Search

Copyright of Chinese Journal of Inorganic Analytical Chemistry / Zhongguo Wuji Fenxi Huaxue is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The study of zeta potential using electro‐kinetic analyzers that measure streaming potential has limitations of measurements to relatively low ionic strength solutions (<0.1 mol/L) due to the threshold limit of streaming potential signal above a certain limit of ionic strength. The objective of this study is to indirectly estimate the zeta potential for higher salinity brine using the zeta potential measurements for low salinity brine, develop an understanding of electrostatic shielding as predicted by the electric double layer (EDL) model, and overcome the limitation of the apparatus. Zeta potential become less negative as ionic strength increases, as per the Gouy–Chapman–Stern theory. It explains the suppression of electro‐kinetic phenomena due to the gradual compression of the diffuse layer. Our calculations show that the zeta potential and the Debye length become nearly constant at higher ionic strength. The ability to estimate zeta potential by the Gouy‐Chapman‐Stern theory at increasing ionic strength is limited. This theory predicts that the concentration of counter‐ions in the Stern layer increases with increasing ionic strength of the brine until the surface charge becomes neutralized and the diffuse layer collapses. However, it ignores the spatial extension of ions. It considers them as a point charge and may not accurately predict the zeta potential at higher ionic strength. The extent of diffuse layer compression is thus limited to the size of the hydrated counter‐ion. It is very unlikely that the measured zeta potential will become zero at higher ionic strength of brines and our calculations show the same. [ABSTRACT FROM AUTHOR]

The development of non-toxic and inexpensive materials for arsenic removal is required due to water sources being polluted by arsenic in many countries around the world. The main aim of this study was to characterise the capacity and behaviour of Mg/Fe layered double hydroxides/biochar [Magnesium/Iron-Layered Double Hydroxide (Mg/Fe-LDH)] composite for arsenate adsorption from solution. Apple tree pruning residues were used to produce biochar at 500 °C under oxygen-limited atmosphere. Mg/Fe-LDH-biochar was synthesised using a spontaneous in situ co-precipitation method. Batch experiments were used for the assessment of the kinetics, isotherms, and the effects of initial solution pH (4, 6, 8, and 10), ionic strength (0.01, 0.1, and 0.2 mol L−1), and co-occurring anions (carbonate and phosphate) on the arsenate removal. Scanning electron microscope images showed Mg/Fe-LDH were loaded on the biochar porous structure, and X-ray diffraction analysis affirmed the presence of crystalline LDH minerals in Mg/Fe-LDH-biochar. Surface modification of biochar by Mg/Fe-LDH increased the maximum arsenate adsorption capacity (3.6 mg g−1) ten times compared to unmodified biochar (0.35 mg g−1). Arsenate removal capacity increased from 4.2 % to 54.2 % with modification of biochar by Mg/Fe-based LDH. Kinetic studies indicated that >90 % of Mg/Fe-LDH-biochar arsenate adsorption from a starting concentration of 10 mg L−1 occurred in the first 120 min. Pseudo-second order and Langmuir models described well the kinetics and isotherm of arsenate adsorption by biochar and Mg/Fe-LDH-biochar. Mg/Fe-LDH-biochar showed maximum arsenate removal capacity at pH 6. Increasing solution ionic strength and the presence of phosphate and carbonate anions suppressed arsenate removal by Mg/Fe-LDH-biochar. In summary, surface modification of biochar using Mg/Fe-LDH produced a potentially more cost-effective, locally available, reusable, and non-toxic arsenic adsorbent for decontamination of surface- and groundwater. [ABSTRACT FROM AUTHOR]

Spinning of cellulosic fibers requires the prior dissolution of cellulose. 3-Alkyl-1-methylimidazolium ionic liquids have proven to be suitable solvents for that purpose, but the degradation of cellulose in the spinning dope can be severe. Suitable stabilizers are therefore required that prevent cellulose degradation, but do not adversely affect spinnability or the long-term yellowing behavior of the fibers. A group of twelve renewables-based antioxidants was selected for stabilizing 5% cellulose solutions in the ionic liquids and their effects on cellulose integrity, dope discoloration, and aging behavior were tested by gel permeation chromatography (GPC) and ISO brightness measurements. Propyl gallate (a gallic acid derivative), hydroxytyrosol (from olives), and tocopheramines (a vitamin E derivative) performed best in the three test categories, minimizing both cellulose degradation, chromophore formation in the spinning dope, and yellowing upon accelerating aging of the spun fibers. The use of these stabilizers for cellulose solutions in the imidazolium-based solvent system can therefore be recommended from the point of view of both performance and sustainability. [ABSTRACT FROM AUTHOR]

However, common nanofabrication protocols to create Ag nanostructures generally involve high-vacuum-assisted deposition and etching processes, which are expensive and slow, and therefore obstruct scalable and practical fabrication of the photonic and other functional devices that use Ag nanostructures [[12]], [[13]], [[14]]. Soft NIL process of Ag nanostructures consists of (a2) ionic Ag ink coating on the target substrate, (b2) soft baking of the ionic Ag ink layer, and (c2) uniform contacting of the PDMS mold by using a roller. Keywords: ionic Ag ink; nanoimprint lithography; polarization-sensitive color filter; soft contact lithography; stretchable nanostructure; transfer printing EN ionic Ag ink nanoimprint lithography polarization-sensitive color filter soft contact lithography stretchable nanostructure transfer printing 2693 2700 8 05/19/22 20220601 NES 220601 1 Introduction The silver (Ag) nanostructures have unique optical tunability and superior applicability to both laboratory and industry, and therefore have been widely used in photonic devices such as color filters [[1]], surface-enhanced Raman spectroscopy [[3]], [[4]], [[5]], [[6]], [[7]], and plasmonic sensors [[8]], [[9]], [[10]], [[11]]. Transfer printing of Ag nanostructures proceeds in the order of (a1) ionic Ag ink coating, (b1) wetting the PDMS mold, and (c1) contacting with the target substrate and Ag-inked PDMS mold. [Extracted from the article]

The gas–liquid two‐phase flow pattern, absorption rate and pressure drop of CO2 absorbed into the aqueous solution of the task‐specific ionic liquids (1‐aminopropyl‐3‐methylimidazole tetrafluoroborate [Apmim][BF4] and 1‐hydroxyethyl‐3‐methylimidazole tetrafluoroborate [OHemim][BF4]) and halide‐free ionic liquid 1‐butyl‐3‐methylimidazolium methylsulfate [Bmim][CH3SO4] were investigated in a microreactor. The absorption mechanism of the three ionic liquids was analyzed employing the 13C NMR spectroscopy. The [Apmim][BF4] was found to have the best ability of CO2 capture compared with the other two ionic liquids, as chemical absorption occurred between [Apmim][BF4] and CO2, while only physical absorption took place between [OHemim][BF4]/[Bmim][CH3SO4] and CO2. The sequence of CO2 absorption rate in three ionic liquids aqueous solutions is: [Apmim][BF4] > [Bmim][CH3SO4] > [OHemim][BF4]. Furthermore, the effects of gas–liquid flow rate and ionic liquids concentration on CO2 absorption rate and pressure drop were studied, the pressure drop models based on various flow patterns were proposed. [ABSTRACT FROM AUTHOR]

