Low Zeta Potential Research Articles

Disinfection of Escherichia coli by Mixing with Bulk Ultrafine Bubble Solutions

For potential use in wastewater management and health control, this study investigates the disinfection effectiveness of bulk ultrafine bubbles (UFBs) with different bubble number densities and solution pH. Initially, neutral UFB solutions with different bubble concentrations were mixed with E. coli suspension for 120 min, but these solutions did not achieve sterilization. The bubble number density did not affect the disinfection ability of the neutral solution. Next, the pH of the UFB solutions was fixed at 5, 7, and 9. When mixed with E. coli suspension, the acidic UFB solutions reduced the colony counts by 12% after 30 min of cultivation and by 66% after 60 min of cultivation. The colony counts increased slightly in neutral and significantly in alkaline UFB solutions. The acidic UFB solutions had lower zeta potentials and smaller number densities after cultivation, implying that the number density reduced through bubble coalescence rather than increased by bubble collapse. Additionally, the UFBs exhibited insignificant fluorescence intensity, suggesting that the colony counts increased by generated ∙OH radicals. This study revealed that the effect of UFB on E. coli significantly depends on the solution pH. Further, an acidified solvent achieves a bactericidal effect, whereas a neutral or alkaline solvent enhances the growth effect. This result is important when using actual wastewater.

Micellar Curcumin Substantially Increases the Antineoplastic Activity of the Alkylphosphocholine Erufosine against TWIST1 Positive Cutaneous T Cell Lymphoma Cell Lines.

Cutaneous T-cell lymphoma (CTCL) is a rare form of cancer with local as well as systemic manifestations. Concomitant bacterial infections increase morbidity and mortality rates due to impaired skin barrier and immune deficiency. In the current study, we demonstrated that the in vitro anti-lymphoma potential of erufosine is diminished by TWIST1 expression and micellar curcumin substantially increases its antineoplastic activity. Pharmacokinetic analysis showed that the micellar curcumin (MCRM) used in our study was characterized by low zeta potential, slow release of curcumin, and fast cell membrane penetration. The combination ratio 1:4 [erufosine:MCRM] achieved strong synergism by inhibiting cell proliferation and clonogenicity. The combined antiproliferative effects were calculated using the symbolic mathematical software MAPLE 15. The synergistic combination strongly decreased the expression of TWIST1 and protein kinase B/Akt as proven by western blotting. Significant reductions in NF-κB activation, induction of apoptosis, and altered glutathione levels were demonstrated by corresponding assays. In addition, the synergistic combination enhanced the anti-staphylococcal activity and prevented biofilm formation, as shown by crystal violet staining. Taken together, the above results show that the development of nanotechnological treatment modalities for CTCL, based on rational drug combinations exhibiting parallel antineoplastic and antibacterial effects, may prove efficacious.

Fabrication and Characterization of Eco-Friendly Polyelectrolyte Bilayer Films Based on Chitosan and Different Types of Edible Citrus Pectin.

The eco-friendly polyelectrolyte bilayer films were prepared by layer-by-layer (LBL) casting method using chitosan (CS) and four types of edible citrus pectin as film substrates. The results showed that the polyelectrolyte bilayer films exhibited excellent comprehensive properties. Furthermore, the interaction between CS and pectin was closely related to the degree of methyl-esterification (DM), molecular weight (Mw), and zeta potential of pectin. The low DM, Mw, and high zeta potential of the low methyl-esterified pectin (LM) resulted in a denser internal structure of the bilayer film, stronger UV shielding performance, and stronger gas barrier ability. The high DM and Mw of the high methyl-esterified pectin (HM) endow the bilayer film with stronger mechanical properties, thermal stability, and antifogging property. The microstructural and spectroscopic analysis showed that there are hydrogen bonds and electrostatic interactions between the layers. Overall, the developed CS-pectin polyelectrolyte bilayer films provided potential applications for food bioactive packaging.

