Maulida Nur Astriyani, Nugraha Edhi Suyatma, Vallerina Armetha
et al.
Ultrasonication offers a safer, lower-temperature method for synthesizing zinc oxide nanoparticles (ZnO-NPs). This study details the development of a pectin-glycerol bionanocomposite film reinforced with ZnO-NPs produced using the top-down ultrasonication method. ZnO-NPs were fabricated with varying ultrasonication durations (0, 30, and 60 min) and the addition of pectin as a capping agent. Extended ultrasonication duration resulted in smaller particle size and more defined morphology. Bionanocomposite films were prepared using the solvent casting method by incorporating ZnO-NPs (0, 0.5, 1, 2.5% <i>w</i>/<i>w</i>) and glycerol (0, 10, 20% <i>w</i>/<i>w</i>) as a plasticizer to a pectin base. The inclusion of ZnO-NPs and glycerol did not affect the shear-thinning behavior of the film-forming solution. FTIR analysis indicated interactions between ZnO-NPs, glycerol, and pectin. The addition of ZnO-NPs and glycerol reduced tensile strength but increased flexibility. ZnO-NPs improved barrier and thermal properties by reducing water vapor permeability and increasing melting point, whereas glycerol lowered glass transition temperature, thus enhancing film flexibility. The best film performance was observed with a combination of 0.5% ZnO and 20% glycerol. These results highlight the effectiveness of the top-down ultrasonication method as a sustainable approach for ZnO-NPs fabrication, supporting the development of pectin/ZnO-NPs/glycerol films as a promising material for eco-friendly packaging.
Mutairu O. Ajiboye, Ayodele A. Daniyan, Paul C. Okonkwo
et al.
Abstract This study presents the first investigation of halogen-substituted aniline-derived Schiff bases (SB1, SB2, SB3) as corrosion inhibitors for mild steel in Nigerian tar sand environments. Key novelty includes introducing inhibition power as a new gravimetric-based performance metric for alkaline conditions where electrochemical methods are limited. Tar sand from Ilubirin was processed with 0.58 M NaOH at 90 °C for 24 h with inhibitors at concentrations of 25–150 ppm. Gravimetric analysis, SEM–EDS, and Langmuir isotherm modelling revealed a significant corrosion rate with effectiveness order SB3 > SB2 > SB1. SB3 achieved 94.4% inhibition efficiency at 150 ppm due to a favourable molecular structure promoting enhanced adsorption. Langmuir analysis confirmed chemisorption (ΔG°ads > − 20 kJ mol−1), while microstructural evaluation demonstrated excellent surface protection. This research demonstrates the effectiveness of inhibition power in assessing corrosion inhibitors using gravimetric data due to the limitations of electrochemical measurement in tar sand environments. The study concludes that Schiff-based compounds offer promising solutions for corrosion control in a harsh alkaline tar sand processing environment.
Chemical technology, Physical and theoretical chemistry
The MnOx/Al2O3 catalysts with different Ce content doping were prepared by an ultrasonic impregnation method, and the catalytic activity for NO oxidation removal was tested in a fixed-bed quartz tube furnace. Simultaneously, the catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), full-automatic physical-chemical adsorption instrument, and field emission scanning electron microscope (FESEM) to analyze the effect of Ce addition on the adsorption capacity and catalytic activity. Experimental results validated that the activity of the MnOx/Al2O3 catalyst was greatly promoted with Ce addition. According to the characterization results, it could be concluded that Ce doping led to significant changes in the crystalline phase on the catalyst surface, which increased the relative content of surface lattice oxygen and promoted the catalytic oxidation of NO. By observing the physical properties of the surface and analyzing the surface elements of the catalyst, it could be inferred that a manganese-cerium solid solution was formed on the surface of Mn0.4Ce0.05/Al. Moreover, Ce addition increased the catalyst pore size, which enhanced the adsorption and contact of NO and O2 with the active sites on the catalyst surface, and reduced the resistance of the reactants during internal diffusion. All these variations assigned to Mn0.4Ce0.05/Al were favorable for the catalytic oxidation of NO.