• The article evaluates relevant thermodynamic properties of ionic solutions. • The research is built on a very competitive model for the mean activity coefficient. • The article develops methods for applying the QRL model up to high concentrations. • The article presents strategies for improving prediction of thermodynamic data. This article focuses on the predictive potentialities of the Quasi-Random Lattice (QRL) model, developed for describing the activity behaviour of electrolytic solutions, and elaborates strategies for their improvement. First, the study critically discusses the computational-experimental procedure (previously published) for determining the QRL parameterization, whose convergence within few iterations is counterbalanced by known experimental issues concerning, in particular, the mean activity coefficient. An alternative procedure is proposed, that makes use of osmotic data at medium-high concentrations, so as to make QRL more interesting from a practical point of view. Second, the study explores the applicability of the model beyond the concentration ranges earlier considered. To this purpose, the solution density is evaluated in detail. Its thermodynamic relationship with the mean activity coefficient yields a parametric Abel Equation of the Second Kind valid in the medium-high range of concentrations. A further density equation is formulated, useful in the low-medium range, based on a classical power-series combined with appropriate analytical constraints to improve estimation and prediction methods. QRL theory, methods and procedures are applied to binary aqueous solutions at 25°C. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Polycations statically and dynamically quench Alexa Fluor® dye fluorescence. • Dye-polycation complexes in water have sub-µM equilibrium dissociation constants. • Dye binding to the polycations decreases with increasing concentrations of NaCl. • Stokes radius of the complexes decreases with increasing ionic strength. Based on the growing range of applications for polycations in research and commercial materials, a continuing need exists to advance the fundamental knowledge and understanding of this class of materials. Spectroscopic and solution properties characterizations of noncovalently labeled, fluorescent Alexa Fluor® dye complexes of two commercial polycations, poly(2-(trimethylamino) ethyl methacrylate) monocation and poly[bis[2-chloroethyl] ether-alt-1,3-bis[3-(dimethylamino) propyl] urea] dication are reported to help address this need. A variety of fluorescence spectroscopic methods are used with a special emphasis on fluorescence correlation spectroscopy (FCS) which is applied to characterize the Stokes radius (R S) and equilibrium dissociation constants (K d) of dye-polycation complexes at nanomolar dye concentrations. Resulting R S values indicate dye binding to individual polycation chains. Measured K d values in the sub-micromolar range are consistent with strong dye binding. Increasing solution ionic strength with sodium chloride addition inhibits dye binding and decreases the R S of dye-polycation complexes due to size collapse of polycation chains. The complexes differ in their solution stability to ionic strength changes suggesting that both electrostatic and hydrophobic binding interactions influence dye binding. This study establishes the viability of noncovalent dye-polycation complexation in concert with FCS characterization as a general approach for investigating the properties of quaternary ammonium ion containing polycations in aqueous solution. [ABSTRACT FROM AUTHOR]

Semiclathrate hydrates are water-based materials formed from aqueous solutions of ionic substances. To enhance the gas capture performance of these materials, it is necessary to direct focus on the cation, which is a key part of construction of the hydrogen-bonding framework. In this paper, we focus on the partly-asymmetric cations, i.e., the n -propyl, tri- n -butylammonium bromide (N3444Br) and tri- n ‑butyl, n -pentylammonium bromide (N4445Br), which are yet to be subjected to gas hydrate formation. The three phase equilibrium (gas–hydrate–liquid) conditions for the systems of (N3444Br or N4445Br) + H 2 O + (CH 4 , CO 2 or N 2) in the range of the pressure and mass fractions of the aqueous solutions between 1 and 11 MPa and 0.10–0.40, respectively, are reported. In all the systems, the semiclathrate hydrates were successfully formed under gas pressure. It was demonstrated that both the N3444Br and N4445Br salts promoted hydrate formation under these gases, while in the case with lean aqueous solutions N3444Br acted as an inhibitor of methane hydrate formation in pure water system. The present data are compared with the literature data, and the effect of the side chain length on the phase behavior of the semiclathrate hydrate phase is discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extended DLVO modeling can predict virus removal by microfiltration (MF) membrane. • The negative secondary minima can remove viruses even with hydrophilic repulsion. • Hydrophobic membranes can remove viruses even with weak electrostatic repulsion. • The electrostatic interactions have a negative correlation with virus removal values. • The hydrophobic interaction defines whether viruses can attach to a membrane surface. Virus removal by membrane filtration is challenging due to the small size of these microorganisms. For microfiltration (MF) membranes, which have pore sizes above 100 nm (i.e., larger than most viruses), surface interactions are of critical importance in determining virus removal. The present study aims to evaluate the impact of surface interactions on virus removal by MF membranes wherein predictions by extended DLVO (XDLVO) modeling are compared with experimental data on virus clearance. The study employed four viruses (MS2, Qβ, phiX174, phi6), two MF cartridge membranes (nylon and PTFE), and several solution chemistry conditions to cover a range of virus-membrane surface interaction scenarios. For the hydrophilic nylon membrane, the highest log removal values (LRVs) were observed at the pH when the filter carried a slightly positive charge. For the hydrophobic PTFE membrane, higher LRVs were attained for high ionic strength solutions, wherein the electric double layer was compressed, even at pH values where the filter was negatively charged. We conclude that the electrostatic interaction determines whether viruses can approach the membrane and hydrophobic interactions are a critical factor in retaining viruses near the membrane surface, preventing viral leakage into the filtrate. The surface interactions have to be considered in virus membrane filtration. [ABSTRACT FROM AUTHOR]

This paper presents an efficient finite element iterative method for solving a nonuniform size-modified Poisson-Nernst-Planck ion channel (SMPNPIC) model, along with an SMPNPIC program package that works for an ion channel protein with a three-dimensional crystallographic structure and an ionic solvent with multiple ionic species. In particular, the SMPNPIC model is constructed and then reformulated by novel mathematical techniques so that each iteration of the method only involves linear boundary value problems and nonlinear algebraic systems, circumventing the numerical difficulties caused by the strong nonlinearities, strong asymmetries, and strong differential equation coupling of the SMPNPIC model. To further improve the method's efficiency, an efficient modified Newton iterative method is adapted to the numerical solution of each related nonlinear algebraic system. In addition, a uniform SMPNPIC model is introduced and solved, numerically, as a special case of the SMPNPIC model. Numerical results for a voltage-dependent anion channel (VDAC) and two mixture solutions of four ionic species, including ATP4− ions, demonstrate the method's convergence, the package's high performance, and the importance of considering nonuniform ion size effects. They also partially validate the SMPNPIC model by the anion selectivity property of VDAC. • Present a novel nonuniform size-modified Poisson-Nernst-Planck ion channel (SMPNPIC) model. • Address nonlinearity, strong equation coupling, and singularity challenges through a novel SMPNPIC reformulation. • Develop a three-block iterative method exclusively utilizing linear problems and nonlinear algebraic systems. • Derive an SMPNPIC software package workable for VDAC crystallographic structures and multiple ionic species. • Demonstrate the method's convergence, the package's performance, and the nonuniform size effects' importance. [ABSTRACT FROM AUTHOR]

