Flake-like Structures Research Articles

Size shrinkage and compressive behaviour of Al2O3 honeycomb structures fabricated via Digital Light Processing technology

Al2O3 ceramic have excellent chemical inertness, superior heat resistance, and excellent corrosion resistance, so they are considered ideal materials for manufacturing high-performance components such as thermal end devices in aerospace, heat dissipation panels in electronic communication, and exhaust filters in the automotive industry. Digital Light Processing (DLP) is a useful technology to fabricate complex Al2O3 ceramic components. However, the size shrinkage effect of DLP-fabricated components need to be investigated deeply before its further application. In this work, we utilized DLP technology to fabricate Al2O3 ceramic honeycomb structures and systematically investigated their microstructure, size shrinkage, and mechanical properties. Our findings revealed that the Al2O3 ceramic grains exhibit flake-like structures with an average diameter of 1–2 μm, and the ceramic particles are tightly bonded. The shrinkage rates in the X and Y axes were 7.54 % and 7.42 %, respectively, while the Z-axis exhibited a more significant shrinkage of 13.04 %. This anisotropic shrinkage in different direction was attributed to accumulation of the interlayer bonding under gravity action during debinding and sintering process. The compressive stress-strain curve of the honeycomb structures demonstrated a typical brittle compressive behavior, including elastic, stress plateau, and brittle fracture stages. The honeycomb structures exhibited an elastic modulus of 54.49 ± 1.22 MPa and a compressive strength of 10.22 ± 0.42 MPa. The fracture analysis indicated that the fractures region of honeycomb structures initiated at the corners of the honeycomb structures, indicating their easy-broken compared to the walls. These findings provide valuable guidance for the high-precision and high-performance manufacturing of complex Al2O3 ceramic components.

Impact of nickel and alkaline earth metals interaction on sustainable carbon nanotubes generation from plastic face masks via catalytic pyrolysis

The one-pot synthesis of carbon nanotubes (CNTs) emerges as a promising approach for plastic valorization, owing to its simplicity and scalability. However, limited attention has been given to catalyst design for this method, particularly regarding the influence of Group 2 alkaline earth metal elements (X) on the Ni-based catalyst activity. This study investigates the impact of X on the catalytic activity of Ni towards sustainable CNTs synthesis using plastic face masks. The findings revealed that X influenced the carbon yield of NiMo-X catalysts and the morphology of the resultant carbon nanomaterials. Notably, NiMo-Ca demonstrated the highest carbon yield, whereas NiMo-Mg and NiMo-Ba exhibited the lowest. Furthermore, NiMo-Mg tends to produce clean and thin CNTs, while NiMo-Ba tends to yield carbon flakes with numerous irregular cokes. In addition to the effect of Ni crystallite size, which influences the transition from tubular to flake-like carbon structures, environmental factors are also considered. Specifically, NiMo-Mg generated a high CO2/CH4 environment, while NiMo-Ba exhibited slower catalytic cracking of polymeric chains from face masks, both of which were unfavorable for CNTs growth. Conversely, NiMo-Ca facilitated higher carbon recovery, likely due to its creation of a low CO2/CH4 environment via CO2 methanation. Optimization studies indicated that increasing pyrolysis temperatures and durations lead to reduced carbon yield, while cyclic pyrolysis of face masks up to five iterations enhances the reusability of NiMo-X catalysts with improved carbon recovery. Overall, this study provides valuable insights into the early pyrolytic gas formation and carbon nucleation phase, which are influenced by the surface Ni fraction and Ni polarization, as well as the later CNTs growth phase, which is related to the Ni crystallite size.