Ismat H. Ali, Mohammad I. Khan, Alhafez M. Alraih
et al.
The current research aimed at investigating the potential corrosion inhibitory effect of essential oil extracted from Moringa peregrina leaves on carbon steel in acidic conditions. Gas chromatography (GC) and scanning electron microscope (SEM) were employed for studying the composition of the inhibitor and surface morphological changes of CS samples. Different experimental techniques such as chemical, electrochemical and surface characterization techniques were utilized for carbon steel (CS) immersed in 1.0 M HCl solution. Experimental observations suggest that through physical and chemical interactions, the inhibitor molecules form a stable layer on steel surface. The nature of adsorption of the investigated inhibitor onto the carbon steel surface obeyed the Langmuir isotherm model. Moreover, the electrochemical results revealed that the investigated inhibitor acts as a mixed-type inhibitor. Density function theory (DFT) calculations and molecular dynamic (MD) simulations were utilized to gain an insight into the possible interactions between the carbon steel surface and the inhibitor molecule mainly 9-Octadecadienoic acid (Z) present in the essential oil.
Industrial electrochemistry, Physical and theoretical chemistry
The effects of Si content on the corrosion behavior and passivation of carbon steel bars in concrete pore solution were studied analytically, and its enhanced corrosion resistance was considered. Electrochemical impedance spectroscopy analysis and polarization techniques were used to investigate the electrochemical corrosion behavior of the samples. The lower mass-loss rate for the steel bar with 0.57 wt% Si content in the initial corrosion indicated an improvement of the corrosion resistance in the carbon steel matrix before the creation of a dense rust layer on the sample surface. The polarization plots exhibited that the steel bar with 0.57% Si content had minimum corrosion-current density compared to the other specimens which were in passive state during the experiment. The electrochemical results show that micro-alloying of Si element in the carbon steel bar matrix improved its corrosion resistance against chloride ion attack and delayed the corrosion initiation into the steel matrix. FESEM images of the specimens indicated that the surface of the carbon steel bar with 0.57% Si was smooth and no noticeable corrosion was found.
Industrial electrochemistry, Physical and theoretical chemistry
The paper presents the results of a study of relaxation of the dielectric permittivities in constant electric fields upon switching the polarization of thin films of lead zirconate-titanate, crystallized at different annealing temperatures. It is shown that the relaxation processes are characterized by at least three relaxation times which depend on the crystallization temperature. It is shown that the relaxation processes depend on the localization of lead oxide in the bulk of the film.
The RMFQT meeting is a long standing tradition within the Mexican Comp.Chem. community; a tradition that is now transcending our borders as more and more foreign students and researchers take part of this party, for it is a festive occasion indeed. This was the first time the RMFQT was held at a private institute, The Monterrey Institute of Technology. As in previous years, our lab contributed with a four posters and one talk by yours truly.
The RMFQT meeting is a long standing tradition within the Mexican Comp.Chem. community; a tradition that is now transcending our borders as more and more foreign students and researchers take part of this party, for it is a festive occasion indeed. This was the first time the RMFQT was held at a private institute, The Monterrey Institute of Technology. As in previous years, our lab contributed with a four posters and one talk by yours truly.
Zinc oxide (ZnO) thin films were grown by potentiodynamic polarization of a pure zinc surface in a chloride medium with different potential scan rates. It was found that the size of the ZnO films mainly dependedon the scan rate. Using oxygen as the precursor of the conversion reaction of the product formed during the scan potential, different morphologies of the films were obtained. The X-ray diffraction pattern and Raman spectraof the samples at different scan rates show the characteristic peaks of the ZnO wurtzite structure. At room temperature, photoluminescence tests showed a UV emission at approximately 390 nm, a visible emission at 442 and a deep-level emission in the green region at 523 nm, which are typical of ZnO.
Industrial electrochemistry, Physical and theoretical chemistry
Sejwal Kushal, Chami Mohamed, Baumgartner Paul
et al.
