Water Stability Research Articles

Stabilization of micaceous residual soil with industrial and agricultural byproducts: Perspectives from hydrophobicity, water stability, and durability enhancement

Micaceous residual soil is prevalent in the tropical regions of southern China. However, it is generally deemed unsuitable as a construction material in earthen structures due to its inferior engineering properties. Despite previous research into stabilizing micaceous soils, there remains an urgent demand for sustainable alternatives to traditional stabilizers to achieve circularity. Furthermore, uncertainties regarding the long-term performance of stabilized soils under hydraulic conditions complicated their use in flood-susceptible areas. To provide a sustainable and low-cost solution for creating stabilized soil for earthen structures in waterlogged regions, this study explores the impact of coir fiber and fly ash, agricultural and industrial byproducts, on the hydrophobicity, durability, and water stability of micaceous residual soil from Hainan, China. The study commenced with the preliminary mechanical tests to ascertain the optimal dosage of coir fiber and fly ash, which were determined to be 1% and 15%, respectively. Then, hydrophobicity, durability, and disintegration tests are conducted on fiber-reinforced fly-ash-treated soil under various stabilization conditions. The microstructural evolution of the soil fabric in response to the stabilization process was meticulously traced using scanning electron microscopy and energy-dispersive spectroscopy. Results indicated that the addition of fly ash could impart severe and persistent water repellency to the studied soil, with the contact angle improving from 16.7° to 102.9°, and the water drop penetration time significantly extending from 3.6 s to approximately 600 s. While incorporating coir fibers into the cemented soil presented negligible improvement on soil hydrophobicity, it markedly enhanced the soil’s durability, mitigated moisture-related deterioration and decelerated disintegration. Notably, the strength residual ratio of fiber-reinforced cemented sample maintained higher than 90% even after 20-day water immersion, and the disintegration rate decreased by 57% compared to unreinforced sample. Microstructural analysis revealed that bonding, friction, and interlocking among fibers, hydration products, and soil particles are the main contributors to the stable and robust matrix, ensuring improved mechanical behavior and longevity of micaceous residual soil. This study provides an innovative method for utilizing waste byproducts in stabilizing micaceous residual soil, as a viable option for earthworks in rain-soaked or flood-prone areas.

Two AIE-Ligand-Based 2-D Luminescent Metal-Organic Frameworks as Fe3+ Sensors.

The design and synthesis of high-performance sensors are very important but remain great challenges. In this work, a new aggregation-induced-emission (AIE) molecule 4,4'-(((9H-fluoren-9-ylidene)methylene)bis(4,1-phenylene))dipyridine (L) was successfully synthesized and first developed as a functional ligand to construct two isomorphic metal-organic frameworks (MOFs) [M(L)(OBBA)]n [M2+ = Cd2+ (1), Co2+ (2); H2OBBA = 4,4'-oxybisbenzoic acid]. They adopt [M2(COO)4] flywheel clusters, OBBA2- bridges, and terminal L ligands as building units to form isomorphic 2-D networks with Lewis base active cites (uncoordinated pyridyl N). Both 1 and 2 exhibit excellent water, pH, and thermal stabilities and extremely efficient Fe3+ sensing abilities in the water environment. The quenching constants and detection limits reach the best levels reported so far. The sensing mechanism of 1 and 2 toward Fe3+ is studied in depth, and the difference in their sensing performance is also explained.

Tailored Porous Ferrocene-Based Metal-Organic Frameworks as High-Performance Proton Conductors.

