Single Solute Research Articles

Reverse Solute Diffusion Enhances Sludge Dewatering in Dead-End Forward Osmosis.

Wastewater treatment plants produce high quantities of excess sludge. However, traditional sludge dewatering technology has high energy consumption and occupies a large area. Dead-end forward osmosis (DEFO) is an efficient and energy-saving deep dewatering technology for sludge. In this study, the reverse osmosis of salt ions in the draw solution was used to change the sludge cake structure and further reduce its moisture content in cake by releasing the bound water in cell. Three salts, NaCl, KCl, and CaCl2, were added to the excess sludge feed solution to explore the roles of the reverse osmosis of draw solutes in DEFO. When the added quantities of NaCl and CaCl2 were 15 and 10 mM, respectively, the moisture content of the sludge after dewatering decreased from 98.1% to 79.7% and 67.3%, respectively. However, KCl did not improve the sludge dewatering performance because of the "high K and low Na" phenomenon in biological cells. The water flux increased significantly for the binary draw solute involving NaCl and CaCl2 compared to the single draw solute. The extracellular polymer substances in the sludge changed the structure of the filter cake to improve the formation of water channels and decrease osmosis resistance, resulting in an increase in sludge dewatering efficiency. These findings provide support for improving the sludge dewatering performance of DEFO.

The variation of the temperature of maximum density of non-polar solutes in water: insights from the pressure change in a constant volume solution process

The effects of non-polar solutes on the temperature of maximum density (T MD) of water are revisited by means of a molecular dynamics study of TIP4P/2005 water and two examples of spherically symmetric non-polar solutes modelled by same size single Lennard-Jones sites, with weak and strong solute–water dispersive interactions. We have adopted a two-stage strategy to model the solution process at constant pressure to reduce the analysis to the description of the pressure variation in the solution process at constant volume. To this end, the Reaction Field treatment of the Coulombic forces was used so as to be able to decompose the different molecular components to the virial pressure and their spatial variation in terms of the distance to the solute molecule. In this way, we have been able to separate which factors induce the increase of water’s T MD observed for weakly interacting non-polar solutes and the decrease that occurs when the solute is strongly interacting.

Personalized peritoneal dialysis prescription—beyond clinical or analytical values

ABSTRACT Traditionally, dialysis adequacy has been assessed primarily by determining the clearance of a single small solute, urea. Nevertheless, it has become increasingly evident that numerous other factors play a crucial role in the overall well-being, outcomes and quality of life of dialysis patients. Consequently, in recent years, there has been a notable paradigm shift in guidelines and recommendations regarding dialysis adequacy. This shift represents a departure from a narrow focus only on the removal of specific toxins, embracing a more holistic, person-centered approach. This new perspective underscores the critical importance of improving the well-being of individuals undergoing dialysis while simultaneously minimizing the overall treatment burden. It is based on a double focus on both clinical outcomes and a comprehensive patient experience. To achieve this, a person-centered approach must be embraced when devising care strategies for each individual. This requires a close collaboration between the healthcare team and the patient, facilitating an in-depth understanding of the patient's unique goals, priorities and preferences while striving for the highest quality of care during treatment. The aim of this publication is to address the existing evidence on this all-encompassing approach to treatment care for patients undergoing peritoneal dialysis and provide a concise overview to promote a deeper understanding of this person-centered approach.

A semi-empirical equation modeling long-range contributions to the activity coefficients of individual ions at high ionic strengths

Molecular thermodynamics is well developed with models like UNIQUAC, UNIFAC and SAFT. These models include robust codes and extensive databases for chemical and petroleum industries through ASPEN, DORTMUND, and others. However, important systems in the pharmaceutical and biotech industries now exist where these codes and their databases are not always sufficient. Cell culture media used to grow mammalian cells are multicomponent aqueous solutions with 50, 100, or more compounds including amino acids, salts, acids or bases, as well as sugars, fatty acids, etc. These components can exhibit both complexation and incomplete dissociation. The thermodynamics of these systems have proven challenging to model, as current solubility descriptions frequently assume complete dissociation in solutions containing a single solute in water at relatively low concentrations. However, not all compounds that are generally considered to be strong electrolytes are completely dissociated even at low concentrations. Further, mixtures of such components can show dramatic changes in dissociation and complexation with concentration, pH, and temperature. In this paper, we present a semi-empirical model for individual ions in aqueous solutions. We use data from 317 compounds to isolate the ionic contribution to a compound’s activity coefficient in aqueous systems from confounding short-range effects. We compare eight robust regression M−estimators with a least-squares estimate and provide a two-parameter equation relating ionic strength, valence, and the activity coefficient not requiring arduous characterization of the solute of interest. We demonstrate that the Fair M−estimator generates an accurate model that can serve as an appropriate reference state for use with a model based on perturbation theory up to 29 molal.

