Unary Systems Research Articles

The effect of photoinitiator systems on resin-based composite containing ZnO-nanoparticles.

Zinc oxide (ZnO) powder possesses antibacterial activity and although white in color, it can severely reduce the depth of cure (DoC) of resin-based composite (RBC). This study investigated the effect of unary and binary photoinitiator systems on the DoC and degree of conversion (DC) of formulated RBC containing ZnO-nanoparticles. Fourteen RBCs (n = 3/group) were formulated consisting of 50 wt% mixture of monomers (Bis-GMA, TEGDMA, and UDMA) and 50 wt% fillers (inert barium glass powder and silica nanoparticles). ZnO-nanoparticles were added at 0 (control), 0.5, 1, 1.5 and 2 wt%. A unary initiator system consists of camphorquinone (CQ) 0.25, 0.5 and 1 wt% and ethyl 4-(dimethylamino)benzoate (EDMAB) 0.75 wt% or a binary initiator system consisting of diphenyliodonium hexafluorophosphate (DPI) 0.25, 0.5 and 1 wt%, CQ 0.25, 0.5 and 1 wt% and EDMAB 0.75 wt% were added to the monomer mixture. To measure the DoC, each specimen was prepared in a custom-made mold with a slot (16 x 8×2 mm) and a top cover plate, irradiated from one end (40 s), stored dry (37° C, 1 d) and measured at increasing depths using Vickers hardness (0.5 mm intervals). 1 mm thick specimens were prepared to measure DC continuously using FTIR, from zero up to 24 h post-irradiation. Increasing the concentrations of ZnO led to a significant reduction of DoC (p < 0.05). But most of the binary initiator groups showed significantly higher DoC (p < 0.05). Depth, at 80 % of max VHN, of unary initiator groups reduced from 6.8 mm (ZnO at 0 wt%) to 2.1 mm (ZnO at 2 wt%) and in binary initiator groups from 8.4 mm to 2.3 mm. Groups with lower photoinitiator concentrations (0.25 wt%) showed a significant increase in DoC compared with groups with higher concentrations (1 wt%) (p < 0.05). DC after 24 h was independent of either ZnO concentration or the photoinitiator system (p > 0.05). However, faster conversions were observed in binary initiator groups. The RPmax of binary groups ranged from 8.1 % to 10.1 %/s, and unary groups ranged from 5.2 % to 7.2 %/s. The addition of DPI resulted in an overall increased curing depth, which was enhanced when lower concentrations of photoinitiators were used. Also, DPI resulted in faster conversions. This is desirable in designing antibacterial RBC containing ZnO.

Precisely Constructing Superlattices of Soft Giant Molecules via Regulating Volume Asymmetry.

Soft matters, particularly giant molecular self-assembly, have successfully replicated complex structures previously exclusive to metal alloys. These superlattices are constructed from mesoatoms─supramolecular spherical motifs of aggregated molecules, and the formation of superlattices critically depends on the volume distributions of these mesoatoms. Herein, we introduce two general methods to control volume asymmetry (i.e., the volumes' ratio of the largest to smallest mesoatoms, VL/VS) within giant molecular self-assembly. Leveraging the spontaneous increase in the mesoatomic volume ratio in unary systems and self-sorted binary blends, we systematically adjust the volume asymmetry from 1.0 to 9.0 across 24 unary systems and 56 binary blends of giant molecules, uncovering the formation of various superlattices, including BCC, Frank-Kasper A15, σ, Laves C14, C15, NaZn13, AlB2, and notably, the first NaCl like superlattice in homogeneous soft matter self-assembly. A geometric-based analysis, combined with experimental results, further establishes a quantitative relationship between volume asymmetry and the corresponding superlattice formations, thus laying a solid foundation for superlattice engineering within giant molecular systems to mimic and even beyond metal alloys. The lattice parameters of various unit cells range from approximately 5 to 20 nm. Our investigation in giant molecules could guide the advancement of mesoscopic, periodic soft matter materials.

