•SF delays C3A hydration at 30%/86% gypsum while promotes it at 10% gypsum.•Delaying effects of SF is caused by the electrostatic interaction.•SF can adsorb Ca2+ and Ca-S ion complexes which will ...weaken the effects of gypsum.
Silica fume is a key component of high-performance concrete due to the physicochemical influences on cement hydration and the hardening process. Despite its importance, the effects of silica fume on C3A-gypsum systems hydration have been poorly studied. This study was carried out to fill this gap, and results suggested that the hydration was greatly affected by the electrostatic feature of silica fume and the sulfate degree in different systems. In poorly sulfated condition (10 wt% gypsum), silica fume promoted the precipitation of hydrates (monosulfoaluminate and katoite) and chemical shrinkage due to the adsorption of silica fume on the surface of hydrates acting as nucleation seeds. However, in the properly and actually ordinary Portland cement sulfated conditions (30 wt% and 86 wt% gypsum), a delayed precipitation of ettringite was found in silica fume-added samples. An increasing zeta potential result suggested that the negatively-charged silica fume could adsorb the positively-charged Ca-S ion complexes (ascribing to the retardation on C3A hydration) and thus weaken the hydration inhibition effect of sulfate on C3A and limited the formation of hydrates. It is believed that these findings could fulfill a better understanding of the role of silica fume in modern concrete.
Heavy metal ions are highly toxic and widely spread as environmental pollutants. New strategies are being developed to efficiently remove these toxic ions. Herein, we use the intrinsic advantages of ...metal-organic frameworks (MOFs) and develop a porous Zn(ii)-based MOF decorated with O
groups for the removal of Pb
. Benefiting from its multiple porosity, sufficient adsorption sites and strong affinity, the activated MOF material exhibits an ultrahigh Pb
uptake capacity (616.64 mg g
), surpassing all those of reported MOF adsorbents. Moreover, it can selectively capture Pb
with high efficiency (>99.27%) against background ions. Even in the presence of a high concentration of competitive ions, such as Ca
or Mg
, effective removal (>99.21%) can also be achieved in a short time. The excellent removal performance demonstrates the strong electrostatic attraction and coordination interaction between the highly accessible O
groups and Pb
. The possible adsorption mechanism was systematically verified by zeta potential, FT-IR and XPS studies. Our work reveals the enormous potential of functionalized MOFs as an appealing platform to construct sorbent materials.
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.
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•Electrokinetic properties of proton-conducting electrolyte suspensions are studied.•The influence of iodine on zeta potential, pH of the suspensions is investigated.•The possible mechanisms of zeta potential inversion and the EPD nature are discussed.•EPD of thin-film doped BaCeO3 and BaCeO3–BaZrO3 electrolytes is implemented.•Dense BCSCuO film on porous NiO–BCSCuO anode by direct EPD at 1450 °C is obtained.
Herein, we report the synthesis and characterization of Ce(iii)-doped UiO-66 nanocrystals, revealing their potential to efficiently remove organic dyes such as methylene blue (MB), methyl orange ...(MO), Congo red (CR), and acid chrome blue K (AC) from aqueous solutions. Specifically, the room-temperature adsorption capacities of Ce(iii)-doped UiO-66 equaled 145.3 (MB), 639.6 (MO), and 826.7 (CR) mg g
, exceeding those reported for pristine UiO-66 by 490, 270, and 70%, respectively. The above behavior was rationalized based on zeta potential and adsorption isotherm investigations, which revealed that Ce(iii) doping increases the number of adsorption sites and promotes π-π interactions between the adsorbent and the adsorbate, thus improving the adsorption capacity for cationic and anionic dyes and overriding the effect of electrostatic interactions. The obtained results shed light on the mechanism of organic dye adsorption on metal-organic frameworks, additionally revealing that the synergetic interplay of electrostatic, π-π, and hydrophobic interactions results in the operation of two distinct adsorption regimes depending on adsorbate concentration.