The trapping effect of transitional metals on oxygen in Mo from first-principles calculations

The trapping effect of solute on oxygen (O) can be benefit for inhibiting its segregation and embrittlement at the GBs in Mo alloys. In this work, the interaction between solutes (including 27 transition metals), interstitial O and vacancy in Mo are implemented by first-principles calculations, and their trapping effects on O are evaluated by Simonovic’s model. Single transition metal solute (TMS) has a strong attraction for O, and it is strengthened by the second solute for all 3d, oversized 4d and 5d series. Furthermore, there is a significant synergistic effect between solute, vacancy, and oxygen for oversized solutes, i.e., the binding energy between solute atom (vacancy) and oxygen atoms is enhanced by the presence of vacancy (solute). The distribution of oxygen indicates that oxygen can be captured by dilute TMS atoms, and more oxygen atoms will be trapped as the solute concentration increases in Mo. Based on our extensive calculations, Sc, Ti, Zr, Hf, and Ta can be the top priority for suppressing the segregation and embrittlement of O in Mo alloys. It is interesting that the interaction between solute and O can be accurately separated into elastic and chemical contributions though delicate calculation, and the counterintuitive strong binding effect of fifth-nearest solute-O pairs for undersized 4d and 5d elements is owning to the chemical contribution driven by Coulomb interaction.

Quantifying the energy of vacancy mediated diffusion of solute Cu, Mg, Ag and Zn atoms in an aluminum Matrix: An insight from ab initio calculations

In this work, a consistent and accurate set of energy barrier values for the migration process, assisted by a vacancy, of atoms of different chemical elements belonging to the two most relevant families of age-hardenable Al-Cu and Al-Zn-based alloys is given. These values were calculated using the Nudged Elastic Band method within the Density Functional Theory framework for a vacancy diffusing in simple configurations of solute atoms, specifically the main alloying elements Cu and Zn involving a single solute atom or more complex configurations, such as pairs of elements of the same or different chemical species. In both cases, in our calculations, the presence of Mg and/or Ag solute atoms is also considered. The results obtained are analyzed in terms of the energetic interaction among vacancies and the different solute atoms. The advantage of having a set of vacancy diffusion energy barrier values calculated under the same criteria is that it can be used as reliable input parameters for future kinetic Monte Carlo simulations to study the precipitation kinetics in a wide type of age-hardenable alloys.

Membrane behavior of clay under mixed solution conditions

Compacted clay is employed as the buffer material for landfills, and multiple ions are dissolved in the leachate restricted by the compacted clay layer. The membrane efficiency is an important indicator to assess the barrier properties of the compacted clay layer and is measured through membrane tests. However, most membrane tests are currently conducted with a single solute solution, which does not reflect the mixed solution characteristics of leachates. To assess the membrane efficiency of compacted clay under mixed solution conditions, 13 membrane tests were conducted on a bentonite-amended soil using KCl–NaCl mixed solutions, KCl–CaCl2 mixed solutions, and KCl–AlCl3 mixed solutions with different mixing ratios at a total concentration of 20 mM. Nuclear magnetic resonance (NMR) tests were conducted on the soil specimen after the membrane tests to investigate the micromechanism of the membrane behavior under mixed solution conditions. Results indicate that the membrane efficiency increased with the mixing ratio of Na+ but decreased with the mixing ratio of Ca2+ or Al3+. In the 13 membrane tests, the lowest membrane efficiency was achieved when the specimen was tested with pure AlCl3 solution. The relationship between the membrane efficiency and mixing ratio was also investigated at the microscopic scale. As the ion valence increases, the diffuse double layer thickness is smaller and the proportion of macropores is larger, as verified by NMR tests.

Effect of Solute on Interfacial Properties and Micelle Structure of Dodecylbenzenesulfonate (DBS): Experimental and Molecular Dynamics Studies.

