Band 239, Heft 10

Surfactants, or surface-active agents, are multifunctional amphiphilic compounds essential across numerous industrial and domestic applications. This review provides an in-depth analysis of surfactant chemistry, focusing on their diverse structures, interfacial behaviors, and self-assembly mechanisms, including micelle formation and emulsification. It outlines the classification of surfactants – anionic, cationic, non-ionic, and zwitterionic – while also exploring innovative types such as biosurfactants, sugar-based, lignin-derived, algal-based, and gemini surfactants. The growing emphasis on environmentally friendly and biodegradable surfactants sourced from renewable materials is highlighted, reflecting a shift away from conventional petroleum-derived options. The review examines key properties like surface tension reduction, wettability enhancement, foaming, detergency, and emulsification, linking them to their wide-ranging applications in sectors such as petrochemicals, pharmaceuticals, nanotechnology, paper manufacturing, and biotechnology. Finally, it underscores the crucial role of surfactants in fostering sustainable advancements and their potential for driving future technological innovations.

Nanotechnology is promising for water filtration and decontamination, eliminating contaminants and pathogens from wastewater with exceptional efficiency. Nanomaterials like metal oxide nanoparticles (MONPs) have received attention for their extraordinary characteristics and versatility in tackling environmental issues. Metal oxides are attractive wastewater treatment materials due to their various physicochemical features. Metal oxide nanoparticles have great promise, but few review studies have examined their relevance in this field. Thus, our understanding of the extensive range of metal oxide nanoparticles and their water filtration applications is poor. A comprehensive investigation of metal oxide nanoparticles that reduce water contamination is the goal of this review paper. MONPs can remove organic and inorganic chemicals, heavy metals, pesticides, and wastewater dyes like azo-dyes. MONPs’ dynamic physiochemical properties high surface-to-volume ratio and low concentration efficacy make them effective wastewater treatment agents. These features help MONPs absorb and breakdown contaminants, improving water treatment. This extensive review examines five metal oxide nanoparticles, as well as their antibacterial and wastewater treatment uses. Titanium dioxide (TiO 2 ), zinc oxide (ZnO), iron oxide (Fe 2 O 3 ), copper oxide (CuO), and manganese oxide (MnO 2 ) prove their environmental flexibility and performance. Due to their photocatalytic activity, TiO 2 nanoparticles degrade organic contaminants and inactivate germs under UV light. ZnO nanoparticles have the ability to adsorb and photocatalyze heavy metals and organic contaminants from wastewater, making them powerful antimicrobials. Fe 2 O 3 nanoparticles can separate from treated water due to their magnetic characteristics. CuO nanoparticles also adsorb organic dyes and heavy metals, making them useful in wastewater cleanup. Finally, MnO 2 nanoparticles have excellent oxidizing characteristics, decomposing organic pollutants and reducing water toxins. Their capacity to catalyze redox reactions makes them essential in water treatment, especially for pollution removal. MONPs, especially in wastewater treatment, have great potential to reduce worldwide water pollution. By using metal oxide nanoparticles, we can improve water purification efficiency and sustainability, preserving our precious water resources and public health.

Nanotechnology has revolutionized material science by enabling the manipulation of matter at the atomic and molecular scale. This review presents an in-depth analysis of nanoparticles (NPs), highlighting their classification into carbon-based, lipid-based, polymeric, metal, semiconductor, and ceramic types. It explores the physical and chemical uniqueness of nanomaterials, such as high surface-area-to-volume ratios and quantum effects, which empower their enhanced performance across domains. Emphasis is placed on synthesis strategies, including both top-down and bottom-up approaches, with a special focus on green and sustainable methods utilizing plant extracts and biological organisms. Furthermore, this review discusses wide-ranging applications of NPs in environmental remediation, medicine, electronics, mechanical systems, and energy harvesting. The potential of nanoparticles to offer targeted drug delivery, water purification, lightweight electronics, and energy-efficient systems makes them vital for future innovations. Challenges and perspectives on the scalability and safe deployment of nanomaterials are also briefly addressed.

In this paper, we investigate the electronic, magnetic, mechanical, dynamical, and thermodynamical properties of novel FeNbGe half Heusler alloy by first principle calculations. The alloy’s thermodynamic and dynamic stability were verified, and it was found feasible to synthesize experimentally. The calculated elastic constants prove the mechanical stability of the material. The malleable and ductile nature of the material was confirmed through Pugh’s and Poisson’s ratios. The electronic properties were calculated using the GGA and TB-mBJ exchange-correlation potentials. The band structure in the spin-down channel reflects metallic behaviour. In contrast, the spin-up channel shows non-metallic behaviour, which infers the half-metallic property of our half-Heusler alloy, which is a desirable property for spintronic materials. The alloy displayed an indirect band gap of 1.06 eV from GGA and 1.15 eV from TB-mBJ functionals. The Heusler alloy under study with 17 valence electrons, was found to be a Ferromagnetic alloy with a total magnetic moment of −1 μ B . The half-metallicity retaining property was studied by imposing expansive volumetric strain. The small band gap, half-metallic property, and the ferromagnetic nature of our material suggest that it can be a suitable material for spintronics applications.