We develop a nonlocal Nernst-Planck model for reaction and diffusion in multicomponent ionic systems. We apply the model to the one-dimensional liquid junction problem, in which two electrolytic solutions of different ionic concentrations are brought into contact via a permeable membrane. Transport of ions through the membrane induces an electric field which is modeled using two separate nonlocal conditions: charge conservation and Gauss' law. We inve1064s that the net charge at each point in the domain is zero, by considering four different initial scenarios. Charge conservation and Gauss' law yield similar results for most practical scenarios in which the initial condition satisfies strict electroneutrality. However, Gauss' law has two important advantages over charge conservation: (i) it is numerically more stable and can be applied even when the concentration of all the charged species drops to zero and (ii) computationally, it is significantly cheaper. Further, this study provides insights on the prescription of electroneutrality conditions necessary to handle the physics of evolving charges in nonlocal peridynamic models that are aimed at modeling nonlocal reaction-diffusion or corrosion-type processes. [ABSTRACT FROM AUTHOR]

Despite considerable efforts over more than two decades, our knowledge of the interactions in electrolyte solutions is not yet satisfactory. Not even one of the most simple and important aqueous solutions, NaCl(aq), escapes this assertion. A requisite for the development of a force field for any water solution is the availability of a good model for water. Despite the fact that TIP4P/2005 seems to fulfill the requirement, little work has been devoted to build a force field based on TIP4P/2005. In this work, we try to fill this gap for NaCl(aq). After unsuccessful attempts to produce accurate predictions for a wide range of properties using unity ionic charges, we decided to follow recent suggestions indicating that the charges should be scaled in the ionic solution. In this way, we have been able to develop a satisfactory non-polarizable force field for NaCl(aq). We evaluate a number of thermodynamic properties of the solution (equation of state, maximum in density, enthalpies of solution, activity coefficients, radial distribution functions, solubility, surface tension, diffusion coefficients, and viscosity). Overall the results for the solution are very good. An important achievement of our model is that it also accounts for the dynamical properties of the solution, a test for which the force fields so far proposed failed. The same is true for the solubility and for the maximum in density where the model describes the experimental results almost quantitatively. The price to pay is that the model is not so good at describing NaCl in the solid phase, although the results for several properties (density and melting temperature) are still acceptable. We conclude that the scaling of the charges improves the overall description of NaCl aqueous solutions when the polarization is not included. [ABSTRACT FROM AUTHOR]

Ionic solutions are often regarded as fully dissociated ions dispersed in a polar solvent. While this picture holds for dilute solutions, at higher ionic concentrations, oppositely charged ions can associate into dimers, referred to as Bjerrum pairs. We consider the formation of such pairs within the nonlinear Poisson-Boltzmann framework and investigate their effects on bulk and interfacial properties of electrolytes. Our findings show that pairs can reduce the magnitude of the dielectric decrement of ionic solutions as the ionic concentration increases. We describe the effect of pairs on the Debye screening length and relate our results to recent surface-force experiments. Furthermore, we show that Bjerrum pairs reduce the ionic concentration in bulk electrolyte and at the proximity of charged surfaces, while they enhance the attraction between oppositely charged surfaces. [ABSTRACT FROM AUTHOR]

The motion of ionic solutes and charged particles under the influence of an electric field and the ensuing hydrodynamic flow of the underlying solvent is ubiquitous in aqueous colloidal suspensions. The physics of such systemsis described by a coupled set of differential equations, along with boundary conditions, collectively referred to as the electrokinetic equations. Capuani et al. [J. Chem. Phys. 121, 973 (2004)] introduced a lattice-based method for solving this system of equations, which builds upon the lattice Boltzmann algorithm for the simulation of hydrodynamic flow and exploits computational locality. However, thus far, a description of how to incorporate moving boundary conditions into the Capuani scheme has been lacking. Moving boundary conditions are needed to simulate multiple arbitrarily moving colloids. In this paper, we detail how to introduce such a particle coupling scheme, based on an analogue to the moving boundary method for the pure lattice Boltzmann solver. The key ingredients in our method are mass and charge conservation for the solute species and a partial-volume smoothing of the solute fluxes to minimize discretization artifacts. We demonstrate our algorithm's effectiveness by simulating the electrophoresis of charged spheres in an external field; for a single sphere we compare to the equivalent electro-osmotic (co-moving) problem. Our method's efficiency and ease of implementation should prove beneficial to future simulations of the dynamics in a wide range of complex nanoscopic and colloidal systems that were previously inaccessible to lattice-based continuum algorithms. [ABSTRACT FROM AUTHOR]

• As(V) and Cd(II) impact on PAA and PEI determination in water samples was studied. • Activated carbons from waste plant biomass were used as adsorbents of heavy metals. • The adsorptive removal of heavy metal ions in ionic polymers presence was examined. • The maximum adsorption capacities are 135.8 mg/g for Cd(II) and 109.6 mg/g for As(V). • Electrokinetic properties of biocarbons were affected in multicomponent systems. Activated biocarbons (AC) obtained in the process of simultaneous pyrolysis and activation of lemon balm (LB) and mint (MT) herbs with H 3 PO 4 were used to purify aqueous solutions of cadmium, arsenate, polyethylenimine (PEI) and poly(acrylic acid) (PAA). The metals show high toxicity in the whole range of their concentrations, whereas the polymers are cytotoxic at high concentrations. The efficiency of As(V) removal from an aqueous solution depends on the pH value, while the Cd(II) adsorption on the activated biocarbons surface is independent on this parameter. The maximum adsorbed amounts are 135.8 mg/g for Cd(II) and 109.6 mg/g for As(V), respectively. The removal of metals ions and polymers from binary systems is lower in comparison to the one-component solutions. This is a consequence of the formation of polymer-metal complexes, that tend to remain in the solution. Additionally, the surface charge density, zeta potential, the size of activated biocarbons aggregates in the aqueous suspensions and the influence of toxic metal ions on the determination of the concentration of polymers in water samples was investigated. The obtained results proved that the PEI concentration can be effectively determined in the presence of metal ions, whereas the procedure of PAA determination requires additional validation. [ABSTRACT FROM AUTHOR]