Surface-charge-mobility-modulated electrokinetic energy conversion in graphene nanochannels

In recent years, electrokinetic energy conversion for pressure-driven flow through hydrophobic nanochannels has attracted increasing attention from numerous researchers. However, the reported electrokinetic energy conversion efficiencies may be overestimated owing to neglect of the surface charge mobility effect of hydrophobic nanochannels. In fact, both the effective slip length and the induced streaming potential are influenced by the surface charge mobility. In this paper, a theoretical model for electrokinetic energy conversion through graphene nanochannels is developed with consideration of the influence of surface charge mobility. The surface charge density σs varies from very low to considerably high. A numerical solution to the electric potential is obtained by using the finite difference method. We also derive analytical solutions for two limiting cases, namely, the case with a low zeta potential and the case without considerable electric double layer overlap. Our results reveal that consideration of the surface charge mobility leads to a 44% reduction in the maximum conversion efficiency. The predicted maximum efficiency is approximately 5.9% at σs = −0.0162 C/m2. Our results may prove useful for predicting and optimizing the electrokinetic conversion efficiency in hydrophobic nanochannels.

Gum Acacia- and Gum Tragacanth-Coated Silver Nanoparticles: Synthesis, Physiological Stability, In-Vitro, Ex-Vivo and In-Vivo Activity Evaluations

The current research article presents development, characterization, stability, antimicrobial activity, antispasmodic activity and antidiarrheal activity of silver nanoparticles synthesized and stabilized by polymeric coating of gum tragacanth solution. The nanoparticles were developed by a chemical reduction of silver nitrate. The reducing sugars and polysaccharides-based natural polymers such as gum acacia, gum tragacanth, alginates and cellulose derivatives were investigated as both reducing agents and stabilizers of silver nanoparticles. Influence of the molar concentration of silver nitrate, type and concentration of reducing agent on the formation and stability of silver nanoparticles have been investigated in detail. The stability or aggregation behavior of silver nanoparticles when diluted with simulated gastric fluid, simulated intestinal fluid and phosphate buffer saline were investigated to understand the influence of biological fluids on the stability of silver nanoparticles. SNPs in basic buffers were found to be more stable compared to those in acidic buffers. Silver nanoparticles were characterized by UV absorption spectrometry, particle size and zeta potential analyzer, FTIR spectroscopy, differential scanning calorimetry, X-ray diffraction and atomic force microscopy. SNPs were found spherical within 2.5–4 nm as per atomic force microscopic studies. The silver nanoparticles developed from gum tragacanth were better and more stable than those produced by gum acacia. The smaller particle size, low polydispersity index and high zeta potential resulted in silver nanosuspensions stable over a period of six months. The silver nanoparticles were found to exhibit significant antimicrobial, antispasmodic and antidiarrheal activities.

Review and Analysis of Electro-Magnetohydrodynamic Flow and Heat Transport in Microchannels

This paper aims to develop a review of the electrokinetic flow in microchannels. Thermal characteristics of electrokinetic phenomena in microchannels based on the Poisson–Boltzmann equation are presented rigorously by considering the Debye–Hückel approximation at a low zeta potential. Several researchers developed new mathematical models for high electrical potential with the electrical double layer (EDL). A literature survey was conducted to determine the velocity, temperature, Nusselt number, and volumetric flow rate by several analytical, numerical, and combinations along with different parameters. The momentum and energy equations govern these parameters with the influences of electric, magnetic, or both fields at various preconditions. The primary focus of this study is to summarize the literature rigorously on outcomes of electrokinetically driven flow in microchannels from the beginning to the present. The possible future scope of work highlights developing new mathematical analyses. This study also discusses the heat transport behavior of the electroosmotically driven flow in microchannels in view of no-slip, first-order slip, and second-order slip at the boundaries for the velocity distribution and no-jump, first-order thermal-slip, and second-order thermal-slip for the thermal response under maintaining a uniform wall-heat flux. Appropriate conditions are conferred elaborately to determine the velocity, temperature, and heat transport in the microchannel flow with the imposition of the pressure, electric, and magnetic forces. The effects of heat transfer on viscous dissipation, Joule heating, and thermal radiation envisage an advanced study for the fluid flow in microchannels. Finally, analytical steps highlighting different design aspects would help better understand the microchannel flow’s essential fundamentals in a single document. They enhance the knowledge of forthcoming developmental issues to promote the needed study area.