Using response surface methodology to optimize foam drying conditions related to drying rate and B-carotene concentration of orange-fleshed sweet potato powder

Response surface methodology and Box-Behnken design (3 factors and 3 levels) were performed to optimize the effects of different egg albumin contents (5-15%), xanthan gum (0.1-0.5%) and drying temperature (50-70oC). Drying rate and β-carotene content are indicators observed through 18 experimental runs and 6 repetitions at the center point. Finally, the physical properties such as color, water solubility index, water absorption index and rehydration ratio together with moisture content, water activity and microstructural of OFSP powder were analysed. The total polyphenol content (TPC), DPPH scavenging activity and β -carotene were analysed. Research results revealed that the optimal egg albumin concentration, xanthan gum concentration and drying temperature of 10.73%, 0.33% and 65.48oC, respectively as foam-mat drying parameters were recorded. From those optimal parameters, the optimal values of drying rate and β-carotene were determined to be 2.34 g water/g dry matter/min (maximize) and 51.82 µg/g (maximize), respectively. Foam-mat dried powder contained low moisture content and water activity, 4.15% and 0.343, respectively, along with water solubility index, water absorption index and rehydration ratio were respectively determined to be 45.87%, 2.36% and 3.97. The color of foam-mat dried OFSP powder was evaluated. According to the findings, the content of β-carotene (48.61±0.5 μg/g) and TPC (2.24±0.04 mgGAE/g) along with antioxidant activity (57.43±1.2%) of OFSP powder products were also determined. SEM analysis of OFSP powder particles at different magnifications showed that they have irregular surface morphology and flake-like structures, different from the structure of powder particles dried by convection drying method, the surface is quite smooth and the structure is intact.

Mg/S@g-C3N4 nanosheets: A promising fluorescence sensor for selective Cu2+ detection in water

This work describes the development of a novel fluorescence sensor based on magnesium/S@g-C3N4 nanosheets for selective detection of copper (Cu2+) ions in water. Mg/S@g-C3N4 nanosheets were prepared by the polycondensation technique and investigated by X-ray diffraction (XRD), ATR-FTIR spectroscopy, scanning electron microscopy (SEM), surface area (BET), and UV–Vis optical absorption measurements. XRD and ATR-FTIR analysis showed the characteristic peaks for S@g-C3N4. The broad full width at half maximum (0.056 radians) implies a smaller crystallite size, representing smaller Mg/S@g-C3N4 sheets. SEM micrograph showed non-exfoliated nanosheets with flake-like structures. The EDS mapping confirmed the presence of magnesium, carbon, nitrogen, and sulfur throughout the nanosheets. The Mg/S@g-C3N4 nanosheets possess a high surface area of 40 m2/g and mesopores within the nanosheets, with a size of 1.57 nm. The band gap of the Mg/S@g-C3N4 nanosheet was estimated to be 3.0 eV. The sensor exhibits a strong quenching response towards Cu2+ ions, with a decrease in fluorescence intensity as the concentration of Cu2+ increased from 1 μM to 20 μM. The Stern-Volmer quenching constant (KSV) showed a relatively high value of 185053 M−1. The estimated value of LOD by the Mg/S@g-C3N4 sensor for Cu2+ was 16.2 nM. The sensor offered high sensitivity and selectivity for Cu2+ detection over other heavy metals.

Synthesis, characterization and LDA+U calculations of zinc oxide nanoparticles

Zinc oxide (ZnO) was prepared by the sol-gel method as thin films deposited using spray pyrolysis. The characterization of the synthesized ZnO has been carried out using x-ray diffraction (XRD), Fourier-transform infrared (FTIR), scanning electron microscopy (SEM), and UV-Visible absorption spectroscopy. The experimental results revealed that the prepared ZnO has a wurtzite hexagonal structure with an average crystallite size of about 26.7 nm. High purity and flake-like structures were achieved as SEM and energy dispersive indicated. FTIR confirmed the prepared ZnO’s high purity as the Zn-O stretching peak was very intense. The optical parameters were comprehensively investigated, including absorption, reflection, extinction coefficient, refractive index, and optical energy gap. The wurtzite hexagonal structure of ZnO was optimized using the local-density approximation with the Hubbard correction method (LDA+U). Our experimental result for the energy gap is 3.28 (eV), which is in excellent agreement with the first principle calculations. We utilize the results from the LDA+U calculation along with our experimental outcomes to calculate the thickness of the thin film in UV-Vis spectroscopy.