The processes of supramolecular self-assembly of Co(III)- meso -tetra-(4-trimethylammoniophenyl)porphyrin (CoP) and bis-(4-(1-imidazolyl)-phenol)-Sn(IV)- meso -tetra(4-sulfophenyl)porphyrin (SnP) were studied using electronic, steady-state and time-resolved fluorescence, one- and two-dimensional NMR spectroscopy in aqueous media. The main product of such interaction at a 2:1 M ratio of Co and Sn porphyrinates was found to be supramolecular porphyrin trimer CoP – SnP – CoP formed due to donor-acceptor, hydrogen and electrostatic interactions. The distinctive features of the resulting trimer are: significant distortion of the spatial structure of the Co-porphyrin fragments and strong quenching of the Sn-porphyrin macrocycles fluorescence (by 70 %). The distortion of the spatial structure of Co porphyrinates is in good agreement with the quantum chemical calculations as well as with the electronic and NMR spectroscopy data. Adding surfactants – both anionic (Cetyltrimethylammonium bromide - CTAB) and cationic (Sodium dodecyl sulfate - SDS) – even at concentrations below the critical micelle concentration (CMC) leads to the supramolecular trimer destruction. In solutions of ionic surfactants, supramolecular trimer destruction is caused by the interaction of either the peripheral macrocycles of the trimer (CoP) with SDS micelles (premicellar aggregates) or the central macrocycle (SnP) with CTAB micelles (premicellar aggregates). This process is prolonged and the rate of trimer destruction depends on the surfactant concentration. The sizes of the CTAB and SDS micelles solubilized with porphyrin molecules were established by dynamic light scattering. In general, surfactant additions lead to an increase in the SnP fluorescence at least due to the destruction of the supramolecular self-assembly, as well as due to the changes in the state of its microenvironment. [Display omitted] • Co(III)- and Sn(IV)- porphyrins self-assembly was studied in aqueous micellar media. • Structure of architectures formed at different molar ratios of the reagents were determined. • Micelle organization determines the supramolecular assembles luminescent properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amphiphilic ionic liquid-based solutions indicated hydrogen/deuterium exchange. • Kinetic H/D exchange was observed. • H/D exchange was controlled by the ion-pairing strength. The hydrogen/deuterium (H/D) exchange of ionic liquid (IL) occurred in the deuterated solutions. Kinetic H/D exchange was investigated via Raman spectroscopy and pH measurements. The ILs employed were amphiphilic 1-alkyl-3-methylimidazolium triflate ([C n mim][OTf] (n = 2, 4, 6, and 8)) and hydrophilic [C 2 mim][X] (X = Cl, Br, I, and BF 4). The H/D exchange occurred in the [C 2 mim][OTf]-deuterated methanol (MeOD-d 4) solutions and was dependent on the additive concentration. For [C 2 mim][X]-D 2 O (X = Cl, Br, and I), which did not possess nano-heterogeneity and the anionic anisotropic shape factor, significant relationships were observed among the H/D exchange rate, pD, and ion-pairing strength. [ABSTRACT FROM AUTHOR]

[Display omitted] • Pentacene is firstly investigated as iodine vapor fluorescent probe. • The interactions between pentacene and iodine are explored. • Pentacene is processed to form homogeneous liquid materials to unleash fluorescent properties. • The pentacene liquid material is equipped with polymer membrane to prepare low-cost and portable detection device. • The application potential, specificity, and stability of the iodine vapor detection device are verified. Materials containing large conjugated structures have good applications prospects in multiple fields due to their electron-rich properties. Nevertheless, the rigid structures of such materials make them difficult to process, making them difficult to be utilized adequately, which limits further development of their performance potentials. Herein, through ionic liquid solution process (ILSP), the electron-rich and fluorescent properties of pentacene have been successfully liberated to detect iodine vapor. Pentacene can be dissolved in BmimNTf 2 to form (Ph) 5 @BmimNTf 2 solution with excellent fluorescence. (Ph) 5 @BmimNTf 2 solution was loaded onto polyamide membranes to prepare composite membrane detectors, which can detect iodine vapors, showing rapid response, portability and low cost. Theoretical calculations indicate a charge-transfer complex is formed between pentacene and iodine. The amount of charge transfer (δQ) between pentacene and iodine monomer molecules can be up to 0.115e. This study provides potential for exploiting the applications of large conjugated materials utilizing ILSP. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cellulose nanocrystals/polyacrylic acid hydrogel derived Fe/N co-doped carbon was prepared. • As-prepared FeN@CP 800 exhibited prominent adsorption capacity for BPA. • Fe 4 N component showed high binding energy with BPA by DFT calculations. • BPA adsorption was accomplished by multiplexing mechanisms. Conventional carbon-based adsorbents encounter insufficient active sites, low adsorption efficiency and poor anti-interference ability for bisphenol A (BPA) removal. Herein, we developed a cellulose nanocrystal/polyacrylic acid hydrogel derived strategy for the preparation of a novel iron/nitrogen co-doped carbon (FeN@CP 800) via simple immersion of iron (III) acetylacetonate and melamine in hydrogel precursors and further carbonization at 800 °C. The precursor scaffold interacted with active species source by swelling behavior to form hydrogen bonds and Fe coordination, thereby facilitating subsequent growth of multiple active conformations without aggregation. The hierarchical porous surface morphology, abundant N doping, multi-active site structure and large specific surface area significantly improved the accessible BPA adsorption of FeN@CP 800. The maximum adsorption capacity calculated by Langmuir model was 309.17 mg·g−1, 4.5 times higher than that of bare CP. Benefited from pore filling, hydrogen bonds, π-π stacking and hydrophobic interactions, the excellent adsorption performance of FeN@CP 800 was retained under varied coexisting ions species, ionic strength and solution pH with 84 % capacity retention after 5 cycles. DFT calculations disclosed the Fe 4 N component was the predominant active sites to improve the adsorption and interfacial transfer process. Thus, these findings provide a new strategy to design high-performance adsorbent for phenolic pollutants removal in water. [ABSTRACT FROM AUTHOR]

Nanobubbles have been increasingly used in various applications involving porous media, such as groundwater remediation and irrigation. However, the fundamental scientific knowledge regarding the interactions between nanobubbles and the media is still limited. The interactions can be repulsive, attractive, or inert, and can involve reversible or irreversible attachment as well as destructive mechanisms. Specifically, the stability and mobility of nanobubbles in porous media is expected to be dependent on the dynamic conditions and the physicochemical properties of the porous media, solutions, and nanobubbles themselves. In this study, we investigated how changes in solution chemistry (pH, ionic strength, and valence) and media characteristics (size and wettability) affect the size and concentration of nanobubbles under dynamic conditions using column experiments. Quartz crystal microbalance with dissipation monitoring provided a deeper understanding of irreversible and elastic nanobubbles' interactions with silica-coated surfaces. Our findings suggest that nanobubbles are less mobile in solutions of higher ionic strength and valence, acidic pH and smaller porous media sizes, while the wettability of porous media has a negligible influence on the retention of nanobubbles. Overall, our findings provide insights into the underlying mechanisms of nanobubble interactions and suggest potential strategies to optimize their delivery in various applications. [Display omitted] • Nanobubble (NB) transport in porous media was evaluated in column experiments. • NBs were less mobile in solutions of higher ionic strength and valence and lower pHs. • Small media sizes resulted in NB retention while wettability had a negligible influence. • Quartz crystal microbalance demonstrated irreversible and elastic interactions. • Correlation was found between transported NB concentrations and their zeta potentials. [ABSTRACT FROM AUTHOR]

• Chalcopyrite surface oxidation was limited in CaCl 2 solution. • Ca2+ ions formed calcium carbonate precipitate under alkaline conditions. • CaCO 3 precipitate served as a passive layer to hinder chalcopyrite oxidation. • Limited chalcopyrite oxidation in CaCl 2 solution caused low surface hydrophobicity. • True chalcopyrite flotation was poorer in CaCl 2 solution than in NaCl solution. Given the increasing use of seawater containing primary ions (e.g. Na+ and Cl-) and secondary ions (e.g. Ca2+ and Mg2+) in flotation plants to counteract the global freshwater scarcity, more and more studies have been performed to determine the impacts of seawater on mineral flotation behaviors. From a new and practical niche, this study aimed to determine the natural floatability of chalcopyrite in the presence of Ca2+ as a secondary ion by considering the alterations of surface hydrophobicity from both the aspects of surface oxidation and metal ion precipitation. Through true collectorless flotation, Cyclic Voltammetry analyses, calcium speciation and Cryogenic X-ray Photoelectron Spectroscopy measurements, this study identified that the true flotation recovery of chalcopyrite was much lower in CaCl 2 solutions than in NaCl solutions even with the same ionic strengths. While the presence of NaCl enhanced chalcopyrite surface oxidation to produce hydrophobic and hydrophilic products, the presence of CaCl 2 inhibited chalcopyrite surface oxidation through the formation of CaCO 3 precipitate which not only served as a passive layer but also being hydrophilic itself. As a result, the surface hydrophobicity on chalcopyrite was determined by the amount of oxidation products in NaCl solutions, but it was determined by the amount of CaCO 3 precipitate in CaCl 2 solutions. Despite the larger amount of CaCO 3 precipitate in CaCl 2 solutions with ionic strengths of 0.7 and 1.2 M, compared to deionized water and CaCl 2 solution with an ionic strength of 0.1, the true flotation recovery of chalcopyrite was higher. This was attributed to much smaller air bubbles generated in CaCl 2 solutions with high ionic strengths of 0.7 and 1.2 M, promoting bubble-particle collision and hence the true flotation of chalcopyrite. [ABSTRACT FROM AUTHOR]