A combined experimental and molecular dynamic simulation approach was used to examine the structure and interfacial properties of solute-saturated micelles. The properties of dodecylbenzenesulfonate (DBS) micelles were examined in dodecane and benzene hydrocarbon systems. Pyrene fluorescence was used to determine the aggregation number of surfactant monomers in the micelle systems. Molecular dynamic (MD) simulations using energy minimization applying the CHARMm force field with the TIP3P model for water. Comparison of the DBS/benzene and DBS/Dodecane micelles equilibrium structures via radial distribution function (RDF) and probability distribution function (PDF) analysis indicates that the area per head group for the DBS/Benzene micelle interface is significantly larger than that of the DBS/Dodecane at the interface. It was also determined that benzene molecules can move freely within the micelle while dodecane is strictly confined in the core of the micelle. The increased interfacial area per monomer caused by the insertion of benzene also reduces the effectiveness of the surfactant, which has implications for use in various environmental applications. However, the DBS/benzene micelle can solubilize many more hydrocarbon molecules in one micelle with less surfactant monomer (i.e., lower aggregation number) per micelle due to the increased available packing positions within the micelle. This, in turn, increases the efficiency of the surfactant in real-world applications which is consistent with previous laboratory results. Understanding the differing solubilization characteristics of surfactants against various classes of hydrocarbons in single solute systems is a necessary step to beginning to understand their solubilization properties in the mixed waste systems prevalent in most surfactant enhanced remediation (SEAR) strategies.

Structural Information on Supramolecular Copper(II) β-Diketonate Complexes from Atomic Force Microscopy and Analytical Ultracentrifugation.

Supramolecular Cu(II) complexes were prepared from two trifunctional β-diketone ligands. The ligands (CH3Si(phacH)3 and CH3Si(phprH)3, represented by LH3) contain three aryl-β-diketone moieties joined by an organosilicon group. The complexes have the empirical formula Cu3L2, as expected for combinations of Cu2+ and L3-. Several metal-organic polyhedra (MOPs) [Cu3L2]n are possible (n = 1-10); a dodecahedron (Cu30L20; n = 10; estimated diameter of ca. 5 nm) should be the most stable because its internal bond angles would come closest to ideal values. Atomic force microscopy (AFM), performed on samples deposited from solution onto mica substrates, revealed a distribution of sample heights in the 0.5-3.0 nm range. The most commonly observed heights were 0.5-1.5 nm, corresponding to the smallest possible molecules (Cu3L2, i.e., n = 1). Some molecular cubes (Cu12L8; ca. 2.5 nm) or larger molecules or aggregates may be present as well. Equilibrium analytical ultracentrifugation (AUC) was also used to probe the compounds. A previously reported reference compound, the molecular square Cu4(m-pbhx)4 (M = 2241 g mol-1), behaved well in AUC experiments in four nonpolar organic solvents. AUC data for the new tris(β-diketonate) MOPs [Cu3L2]n in toluene and fluorobenzene did not agree well with the theoretical results for a single solute. The data were fit well by a two-solute model, but these results were not consistent in the two solvents used, and some run-to-run variability was noted even in the same solvent. Also, the calculated molecular weights differed significantly from those expected for [Cu3L2]n ([Cu3(CH3Si(phac)3)2]n, multiples of 1322 g mol-1; or [Cu3(CH3Si(phpr)3)2]n, multiples of 1490 g mol-1).

Theoretical Investigation of the Nonlinear General Rate Model with the Bi-Langmuir Adsorption Isotherm Using Core-Shell Adsorbents.

Core-shell particles enable the separation of intricate mixtures in a highly efficient and rapid manner. The porous shell particles increased the separation efficiency with expedited flow rates due to an abatement in the pore volume accessible for longitudinal diffusion and a decrease in diffusion path length. This study focuses on the numerical approximation of a nonlinear isothermal general rate model applied to stationary bed columns that are replete with inert core adsorbents featuring double adsorption sites. The transport of solute in heterogeneous porous media can be modeled by a nonlinear convection acquiescent partial differential equation system together with a specific nonlinear algebraic relation: the bi-Langmuir adsorption isotherm. Therefore, it is important to develop accurate and reliable numerical techniques that can perform accurate numerical simulations of these models. We extended and implemented a second-order, semidiscrete, high-resolution finite volume method to simulate the governing equations of the model. Single solute flow and multi component mixture flows are assessed through a series of numerical experiments to theoretically illustrate the repercussions of intraparticle diffusion, film mass resistance, axial dispersion, and the size of the inert core radius upon simulated elution curves. Standard performance criteria are assessed to determine the optimal core radius fraction range for optimizing the separation performance.