Hawthorn Juice Simulation System for Pectin and Polyphenol Adsorption Behavior: Kinetic Modeling Properties and Identification of the Interaction Mechanism.

The interaction between polyphenols and polysaccharides plays an important role in increasing the turbidity stability of fruit juice and improving unpleasant sensory experiences. The binding adsorption behavior between hawthorn pectin (HP) and polyphenols (epicatechin and chlorogenic acid) accorded with the monolayer adsorption behavior driven by chemical action and were better fitted by pseudo-second order dynamic equation and Langmuir model. The HP binding sites (Qm) and adsorption capacity (Qe) to epicatechin were estimated at 75.188 and 293.627 μg/mg HP, respectively, which was about nine and twelve times higher than that of chlorogenic acid. The interaction between HP and polyphenols exhibited higher turbidity characteristics, particle size and lower zeta potential than epicatechin and chlorogenic acid alone. Meanwhile, according to Fourier Transform Infrared Spectroscopy (FT-IR) analysis, it could be speculated that the interaction between HP and polyphenols resulted in chemical combination. Moreover, ΔH < 0 and TΔS < 0, which indicated that the interaction between HP and polyphenols was mainly driven by hydrogen bonds and van der Waals forces.

Impact of carrier oil on interfacial properties, CBD partition and stability of emulsions formulated by whey protein or whey protein-maltodextrin conjugate

Oil phase composition may affect properties of the oil-water interface and the characteristics of fabricated emulsions. This study aims to investigate the impacts of varying oil phase composition of medium-chain triglyceride (MCT) and long-chain triglyceride (LCT) at volume ratios ranging from 0/100 to 100/0 on biomechanical properties of cannabidiol (CBD)-loaded emulsions stabilized by whey protein (WP) or whey protein-maltodextrin (WP-MD) conjugate. Interfacial tension, surface protein load, droplet size and zeta potential of emulsions significantly increased with increased LCT ratio (p < 0.05). Partition analysis indicated that CBD was mainly located in the oil phase, and its presence was enhanced from 90% to 96% by increasing the LCT proportion. Increased LCT ratio was not beneficial for the physical or oxidation stability of emulsions, but it did increase CBD retention during an accelerated 16-day storage test (55 °C). At all oil compositions, WP-MD stabilized emulsions showed higher surface protein load, smaller particle size, narrower size distribution, lower zeta potential, better protection towards CBD, and improved oxidation stability in comparison with those emulsified with WP alone. These results provide insight into the influences of carrier oil on emulsion characteristics and offer guidance for the rational selection of suitable oil phases for emulsion-based delivery systems.

Transferrin-functionalized liposomes loaded with vitamin VB12 for Alzheimer's disease therapy

Despite the efforts of the pharmaceutical and research sectors, Alzheimer’s disease (AD) remains incurable, imposing the demand for new effective strategies. Vitamin B12 (VB12) has aroused interest due to its in vitro anti-amyloidogenic properties. However, the high molecular weight and hydrophilicity of VB12 are the main obstacles to its clinical application by hindering its passage through the blood–brain barrier (BBB). In recent years, drug delivery systems (DDSs) capable of transporting molecules across the BBB have gained attention for their effective brain delivery. In this work, VB12-loaded liposomes functionalized with transferrin (Tf) were produced, envisaging the dual-targeting of VB12 to the BBB and neuronal cells, due to the overexpression of Tf receptors in these cells. The produced liposomes presented sizes smaller than 200 nm, with low polydispersity and neutral zeta potential, being suitable for brain delivery. The nanoparticles exhibited an adequate encapsulation efficiency, a sustained release of VB12 for 9 days, and physical stability at storage conditions for up to 2 months. The developed nanosystem was capable of delaying the formation of Aβ fibrils and disrupting mature fibrils, highlighting its great potential for the prevention and treatment of AD.