Membrane proteins are vital to life and major therapeutic targets. Yet, understanding how they function is limited by a lack of structural information. In biological cells, membrane proteins reside in lipidic membranes and typically experience different buffer conditions on both sides of the membrane or even electric potentials and transmembrane gradients across the membranes. Proteoliposomes, which are lipidic vesicles filled with reconstituted membrane proteins, provide an ideal model system for structural and functional studies of membrane proteins under conditions that mimic nature to a certain degree. We discuss methods for the formation of liposomes and proteoliposomes, their imaging by cryo-electron microscopy, and the structural analysis of proteins present in their bilayer. We suggest the formation of ordered arrays akin to weakly ordered two-dimensional (2D) crystals in the bilayer of liposomes as a means to achieve high-resolution, and subsequent buffer modification as a method to capture snapshots of membrane proteins in action.
Pabitra K. Nayak, David T. Moore, Bernard Wenger
et al.
Single crystals of lead halide perovskites exhibit good optoelectronic properties. Here, the authors study and deduce the mechanism for crystallisation and show how controlling dissolution of colloids through varying the acidity and temperature can improve the quality of the single crystals.
Ana C Santos Leite da Silva, Nadia Woitovich Valetti, María E Brassesco
et al.
This work explores the kinetics, equilibrium and thermodynamics of peroxidase adsorption onto spherical guar gum–alginate matrices. The effect of contact time, solution pH, initial protein concentration and temperature was studied in batch experiments. The results show that peroxidase adsorption increased with rising contact time and initial enzyme concentration, and was higher at pH 4.0. The kinetic processes can be predicted by both the pseudo-first-order rate kinetics and the pseudo-second-order rate kinetics. Equilibrium adsorption data were analyzed with different isotherm models. The experimental data fitted to the Freundlich model in agreement with the low energy activation, demonstrating the presence of a high physical and unspecific interaction between the enzyme and the matrix.
Jerzy Choma, Łukasz Osuchowski, Aleksandra Dziura
et al.
A commercially available styrene divinylbenzene ion-exchange resin, Amberjet 1200 H, was used to prepare a series of activated carbons through carbonization and subsequent activation with varying amounts of KOH. The resulting activated carbons showed a well-developed porous structure with specific surface area in the range of 730–3870 m 2 g −1 , total pore volume in the range of 0.44–2.07 cm 3 g −1 and micropore volume in the range of 0.30–1.59 cm 3 g −1 . Importantly, these structural parameters can be changed by varying the amount of KOH used for the activation. These carbons showed extremely good adsorption properties towards benzene and methane at 20°C. The best uptakes for benzene and methane (19.6 and 1.68 mmol g −1 , respectively) were obtained for the carbon activated using the KOH/C ratio of 4. These values correspond to the gravimetric adsorptions of 1.53 g/g and 27 mg/g, respectively. Benzene adsorption was analyzed using the Dubinin–Radushkevich (DR) equation. The micropore volume calculated using the DR equation based on benzene adsorption corresponds well with the micropore volume calculated from nitrogen adsorption by the α s comparative method. The high values of the structural parameters and the resulting high benzene and methane uptakes render the obtained activated carbons as prospective materials for use in environmental remediation and energy-related applications such as volatile organic compound adsorption and methane storage.
Each year the Mexican community who works in the realm of computational and theoretical chemistry gathers to share the most recent work done around our country. This year, I tried to live Tweet the event and although I failed miserably in doing so -as well as in convincing others to join me- I'm trying to put together the things that caught my attention. I also tried to Storify it but I cannot embed the result here in WordPress.
Each year the Mexican community who works in the realm of computational and theoretical chemistry gathers to share the most recent work done around our country. This year, I tried to live Tweet the event and although I failed miserably in doing so -as well as in convincing others to join me- I'm trying to put together the things that caught my attention. I also tried to Storify it but I cannot embed the result here in WordPress.
Fe-based nanocrystalline alloys provide a viable strategy to enhance the energy conversion efficiency for next-generation electrics by utilizing nanotechnology. This paper reviews current research activities that focus on Fe-based amorphous/nanocrystalline alloys with high Bs and low Hc values as well as their applications in industry.