Although crystalline metal-organic frameworks (MOFs) have gained a great deal of interest in the field of proton conduction in recent years, the low stability and poor proton conductivity (σ) of some MOFs have hindered their future applications. As a result, resolving the issues listed above must be prioritized. Due to their exceptional structural stability, MOFs with ferrocene groups that exhibit particular physical and chemical properties have drawn a lot of attention. This study describes the effective preparation of a set of three-dimensional ferrocene-based MOFs, MIL-53-FcDC-Al/Ga and CAU-43, containing both main group metals and 1,1'-ferrocene dicarboxylic acid (H2FcDC). Multiple measurements, including powder X-ray diffraction (PXRD), infrared (IR), and scanning electron microscopy (SEM), confirmed that the addition of ferrocene groups enhanced the thermal, water, and acid-base stabilities of the three MOFs. Consequently, their proton-conductive behaviors were meticulously measured utilizing the AC impedance approach, and their best proton conductivities are 5.20 × 10-3, 2.31 × 10-3, and 1.72 × 10-4 S/cm at 100 °C/98% relative humidity (RH), respectively. Excitingly, MIL-53-FcDC-Al/Ga demonstrated an extraordinarily ultrahigh σ of above 10-4 S·cm-1 under 30 °C/98% RH. Using data from structural analysis, PXRD, SEM, thermogravimetry (TG), and activation energy, their proton transport mechanisms were thoroughly examined. The fact that these MOFs are notably easy to assemble, inexpensive, toxin-free, and stable will increase the range of practical uses for them.

Confined-Coordination Induced Intergrowth of Metal-Organic Frameworks into Precise Molecular Sieving Membranes.

Metal-organic framework (MOF) membranes with rich functionality and tunable pore system are promising for precise molecular separation; however, it remains a challenge to develop defect-free high-connectivity MOF membrane with high water stability owing to uncontrollable nucleation and growth rate during fabrication process. Herein, we report on a confined-coordination induced intergrowth strategy to fabricate lattice-defect-free Zr-MOF membrane towards precise molecular separation. The confined-coordination space properties (size and shape) and environment (water or DMF) were regulated to slow down the coordination reaction rate via controlling the counter-diffusion of MOF precursors (metal cluster and ligand), thereby inter-growing MOF crystals into integrated membrane. The resulting Zr-MOF membrane with angstrom-sized lattice apertures exhibits excellent separation performance both for gas separation and water desalination process. It was achieved H2 permeance of ~1200 GPU and H2/CO2 selectivity of ~67; water permeance of ~8 L ⋅ m-2 ⋅ h-1 ⋅ bar-1 and MgCl2 rejection of ~95 %, which are one to two orders of magnitude higher than those of state-of-the-art membranes. The molecular transport mechanism related to size-sieving effect and transition energy barrier differential of molecules and ions was revealed by density functional theory calculations. Our work provides a facile approach and fundamental insights towards developing precise molecular sieving membranes.

Confined‐Coordination Induced Intergrowth of Metal–Organic Frameworks into Precise Molecular Sieving Membranes

AbstractMetal–organic framework (MOF) membranes with rich functionality and tunable pore system are promising for precise molecular separation; however, it remains a challenge to develop defect‐free high‐connectivity MOF membrane with high water stability owing to uncontrollable nucleation and growth rate during fabrication process. Herein, we report on a confined‐coordination induced intergrowth strategy to fabricate lattice‐defect‐free Zr‐MOF membrane towards precise molecular separation. The confined‐coordination space properties (size and shape) and environment (water or DMF) were regulated to slow down the coordination reaction rate via controlling the counter‐diffusion of MOF precursors (metal cluster and ligand), thereby inter‐growing MOF crystals into integrated membrane. The resulting Zr‐MOF membrane with angstrom‐sized lattice apertures exhibits excellent separation performance both for gas separation and water desalination process. It was achieved H2 permeance of ~1200 GPU and H2/CO2 selectivity of ~67; water permeance of ~8 L ⋅ m−2 ⋅ h−1 ⋅ bar−1 and MgCl2 rejection of ~95 %, which are one to two orders of magnitude higher than those of state‐of‐the‐art membranes. The molecular transport mechanism related to size‐sieving effect and transition energy barrier differential of molecules and ions was revealed by density functional theory calculations. Our work provides a facile approach and fundamental insights towards developing precise molecular sieving membranes.