A systematic investigation of single solute, binary and ternary PFAS transport in water-saturated soil using batch and 1-dimensional column studies: Focus on mixture effects

This study aimed to investigate the transport and release of per- and polyfluoroalkyl substances (PFAS), as single solutes and binary and ternary mixtures, and associated competitive sorption effects in water-saturated soil. Batch sorption isotherm and desorption, and one-dimensional miscible displacement studies were conducted. For the batch study, the mixtures exhibited extensive sorption isotherm nonlinearity at aqueous concentrations exceeding 20 µg/L. At and above this threshold, competitive effects significantly decreased PFAS sorption, mostly affecting perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS). Importantly, mixture effects exacerbated isotherm nonlinearity and may increase the leaching of PFAS in subsurface soil and groundwater. Further, up to 100% desorption occurred for single solutes and mixtures, indicating that the studied PFAS were weakly sorbed. For the column study, at influent concentrations (21 – 27 µg/L, depending on PFAS) near the threshold, PFOA and PFHxS breakthrough curves (BTC) generally exhibited equilibrium (nonlinear) transport, whereas perfluorooctane sulfonate (PFOS) exhibited nonequilibrium transport, with minimal or no mixture effects. Nonequilibrium transport of PFOS was driven by rate-limited sorption, especially as flow interruption tests confirmed the absence of physical nonequilibrium. The sorption distribution coefficients (Kd) from moment and frontal analyses, and 2-site modelling of the BTC, were consistent with the batch-derived Kd, although comparatively smaller. Such discrepancies may limit the applicability of batch-derived Kd values for predictive transport modelling purposes. Overall, understanding mixture impacts may aid effective predictive modelling of PFAS transport and leaching, especially in aqueous film forming foam (AFFF)-source zone areas associated with elevated PFAS concentrations. At low or environmental PFAS concentrations, mixture effects can be expected to be play a minor role in influencing PFAS transport.

Analytical solutions for transport of organic solutes in multi-layered porous media

In this study, analytical solutions for one-dimensional transport of organic solutes in multilayered porous media are developed using the methods of matrix transfer and variable separation, where multiple factors such as advection, diffusion, mechanical dispersion, adsorption, degradation, boundary condition type and change in concentration are systematically incorporated for the first time. Compared with the existing analytical solutions solved by the techniques of integral transformation or Laplace transformation, the approaches adopted in this paper are simpler and have a quicker convergence speed. Also, the proposed analytical solutions are more practical with clear expressions and consideration of multiple factors, which can be applied to various engineering cases such as bottom liner systems at landfills, covering systems of contaminated sediments and vertical barrier systems in contaminated sites. Furthermore, the correctness of the derived analytical solutions is effectively validated by comparison with the experimental results, as well as with the existing analytical solution and a numerical method. Following this, the effects of different factors on the transport process of a single organic solute in a five-layered medium are investigated, and some novel and vital laws are obtained. Overall, this research contributes to appropriate evaluation of the transport behaviours in multilayered porous media.

Nonlinear liquid-liquid chromatography: Modeling a binary mixture separation

In liquid-liquid chromatography (LLC), mixture components are separated due to their different distribution between the phases of a biphasic liquid system composed of three or four solvents. LLC separations are typically modeled assuming that only the solutes distribute between the two liquid phases and their distribution can be described with a concentration-independent distribution constant. With increasing solute concentration, the physicochemical properties of the biphasic system change, and the distribution of the solutes becomes a function of their concentration. However, the experimental determination of liquid-liquid equilibria in multicomponent systems is time-intensive, and its prediction using thermodynamic models is often not sufficiently accurate for process design purposes. Thus, in this work, we propose a simple approach to model and simulate LLC separations in the nonlinear (concentration-dependent) range of the solutes’ distribution equilibria, namely cannabidiol (CBD) and cannabigerol (CBG). Using the inverse method, the distribution equilibrium equation parameters were estimated from pulse injection experiments of single solutes at concentrations ranging from 1 to 100 mg/mL and 1–50 mg/mL for CBD and CBG, respectively. The obtained parameters were then successfully used to predict the elution profiles of binary mixtures of different compositions at 40 mg/mL total cannabinoid concentration. The approach was demonstrated and validated for CBD and CBG as model compounds and n-hexane/methanol/water 10/7.5/2.5 (v/v/v) as the biphasic solvent system. It should be noted that the applicability of the proposed approach is system-dependent, and hence, it should be evaluated for each separation task individually.