Strontium-90 (90Sr) is a major contaminant at nuclear legacy sites. The mobility of 90Sr is primarily governed by sorption reactions with sediments controlled by high surface area phases such as clay and iron oxides. Sr2+ adsorption was investigated in heterogeneous unconsolidated aquifer sediments, analogous to those underlying the UK Sellafield nuclear site, with grainsizes ranging from gravels to clays. Batch sorption tests showed that a linear K d adsorption model was applicable to all grainsize fractions up to equilibrium [Sr] of 0.28 mmol L−1. Sr2+ sorption values (K d ; Langmuir q max) correlated well with bulk sediment properties such as cation exchange capacity and surface area. Electron microscopy showed that heterogeneous sediments contained porous sandstone clasts with clay minerals (i.e. chlorite) providing an additional adsorption capacity. Therefore, gravel corrections that assumed that the > 2 mm fractions are inert were not appropriate and underestimated K d (bulk) adsorption coefficients. However, K d (<2 mm) values measured from sieved sediment fractions, were effectively adjusted to within error of K d (bulk) using a surface area dependant gravel correction based on particle size distribution data. Amphoteric pH dependent Sr2+ sorption behaviour observed in batch experiments was consistent with cation exchange modelling between pH 2–7 derived from the measured cation exchange capacities. Above pH 7 model fits were improved by invoking a coupled cation exchange/surface complexation which allowed for addition sorption to iron oxide phases. The overall trends in Sr2+ sorption (at pH 6.5–7) produced by increasing solution ionic strength was also reproduced in cation exchange models. Overall, the results showed that Sr2+ sorption to heterogeneous sediment units could be estimated from K d (<2 mm) data using appropriate gravel corrections, and effectively modelled using coupled cation exchange and surface complexation processes. • Sr sorption was determined in a range of heterogeneous aquifer sediments. • Gravels contained porous sandstone clasts containing clays and iron oxides. • K d (bulk) could be estimated from K d (<2 mm) using appropriate gravel corrections. • pH and ionic strength effects could be modelled as cation exchange processes. [ABSTRACT FROM AUTHOR]

The CO 2 -based reversible ionic liquid solution of 1,1,3,3-tetramethylguanidine (TMG) and ethylene glycol (EG) in dimethyl sulfoxide (DMSO) after capturing CO 2 , (2[TMGH]+[O 2 COCH 2 CH 2 OCO 2 ]2−/DMSO (χ RILs = 0.1), provides a sustainable and effective platform for cellulose dissolution and homogeneous utilization. Highly porous cellulose aerogel beads and monoliths were successfully prepared via a sol-gel process by extruding cellulose solution into different coagulation baths (NaOH aqueous solution or alcohols) and exposing the cellulose solution in open environment, respectively, and followed by different drying techniques, including supercritical CO 2 -drying, freeze-drying and air-drying. The effect of the coagulation baths and drying protocols on the multi-scale structure of the as-prepared cellulose aerogel beads and monoliths were studied in detail, and the sol-gel transition mechanism was also studied by the solvatochromic parameters determination. High specific surface area of 252 and 207 m2/g for aerogel beads and monoliths were achieved, respectively. The potential of cellulose aerogels in dye adsorption was demonstrated. A viable and sustainable methodology for production of pure cellulose aerogel beads and monoliths with satisfactory porosities and specific surface area were developed from the newly developed CO 2 -based reversible ILs solvent system. [Display omitted] • First study of cellulose aerogel beads and monoliths from the CO 2 -based reversible ionic liquid/DMSO system • Multi-scale structure of the cellulose aerogel beads and monoliths were studied. • Solvatochromic parameters α and β play a key role in the sol-gel process. • Congo red adsorption behavior follows a pseudo-second-order rate model and the Langmuir isotherm. [ABSTRACT FROM AUTHOR]

• The TBAAc aqueous solution surface tensions decreased with increasing concentration. • The TBAAc aqueous solution surface tensions were higher than those of TBAB aqueous solution by approximately 2 mN·m−1. • The surface excess of TBAAc aqueous solution increases as the concentration is increased. Aqueous solutions of simple ionic salts such as NaCl and NaBr have higher surface tensions compared to that of pure water and the surface tension of the solution increases with the increasing concentration of the salt. In contrast, the aqueous solutions of the ion sodium acetate (NaAc), which has an anion with both hydrophilic and hydrophobic parts, have a surface tension less than that of pure water, with the surface tension decreasing with salt concentration. The presence of large cations in the salt may change these trends. In this work, the interfacial tension of aqueous solutions of the organic ionic salt tetrabutylammonium acetate (TBAAc) is measured and compared with that of tetrabutylammonium bromide (TBAB). The surface tension of TBAAc aqueous solutions with mole fractions ranging from 0.00417 to 0.04191 were measured for temperatures ranging from 288.2 to 308.2 K and compared with the surface tension of TBAB solutions at similar concentrations. The experimental results showed that the interfacial tensions of TBAAc and TBAB aqueous solutions decreased with increasing concentration, leveling at around 0.04 mol fraction. At each concentration, the interfacial tensions of the TBAAc solutions were larger than those of the TBAB solutions. For the TBAAc and TBAB solutions, the surface excess concentrations of the salts in the solutions are calculated. The impact of these results structures and properties of these solutions are discussed. [ABSTRACT FROM AUTHOR]

Rapid diagnosis of diseases is one of the challenging areas in clinical research. From the analytical chemist's perspective, the main challenges are isolating the compounds from the bio-specimen and lengthy analysis times. In this regard, solid phase microextraction offers a platform to address the abovementioned challenges. Moreover, its sharp tip-thin film geometry, known as coated blade spray (CBS), can enhance the extraction and act as an ionization source in direct mass spectrometric analysis. In this study, a new CBS device specifically designed for polar analytes was prepared and optimized to determine urinary metabolites. For this purpose, polyacrylonitrile (PAN) was selected as a base polymer as it can be electrospun to form a nanofibrous structure, and it can be modified with weak ion exchange moieties to interact with polar analytes. Following the electrospinning of PAN, hydrolysis was optimized, and conditions leading to sufficient extraction enhancement without dissolving the polymer were obtained when probes were treated with 5.0 M of NaOH for 2.5 h. Using the coated blades prepared as explained, the evaluation of various extraction conditions showed that 5 min is sufficient for equilibrium extraction. In addition, the solution's ionic strength and pH significantly affect the extraction. Optimum sorption was obtained at no salt added and pH 7.0 conditions. The CBS-MS optimization showed that 10.0 µL of ACN/MeOH/H 2 O (40:40:20, v/v/v) with formic acid kept for 15 seconds on the blade before voltage application leads to the highest signal. The limits of quantification of the analytes are between 50 and 100 ng/mL. [Display omitted] • Hydrolyzed electrospun PAN can be used for extraction of polar metabolites. • New electrospun based extractive phase provides fast extraction kinetics. • The CBS-MS method is only 6 min and can be used as a fast diagnostic tool. [ABSTRACT FROM AUTHOR]