Computational screening of 2D ternary penta-materials with auxetic properties and efficient photocatalytic CO2 reduction

Due to unique structural and electronic properties, pentagon-based two-dimensional (2D) materials have captured significant interest in recent years. However, previous studies on these materials have primarily focused on unary and binary systems, with less exploration of ternary pentagonal structures. Herein, we conducted first-principles calculations to evaluate the stability of 122 ternary pentagonal monolayers composed of metals, nitrogen, and chalcogen. We identify six highly stable candidates, including AuNS, CuNTe, GaNS, InNS, SbNS, and SbNSe that meet the criteria for thermodynamic, mechanical, and dynamic stability. Mechanical property analysis reveals that five of these monolayers demonstrate auxetic behavior. Electronic structure calculations show that all candidates are semiconductors with band gaps ranging from 0.12 to 3.42 eV. Specifically, the SbNS and SbNSe monolayers are indirect semiconductors with band gaps of 2.25 and 2.27 eV, respectively. These materials exhibit strong visible light absorption, and potentially serve as exceptional photocatalysts for the reduction of CO2 to CH4 due to the optimal band alignment. The free energy change in the rate-limiting step is even lower than those found in g-C3N4 and MoS2-based systems. Our findings highlight new pentagon-based 2D materials with remarkable electronic, mechanical, and optical properties, making them promising candidates for applications in mechanics and energy conversion.

Ecofriendly magnetic nanocomposite (Fe3O4/SiO2/Ag) fabrication for sustainable dye wastewater management: catalysis and SERS for a cleaner approach.

Our study focuses on sustainable dye wastewater management through catalysis, scrutinized by surface-enhanced Raman spectroscopy (SERS) using an ecofriendly magnetic nanocomposite (Fe3O4/SiO2/Ag (FSA)). To our knowledge, the use of green synthesis for fabricating nanocomposites from a single source, namely Nerium oleander leaves, has not been extensively explored. This poses a distinctive and challenging approach, differentiating it from conventional chemical methods. Analytical investigations confirm the nanocomposite morphology, featuring Fe3O4 cubic cores with SiO2 spheres and silver nanoparticles (AgNPs) decoration. Efficient catalysis rapidly degrades unary and binary dye systems (MB, RhB, and MB + RhB), with high efficiency in short durations (MB: 96% in 10min, RhB: 94% in 2min, MB + RhB: 96% MB and 91% RhB in 9min) and with elevated "k" values. SERS monitors water quality, revealing complete degradation and quenching of dye fingerprints with fabricated nanocomposite FSA. The nanocomposite exhibits reusability over four cycles by easy recovery of catalyst with external magnet. The nanocomposite achieved 89.7% degradation efficiency in real-time household wastewater treatment. The proposed research aligns with UN SDGs 6 and 15 and this approach holds promise for advancing industrial waste management.

On the theory of the nucleation of gas bubbles at grain boundaries and incoherent inclusions

On the base of the critical analysis of two-dimensional models of the nucleation of gas filled bubbles at grain boundaries of helium-implanted specimens under the action of tensile stresses, a new model is developed within the framework of the Reiss theory of homogeneous nucleation in binary systems. This approach considers that gas bubbles are formed as a result of agglomeration in a binary system of vacancies and gas atoms at grain boundaries, avoiding significant simplifications of previous models based on the classical nucleation theory for single-component (unary) systems. The new model is extended to consider the nucleation of Xe bubbles at grain boundaries in UO2 under irradiation conditions and can be used for numerical analysis of experimental observations after the foreseen implementation in a fuel performance code. A similar approach can be applied to the nucleation and growth of gas bubbles on incoherent inclusions, such as those observed in irradiated ODS steels.