Columnar-to-equiaxed transition and grain refinement by solute interaction effects

The effects of single solute on grain refinement of binary alloys during casting have been revealed with supercooling parameter (P) and growth restriction factor (Q) theory in the literature. However, multiple-solute effects are still not clear due to the interaction between different solutes. In this work, we proposed a method to make remarkable grain refinement effects with minor Ti and C solutes. In addition, a novel method for columnar-to-equiaxed transition and grain refinement was also put forward based on solute interaction effects between multiple solute elements. Two solutes were designed first by considering (a) both segregated in solid-liquid interfaces with partition coefficients <1 and (b) with properly strong interaction energy. The interaction effect between the solutes enhances build-ups ahead of the solid-liquid interface and generate stronger constitutional supercooling, which leads to significant grain refinement in the selected model metals of Ni and Fe.

Coexisting ions and long-chain per- and polyfluoroalkyl substances (PFAS) inhibit the adsorption of short-chain PFAS by granular activated carbon

We assessed the competitive adsorption between long-chain and short-chain PFAS and the impact of coexisting ions to understand the mechanisms leading to the early breakthrough of short-chain PFAS from granular activated carbon (GAC) filters. Three pairs of short-chain and long-chain PFAS representing different functional groups were studied using GAC (Filtrasorb 400) in batch systems. In bisolute systems, the presence of long-chain PFAS decreased the adsorption of short-chain PFAS by 30–50% compared to their single solute adsorption capacity (0.22–0.31 mmol/g). In contrast to the partial decrease observed in bisolute systems, the addition of long-chain PFAS to GAC pre-equilibrated with short-chain PFAS completely desorbed all short-chain PFAS from GAC. This suggested that the outermost adsorption sites on GAC were preferentially occupied by short-chain PFAS in the absence of competition but were prone to displacement by long-chain PFAS. The presence of inorganic/organic ions inhibited the adsorption of short-chain PFAS (up to 60%) but had little to no impact on long-chain PFAS, with the inhibitory trend inversely correlated with Kow values. Study results indicated that the displacement of short-chain PFAS by long-chain PFAS and charge neutralization are important mechanisms contributing to the early breakthrough of short-chain PFAS from GAC systems.

Embedding Nonrigid Solutes in an Averaged Environment: A Case Study on Rhodopsins.

Many simulation methods concerning solvated molecules are based on the assumption that the solvated species and the solvent can be characterized by some representative structures of the solute and some embedding potential corresponding to this structure. While the averaging of the solvent configurations to obtain an embedding potential has been studied in great detail, this hinges on a single solute structure representation. This assumption is re-examined and generalized for conformationally flexible solutes and tested on 4 nonrigid systems. In this generalized approach, the solute is characterized by a set of representative structures and the corresponding embedding potentials. The representative structures are identified by means of subdividing the statistical ensemble, which in this work is generated by a constant-temperature molecular dynamics simulation. The embedding potential defined in the Frozen-Density Embedding Theory is used to characterize the average effect of the solvent in each subensemble. The numerical examples concern the vertical excitation energies of protonated retinal Schiff bases in protein environments. It is comprehensively shown that subensemble averaging leads to huge computational savings compared with explicit averaging of the excitation energies in the whole ensemble while introducing only minor errors in the case of the systems examined.

Sustainable utilization of Sedum plumbizincicola as superior hydrochar for efficient nutrients recovery

To realize sound disposal of hyperaccumulator harvested from phytoremediation, hydrothermal carbonization (HTC) has been employed to obtain superior hydrochar adsorbents for removal of phosphate and ammonium from water body. A series of hydrochars have been prepared under tuned HTC conditions to tailor hydrochar with desired properties. Generally, increased temperature and prolonged reaction time facilitated acidic oxygen functional groups on hydrochars, thereby improving adsorption capacity of hydrochar. In single solute system, a superior hydrochar, derived from HTC under 260 °C for 2 h, achieved a maximum phosphate and ammonium adsorption capacity of 52.46 mg/g and 27.56 mg/g at 45 °C, respectively. In binary system, synergistic adsorption was observed only in lower solute concentration, whereas competitive adsorption occurred under higher solute concentration. Characterization and adsorption kinetics suggested chemisorption may dominate the adsorption process, thus the adsorption capacity could be improved by tuning pHpzc of hydrochar. This study firstly demonstrates the sustainable utilization of hyperaccumulators into nutrients-enriched hydrochar as fertilizer for in-situ phytoremediation of contaminated sites with minimized environmental risks towards circular economy.