Electron and surface engineering of Ni2P/MnP4 heterojunction as high performance bifunctional electrocatalyst for amperage-level overall water splitting

Producing hydrogen through electrocatalytic overall water splitting with ampere-level current density is still limited by the high cost and poor stability of electrocatalysts. In this work, a new type Ni2P/MnP4 heterojunction composite material was designed and prepared as bifunctional electrocatalyst. Based on XPS spectra and theoretical calculation, the formation of Ni2P/MnP4 heterojunction successfully modulates the local electronic structure of Ni2P and enhances the ionization of H and Ni by increasing the electron transfer rate. Moreover, the special nanovilli structure and superhydropholic/superaerophobic surface of Ni2P/MnP4 heterojunction accelerates the transfer of electrolyte and gaseous products. Benefiting from these advantages, the as-prepared Ni2P/MnP4/CF not only exhibits superior electrocatalytic performance, which can release 10 mA/cm2 current density with a low overpotential of 69 mV and 247 mV for HER and OER respectively, but also shows admirable stability of continuous overall water splitting to drive 1000 mA/cm2 for 180 h without notable activity degradation. We believe this material possesses outstanding potential for industrial applications, and our strategy may provide a new pathway to design relative materials.

Stacked High‐Entropy Hydroxides Promote Charge Transfer Kinetics for Photoelectrochemical Water Splitting

AbstractAlthough various kinds of cocatalyst are developed and decorated on the bismuth vanadate (BiVO4) photoanode, its photoelectrochemical (PEC) water splitting performance is limited owing to severe charge recombination and sluggish oxygen evolution reaction (OER). Herein, a high‐entropy hydroxide electrocatalyst (FeCoNiMoCrOOH) is constructed as a co‐catalyst deposited on BiVO4 with a good PEC activity and stability in potassium borate buffer, addressing substantial charge recombination and poor surface oxygen evolution reaction of the material. FeCoNiMoCrOOH synthesized by a simple electrodeposition stacking strategy, delivers an overpotential of 172 mV at 10 mA cm−2 with a stability of 600 h under alkaline conditions, representing one of the best performances on high‐entropy‐based catalysts. The FeCoNiMoCrOOH/BiVO4 photoanode shows a photocurrent density of 5.23 mA cm−2 at 1.23 VRHE with 100 h durability in potassium borate buffer. Experimental investigations and theoretical calculations demonstrate that the synergistic effect of Mo and Cr in FeCoNi catalyst effectively decreases the dissolution Fe, Co, and Ni after long‐term operation, increases the charge transfer kinetics, and promotes OER and PEC performances, therefore enhancing the photocorrosion resistance of BiVO4. This work provides a new avenue to design high entropy‐based electrocatalysts boosting solar water splitting activity and stability.

Synergistic Effects of Recycled Demolition Waste and GGBS-FA based Geopolymers on the Mechanical Properties and Stabilization Mechanism of High Plasticity Clay

Recycled demolition waste (RDW) and ground granulated blast furnace slag-fly ash-based geopolymer (GFG) are promising materials for treating high-plasticity clay (CH) in highway subgrades. However, the underlying synergistic stabilization mechanisms remain unclear. To elucidate the fundamental mechanisms governing post-treatment soil stabilization, a multi-scale laboratory investigation was undertaken. This investigation encompassed the evaluation of mechanical properties (compaction, California bearing ratio (CBR), and unconfined compressive strength (UCS)) to quantify the enhanced performance of the treated soil. Additionally, microstructural and mineralogical characterization was performed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and atomic force microscopy (AFM) to elucidate the microscopic mechanisms responsible for this improvement. The results indicated that the addition of RDW led to a reduction in the optimum moisture content (OMC) while increasing the maximum dry density (MDD) of CH. Moreover, upon incorporating RDW-GFG, the mechanical properties of the cured soil exhibited significant improvement. Specifically, the addition of 25% RDW to CH resulted in a 184% increase in CBR and effective improvement in water stability (immersion swelling percentage is reduced). Furthermore, when 25% RDW and 15% GFG were added to CH, the UCS has increased significantly by 8 times. The addition of RDW effectively enhanced the particle size distribution, compacted the soil, thus increased the shear strength. The results from XRD and SEM analyses revealed that the inclusion of GFG could generate geopolymer cementitious bonding network in the soil matrix. These materials facilitated bonding between CH particles and RDW, filling the pores and densifying the overall structure, thus increasing its strength. The synergy of RDW-GFG substantially improved the highly plastic soil through physicochemical actions, markedly elevating both its strength and water stability. Consequently, the outcomes of this experimental study offer valuable insights for road engineering applications.