• Lithium is recovered by pseudocapacitive electrodes in electrosorption. • Two Ti-based intercalating materials were used as electrodes. • Impurity ions were preferentially removed so lithium is enriched. • High purity lithium solution was achieved from a binary ionic solution. • This demonstrate using the electrosorption process to recover lithium ions. Lithium is a crucial component in rechargeable lithium-ion batteries for many applications, including the powering of electric vehicles and stationary energy storage systems. This investigation focused on two hybrid pseudocapacitive materials, the polystyrene sulfonate-MXene composite (PM) and the sodium titanate/graphene oxide composite (NG), for lithium ions recovery from aqueous Li+ resources. This was achieved by selectively removing unwanted divalent Ca2+ and Mg2+ ions, as well as monovalent K + ions, through capacitive deionization (CDI) using a single-cell system, resulting in a final solution enriched with Li+ ions. Based on the ion selectivity order observed previously as Mg2+≈ Ca2+ > K + > Li+, a series of CDI experiments were conducted with sequential steps to remove more selective ions first and to obtain a lithium-enriched solution with higher purity and maximum extracted fraction. Both PM and NG electrodes demonstrated promising performance when tested in binary, ternary, and quaternary ionic solutions with the recovered lithium solution purity in the range of 59.09 %-95.94 % and 59.75 %-77.17 %, respectively. Further, the highest enrichment factor values observed were S Li+,Mg2+ ; 268.1 for PM and S Li+,Ca2+ ; 44.25, for NG electrodes. The PSS-modified MXene composite electrode in obtaining the Li+ solution with the highest purity when separated Ca2+ from a binary solution. These findings offer valuable insights into the selective electrosorption of divalent ions over lithium ions through the utilization of ion intercalation pseudocapacitive nanocomposite electrodes. The obtained results hold significance in advancing novel non-precipitation techniques for the recovery of lithium ions from aqueous lithium resources. [Display omitted] [ABSTRACT FROM AUTHOR]

Surfactant solutions play key roles in scientific research and technological applications. Here we investigated solutions that combined an ionic surfactant, Cetylpyridinium Chloride (CPyCl), with a non-steroidal, anti-inflammatory drug, Sodium Diclofenac (Diclo). The study covered a wide range of compositions and utilized both rheology and cryogenic-Electron Microscopy (cryo-EM). The solutions were prepared at three different concentrations of CPyCl: 5.0 mM, 16.7 mM and 33.0 mM, and we maintained the ratio of surfactant to salt, R=CPyCl/Diclo, within the range of 0.24

[Display omitted] • The transport property of Li+-TFSI− electrolyte is investigated by MD simulations. • Nano-porous PE films are obtained through uniaxial stretching simulation. • PE films do not cause biased distributions of ionic solutions. • PE films with small pores impede the migration of ions and solvents. • Increasing Li+ concentrations restricts the migration of ions across porous films. The performance of lithium-ion batteries relies heavily on the solvate structures of electrolytes and how the electrolytes interact with porous polymeric separators. In the present work, the thermodynamics and electrodynamics of Li+-TFSI− electrolytes in 1,2-dimethoxyethane (DME) and 1,3-dioxolane (DOL) solutions with and without porous polyethylene films are investigated by molecular dynamics simulations. DME/DOL molecules exhibit competitive binding affinities in the first solvation shells of Li+ ions and an increase in the Li+-TFSI− concentration leads to more structured solvent configurations, thus reducing the diffusivities of the constituents in the ionic solutions. In addition, nano-porous polyethylene films, obtained through uniaxial stretching processes, are able to regulate the transport properties of Li+ ions with or without external electric fields. Reducing the pore sizes of polyethylene films or increasing Li+ concentrations in the lithium-ion battery systems impedes the migration of ions and solvents across the porous films. Finally, due to the weak interaction between polyethylene films and ionic solutions, the presence of polyethylene films does not cause biased distributions of ionic solutions during the diffusion process. The present work provides molecular insights into the working principle of the Li+-TFSI− electrolytes with nano-porous polymer separators and their interfaces. [ABSTRACT FROM AUTHOR]

Although Lecitase and the lipase from Thermomyces lanuginosus (TLL) could be coimmobilized on octyl-agarose, the stability of Lecitase was lower than that of TLL causing the user to discard active immobilized TLL when Lecitase was inactivated. Here, we propose the chemical amination of immobilized TLL to ionically exchange Lecitase on immobilized TLL, which should be released to the medium after its inactivation by incubation at high ionic strength. Using conditions where Lecitase was only adsorbed on immobilized TLL after its amination, the combibiocatalyst was produced. Unfortunately, the release of Lecitase was not possible using just high ionic strength solutions, and if detergent was added, TLL was also released from the support. This occurred when using 0.25 M ammonium sulfate, Lecitase did not immobilize on aminated TLL. That makes the use octyl-vinylsulfone supports necessary to irreversibly immobilize TLL, and after blocking with ethylendiamine, the immobilized TLL was aminated. Lecitase immobilized and released from this biocatalyst using 0.25 M ammonium sulfate and 0.1% Triton X-100. That way, a coimmobilized TLL and Lecitase biocatalyst could be produced, and after Lecitase inactivation, it could be released and the immobilized, aminated, and fully active TLL could be utilized to build a new combibiocatalyst. • Lecitase and TLL can be coimmobilized on octyl agarose, but Lecitase is far less table than TLL. • The amination of immobilized TLL transform the enzyme in a anion exchanger. • Lecitase can be ionically exchanged in aminated TLL • Using octyl agarose, the reuse of TLL is not possible because Lecitase cannot be selectively desorbed, • The use of vinyl sulfone-octyl agarose permitted the reuse of immobilized and aminated TLL [ABSTRACT FROM AUTHOR]

Background electrolytes affect calcite precipitation and dissolution rates and hence have the potential to impact kinetic isotope fractionation between calcite and the dissolved inorganic carbon (DIC) species. We grew inorganic calcite from NaCl-CaCl 2 solutions (T = 25 °C, pH = 8.3, and crystal growth rate = 10−6.3 ± 0.3 mol m−2 s−1) to test for potential ionic strength effects on the oxygen isotope fractionation between calcite and an isotopically equilibrated inorganic carbon pool (α c/EIC). Calcite was grown in the presence of the enzyme carbonic anhydrase from bovine erythrocytes (bCA) to promote isotopic equilibration of the DIC pool. No evidence of an ionic strength effect on α c/EIC was found for NaCl concentrations up to 0.35 M (1000lnα c/w = 28.0 ± 0.1; n = 7). For experiments conducted with [NaCl] > 0.35 M, the DIC pool could not be maintained in isotopic equilibrium with water due to the inhibitory effect of NaCl on bCA. The use of other types of CA may be required to maintain isotopic equilibration of DIC in solution with ionic strength close to or above that of seawater. The oxygen isotope results were modeled successfully with an isotopic box model for a CO 2 -fed solution that tracks the isotopic composition of each DIC species and CaCO 3. The experimental and modeling results suggest that the efficacy of bCA decreases exponentially with increasing [NaCl]. We quantify the salt effect on the quantity k cat / K M , which relates the catalyzed rate constant for CO 2 hydration to the concentration of bCA. The salt effect can be implemented in models of biomineralization with potential to extend our knowledge of oxygen isotope vital effects in marine organisms. [ABSTRACT FROM AUTHOR]

