h, while 17β-estradiol (−1.31 mV) and pendimethalin (−11.4 mV) showed the biggest changes at 12 h comparing to control. These changes of n-TiO2 diameter and zeta potential may implicate the effects of unique physico-chemical properties of each EOC on the surface modification of n-TiO2. Based on the interaction results, this study investigated the QSARs between n-TiO2 aggregation and physico-chemical descriptors of EOCs with 7 representative descriptors (pKa, Cw, log Kow, M.W., P.S.A., M.V., # of HBD) for predicting n-TiO2 aggregation rate kinetics at 0 h and 12 h by applying MATLAB statistical methods (model 1 - fitlm and model 2 - stepwiselm). In a model 1, QSARs showed the good coefficients of determination (R2 = 0.92) at 0 h and (R2 = 0.87) at 12 h with 7 descriptors. In a model 2, QSARs showed the goodness of fit of a model (R2 = 0.9998) with 8 descriptors (pKa, Cw, log Kow, M.W., P.S.A., M.V., #HBD, pKa⋅#H bond donors) at 0 h, while QSARs showed the coefficients of determination (R2 = 0.68) with 2 descriptors (pKa, M.V.) at 12 h. Particularly, we observed that some descriptors of EOCs such as pKa and # of HBD having polarity have more influenced on the n-TiO2 aggregation rate kinetics. Our developed QSARs demonstrated that the 7 descriptors of EOCs were significantly effective descriptors for predicting n-TiO2 aggregation rate kinetics in favorable conditions, which may implicate the complexity interactions between heterogeneous surfaces of n-TiO2 and physico-chemical properties of EOCs.