Synthesis and fluorescence properties of a two-dimensional Cd-complex for the ratiometric fluorescence detection of Zn2+ ions

The two-dimensional complex [Cd3(L)(2,2'-bpy)2]n (1) was synthesized solvothermally from 4,5-di(3,5-dicarboxylphenoxy)phthalic acid (H6L) and 2,2'-bipyridine (2,2'-bpy) and fully characterized by elemental analysis, infrared spectroscopy, single crystal and powder X-ray diffraction. Complex 1 displays high stability in water and resistance towards acidic and basic media. Fluorescence studies revealed that it may be acted as a ratiometric fluorescence probe to detect Zn2+ ions in water with a superior detection limit of 3.48 nM. The fluorescence recognition mechanism stems from weak interactions between Zn2+ ions and complex 1. Its pronounced stability and recyclability suggest that the new material may be used for high-precision detection of Zn2+ ions in real-life aqueous samples, even under acidic and basic conditions.

Hydrostability, mechanical resilience, and biodegradability of paper straws fabricated through lignin-based polyurethane and chitosan binary emulsion bonding

This study focuses on enhancing the strength and water stability of paper straws through a novel approach involving a binary emulsion of lignin-based polyurethane and chitosan. Kraft lignin serves as the raw material for synthesizing a blocked waterborne polyurethane, subsequently combined with carboxylated chitosan to form a stable binary emulsion. The resulting emulsion, exhibiting remarkable stability over at least 6 months, is applied to the base paper. Following emulsion application, the paper undergoes torrefaction at 150 °C. This process deblocks isocyanate groups, enabling their reaction with hydroxyl groups on chitosan and fibers, ultimately forming ester bonds. This reaction significantly improves the mechanical strength and hydrophobicity of paper straws. The composite paper straws demonstrate exceptional mechanical properties, including a tensile strength of 47.21 MPa, Young's modulus of 4.33 GPa, and flexural strength of 32.38 MPa. Notably, its water stability is greatly enhanced, with a wet tensile strength of 40.66 MPa, surpassing commercial paper straws by 8 folds. Furthermore, the composite straw achieves complete biodegradability within 120 days, outperforming conventional paper straws in terms of environmental impact. This innovative solution presents a promising and sustainable alternative to plastic straws, addressing the urgent need for eco-friendly products.

A multiscale study of the influence of aggregate type on adhesion at the asphalt–aggregate interface

In order to examine the influence of aggregate type on the asphalt–aggregate interface, the adhesion performance between asphalt and aggregate was investigated at three scales. The pull-out test was conducted on asphalt and three kinds of aggregates at the macroscale to directly estimate the adhesion performance between them. At the microscale, the surface energies between asphalt and limestone, basalt, and andesite were examined through a surface energy experiment, and then the adhesion and debonding work were assessed. At the nanoscale, the interfacial behavior between six mineral compositions (SiO2, CaO, MgO, Al2O3, Fe2O3, and Na2O) of these aggregates and asphalt was determined using molecular dynamics simulation. The correlation of adhesion work at the microscale and nanoscale was further explored to unveil the bonding mechanisms between asphalt and aggregate. The macroscale results indicate that the adhesion force of andesite is slightly greater than that of limestone, probably because andesite has a greater surface roughness than limestone. The microscale results show the best adhesion and water stability between asphalt and limestone. The finding further explains that alkaline aggregates exhibit superior interfacial adhesion to asphalt. The nanoscale results show that the adhesion work of alkaline oxides with asphalt is more significant than that of acidic oxides with asphalt. Limestone and basalt have better adhesion to asphalt due to higher alkaline oxide content, while andesite has poorer adhesion to asphalt due to lower alkaline oxide and higher SiO2 content. The interfacial adhesion work increases from the microscale to the nanoscale by a factor of 2.91–4.75.