Heavy metals biosorption in unary, binary, and ternary systems onto bacteria in a moving bed biofilm reactor

Toxic and heavy metals cause direct and indirect damage to the environment and ultimately to humans. This study involved the isolation of indigenous bacteria from heavy metal-contaminated environments that have the ability to bioabsorb heavy metals such as cadmium, nickel, and lead. The bioabsorption process was optimized by varying parameters such as temperature, metal concentration, number of bacteria, pH, and more. The bacterial isolates were investigated in terms of morphology, biochemistry, and phylogeny, with 12 strains chosen in the initial stage and one strain chosen in the final stage. It should be remembered that the metal uptake capacity of all isolates was approximately calculated. A box and reactor were designed to house these optimized microorganisms. Based on biochemical, morphological, and molecular results, the isolated strain was found to be closely related to the Bacillus genus. In the first five steps of testing, the ideal pH for removing lead alone, lead with cadmium, lead with nickel, and lead ternary (with cadmium and nickel) by Bacillus bacteria was found to be 7, 6, 5.5, and 6.5, respectively. The absorption efficiencies for single lead (unary), lead together with nickel, cadmium (binary), and ternary (lead with cadmium and nickel) were found to be 0.36, 0.25, 0.22, and 0.21 mmol/g, respectively. The ideal temperature for lead removal was around 30 °C. The adsorption isotherm for each lead metal in different states was found to be similar to the Langmuir isotherm, indicating that the surface absorption process is a single-layer process. The kinetics of the process follow the second-order kinetic model. The amount of Bacillus bacteria biomass obtained during this process was approximately 1.5 g per liter.

Predicting melting temperature of inorganic crystals via crystal graph neural network enhanced by transfer learning

The melting temperature, a crucial material property, is particularly challenging to measure accurately for inorganic crystals. The data-driven approach emerges as a potential solution, although its effectiveness is hindered by the limitation of available data. To counter this challenge, we implement transfer learning, leveraging a vast computational database of atomization energy. We first pre-train a geometric-information-enhanced crystal graph neural network (GeoCGNN) using atomization energies of approximately 36,000 materials that are computed by the density functional theory. Subsequently, the pre-trained model is fine-tuned using melting temperatures measured for 799 crystals, encompassing 83 elements, ranging from unary to quaternary systems. This transfer learning strategy decreases the root mean square error from 407 to 218 K, attesting to a marked improvement in prediction accuracy. Furthermore, transfer learning significantly mitigates error variability across unary, binary, and ternary (or higher-order) systems, thereby enhancing the reliability of predictions across a broader range of crystals. We also show that transfer learning allows effective task adaptation by leveraging representation learned from pre-training. Therefore, it can achieve better prediction performance even with a limited number of data for predicting melting points.

Molecular dynamics simulation of vapor-liquid equilibrium in 1-alkanol unary systems: a study of surface tension, density, and vapor pressure of TraPPE-UA force field

Molecular dynamics simulation of vapor-liquid equilibrium in 1-alkanol unary systems: a study of surface tension, density, and vapor pressure of TraPPE-UA force field

Exploring fullerene-based superlattices self-assembled via giant molecules

Fullerene, as a novel building block of functional materials, possesses a wide range of intriguing properties, some of which are closely related to hierarchical structures. Advancing the methodology for manipulating fullerene hierarchical structures could facilitate developments of novel fullerene-based materials with desired properties. In the present work, we report our exploration of a series of fullerene-based unconventional spherical packing nanostructures, including Frank-Kasper (FK) A15 and σ phases as well as dodecagonal quasicrystalline (DDQC) phase in unary self-assembly systems of fullerene-based giant molecules. Also, in giant molecule binary blends, alloy-type spherical phases with high volume asymmetries such as FK Laves C14 (MgZn2) and C15 (MgCu2) phases and quasi-FK AlB2 phase can also be found. These observations showcase the feasibility of fabricating a wide range of fullerene-based superlattices through self-assembly of specifically designed giant molecules. Superlattice engineering offers a promising avenue for constructing specific structures and functions in order to achieve desired properties, in particular, for developing innovative fullerene-based materials.