Carbon based Nanofillers Embedded Fouling Resistant Polyvinyl Chloride Nanocomposite Membranes for Oil-water Separation

Herein, we discussed the development of polyvinyl chloride (PVC) based nanocomposite ultrafiltration (UF) membrane by embedment of nanofillers such as carbon black (CB), graphitized carbon black (GCB) or mesoporous carbon, multiwalled carbon-nanotube (MWCNT), carboxylated multiwalled carbon-nanotube (CMWCNT) with increased permeate flux and fouling resistance. Ultrafiltration membranes were prepared using casting solution of PVC in N, N-dimethylacetamide (DMAc) solvent with polyethylene glycol with average MW 600Da (PEG-600) as additives with and without nanofillers. Membranes prepared were characterized in terms of pure water permeability, separation of single uncharged solutes like polyethylene oxide (PEO), water contact angle and tensile strength. Membranes were tested with synthetic oily waste water (1000 ppm oil-water emulsion) followed by pure water flux recovery after cleaning by flow reversal flushing using deionized water. The product flux was observed to increase by ~35.5%, ~11.4% &amp; ~44.4% in PVC-GCB, PVC-MWCNT and PVC-CMWCNT membranes respectively than the pure PVC membranes. The flux recovery on cleaning of fouled membranes is ~56% in pure PVC membrane, whereas it is ~72%, ~74% &amp; ~80% for PVC-GCB, PVC-MWCNT and PVC-CMWCNT membranes respectively. Incorporation of the carbon based nanofillers in pure polymer matrixes not only enhances the water permeability with marginal decrease of the separation performances but also it increases mechanical strength and the fouling resistance of the membranes. The carbon fillers-based PVC nanocomposite membranes are found promising candidates for cleaning oily wastewater.

Simultaneous removal of Cd(II) and 2-chlorophenol from aqueous solution using activated carbon supported titanate nanotubes

Combined heavy metals and chlorinated organic compounds have been widely reported in industrial wastewater. Yet, simultaneous removal of these contaminants remains challenging. In this study, a bi-functional composite (TNTs@AC) was prepared based on commercial titanium dioxide (TiO2) and activated carbon (AC) and tested for simultaneous removal of Cd(II) and 2-chlorophenol (2-CP). Under the action of high temperature and pressure, TiO2 was transformed into titanate nanotubes (TNTs) and bound to AC, and in the meanwhile, nanoscale AC particles were patched on the TNTs. In the mixed TNTs and AC phases, TNTs was responsible for taking up Cd(II), whereas AC for 2-CP. As such, the relative adsorption capacities of the composite for Cd(II) and 2-CP varied with the mass ratio of TiO2:AC, with decent uptakes for both chemicals in the mass ratio rage of 1:3 ∼1:1. TNTs@AC (prepared at TiO2:AC = 1:1) demonstrated fast sorption kinetics and high sorption capacities for both Cd(II) and 2-CP, with a maximum Langmuir adsorption capacity of 109 and 52 mg/g, respectively, in the single solute systems. In the binary systems, the adsorption capacity of Cd(II) was not affected by the presence of 2-CP, whereas the presence of Cd(II) slightly increased the uptake of 2-CP in the low Cd concentration domain (final Cd < 7 mg/L) but mildly inhibited the uptake at Cd > 7 mg/L. The dominant adsorption mechanism of Cd(II) was ion exchange between Cd(II) and Na+/H+ of the -ONa/H group of TNTs; while AC served as the primary sink for 2-CP via hydrophobic interaction along with some other possible mechanisms such as surface complexation and hole filling. TNTs@AC also performed well under common environmental conditions (pH, common co-ions, and dissolved organic matter). The formation of mixed TNTs and AC microphases appears promising for simultaneous removal of heavy metals and organic compounds from contaminated water.

Synergy of multiple precipitate/matrix interface structures for a heat resistant high-strength Al alloy

High strength aluminum alloys are widely used but their strength is reduced as nano-precipitates coarsen rapidly in medium and high temperatures, which greatly limits their application. Single solute segregation layers at precipitate/matrix interfaces are not satisfactory in stabilizing precipitates. Here we obtain multiple interface structures in an Al-Cu-Mg-Ag-Si-Sc alloy including Sc segregation layers, C and L phases as well as a newly discovered χ-AgMg phase, which partially cover the θ′ precipitates. By atomic resolution characterizations and ab initio calculations, such interface structures have been confirmed to synergistically retard coarsening of precipitates. Therefore, the designed alloy shows the good combination of heat resistance and strength among all series of Al alloys, with 97% yield strength retained after thermal exposure, which is as high as 400 MPa. This concept of covering precipitates with multiple interface phases and segregation layers provides an effective strategy for designing other heat resistant materials.