MoS2/graphene dispersed 2‐acrylamide‐2‐methyl propane sulfonic acid grafted polyarylene ether of di‐phenylenedi‐acetal high temperature‐proton exchange membrane fuel cell application

AbstractA polyaryleneether has been synthesized from bis‐(4‐cholorophenyl)di‐acetal (DPDA) monomer with bisphenol A and allyl bisphenol‐A. The copolymer was then functionalized with 2‐acrylamide‐2‐methyl propane sulfonic acid through radical grafting (SPAE/DPDA). The successfully synthesized SPAE/DPDA polymer was validated by using FTIR and NMR. Secondly, a composite nanostructure of MoS2/GNS nanosheet has been prepared and characterized using PXRD, FE‐SEM, and HR‐TEM. The composite membrane casted with SPAE/DPDA and varying weight percentage of 1%, 2%, 3%, 5%, 7%, and 10% MoS2/GNS nanosheet, has been characterized for ion exchange capacity (IEC), water stability (WU), swelling properties (SR), oxidative stability, and proton conductivity (PC).The MoS2/GNS dispersed SPAE/DPDA polymer nanocomposites membrane showed a chemical degradation of 22.56% and proton conductivity (PC) of 2.5 × 10−2 S/cm at 110°C. The results show that these membranes have high proton conductivity and can be used in proton exchange membrane fuel cells (HT‐PEMFCs).

Interface Regulation of Bi3TiNbO9/Rh Photocatalysts by Introducing Ultrathin Heterolayer to Enhance Overall Water Splitting

AbstractAurivillius compounds‐based photocatalysts have attracted extensive interest largely due to their ferroelectric properties and modifiable characteristics arising from the alternate stacking of structural units. However, the interfacial Schottky barrier between such semiconducting compounds as light absorbers and metallic cocatalysts for hydrogen evolution restrains the transfer of photogenerated electrons, resulting in low photocatalytic overall water splitting activity and stability. Here, an anions‐induced surface structure transformation strategy is employed to modulate the interface structure between Bi3TiNbO9 as a typical Aurivillius compound and the cocatalyst Rh by in situ growing ultrathin Bi2MoO6 heterolayer on the surface of Bi3TiNbO9 nanosheets. The introduction of Bi2MoO6 heterolayer lowers the energy barrier near the Bi3TiNbO9 surface, which can facilitate the transfer of the photogenerated electrons from bulk to surface and thus the reduction of Rh cocatalyst for highly active hydrogen production. Compared with the Bi3TiNbO9‐Rh photocatalyst, the proportion of low‐valence metallic Rh0 in Bi2MoO6 heterolayer‐modified Bi3TiNbO9‐Rh (Bi3TiNbO9‐Bi2MoO6‐Rh) is improved by 7.76%, giving rise to a photocatalytic overall water splitting activity enhancement by a factor of 4.74. This strategy emphasizes the importance of interface regulation in promoting the transfer of photogenerated charge carriers in Aurivillius‐type photocatalysts, providing an effective pathway for designing and fabricating high‐performance photocatalysts.

Enantiomeric separation of tryptophan via novel chiral polyamide composite membrane.

The separation of chiral drugs continues to pose a significant challenge. However, in recent years, the emergence of membrane-based chiral separation has shown promising effectiveness due to its environmentally friendly, energy-efficient, and cost-effective characteristics. In this study, we prepared chiral composite membrane via interfacial polymerization (IP), utilizing β-cyclodextrin (β-CD) and piperazine (PIP) as mixed monomers in the aqueous phase. The chiral separation process was facilitated by β-CD, serving as a chiral selective agent. The resulting membrane were characterized using SEM, FT-IR, and XPS. Subsequently, the chiral separation performance of the membrane for DL-tryptophan (Trp) was investigated. Lastly, the water flux, dye rejection, and stability of the membrane were also examined. The results showed that the optimized chiral PIP0.5β-CD0.5 membrane achieved an enantiomeric excess percentage (ee%) of 43.0% for D-Trp, with a solute flux of 66.18 nmol·cm-2·h-1, and maintained a good chiral separation stability. Additionally, the membrane demonstrated positive performance in the selective separation of mixed dyes, allowing for steady operation over a long period of time. This study offers fresh insights into membrane-based chiral separations.