Remediation of Pb(II) and Cd(II) in polluted waters with calcium thioglycolate–modified straw biochar

The pollution of water bodies by heavy metals (HMs) such as Pb(II) and Cd(II) poses a serious environmental risk. Herein, rice straw biochar (RBC) modified with calcium thioglycolate was used to remove Pb(II) and Cd(II) from aqueous solutions. The adsorption performance of the modified biochar was investigated via adsorption kinetics and isotherm model fitting. Furthermore, scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) were used to elucidate the modification and adsorption mechanisms. The results showed that the modification process loaded sulfur-containing functional groups, calcium carbonate, and calcium oxalate crystals on the biochar surface, considerably enhancing its complexation performance and ion-exchange capacity. The equilibrium adsorption amounts for Pb(II) and Cd(II) reached 124.92 and 65.44 mg g−1 in unary systems, respectively; they reached 121.34 and 39.43 mg g−1 in a binary Pb(II) and Cd(II), respectively. Moreover, the optimal adsorption conditions were as follows: pH = 6, temperature = 25 °C, dosage = 0.8 g L−1, and contact time = 2 h. In the binary Pb(II) and Cd(II) system, the adsorption process obeyed the Langmuir competitive adsorption model, which means that one adsorption site on the modified biochar was effective for only one heavy-metal ion, and the modified biochar was more selective for Pb(II) than for Cd(II). The adsorption mechanism, which was dominated by chemisorption, mainly involved complexation, precipitation, ion exchange, and cation-π interactions. Meanwhile, adsorption and desorption experiments indicated that the modified biochar exhibited satisfactory recycling performance, demonstrating its feasibility as an inexpensive and efficient heavy-metal adsorbent for polluted water.

Adsorption of Zn(II), Pb(II), and Cu(II) by Residual Soil-Derived Zeolite in Single-Component and Competitive Systems

Using construction residual soil (RS) as the raw material, RS-derived zeolite (RSDZ) was prepared through a fusion-hydrothermal process. The adsorption performance and mechanisms of RSDZ for Pb2+, Zn2+, and Cu2+ were investigated in single-component and competitive systems. The strong RSDZ X-ray diffraction peaks at 2θ = 12.47, 17.73, 21.65, 28.18, and 33.44°, together with the results of scanning electron microscopy and Fourier transform-infrared spectroscopy (FT-IR) indicated that NaP1 zeolite (Na6Al6SiO32∙12H2O) was successfully synthesised. The Brunauer–Emmett–Teller surface area, average pore size, and cation exchange capacity increased from 9.03 m2∙g−1, 18.85 nm, and 0.12 meq∙g−1 to 47.77 m2∙g−1, 41.60 nm, and 0.61 meq∙g−1, respectively, after the fusion-hydrothermal process. The maximum Langmuir adsorption capacity of RSDZ for Zn2+, Pb2+, and Cu2+ in the unary systems was 0.37, 0.38, and 0.40 mmol·g−1, respectively. Increasing the initial solution pH facilitated the adsorption reaction, and the adsorption performance was stable when pH &gt; 3. The distribution coefficients in the binary and ternary systems indicated that RSDZ had greater affinity for Pb2+ and Zn2+ than for Cu2+ due to the larger ionic radius and relative atomic weight of the former two cations. The relative affinity to Pb2+ and Zn2+ was related to their concentration, with more competitive adsorption of Pb2+ at concentrations higher than 0.4 mmol·L−1 in binary systems and 0.25 mmol·L−1 in ternary systems. X-ray photoelectron spectroscopy and FT-IR analyses indicated that ion exchange was the main mechanism involved in the adsorption of heavy metal ions by RSDZ, accompanied by ligand exchange.

