Key Engineering Materials Vol. 1044

Abstract: This study examined the influence of pH (4, 7, 10), temperature (20 °C, 30 °C, 40 °C), nanoparticle concentration (13 ppm, 26 ppm), and Pb²⁺ addition (0 , 7 ppm) on the dispersion behavior of bentonite nanoclays in water. Using light scattering techniques, the hydrodynamic radius, zeta potential, and diffusion coefficient were measured. Results showed pH as the primary control, with aggregation highest at neutral pH and stability greatest under basic conditions. Concentration changes modestly influenced dispersion, while Pb²⁺ reduced stability through electric double layer compression and induced precipitation at high pH. Temperature effects were minimal. The results highlight the importance of pH and ionic environment in regulating nanoclay behavior and stability, with implications for its use in water treatment and remediation systems.

Abstract: Enhancing ion transport through Metal-Organic-Framework (MOF) membranes is becoming increasingly important in various research fields, such as heavy metal separation from water, CO₂ absorption, and energy conversion. Using two-dimensional metal-organic framework (2D MOF) material has received tremendous attention in the salinity gradient power (SGP) and molecular separation due to its high surface area, tunable pore size, chemical stability, and flexibility. However, low ion flux is crucial yet challenging with standard 2D nanomaterial, due to limited pore, long ion path, and low ion selectivity. The insertion of nanofiber into 2D nanoporous Cu-TCPP membrane can generate interconnections between the interplanar nanofibers and the lamellar 2D nanoporous MOF membrane, introducing a fixed space‑charge density of –1.0×10⁷ C m⁻³ and resulting in increased mechanical strength, ion flux, and ion selectivity compared to the pure 2D MOF membrane. This study focuses on MOF/natural nanofiber membrane applied in converse energy from sustainable resource of seawater and river water. Regarding experiment, green and inexpensive natural-based fiber would be used to synthesize nanofiber (NNF) which are then compounded with 2D nanoporous Cu-TCPP to prepare Cu-TCPP@NNF nanofluidic membranes. The experimental results can be validated by means of COMSOL Multiphysics simulations based on the Poisson-Nernst-Planck and Navier-Stokes equations to indicate the effect of NNF on increasing space charge density and enhancing the ion transport through the membrane. Simulation results show that under a 500/10 mM NaCl gradient, the CuTCPP@NNF membrane delivers an opencircuit voltage (Voc) of 43.6 mV and a shortcircuit current (Isc) of 4.25 mA/m, which are 9% and 21% higher than those of the pristine CuTCPP film (40 mV, 3.5 mA/m). COMSOL simulations replicate experimental diffusion voltage within 1% of errors. These quantitative results demonstrate that NNF integration effectively elevates space charge, amplifies ion‑diffusion‑driven potentials and currents.

Abstract: The self-assembly system driven by hydrogen bonding has been widely used in various fields. Two hydrogen-bonded cyclophosphazene derivatives with amino groups (AGHP) and carbonyl groups (CGHP) were synthesized by introducing hydrophobic groups and amino groups and hydrophilic groups and carbonyl groups into cyclophosphazene respectively through nucleophilic substitution. After they were dissolved in oil water two phases, stable emulsion, and self-loading membrane structures were obtained through self-loading behavior. The results indicate that strong hydrogen bonding can be formed between these two cyclic phosphazene derivatives with amino and carbonyl groups. This hydrogen bonding can significantly reduce the interfacial tension between water/oil phases (from around 33 mN/m to below 7 mN/m) and improve the interfacial coverage (which can reach over 80%). Meanwhile, under the hydrogen bonding between amino and carbonyl groups, an amphiphilic self-assembled film was obtained at the water oil interface. Through contact angle testing, it was found that the hydrophilic side of this self-assembled film had a contact angle of 77.5° and the hydrophobic side had a contact angle of 124.8°.

Abstract: A concrete mixture formulation consisting of industrial wastes such as fly ash and gypsum from ceramic mold waste as partial replacements for cement was developed in this two-part study to lessen the carbon footprint from processing the conventional materials used in the construction industry. The first part aims to determine the optimum composition of the ternary binder (cement, fly ash and recycled gypsum) and the curing period (7, 28 and 90) that will provide the highest compressive strength for the casted concrete cylinders. The second part focuses on establishing the effective polypropylene fiber (PPF) dosage, utilizing the pre-optimized binder composition. The structural integrity of the concrete cylinders was evaluated through compressive strength and split tensile tests following water curing periods of 7, 28, and 90 days. Results from the initial mechanical tests revealed that the optimum ternary binder composition was C60-F37.5-G2.5 cured for 90 days. While fiber reinforcement typically has limited impact on compressive strength, the addition of 1.5% PPF yielded better long-term compressive strength development compared with other PPF dosages. For tensile strength, 0.5%-1% PPF achieved the highest values at 28 days, whereas 1.5% PPF provided the peak performance under prolonged curing at 90 days. This shift in behavior is attributed to the progressive increase in fiber-bridging effectiveness over time. Findings from these mechanical tests were supported by the results from X-Ray Diffraction (XRD) analysis and optical microscopy.

Abstract: Cissampelos pareira, locally known as Krueo Ma Noy or Monoi, is a traditional Thai medicinal plant whose leaf mucilage has long been used as an edible gel and dessert ingredient. The mucilage, a natural hydrophilic polymer produced by plant metabolism, possesses film-forming potential that could be useful in pharmaceutical applications. This study aimed to develop and evaluate the mechanical properties of films prepared from dried C. pareira leaf mucilage, with the incorporation of various plasticizers—glycerin (Gly), propylene glycol (PG), polyethylene glycol-400 (PEG-400), and low-protein natural rubber latex (LPNRL)—to enhance film flexibility and usability. The unplasticized mucilage film exhibited a high tensile strength of 15.81 ± 0.58 MPa but was brittle, with low elongation at break recorded at 1.62 ± 0.24 percent. The addition of plasticizers significantly improved film elasticity, increasing elongation to a range of 21.41 to 29.93 percent, while reducing tensile strength to between 6.10 and 10.73 MPa. Among the plasticizers tested, LPNRL showed the most favorable mechanical profile, providing a flexible yet sufficiently strong film structure. These results indicate that C. pareira mucilage, when properly modified, can serve as a sustainable and biodegradable alternative for use in pharmaceutical film formulations, including wound dressings, transdermal systems, or oral thin films.

Abstract: This investigation reports the successful synthesis and characterization of a co-crystal composed of paracetamol (PCM) and metal sulfates of zinc and iron using an adapted antisolvent addition technique which leveraged the antagonistic solvent affinities of PCM and the metal sulfates. Ethanol and water acted as solvents for PCM and the metal sulfates, respectively, while simultaneously serving as antisolvents for the other constituent. Scanning Electron Microscopy (SEM) micrographs revealed crystals exhibiting a rod-like structure and a surface covered by flakes, which are both characteristic features of PCM and zinc sulfate, suggesting the formation of a new crystalline phase. This is further supported by the distinct powder x-ray diffraction pattern for the co-crystal when compared with that of the individual constituents. Analysis of Fourier Transform Infrared (FTIR) spectra suggests that the interacting functional groups which formed a new hydrogen bond network are the amide N-H and the water in the aquo complex formed by the metals in aqueous solutions. The findings highlight the simplicity of the crystallization technique and provide insights into the structural and mechanistic aspects of organic-inorganic co-crystals. This study contributes to the advancement of co-crystal engineering and lays the groundwork for exploring the pharmaceutical and functional applications of PCM-metal sulfate co-crystals.