Alkaline solubilization of microalgal protein and its impact on the functional properties of protein extract

Microalgal alternative proteins are increasingly recognized as a sustainable and promising source for future food production. Despite the widespread use of alkaline solubilization in protein extraction, its influence on the functional properties of microalgal protein extracts has received limited attention. This study marks the pioneering effort to assess the impact of alkaline (NaOH) solubilization on both the extraction process and the functional properties of Chlorella vulgaris protein extract (CVPE) obtained through isoelectric precipitation. With the gradual escalation of alkaline concentration from 0 to 0.7 M, there was a notable improvement in protein extraction efficiency, increasing significantly from 6.22% to 56.23%. However, elevated NaOH concentrations resulted in protein degradation, as evidenced in SDS-PAGE studies. Alkaline solubilization exhibited a positive impact on various functional properties of CVPE. It enhanced solubility, water absorption capacity, foaming capacity and stability, as well as emulsifying activity and stability. However, there was a slight decrease in oil absorption capacity with increasing NaOH concentration. Notably, the maximum solubility, oil adsorption capacity, foaming capacity, and emulsion activity of CVPE were 2.3-, 1.8-, 2-, and 1.3-fold higher, respectively, than those of commercial soy protein isolate (SPI). This highlights the effectiveness of alkaline solubilization in in modifying C. vulgaris protein and emphasizes the high potential of CVPE as a functional food ingredient.

Supercritical fluid extraction of emulsion-assisted encapsulation of hypocholesterolemic bioactive compounds

β-sitosterol and Curcumin, known for their hypocholesterolemic effects, have difficulties for application in aqueous foods due to their reduced water solubility and stability. The encapsulation technique allows these compounds to be protected, resulting in increased bioavailability and bioaccessibility. This study investigated the feasibility of producing capsules using different biopolymeric coating materials through a Supercritical Fluids Extraction of Emulsions (SFEE) encapsulation process. Emulsions with homogeneous droplet sizes were processed at 40 [°C] by the SFEE method at pressures of 9 and 13 [MPa]. β-sitosterol powder was successfully encapsulated in both polycaprolactone and modified-starch matrices. Curcumin could only be encapsulated in modified starch, probably because of the highly hydrophobic nature of this compound. The resulting powders, with process efficiencies higher than 60%, were characterized by thermal, structural and morphological analyses, indicating agglomerated spherical capsules. Optimal encapsulation was at 9 [MPa] due to smaller capsule sizes, lower pressure requirements and reduced CO2 consumption.

Water at negative pressure: nuclear quantum effects

Various condensed phases of water, spanning from the liquid state to multiple ice phases, have been systematically investigated under extreme conditions of pressure and temperature to delineate their stability boundaries. This study focuses on probing the mechanical stability of liquid water through path-integral molecular dynamics simulations, employing the q-TIP4P/F potential to model interatomic interactions in flexible water molecules. Temperature and pressure conditions ranging from 250 to 375 K and − 0.3 to 1 GPa, respectively, are considered. This comprehensive approach enables a thorough exploration of nuclear quantum effects on various physical properties of water through direct comparisons with classical molecular dynamics results employing the same potential model. Key properties such as molar volume, intramolecular bond length, H–O–H angle, internal and kinetic energy are analysed, with a specific focus on the effect of tensile stress. Particular attention is devoted to the liquid-gas spinodal pressure, representing the limit of mechanical stability for the liquid phase, at several temperatures. The quantum simulations reveal a spinodal pressure for water of − 286 and − 236 MPa at temperatures of 250 and 300 K, respectively. At these temperatures, the discernible shifts induced by nuclear quantum motion are quantified at 15 and 10 MPa, respectively. These findings contribute valuable insights into the interplay of quantum effects on the stability of liquid water under diverse thermodynamic conditions.