PHYSICAL AND SUB-PHYSICAL PARADIGMS

Promising tasks in three dualistic metaphysical paradigms are noted. The prospects of the relational-statistical interpretation (interpretation) of quantum mechanics are indicated. In relational physics, the importance of studying the possibility of controlling gravity due to an electromagnetic field is noted. In the field-theoretic approach, it is necessary to investigate the possibility of developing a gauge theory of time. A way of constructing the geometry of praspinors based on unary systems of complex relations is proposed. The hypothesis of pre-physical reality and the prospect of creating binary geometrosubphysics are discussed.

Reversible Diffusionless Phase Transitions in 3D Nanoparticle Superlattices

Nanocomposite tectons (NCTs), polymer brush-grafted nanoparticles that use supramolecular interactions to drive their assembly, form ordered nanoparticle superlattices (NPSLs) with well-defined unit cell symmetries when thermally annealed. In this work, we demonstrate that appropriate assembly and processing conditions can also enable control over the microstructure of NCT lattices by balancing the enthalpic and entropic factors associated with ligand packing and supramolecular bonding during crystallization. Unary systems of NCTs are assembled via the addition of a small molecule capable of binding to multiple nanoparticle ligands; these NCTs initially form face-centered-cubic (FCC) structures in solvents that are favorable for the particles' polymer brushes. However, the FCC lattices undergo a reversible, diffusionless phase transition to body-centered-cubic (BCC) lattices when transferred to a solvent that induces polymer brush collapse. The BCC superlattices maintain the same crystal habit as the parent FCC phase but exhibit significant transformation twinning similar to that seen in martensitic alloys. This previously unseen diffusionless phase transformation in NPSLs enables unique microstructural features in the resulting assemblies, suggesting that NPSLs could serve as models for the investigation of microstructural evolution in crystalline systems and extend our understanding of NPSLs as atomic material analogues.

Molecular dynamics investigation on the vapor–liquid interface behavior of long-chain alkanes, alcohols, and their mixtures

The accurate description of the liquid–vapor interface behavior of higher alkanes and alcohols is an important topic in many petroleum and chemical industries. This research provides molecular-level information on the vapor–liquid interfaces (phase behavior, surface tension, self-diffusion, and solvation structure). Through the use of molecular dynamics simulation, five selected long-chain alkanes (n-dodecane, 5-methyl-undecane), alcohols (1-dodecanol, 1,12-dodecanediol, and 2-butyl-1-octanol), and their mixtures (n-dodecane + 1-dodecanol or 1,12-dodecanediol) have been modeled over a broad temperature range from 323.15 to 573.15 K. The aforementioned properties are qualitatively reproduced using the Optimized Potential for Liquid Simulations–All Atom (OPLS and L–OPLS) and the Transferable Potential for Phase Equilibria–United Atom (TraPPE–UA) force fields, respectively. The current findings are in good agreement with earlier experimental measurements as well as other simulated results. Moreover, the molecule orientations and chain conformation in the bulk liquid area are fully investigated by monitoring the center-of-mass radial distribution function and the probability distributions of end-to-end lengths for certain components. All five hydrocarbons exhibit equivalent propensities for ordering and chain conformation at the interface when subjected to the same isotherm. In addition, we compare the physical and structural characteristic of the unary and binary systems at the same temperature to further investigate the process by which molecular arrangement affects macroscopic thermophysical features. These simulations will provide specific guidance for choosing these widely used force fields to study petrochemical technologies.