Development and Evaluation of Elaeagnus rhamnoides (L.) A. Nelson Oil-Loaded Nanostructured Lipid Carrier for Improved Skin Hydration

Sea buckthorn (SB) (Elaeagnus rhamnoides (L.) A. Nelson) is rich in flavonoids, phenolic compounds, anthocyanins, carotenoids, and phytosterol. Its phytochemicals exhibit various biological activities, such as antioxidant, immunomodulatory and anti-carcinogenic activities. SB also helps prevent the development of wrinkles and protects the skin’s surface from UV rays. The purpose of the present study was to develop and characterize an SB oil (SBO)-loaded nanostructured lipid carrier (NLC) for improved skin hydration. The response surface methodology (RSM) and central composite design (CCD) were employed to optimize the influencing factors (wax percentage, surfactant percentage, and PEG400 percentage in the surfactant) to achieve the desirable qualities in SBO-NLCs. The optimum (minimum) size of SBO-NLCs (105.26 nm) was obtained with a combination of 2.5% wax, 7.5% surfactant, and 30% PEG400 in the surfactant. A narrow polydispersity index (PDI; 0.16), relatively low zeta potential (ZP; −15.63 mV), and high entrapment efficiency (EE; 90.88%) were observed in this study. Reduced quadratic and reduced 2FI models were adapted to predict conditions to attain the optimum size and PDI of SBO-NLCs, respectively. ZP and EE were predicted with the help of a reduced cubic model. All of the predicted models were statistically significant. Differential scanning calorimetry results suggested that the SBO-NLCs had less crystallinity and therefore reduced the rate of drug expulsion from the inner core of the NLCs. A noticeable level of occlusion effect was observed in the SBO-NLCs. The SBO-NLCs showed a faster vitamin E (biomarker for the drug) release rate into the skin within 24 h, and the released vitamin E level after 48 h was significantly higher than that for the free SBO. Additionally, SBO-NLCs delivered vitamin E into the inner skin significantly (22.73 ± 1.67 µg/cm2 of skin). In conclusion, the SBO-NLC is a potential delivery system that can be used to prevent skin water loss and improve skin hydration. Further investigations, such as drug stability and safety evaluations, are required prior to commercialization for human use.

Biocompatibility and colorectal anti-cancer activity study of nanosized BaTiO3 coated spinel ferrites

In the present work, different nanoparticles spinel ferrite series (MFe2O4, Co0.5M0.5Fe2O4; M = Co, Mn, Ni, Mg, Cu, or Zn) have been obtained via sonochemical approach. Then, sol–gel method was employed to design core–shell magnetoelectric nanocomposites by coating these nanoparticles with BaTiO3 (BTO). The structure and morphology of the prepared samples were examined by X-ray powder diffraction (XRD), scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), high-resolution transmission electron microscope (HR-TEM), and zeta potential. XRD analysis showed the presence of spinel ferrite and BTO phases without any trace of a secondary phase. Both phases crystallized in the cubic structure. SEM micrographs illustrated an agglomeration of spherical grains with nonuniformly diphase orientation and different degrees of agglomeration. Moreover, HR-TEM revealed interplanar d-spacing planes that are in good agreement with those of the spinel ferrite phase and BTO phase. These techniques along with EDX analyses confirmed the successful formation of the desired nanocomposites. Zeta potential was also investigated. The biological influence of (MFe2O4, CoMFe) MNPs and core–shell (MFe2O4@BTO, CoMFe@BTO) magnetoelectric nanocomposites were examined by MTT and DAPI assays. Post 48 h of treatments, the anticancer activity of MNPs and MENCs was investigated on human colorectal carcinoma cells (HCT-116) against the cytocompatibility of normal non-cancerous cells (HEK-293). It was established that MNPs possess anti-colon cancer capability while MENCs exhibited a recovery effect due to the presence of a protective biocompatible BTO layer. RBCs hemolytic effect of NPs has ranged from non- to low-hemolytic effect. This effect that could be attributed to the surface charge from zeta potential, also the CoMnFe possesses the stable and lowest zeta potential in comparison with CoFe2O4 and MnFe2O4 also to the protective effect of shell. These findings open up wide prospects for biomedical applications of MNPs as anticancer and MENCs as promising drug nanocarriers.