Contrastive study on mechanical and microstructure properties of silt improved by nano material stabilizers

Silt is generally stabilized with industrial waste for subgrade filler material. However, problems such as high cost, poor water stability, and easy shrinkage hinder the use of industrial waste-stabilizing materials. Experiments are conducted to compare the effect of nano-silica (NS) and nano-MgO (NM) on the unconfined compressive strength (UCS) of silt. It is undertaken by stabilized silt with NM and NS in four different concentration grades of NM(S)-3, NM(S)-4, NM(S)-5, NM(S)-6 ( 0.3%, 0.4%, 0.5%, 0.6% by weight of silt). XRD, FT-IR, and SEM tests are carried out to discern the latent mechanisms so that the mineral composition and pore structure within the soil matrix can be explained. The results demonstrate that the increase in different grades of nano-MgO and nano-silica stabilized silt plays an important role in improving the mechanical properties of the silt. Nano-silica is more conducive to strength and water resistance enhancement due to the formation of ettringite and C-S-H gel. Nevertheless, a small amount of nano-MgO can better improve the water stability of stabilized silt in the early stage. Optimal results are obtained for silt treated with NS-5 (2% cement, 2% GGBS, 1% FA, 0.5% nano-silica) and NM-5 (2% cement, 2% GGBS, 1% FA, 0.5% nano-MgO). XRD, FT-IR, and SEM analysis of the samples show, respectively, that the amorphous (C-S-H) structure and the soil particles embedded in the cementitious matrix comprise the strength of the silt. Nano-MgO is mainly involved in carbonation and pozzolanic reactions. The cement hydration reaction and ettringite formation, which unite smaller particles to produce larger particles, are enhanced by the addition of SiO2. In summary, this paper recommends the use of nano-MgO to improve the early strength of stabilized silt, and the use of nano-silica to improve the long-term strength.

Luminescent Perovskite-Cross-Linked Polymer with Low Shrinkage and Excellent Stability.

When organic cross-linked polymers are combined with metal halide perovskite nanocrystals (PNCs) for realizing luminescent perovskite-polymer display materials, the stability of PNCs is enhanced and their shrinkage is suppressed. This work presents a feasible strategy for preparing CsPbBr3 nanocrystals (NCs) within a polydicyclopentadiene (PDCPD) thermosetting cross-linked resin matrix simultaneously via a one-step reaction. The obtained PDCPD@PNCs composite exhibits narrow peak half-widths (15-20 nm), high light transmittance (80%), low curing volume shrinkage (1.4%), tunable tensile properties, excellent stability, and a photoluminescence quantum yield (PLQY) of 44.3%. The composite material exhibits long-term stability in water, acid, and base solutions for over 90 days, with the PL intensity being maintained at over 90%. Furthermore, the composite is highly resistant to polar organic solvents owing to the insolubility imparted by cross-linking. White LEDs (WLED) fabricated using the as-prepared composite demonstrate excellent potential as light sources in optical devices.

Synthesis, Structure and (Photo)Catalytic Behavior of Ce-MOFs Containing Perfluoroalkylcarboxylate Linkers: Experimental and Theoretical Insights.

Cerium-based Metal-Organic frameworks (Ce-MOFs) are attracting increasing interest due to their similar structural features to zirconium MOFs. The redox behavior of Ce(III/IV) adds a range of properties to the compounds. Recently, perfluorinated linkers have been used in the synthesis of MOFs to introduce new characteristic into the structure. We report the synthesis and structural characterization of Ce(IV)-based MOFs constructed using two perfluorinated alkyl linkers. Their structure, based on hexanuclear Ce6O4(OH)4 12+ clusters linked to each other by the dicarboxylate ions, has been solved ab-initio from X-ray powder diffraction data and refined by the Rietveld method. The crystallization kinetics and the MOF formation mechanism was also invesitigated by Synchrotron radiation with XAS spectroscopies (EXAFS and XANES). The MOFs present the same fcu cubic topology as observed in MOF-801 and UiO-66, and they showed good stability in water at different pH conditions. The electronic structure of these MOFs has been studied by DFT calculations in order to obtain insights into the density of states structure of the reported compounds, resulting in band gaps in the range of 2.8-3.1 eV. Their catalytic properties were tested both thermally and under visible light irradiation for the degradation of methyl orange (MO) dye.