Integration of Light Curve Brightness Information and Layered Discriminative Constrained Energy Minimization for Automatic Binary Asteroid Detection

Binary asteroid exploration is an important research focus in the areas of deep space exploration and space informatics because of its unique scientific value in analyzing the structure and gravitational dynamic properties of asteroids, as well as the origin and evolution of celestial bodies in the solar system. Remote photometric observations can reveal the key characteristics of binary asteroids that differ from other kinds of asteroids, especially unary asteroids, and provide an efficient and convenient way to discover binary asteroids. However, the automatic binary asteroid detection problem by advanced machine learning methodology remains unresolved when handing complex asteroid photometric data. For this problem, this article proposes to simulate unary and binary asteroid systems using cellinoid and oblate sphere shape models and generate the corresponding light curve brightness information with different asteroid physical parameters. Then, a benchmark unary and binary asteroid light curve dataset is constructed. Afterward, a layered discriminative constrained energy minimization (LDCEM) method is developed to train a binary asteroid detector in a layered learning manner by enlarging the response differences between the light curve data of unary and binary asteroids such that the two common kinds of asteroids can be well distinguished. The experimental results on the simulated asteroid light curve data, as well as the real observed asteroid light curve data, show that the proposed LDCEM method can yield promising binary asteroid detection performance in comparison with some representative detection methods.

Sorting in Memristive Memory

Sorting data is needed in many application domains. Traditionally, the data is read from memory and sent to a general-purpose processor or application-specific hardware for sorting. The sorted data is then written back to the memory. Reading/writing data from/to memory and transferring data between memory and processing unit incur significant latency and energy overhead. In this work, we develop the first architectures for in-memory sorting of data to the best of our knowledge. We propose two architectures. The first architecture is applicable to the conventional format of representing data, i.e., weighted binary radix. The second architecture is proposed for developing unary processing systems, where data is encoded as uniform unary bit-streams. As we present, each of the two architectures has different advantages and disadvantages, making one or the other more suitable for a specific application. However, the common property of both is a significant reduction in the processing time compared to prior sorting designs. Our evaluations show on average 37 × and 138× energy reduction for binary and unary designs, respectively, compared to conventional CMOS off-memory sorting systems in a 45 nm technology. We designed a 3×3 and a 5×5 Median filter using the proposed sorting solutions, which we used for processing 64×64 pixel images. Our results show a reduction of 14× and 634× in energy and latency, respectively, with the proposed binary, and 5.6× and 152×10 3 in energy and latency with the proposed unary approach compared to those of the off-memory binary and unary designs for the 3 × 3 Median filtering system.

Geopolymer: A Systematic Review of Methodologies.

The geopolymer concept has gained wide international attention during the last two decades and is now seen as a potential alternative to ordinary Portland cement; however, before full implementation in the national and international standards, the geopolymer concept requires clarity on the commonly used definitions and mix design methodologies. The lack of a common definition and methodology has led to inconsistency and confusion across disciplines. This review aims to clarify the most existing geopolymer definitions and the diverse procedures on geopolymer methodologies to attain a good understanding of both the unary and binary geopolymer systems. This review puts into perspective the most crucial facets to facilitate the sustainable development and adoption of geopolymer design standards. A systematic review protocol was developed based on the Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist and applied to the Scopus database to retrieve articles. Geopolymer is a product of a polycondensation reaction that yields a three-dimensional tecto-aluminosilicate matrix. Compared to unary geopolymer systems, binary geopolymer systems contain complex hydrated gel structures and polymerized networks that influence workability, strength, and durability. The optimum utilization of high calcium industrial by-products such as ground granulated blast furnace slag, Class-C fly ash, and phosphogypsum in unary or binary geopolymer systems give C-S-H or C-A-S-H gels with dense polymerized networks that enhance strength gains and setting times. As there is no geopolymer mix design standard, most geopolymer mix designs apply the trial-and-error approach, and a few apply the Taguchi approach, particle packing fraction method, and response surface methodology. The adopted mix designs require the optimization of certain mixture variables whilst keeping constant other nominal material factors. The production of NaOH gives less CO2 emission compared to Na2SiO3, which requires higher calcination temperatures for Na2CO3 and SiO2. However, their usage is considered unsustainable due to their caustic nature, high energy demand, and cost. Besides the blending of fly ash with other industrial by-products, phosphogypsum also has the potential for use as an ingredient in blended geopolymer systems. The parameters identified in this review can help foster the robust adoption of geopolymer as a potential “go-to” alternative to ordinary Portland cement for construction. Furthermore, the proposed future research areas will help address the various innovation gaps observed in current literature with a view of the environment and society.