Enhanced specific capacitance, structural, optical, and morphological study of carbon ions incorporated into the lattice of ZrCuO2 nanoparticle synthesized by hydrothermal method

In this study, ZrCuO2 nanoparticles were made using the hydrothermal method and potassium hydroxide as the precipitant. The material was irradiated with 500 keV carbon (C++) ions at doses of 1 × 1014, 1 × 1016, and 1 × 1018 ions/cm2. The ZrCuO2 nanoparticles exhibited cubic crystal structures with clear peaks on different orientation planes, both before and after being irradiated with carbon ions (C++). By incorporating carbon ions, the peak intensity and crystallinity of CuO nanostructures were enhanced. The non-irradiated micrographs display groups of tiny pebbles, whereas the carbon ion irradiated ZrCuO2 nanoparticles show flake-like structures. The material became denser because of carbon ion irradiation, which increased the carrier concentration. The absorption rate increase of the material reveals the impact of a carbon ion on irradiated ZrCuO2 nanoparticles. The absorbance of ZrCuO2 nanoparticles is enhanced through carbon ion implantation. The material has a bandgap energy of 1.95 eV without irradiation. The bandgap energy range of the irradiated material is 1.55–1.82 eV. The energy bandgap of the synthesized material was reduced because of carbon ion irradiation. The ZrCuO2 nanoparticle electrode with a specific capacitance value of 225 F/g. The electrodes prepared at 500 keV carbon (C++) ions with dosages of 1 × 1014, 1 × 1016, and 1 × 1018 ions/cm2 yielded specific capacitance values of 275 F/g, 300 F/g, and 312.5 F/g, respectively.

In situ grown cyclodextrin metal-organic framework nanoparticles templated stripe nano-wrinkled polyamide nanofiltration membranes for efficient desalination and antibiotic removal

Nanofiltration membranes composed of polyamide (PA) and characterized by a refined, periodic stripe pattern morphology are identified as promising solutions to address the permeability-selectivity trade-off in membrane technology. Modifying the morphology of PA membranes by utilizing pre-deposited soluble nanoparticles as templates has been investigated, yet the attainment of a periodic stripe pattern using this method is still a considerable challenge. This study successfully employed cyclodextrin-based metal-organic framework (CD-MOF) nanoparticles, grown in-situ, to create periodic stripe patterns on PA membranes. Morphological characterization revealed that in-situ grown CD-MOF nanoparticles, unlike those pre-deposited through vacuum filtration which formed noticeable aggregations and large flake-like PA structures, displayed a more evenly distributed pattern with reduced aggregation, aiding in the development of a striped PA morphology. The resulting membrane, with enhanced surface area, reduced thickness, increased hydrophilicity, and lower cross-linking degree, demonstrated an impressive 617 % augmentation in pure water permeance relative to the control PA membrane, achieving 29.4 L m-2 h-1 bar-1. Furthermore, this membrane displays a 99.0 % Na2SO4 rejection and maintained over 95 % efficacy in rejecting antibiotics. This research sheds light on the mechanisms by which nanoparticle templates influence polyamide morphology and introduces an innovative approach for precisely tailoring high-performance PA membranes.

Photodiode behavior and capacitive performance of ZnO nanoflakes synthesized by electrochemical deposition

ZnO flake interlayers were fabricated by the electrochemical deposition technique on p-Si to obtain Au/ZnO/p-Si heterostructures for Schottky-type photodiode applications and to test the capacitive performance of the structures. ZnO flake structures were investigated by x-ray diffractometry and scanning electron microscopy measurements, and their crystalline and flake-like structures were confirmed. The Au/ZnO/p-Si heterostructures were characterized by current–voltage (I–V) measurements for various illumination densities of light from dark to 150 mW cm−2. Various heterostructure parameters such as the ideality factor, barrier height, series resistance and rectifying ratio (RR) values were determined by I–V characteristics. The heterostructure exhibited a high RR of 6.85 × 103. The detection parameters revealed 0.49 mA W−1 responsivity and 2.69 × 109 Jones specific detectivity values. Furthermore, capacitance–voltage (C–V) measurements were employed to obtain the capacitive behavior of the Au/ZnO/p-Si heterostructure at various frequencies. Based on these results, Au/ZnO/p-Si heterostructures have potential for photodiode applications.