Adequate characterization of NPs (nanoparticles) is of paramount importance to develop well defined nanoformulations of therapeutic relevance. Determination of particle size and surface charge of NPs ...are indispensable for proper characterization of NPs. DLS (dynamic light scattering) and ZP (zeta potential) measurements have gained popularity as simple, easy and reproducible tools to ascertain particle size and surface charge. Unfortunately, on practical grounds plenty of challenges exist regarding these two techniques including inadequate understanding of the operating principles and dealing with critical issues like sample preparation and interpretation of the data. As both DLS and ZP have emerged from the realms of physical colloid chemistry – it is difficult for researchers engaged in nanomedicine research to master these two techniques. Additionally, there is little literature available in drug delivery research which offers a simple, concise account on these techniques. This review tries to address this issue while providing the fundamental principles of these techniques, summarizing the core mathematical principles and offering practical guidelines on tackling commonly encountered problems while running DLS and ZP measurements. Finally, the review tries to analyze the relevance of these two techniques from translatory perspective.
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► The Zn and Zn–ZrO
2 composite coatings were produced by electrodeposition technique using sulphate bath ► The ZrO
2 nanoparticles have been selected for generating and investigating ...the corrosion behavior of Zn–ZrO
2 composite coating ► The ZrO
2 particle size distribution in the plating bath and Zeta potential and the ZrO
2 were measured using dynamic light scattering technique (DLS) ► The corrosion resistance properties of Zn and Zn–ZrO
2 composite coatings were compared by examining the experimental data acquired through polarization, open circuit potential (OCP) and Tafel measurements ► The corrosion environment was 3.5
wt% NaCl solution. The results were analyzed to establish the superiority of Zn–ZrO
2 composite over Zn coating.
The Zn and Zn–ZrO
2 composite coatings were produced by electrodeposition technique using sulphate bath. ZrO
2 particles were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The ZrO
2 particle size distribution in the plating bath and Zeta potential and the ZrO
2 were measured using dynamic light scattering technique (DLS). The corrosion resistance properties of Zn and Zn–ZrO
2 composite coatings were compared by examining the experimental data acquired through polarization, open circuit potential (OCP) and Tafel measurements. The corrosion environment was 3.5
wt% NaCl solution. The variation of amount of ZrO
2 in the solution on their % wt inclusion in the composite and on composite microhardness was investigated. XRD patterns were recorded for Zn and Zn–ZrO
2 coatings to compare their grain size. The SEM images of coatings before and after corrosion under chemical and electrochemical conditions were presented. The results were analyzed to establish the superiority of Zn–ZrO
2 composite over Zn coating.
Removals of Rhodamine B (RhB) and Acid red 1 using the organic modification of bentonite from aqueous phase were optimized. The organobentonite was synthesized by replacing exchangeable Na+ ions in ...Na-bentonite (Na-Bt) with cetyl trimethylammonium bromide (CTAB) and systematically explored for its adsorption behavior as an efficient adsorbent for the removal of dyes. Batch adsorption studies manifested that the maximum adsorption capacity of dyes were found to be 173.5 mg/g and 157.4 mg/g for RhB and Acid red 1 at the initial concentration of 300 mg/L at 30 °C and pH 9 and 8, respectively. The investigations of adsorption isotherm and kinetics model showed that the adsorption isotherm data were fitted well to the Langmuir isotherm and the adsorption kinetic was better by pseudo-second-order kinetic model. Besides, the thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic. Furthermore, the properties of the obtained samples were characterized by X-ray diffraction (XRD), Scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectrometry (FT-IR) and zeta potential analysis. The results of the characterization provided evidence of the morphological properties and how well the adsorption process performed.
图 Schematic diagram of organic modified bentonite and adsorption dyes. Display omitted
•Adsorption ability of different types of dyes onto CTAB-bentonite was investigated.•The relationship of structures and adsorption properties of adsorbent was explored.•The influence of different factors on the properties of the adsorbent was revealed.