Structural and rheological properties of nanocellulose with different polymorphs, nanocelluloses I and II, prepared by natural deep eutectic solvents from sugarcane bagasse

Sugarcane bagasse, a sugar industry waste, has plentiful cellulose. The present work was aimed to prepare the quality nanocellulose with different polymorphs, nanocelluloses I (NC-I) and II (NC-II) utilizing natural deep eutectic solvents (choline chloride and oxalic acid dihydrate) combined with mechanical treatment from purified cellulose (celluloses I and II), which were prepared from sugarcane bagasse, and to further compare the structural and rheological properties of NC-I and NC-II. Results showed that the yields of NC-I and NC-II were 73.66 ± 0.11 % and 75.15 ± 0.08 %, respectively. Morphology indicated that NC-I had a needle-like appearance with a length of 769.9 ± 76.4 nm and a width of 4.9 ± 1.3, while NC-II displayed a rod-like profile with a smaller size (length: 196.3 ± 50.1 nm; width: 14.9 ± 3.8 nm). Structural characterization revealed that both NC-I and NC-II had high purity, good thermal stability (>300 °C) and high crystallinity (85.5 % and 86 %, respectively). Rheological and zeta potential properties revealed that NC-I suspension had bigger shear resistance, viscoelasticity and lower zeta potential, resulting in better storage stability compared with NC-II suspension. Therefore, the NC-I and NC-II with different characteristics may have potential applications in multiple fields, such as the food, pharmaceutical, and chemical industry.

Effect of Ce-Doping on Microstructure and Adsorption- Photodegradation Behaviors of the Hydrothermally-Synthesized TiO2 Nanotubes

Ce-doped TiO2 nanotubes (Ce-TNTs) were synthesized by a hydrothermal method to obtain high-efficiency adsorption and photodegradation abilities for methylene blue (MB) dye. The transmission electron microscope (TEM), X-ray diffractimeter (XRD), nitrogen adsorption, X-ray photoelectron spectrum (XPS), and photodegradation tests were used to characterize the morphology, microstructure, ionic valance, and degradation behaviors of the TNTs. Results show that the Ce-doped TNTs are composed of anatase tubulars with an inner-hole diameter of 5 nm, outer diameter of 10–15 nm, length of several hundred nanometers, and a small amount of CeO2 nanoparticles. Ce3+ and Ce4+are dissolved in the anatase crystals, the ratio of which increases with an increase in Ce addition. Ce-doping yields a higher amount of surface oxygen, which results in a strong physical and chemical adsorption to the cationoid MB. 2.5 mol% Ce-doping produces the largest specific surface area, porosity, and photoabsorption threshold and the lowest Zeta potential, yielding the highest adsorption efficiency and photocatalytic ability even under sunlight irradiation.

Settling of Iron and Aluminum Particles in Acid Solutions for Acid Drainage Remediation

Mineral processing is intensive in water usage. Unfortunately, a large portion of this valuable asset is contaminated by toxic species that leach from tailings or mineral ore, leading to the formation of acid drainage. Water from acid drainages can still be recovered by passive environmentally friendly treatments. An underestimated passive treatment is the settling of harmful metals, such as iron and aluminum. In this sense, floc settling from acid drainage has not been well studied. The objective of this work is to research the phenomena governing iron and aluminum floc settling in acid drainage, particularly, the chemical conditions that promote settling. The settling velocity of iron and aluminum flocs was studied in a column at different pH and iron/aluminum concentrations. Stability was studied through zeta potential. According to the results, iron flocs settle faster than aluminum and aluminum+iron (mixed) flocs, and a lower pH promotes a higher settling velocity and greater floc stability, which a lower zeta potential (which favors aggregation) allows for. The results improve the understanding of the interactions between the chemical and physical processes involved in floc settling, which, in turn, can improve the optimization of water treatment design. Future experiments must include particle size distribution, floc porosity, and effective particle density of iron and/or aluminum particles in acid waters.