Generalization of thermodynamic Langmuir isotherm for mixed‐gas adsorption equilibria

AbstractThis work presents a comprehensive thermodynamic model for both pure component isotherms and mixed‐gas adsorption equilibria. A generalization of thermodynamic Langmuir isotherm, the proposed model assumes competitive adsorption of multiple adsorbates on adsorbent surface for mixed‐gas adsorption equilibria, and it applies an area‐based adsorption nonrandom two‐liquid activity coefficient model in the activity coefficient calculations for the adsorbate phase. The resulting generalized Langmuir isotherm properly captures both surface loading dependence and adsorbate phase composition dependence for mixed‐gas adsorption equilibria. The model is validated with accurate representations of gas adsorption equilibrium data for varieties of unary, binary, and ternary gas systems. The model results are further compared with those calculated from extended Langmuir isotherm and Ideal Adsorbed Solution Theory.

Binary Ti–Fe system. Part II: Modelling of pressure-dependent phase stabilities

Based on the experimental and calculated data from literature, the thermodynamic assessment of the binary Ti–Fe system under hydrostatic pressure was performed. The pressure-independent part of the Gibbs energy was modelled using the heat capacity data. The description of the pressure-dependent part of the Gibbs energy was based on the molar volume, thermal expansion and bulk modulus data, and on their pressure derivatives. Using the Murnaghan equation of state, the binary phase stabilities in the Ti–Fe system were assessed to reproduce the experimental results in the pressure range between 2.3 and 2.7 GPa. The thermodynamic functions were converted into the parameters of a phenomenological pressure model, which is implemented in the Thermo-Calc software. The reliability of the assessment is illustrated on the unary systems Ti and Fe containing high-temperature and high-pressure phases, and on the binary Ti–Fe system containing intermetallic phases TiFe and TiFe2 in addition to the terminal solid solutions. It is shown that the calculation of the T0 lines can help in understanding the formation of α′-Ti(Fe) martensite and the high-pressure phase ω-Ti and its metastability at atmospheric pressure.

Simultaneous removal of Pb2+ and direct red 31 dye from contaminated water using N-(2-hydroxyethyl)-2-oxo-2H-chromene-3-carboxamide loaded chitosan nanoparticles.

This study reports the preparation of a new material that can remove synthetic dyes and trace metals simultaneously. A new coumarin derivative was synthesized and its chemical structure was inferred from spectral data (FT-IR, 1H-NMR, 13C-NMR). Meanwhile, chitosan nanoparticles (CsNPs) were prepared then used as a carrier for two different concentrations of the coumarin derivative (C1@CsNPs and C2@CsNPs). The TEM, SEM and DLS findings illustrated that the prepared nanocomposites exhibited spherical shape and small size (less than 200 nm). The performance of the prepared material for the removal of an anionic dye (direct red 31, DR31) and cationic trace metal (Pb2+) was evaluated in unary and binary systems. The results revealed that complete removal of 10 mg L−1 of DR31 and Pb2+ in unary system was achieved at pHo 3.0 and 5.5 using 0.5 and 2.0 g L−1, respectively, of C2@CsNPs. The adsorption of DR31 and Pb2+ followed different mechanisms as deduced from the effect of pHo, kinetic, isotherm and binary adsorption studies. The adsorption of DR31 followed the Langmuir isotherm model and the pseudo-first-order kinetic model. While, the adsorption of Pb2+ followed Freundlich isotherm model and Elovich kinetic model. In the binary system, the co-presence of DR31 and Pb2+ did not affect the adsorption of each other's. Overall, the prepared material showed promising results for the removal of anionic dyes and cations trace metals from contaminated water.