[Display omitted] Understanding ionic solutions in single-digit nanoconfinement is crucial to explain the behavioral transition of confined solutions. This is particularly the case when the system length scale crosses the classical key length scales describing energetics and equilibrium of ionic solutions next to surfaces. Experimentally probing nanoconfinement would open large perspectives to test modelling or theory predictions. Here, using a new test vehicle that consists in 3 and 5 nm-height silica nanochannels associated with an original characterization technique based on the interface hard X-ray reflectivity analysis, we directly probed the transport of solutions containing cations having increasing kosmotropic properties (XCl 2 with X: Ba < Ca < Mg) and obtained their distributions inside the nanochannels. We observed that cation adsorption decreases with the size of the confinement and that small cation adsorption is favored. In addition, nanochannel clogging occurs when ions tend to form ion pairs. These ion pairs may play the role of nano-sized prenucleation clusters leading to phase precipitation. These results evidence the specific ion effect in single-digit nanoconfinement that may result in dramatic changes of solution properties. In this line, our new method opens new perspectives for the characterization of ionic solutions and of interfaces in single-digit nanoconfinement. [ABSTRACT FROM AUTHOR]

[Display omitted] In this work, nitrogen and phosphorus dual-doped alkali lignin-based carbon microspheres (MLCM) were prepared by pre-oxidation and carbonization of ionic liquid ([Mmim]DMP) -lignin solution and used as green-based supercapacitor electrode materials. Compared with the directly carbonized alkali lignin carbon (LC), MLCM had a spherical structure with higher specific surface area (938.1 m2/g) and pore volume (0.64 cm3/g). Moreover, MLCM materials showed superior electrochemical performance. In the 1 mol/L H 2 SO 4 electrolyte system, MLCM presented the highest specific capacitance of 338.2F/g at a current density of 0.8 A/g. Furthermore, MLCM was used as a positive and negative electrode material to assemble a symmetrical supercapacitor. The resultant device maintained excellent cycle stability after 5000 times of charging and discharging process at 2 A/g. Overall, the facile, green and sustainable synthesis strategy of heteroatom-doped porous carbon microspheres developed in this work opens a new avenue for the fabrication of high-performance carbon electrode materials, especially based on abundant and renewable lignin. [ABSTRACT FROM AUTHOR]

Sperm are stored for extended periods of time in the epididymis, but upon ejaculation motility is increased and lifespan is decreased. The objective of this study was to identify differences in proteins between epididymis and ejaculated samples that are associated with longevity. Ejaculated semen was collected from mature Angus bulls (n = 9); bulls were slaughtered and epididymal semen was collected. Epididymal and ejaculated semen were centrifuged to separate sperm and fluid. Fluids were removed and sperm pellets were resuspended in a high ionic solution and vortexed to remove loosely attached proteins. Sperm samples were centrifuged, and the supernatant was removed; both fluid and sperm samples were snap frozen in liquid nitrogen and stored at −80 °C. Protein analysis was performed by LCMS/MS. A different group of yearling Angus cross bulls (n = 40) were used for sperm cultures. Ejaculated (n = 20) and epididymal (n = 20) semen were diluted and cultured in a commercial media at pH 5.8, 6.8 and 7.3, at 4 °C. Sperm were evaluated for motility and viability every 24 h until motility was lower than 20%. There was an effect of pH, time and pH by time interaction for motility and viability for both ejaculated and epididymal sperm (P ≤ 0.05). At 216 h of incubation epididymal sperm at pH 7.3 and ejaculated sperm at pH 6.8 reached motility below 20%. A total of 458 unique proteins were identified; 178, 298, 311, and 344 proteins were identified in ejaculated fluid, ejaculated sperm, epididymal fluid and epididymal sperm, respectively. There were 8, 24, 10, and 18 significant KEGG pathways (FDR <0.05) for ejaculated fluid, epididymal fluid, ejaculated sperm, and epididymal sperm, respectively. The metabolic pathway was identified as the most important KEGG pathway; glycolysis/gluconeogenesis, pentose phosphate, and glutathione metabolism pathways were significant among proteins only present in epididymal samples within the metabolic pathway. Other proteins identified that may be related to epididymal sperm's increased longevity were peroxidases and glutathione peroxidases for their antioxidant properties. In summary, energy metabolism in the epididymis appears to be more glycolytic compared to ejaculated and epididymis sperm have a larger number of antioxidants available which may be helping to maintain sperm in a quiescent state. Epididymal sperm remained viable (membrane integrity) longer than ejaculated sperm when cultured at the same pH. [Display omitted] • Epididymal sperm maintained viability longer than ejaculated sperm in culture. • Ejaculated sperm maintained motility longer when cultured at pH 6.8. • The metabolic pathway was identified as the most important for increased longevity. • Energy metabolism in the epididymis appears to be more glycolytic. • Increased numbers of antioxidants may help maintain sperm in a quiescent state. [ABSTRACT FROM AUTHOR]

Grape fruit contains some nutrients and high amounts of biologically active phenolic substances, but fungal decay and quality loss are important factors limiting its shelf-life for fresh -consuming and export. Rasheh vine (Vitis vinifera cv. Rasheh) is mainly grown in rainfed vineyards in the western half of Iran, and its berries are rich in anthocyanins, flavonoids and soluble solids. In this study, the effect of natural coatings of nano -chitosan and acetic acid on the post -harvest quality characteristics of Rasheh grape fruit was investigated. Nano -chitosan suspension with a particle size distribution of 5 -30 nm was prepared in acetic acid solution by the conventional ionic gelation method. Grape fruits were coated by immersion in the nano - chitosan suspension (0.2%), acetic acid solution (0.5%) or distilled water (control) for 1 min and their microbial, physicochemical and sensory properties were measured during 8 weeks storage at 4 °C and 90% relative humidity. In general, the fruits coated with nano -chitosan or acetic acid had lower aerobic mesophilic bacteria count, mold and yeast count and decay percentage, and higher firmness, soluble solids, titratable acidity and vitamin C, as well as, better sensory properties, compared to the control. The nano -chitosan was more effective than acetic acid in improving the post -harvest quality and shelf life of grape fruit. No significant difference was observed in the weight loss percentage and pH values of the samples. Therefore, the nano -chitosan suspension prepared in acetic acid solution, as a natural and customer -friendly coating, is suitable for improving the shelflife and post-harvest quality of grape fruit, but some of its beneficial effects are due to acetic acid. [ABSTRACT FROM AUTHOR]