A Personalized Electronic Tattoo for Healthcare Realized by On-the-Spot Assembly of an Intrinsically Conductive and Durable Liquid-Metal Composite.

Conventional electronic (e-) skins are a class of thin-film electronics mainly fabricated in laboratories or factories, which is incapable of rapid and simple customization for personalized healthcare. Here a new class of e-tattoos is introduced that can be directly implemented on the skin by facile one-step coating with various designs at multi-scale depending on the purpose of the user without a substrate. An e-tattoo is realized by attaching Pt-decorated carbon nanotubes on gallium-based liquid-metal particles (CMP) to impose intrinsic electrical conductivity and mechanical durability. Tuning the CMP suspension to have low-zeta potential, excellent wettability, and high-vapor pressure enables conformal and intimate assembly of particles directly on the skin in 10 s. Low-cost, ease of preparation, on-skin compatibility, and multifunctionality of CMP make it highly suitable for e-tattoos. Demonstrations of electrical muscle stimulators, photothermal patches, motion artifact-free electrophysiological sensors, and electrochemical biosensors validate the simplicity, versatility, and reliability of the e-tattoo-based approach in biomedical engineering.

Target selectivity of cholesterol-phosphatidylcholine liposome loaded with phthalocyanine for breast cancer diagnosis and treatment by photodynamic therapy

This study investigated the ability of cholesterol-phosphatidylcholine liposomes loaded with chloride aluminum phthalocyanine (CL-AlClPc) to discriminate between healthy (MCF-10A) and neoplastic (MCF-7 and MDA-MB-231) breast cells for breast cancer diagnosis and treatment by photodynamic therapy (PDT) using a new drug delivery system consisting of CL-AlClPc. When PDT treatment was applied at an energy fluence of 700 mJ/cm², CL-AlClPc was more cytotoxic to neoplastic cells than to healthy breast cells because CL-AlClPc was better internalized by the tumor cells. An even higher fluorescence signal is expected for neoplastic cells during clinical treatment than for healthy cells, which will be useful for precise and targeted tumor cell detection. CL-AlClPc also facilitated better drug distribution and targeting of essential organelles inside the cells. This selectivity is critical for future in vivo diagnosis and treatment; it prevents side effects because it prioritizes tumor cells and tissues instead of healthy ones. The CL-AlClPc system designed herein had a small size (150 nm), low zeta potential (-6 mV), low polydispersity (0.16), high encapsulation rate efficiency (82.83%), and high shelf stability (12 months).

Behavior of Silver Nanoparticles in Chlorinated Lettuce Wash Water

Use of silver nanoparticles (Ag NPs) in pesticides may lead to residual levels in food crops, thus raising food safety and environmental concerns. Because little is known about Ag NP behavior in wash water during typical commercial washing of fresh produce, this study assessed the temporal changes in Ag NP behavior when exposed to 2 to 100 mg/L free chlorine (Cl2) in simulated lettuce wash water for up to 10 days. Aggregate size and zeta potential of Ag NPs (5 mg/L) were evaluated in the presence and absence of dissolved lettuce extract (DLE, 0.1%), with Ag NPs in deionized water serving as the control treatment. In the presence of chlorine, greater aggregation of Ag NPs occurred over time (49 to 431 nm) compared with the control treatment (P < 0.05). Lower zeta potentials (-39 to -95 mV) were observed in the chlorine-only treatments, likely due to the formation of AgCl particles. Larger aggregates and lower zeta potentials were also observed in DLE (84 to 273 nm and -28 to -32 mV, respectively), as compared with the control treatment. After 7 to 10 days, larger aggregates were seen in the chlorine-only treatments as compared with the DLE treatments, despite lower zeta potentials, probably facilitated by nucleation and crystal growth of AgCl. Transmission electron microscopy with energy dispersive spectroscopy confirmed the formation of AgCl-Ag NP composite particles with chlorine and the embedding of AgCl and Ag NPs in the DLE matrix. Thus, DLE might stabilize and protect Ag NPs from chlorine. These findings indicate that chlorine and plant-released organic material can substantially change the behavior of Ag NPs, which may, in turn, impact both removal from fresh-cut produce during washing and their environmental fate.