Key role of three-dimensional reticular interface membranes in the formation of single polysaccharide–stabilized high internal phase emulsions

Although the interfacial activity of polysaccharides is believed to be insufficient for their applications as individual emulsifying stabilizers, four single polysaccharides examined herein, namely sodium carboxymethyl cellulose (Na-CMC), sodium alginate (SA), high-methoxyl pectin (HMP), and low-methoxyl pectin (LMP) are shown to effectively stabilize high internal phase emulsions (HIPEs) at loadings as low as 0.1 wt% under acidic conditions, that is, at pH 0.5–5.2 (Na-CMC), 0.5–4.0 (SA), 1.0–4.2 (HMP), and 1.0–3.0 (LMP). Despite their structural differences, the four studied polysaccharides feature similar HIPE stabilization mechanisms that mainly involve the formation of three-dimensional reticular interface membrane structures with fiber branching chains. Within the pH range suitable for HIPE formation, the polysaccharides mainly exist as nanofiber network structures with a grid width of 50–100 nm but adopt flake-like and other structures at higher pH. Further insights are provided by the relationship between network membrane structures formed at the interface and the fiber network structures formed by polysaccharides in the original aqueous phase. In addition, the inferred emulsification and stabilization mechanisms are shown to be significantly different from those observed for mainstream Pickering HIPE stabilizers. Thus, our work expands the understanding of the interfacial activity function of polysaccharides, provides conceptual thinking reference and design rules for the development of simple, efficient, safe, and cheap polysaccharide-based HIPEs, and supplements and furthers the theory of HIPE stabilization.

3D Aerosol Jet® printing for microstructuring: Advantages and limitations

Aerosol Jet® printing (AJ®P) is a direct writing printing technology that deposits functional aerosolized solutions on free-form substrates. Its potential has been widely adopted for two-dimensional (2D) microscale constructs in printed electronics (PE), and it is rapidly growing toward surface structuring and biological interfaces. However, limited research has been devoted to its exploitation as a three-dimensional (3D) printing technique. In this study, we investigated AJ®P capabilities for 3D microstructuring of three inks, as well as their advantages and limitations by employing three proposed 3D AJ®P strategies (continuous jet deposition, layer-by-layer, and point-wise). In particular, 3D microstructures of increasing complexity based on silver nanoparticle (AgNPs)-, poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS)-, and collagen-based inks were investigated at various aspect ratios and resolutions. Biocompatibility assays were also performed to evaluate inks cytotoxicity effects on selected cellular lineages, including neuronal and osteoblast cell lines. Results show the possibility to print not only arrays of micropillars of different aspect ratios (AgNPs-ARs ~ 20, PEDOT:PSS-ARs ~ 4.5, collagen-ARs ~ 2.5), but also dense and complex (yet low reproducible) leaf- or flake-like structures (especially with the AgNPs-based ink), and lattice units (collagen-based ink). Specifically, this study demonstrates that the fabrication of 3D AJ®-printed microstructures is possible only with a specific set of printing parameters, and firmly depends on the ink (co-)solvents fast-drying phenomena during the printing process. Furthermore, the data concerning inks biocompatibility revealed high cytotoxicity levels for the AgNPs-based ink, while low ones for the PEDOT:PSS and the collagen-based inks. In conclusion, the paper provides general guidelines with respect to ink development and print strategies for 3D AJ®P microstructuring, opening its adoption in a vast range of applications in life science (tissue engineering, bioelectronic interfaces), electronics, and micromanufacturing.