The accumulation of rabbit muscle glycogen phosphorylase b (RMGP b) in electrostatic complexes with the cationic polyelectrolyte poly 2-(dimethylamino) ethyl methacrylate in its quenched form (QPDMAEMA) was studied in two buffer solutions. In the N -bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES) buffer, large complexes of RMGPb-QPDMAEMA were formed which adopted smaller sizes as QPDMAEMA concentration increased. However, in N -(2-hydroxyethyl)piperazine- N ′-(2-ethanesulfonic acid) (HEPES) buffer, the hydrodynamic radius of the formed complexes gradually increased as the polymer concentration increased. Zeta potential measurements (ζ p) showed that RMGP b significantly changed the ζ p of the QPDMAEMA aggregates. Fluorescence studies showed that the interaction between RMGP b and QPDMAEAMA was enhanced as polymer concentration increased. Specifically, 8-anilinonaphthalene-1-sulfonic acid (ANS) fluorescence indicated that in the BES buffer the aggregates became denser as more QPDMAEMA was added, while in the HEPES buffer the density of the formed structures decreased. RMGP b 's secondary structure was examined by Attenuated Total Reflection - Fourier Transform Infrared (ATR-FTIR) and Circular Dichroism (CD) showing that QPDMAEMA interaction with RMGP b does not induce any changes to the secondary structure of the enzyme. These observations suggest that cationic polyelectrolytes may be utilized for the formulation of RMGP b in multifunctional nanostructures and be further exploited in innovative biotechnology applications and bioinspired materials development. [Display omitted] • RMGP b forms large complexes with the cationic polyelectrolyte QPDMAEMA. • Complexes are studied in two buffer solutions of different ionic strength. • The nanostructures depend on the protein/polymer mixing ratio and ionic strength. • Complexation does not affect the secondary structure of the protein. • The work illustrates an allosteric, dimeric enzyme complex with a polyelectrolyte. [ABSTRACT FROM AUTHOR]

This study evaluates the performance of electrokinetic (EK) treatment to improve the engineering properties of soft soils. Laboratory tests were conducted using ionic solutions of calcium chloride, CaCl2 and sodium carbonate, Na2CO3. Atterberg limits, unconfined compression, electrochemical, thermal, and microscopic tests were performed in terms of treatment duration, anode-to-cathode distances, and different combinations of ionic solutions as calcium chloride-distilled water (CaCl2-DW), sodium carbonate-distilled water (Na2CO3-DW) and calcium chloride-sodium carbonate (CaCl2-Na2CO3). EK treatment caused a reduction in the specific surface area, Sa, cation exchange capacity, CEC, and plasticity resulting in 26%, 14%, 19% reduction using CaCl2-DW, Na2CO3-DW, and CaCl2-Na2CO3 ionic solutions, respectively. The formation of the new compounds, calcium aluminosilicate hydrates, CASH resulted in the strength gain of the EK treated soils and increased the strength from 21 kPa to 90 kPa, 63 kPa, and 92 kPa with the ionic solutions of CaCl2-DW, Na2CO3-DW, and CaCl2-Na2CO3, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] We describe the deposition behavior of monodispersed silica nanoparticles on polystyrene spherical particles by using modified pairwise DLVO (Derjaguin-Landau-Verwey-Overbeek) interaction force profiles at pH values between two and twelve. Our modified model contains a new nonlinear charge regulation parameter that considers redistribution of ions, which allows us to realistically express the electrical double layer (EDL) interaction forces. Silanol-terminated silica nanoparticles (7.6 ± 0.4 nm), l -lysine-covered silica nanoparticles (7.8 ± 0.4 nm), and polyallylamine hydrochloride-covered polystyrene (PAH/PS) particles (348 ± 1 nm) were synthesized. Then, each type of silica nanoparticle was deposited on the PAH/PS particles at a range of pH values. Our new regulation parameter describes the realistic redistribution of charges governed by pH, total salt concentration, ionic strength of solution, and separation distance of particles. We find that this regulation parameter can be roughly approximated from the absolute values of theoretically calculated surface charge density and potential distributions, as well as experimentally measured ζ-potentials. Morphological analysis using electron microscopy of the experimental systems shows that the modified pairwise DLVO interaction forces exceptionally describe the deposition behavior of the silica nanoparticles physically adsorbed on the PAH/PS particle substrates. [ABSTRACT FROM AUTHOR]

A detailed investigation of the performance of commercially available tubular membranes is carried out under varying operating conditions. Trans‐membrane pressure, feed concentration, and cation types were chosen to study their effects on the membrane's performance. Commercially available tubular membranes AFC80, AFC 30, ES404, and PU608 were selected. Aqueous solutions of varying ionic strength (2500 ppm, 5000 ppm,10000 ppm) of three salts, sodium chloride, magnesium chloride, and lead chloride were filtered to measure the permeate flux and rejection of selected tubular membranes. The AFC80 membrane had better rejection among all selected tubular membranes for all types of salts tested here. It is deduced that selected membranes carried a negative surface charge, which played a vital role during the separation mechanism. Finally, rejection of lead chloride and sodium chloride aqueous solutions was predicted accurately using the Spiegler‐Kedem model with R2 reaching 0.9. [ABSTRACT FROM AUTHOR]

Biofilms covering porous media will interact with particles and affect particle migration. In order to investigate the migration mechanism of particles in porous media covered by biofilms, the migration process of particles with different particle sizes under the condition of the changing ionic strength is analyzed by using the lattice Boltzmann method–discrete element method (LBM‐DEM) coupling method from mesoscopic scale. The variation patterns of ion strength include gradient and mutation, respectively. Also, the agglomeration of particles at the pore throat in porous media is investigated under different conditions. The main results are obtained as follows. First, both the change of ionic strength and its changing mode significantly affect the migration behavior of particles in NaCl solution but have little effect on the behavior of particles in CaCl2 solution. Second, when the pressure difference between the pressure difference between the inlet and outlet of porous media is 0.4 kPa, the residual permeability of 1.5‐μm particles in the NaCl solution with ionic strength mutation is the highest, which has value of 64.92%. Third, at the specific flow rate, the particles in low ionic strength solution are more likely to be settled. The attraction of particles in the CaCl2 solution is one order of magnitude less than that in the NaCl solution, and the accumulated particles are more likely to be dispersed. [ABSTRACT FROM AUTHOR]

In the context of the raw material change for sustainable production of chemicals, the selected bio-based amino acids and carboxylic acids are considered as promising platform chemicals. After fermentation, the acids are present in aqueous solutions with many side components and elevated ionic strength. The ionic strength is even further increased when pH-shift operations are applied for the separation of the target compounds. Since high ionic strengths strongly affect the solution properties, particularly the solid–liquid-equilibrium and the dissociation equilibrium in the solution, the high ionic strengths and the resulting effects on the solutions must also be taken into account in process modeling and the design of downstream processes. Various models have been reported in the literature but the majority cannot be applied for predicting the solution composition and pH at high ionic strengths. In this work, a procedure for the calculation of the composition, i.e. the distribution of the present species and pH, of aqueous itaconic acid solutions based on ePC-SAFT is developed and evaluated at different levels of ionic strengths. The ePC-SAFT parameters of itaconic acid are determined based on experimental solubility data from literature. The resulting model is validated with experimentally measured titration curves and compared with the ideal model and the Davies approximation to the Debye–Hückel model. It is demonstrated that the ePC-SAFT approach provides reliable results at high ionic strengths with lower deviations from experimental data than current literature models. [ABSTRACT FROM AUTHOR]