Thermal analysis of micropolar fluid flow driven by electroosmosis and peristalsis in microchannel

Thermo-micropolar fluids contain small conductive particles which would be useful for drug delivery and localized heating. Considering the importance of the special fluid model (micropolar fluids), a mathematical model is formulated to analyse the heat transfer in electroosmotic flow of thermo-micropolar fluid in curved microchannel. A curvilinear coordinate system is adopted to describe the curved microchannel which is propagated by peristaltic pumping and generate the pressure gradient in addition to electroosmotic force. Eringen’s micropolar theory is employed to introduce the conservation of mass, linear momentum, angular momentum, and energy to model the problem. Numerical solutions are computed for low zeta potential and low Reynolds number using Mathematica NDSolver. The effects of microchannel curvature, electrokinetic, zeta potential, micropolar parameter and viscosities (shear and vortex viscosities) ratio on velocity fields, pressure gradient, temperature, contour of stream lines, shear stress isotherms and heat transfer coefficient are examined to provide a parametric analysis. Numerical results reveal that the pressure has slight deviation with wall curvature however the pressure changes significantly with variation in coupling number and electric field. Further, the linear and angular velocities of the micropolar fluid could be controlled by the electrokinetic phenomena.

Encapsulation of curcumin within oil-in-water emulsions prepared by premix membrane emulsification: Impact of droplet size and carrier oil on the chemical stability of curcumin

Oil-in-water emulsions containing curcumin with different droplet sizes were produced by premix membrane emulsification with different carrier oils: tributyrin (short chain triglycerides, SCT), medium chain triglycerides (MCT) and corn oil (long chain triglycerides, LCT). The influence of carrier oil type and droplet size on the physical stability, chemical stability of curcumin and lipid oxidation stability of emulsions were investigated. Turbiscan results indicated that the physical stability of emulsions was related to both carrier oils and emulsion droplet sizes. The oil type and droplet size of emulsions stored at 25 °C showed limited effect on the stability of curcumin, but significantly affected the stability of curcumin at 55 °C. Chemical stability of curcumin decreased with the decrease of emulsion droplet sizes. For each droplet size emulsions, the stability of curcumin decreased in the order SCT > MCT > LCT. Moreover, the lipid oxidation in LCT-based emulsions resulted in lower zeta potential of droplets, which was independent of emulsion droplet sizes. The presence of curcumin improved the oxidative stability of emulsions.

Experimental evaluation of the surfactant adsorptions performance on coal particles with different properties

The prevalence of Coal Workers’ Pneumoconiosis (CWP) increased with the increasing coal production. Currently, water spray is a commonly used method to control coal dust in underground coal mines. However, coal dust is well known for its hydrophobic property. Due to this, it is challenging in underground mines to suppress coal dust concentration to regulatory limits, thus, thousands of miners are under the threat of CWP caused by the high coal dust concentration. Surfactants aid water spray are believed an effective method to lower coal dust concentration. In this study, zeta potential and adsorption of three types of surfactants on coal particles with different ranks and particle sizes were studied. It was confirmed that the coal surface was negatively charged and the zeta potential of coal particles was changed based on the addition of surfactant type. In SDBS and CTAB, the lower rank coal particles showed lower zeta potential and the finer coal particles possessed the larger zeta potential, while opposite results were found in TX100. The lignite adsorbed more SDBS and less TX100 than subbituminous and anthracite, but anthracite adsorbed the most amount CTAB at a higher concentration. The finer coal particles adsorbed the more surfactant amount for all the surfactants at each concentration. Increasing temperature help to improve all the surfactant adsorption capacity but failed to lift all the coal particles’ zeta potential at the tested surfactant concentrations. Adding salts increased the SDBS adsorption but no obvious improvement was found for the other two surfactants.