Zn metal as one of promising anode materials for aqueous batteries but suffers from disreputable dendrite growth, grievous hydrogen evolution and corrosion. Here, a polycation additive, polydiallyl ...dimethylammonium chloride (PDD), is introduced to achieve long‐term and highly reversible Zn plating/stripping. Specifically, the PDD can simultaneously regulate the electric fields of electrolyte and Zn/electrolyte interface to improve Zn2+ migration behaviors and guide dominant Zn (002) deposition, which is veritably detected by Zeta potential, Kelvin probe force microscopy and scanning electrochemical microscopy. Moreover, PDD also creates a positive charge‐rich protective outer layer and a N‐rich hybrid inner layer, which accelerates the Zn2+ desolvation during plating process and blocks the direct contact between water molecules and Zn anode. Thereby, the reversibility and long‐term stability of Zn anodes are substantially improved, as certified by a higher average coulombic efficiency of 99.7 % for Zn||Cu cells and 22 times longer life for Zn||Zn cells compared with that of PDD‐free electrolyte.
A polycation additive is introduced to simultaneously regulate the electric fields of electrolyte and Zn/electrolyte interface, which improves Zn2+ migration behaviors and guides dominant Zn (002) deposition, thereby facilitating homogeneous Zn nucleation and growth concomitantly, and blocking the parasitic side reactions derived from water.
This review summarizes the theory of zeta potential (ZP) and the most relevant data about how it has been used for studying bacteria. We have especially focused on the discovery and characterization ...of novel antimicrobial compounds. The ZP technique may be considered an indirect tool to estimate the surface potential of bacteria, a physical characteristic that is key to maintaining optimal cell function. For this reason, targeting the bacterial surface is of paramount interest in the development of new antimicrobials. Surface-acting agents have been found to display a remarkable bactericidal effect and have simultaneously revealed a low tendency to trigger resistance. Changes in the bacterial surface as a result of various processes can also be followed by ZP measurements. However, due to the complexity of the bacterial surface, some considerations regarding the assessment of ZP must first be taken into account. Evidence on the application of ZP measurements to the characterization of bacteria and biofilm formation is presented next. We finally discuss the feasibility of using the ZP technique to assess antimicrobial-induced changes in the bacterial surface. Among these changes are those related to the interaction of the agent with different components of the cell envelope, membrane permeabilization, and loss of viability.
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•Advanced instruments to measure the ZP in an easy and economic way underline the applications of this technique to bacteria.•Zeta potential can be used as a diagnostic tool in bacteria.•Zeta potential can provide information about membrane permeability and viability, among other variables, in bacteria.•Zeta potential has an enormous potential for assessing the interactions of novel antimicrobial compounds with bacteria.
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Nanofluids are complex fluids, mainly proposed to improve the efficiency of thermal systems. However, their poor stability, caused by the agglomeration and sedimentation of ...nanoparticles over time, has limited their practical application. A common technique to increase the stability of nanofluids is to add surfactants, which produce electrostatic or steric repulsion between nanoparticles, thus avoiding their agglomeration. This work evaluated the effects of surfactants and their concentration on the zeta potential and hydrodynamic diameter at different pH values as an indicator of nanofluids stability. Commercial alumina nanoparticles (0.1 wt.%) were dispersed in deionized water using two surfactants (cetyltrimethylammonium bromide, CTAB and sodium dodecylbenzenesulfonate, SDBS) at different concentrations, and the pH values were varied (2–12) by adding hydrochloric acid and sodium hydroxide. The results show the importance of the critical micelle concentration value in the nanofluids stabilization by electrostatic repulsion between nanoparticles and indicate that SDBS at a concentration of 0.064 wt.% (critical micelle concentration) offers the best dispersion conditions according with their zeta potential values, allowing high stability regardless of the pH value of the suspension.
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