Owing to the growing prevalence of uropathogenic Escherichia coli (UPEC) strains that are more recently resistant to last-line antibiotic treatments, such as carbapenems and colistin drugs, urinary tract infections (UTIs) are a prime example of the antibiotic resistance crisis and emphasize the need for new approaches to treat and prevent bacterial infections. The antibacterial effect of 4-((5-bromo-2-hydroxybenzlidene) amino)-1,5-dimethyl1-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (BDP), a Schiff base derivative, was tested against UPEC, a bacterium responsible for urinary tract infections. This Schiff base compound was optimized in five phases at the ωB97XD/6–311++G(2d,2p) level of theory; therefore, density functional theory studies, spectroscopic analysis, molecular docking analysis, and pharmacokinetic prediction were employed. The stability of the BDP compound was predicted via geometric structural studies, natural bond orbital (NBO) theory, quantum chemical descriptors, and spectral studies such as FT-IR and UV‒vis studies. The ab initio calculation of NBO revealed greater stability of the compound despite the solvation effects of DMSO, methanol, ethanol, and water. This claim was supported by frontier molecular orbital prediction, where the energy gaps were 6.60 eV, 7.45 eV, 7.45 eV, 7.43 eV, and 7.44 eV for the BDP compound present in the gas phase, water, DMSO, ethanol and methanol, respectively. The molecular docking results revealed the antibacterial efficacy of BDP. 5C5Z + BDP and 5VQ5+BDP interactions produced −4.5 and −5.4 kcal/mol binding affinities respectively. BDP displayed stronger interaction with 5VQ5 than with 5C5Z and had better docking activities than FOS. Overall, result has shown that BDP is a potential therapeutic candidate for the treatment of UPEC caused UTIs and has the potential to mitigate the challenges associated with urinary tract infections, hence, should be considered a promising candidate for UTI treatment.

Hot water freezing faster than cold water is simply startling, and this observation is known as the Mpemba effect since its rediscovery in 1969. But we are still confused and grappling in search of the underlying experimental conditions and the microscopic physics that can confirm, experimentally and theoretically whether this effect is real or misunderstood. Here, we derive the macroscopic physics of water freezing based on Newtonian cooling. Subsequently, we invoke the effect of covalent-bonded hydrogen and oxygen atoms with polarized electrons to evaluate the temperature ( T )-dependent interaction strength between water molecules that determines the length of dynamical hydrogen bonds. After doing so, we expose the hidden Mpemba physics of superfreezing – low-density hot water (due to repulsion caused by highly polarized electrons) induce faster complete freezing compared to high-density cold water if and only if the cooling rate is sufficiently and continuously rapid. However, the question as to which water starts to freeze first (and/or reaches 0 °C first), is conditional. Along the way, we also derive the microscopic interaction potential inequality responsible for supercooling that delays freezing of cold water.

In the present work, an attempt was made to adopt solvent casting approach to synthesize and compare PEO/CNT and PMMA/CNT composites with varying concentration of CNTs while using SDS as a surfactant to enhance dispersion and prevent agglomeration. Different characterization techniques namely Thermal Gravimetric Analysis, Scanning Electron Microscopy, X-ray Diffraction Analysis and Universal Testing Machine were betrothed to characterize and evaluate the effect of CNT loading on PEO/CNT with PMMA/CNT composites. TGA revealed that thermal sturdiness of PEO/CNT’s lifts sharply by CNT’s whereas PMMA/CNT’s thermal stability increases gradually. SEM images exposed that functionalized multiwall CNT in PEO accelerates the crystal growth by showing fungus like morphology as witnessed in low magnification images. The low magnification SEM images for PMMA/CNT shows bubble like morphology. The sharp peaks and semi crystalline nature of PEO/CNT and Humps and increase in crystallinity with CNT for PMMA/CNT composites were confirmed by XRD. UTM investigation confirmed that plasticity amplifies with increasing CNT loading in fabricated hybrid. Similarly UTM investigation explored that incorporation of CNT in both polymers augments mechanical performance. Evaluation of decomposition thermal energy confirmed that CNT loading boosts up thermal activation energy more for PMMA in contrary to PEO. Based on our findings it is safe to conclude that physical attributes of polymeric system is highly sensitive to the CNT loadings and must be incorporated with care as linear increasing CNT effects various parameters (Crystallinity, thermal strength and mechanical performance) unsymmetrically.

There are various thermodynamic models to quantitatively describe the adsorption of surfactant molecules at the surface of their aqueous solutions. The Frumkin adsorption model is one of the most successful ones as it provides essential parameters, such as the surface activity of the studied surfactant, the minimal required molecular area at the interface, and the intermolecular interaction in the adsorption layer. Since it was published 100 years ago, the model has served as the starting point for various refinements, such as for molecular reorientations or two-dimensional aggregations at fluid interfaces or as generalized model for the adsorption of surfactant mixtures. Also, the recently developed approach for understanding the cooperativity in the formation of surfactant adsorption layers at water/oil interfaces is based on Frumkin’s model. Due to its clear physical idea, it was successfully applied to quantitatively describe various types of surfactant systems. The values of the three model parameters allow for a categorization of surfactants with respect to their efficient application in numerous technological fields.