Corrosion and Formation of Surface Films on AZ31 Mg Alloy in Aqueous Solution Containing Sulfate Ions with Different pHs

This study aims to clarify how a solution’s pH can influence the corrosion and formation of surface films on the AZ31 Mg alloy in aqueous solutions containing sulfate ions. The corrosion and surface film formation behaviors were examined using in situ observation, open-circuit potential (OCP) transient, weight change measurement and electrochemical impedance spectroscopy (EIS). The morphologies of the surface films were analyzed via metal/insulator/metal (MIM) coloring and FESEM. The findings show that at pH 2, severe corrosion occurred together with rapid hydrogen evolution and formation of a highly porous surface film with numerous cracks. However, at pH 3, the corrosion rate dropped significantly and remarkably low corrosion rates were observed at pH 4 and 10. At pH 11 and 12, weight gains were noticed, suggesting the growth of surface films on the AZ31 Mg alloy. Flake-like films formed at pH 12, while needle-like structures were present between pH 3 and 11. Impedance measurements revealed increased impedance at higher pH of sulfate-ion-containing solutions. Higher impedance was related to the formation of denser surface films on the AZ31 Mg alloy. In addition, the films displayed metal/insulator/metal (MIM) colors via Au coating above pH 4, indicating uniform film thickness despite the presence of needle-like or flake-like structures.

A novel dual-functional layer exhibiting exceptional protection and photocatalytic activity by organic functionalization of plasma electrolyzed layer

The formation of inorganic-organic hybrids (IOH) on the metallic substrates would play a decisive role in improving their structural and functional features. In this work, the growth of organic coating (OC) consisting of coumarin-3-carboxylic acid (3-CCA) and albumin (ALB) on the inorganic layer (IC), produced by plasma electrolysis of AZ31 Mg alloy, led to enabling organically synergistic reactions on the porous inorganic surface, forming a flake-like structure sealing the structural defects of IC. Synergistic actions between OC and IC endow the flake-like structures with chemical protection and photocatalytic performance. Upon contact with a corrosive solution, the IOH layer possesses stable morphologies that delay the corrosive degradation of the whole structure. The electrochemical stability of the sample produced by immersion IC in the organic solution for 10 h (IOH2 sample) was superior to the other samples as it had the lowest corrosion current density (1.69×10−10 A.cm−2) and the highest top layer resistance (1.2 × 107 Ω.cm2). Moreover, the IOH layer can photodegrade the organic pollutants in model wastewater, where the highest photocatalytic efficiency of 99.47% was found in the IOH2 sample. Furthermore, computational calculations were performed to assess the relative activity of different parts of the ALB and 3-CCA structures, which provide helpful information into the formation mechanism of the IOH materials.

Hydrogelation behaviour of methoxy terpyridine ligand induced by transition metal ions

We reported the hydrogel formation ability of 4′-(4-methoxyphenyl)-2,2′:6′,2′'-terpyridine L with different transition metal ions in a mild acidic medium. Irreversible, thixotropic and translucent hydrogel was achieved in case of divalent Cu2+, Zn2+, Cd2+ and Hg2+ ions. FESEM images of the hydrogels showed that Cu2+ hydrogel exhibited a fibrous network, while Zn2+ based hydrogel comprised a non-uniform fibrous structure. On the other hand, Cd2+ and Hg2+ hydrogels showed unusual flake-like structures. Further, Zn2+, Cd2+ and Hg2+ hydrogels exhibited blue fluorescence upon exposure to UV light (365 nm).

Entropically-Driven Co-assembly of l-Histidine and l-Phenylalanine to Form Supramolecular Materials.

Molecular self- and co-assembly allow the formation of diverse and well-defined supramolecular structures with notable physical properties. Among the associating molecules, amino acids are especially attractive due to their inherent biocompatibility and simplicity. The biologically active enantiomer of l-histidine (l-His) plays structural and functional roles in proteins but does not self-assemble to form discrete nanostructures. In order to expand the structural space to include l-His-containing materials, we explored the co-assembly of l-His with all aromatic amino acids, including phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp), all in both enantiomeric forms. In contrast to pristine l-His, the combination of this building block with all aromatic amino acids resulted in distinct morphologies including fibers, rods, and flake-like structures. Electrospray ionization mass spectrometry (ESI-MS) indicated the formation of supramolecular co-assemblies in all six combinations, but time-of-flight secondary-ion mass spectrometry (ToF-SIMS) indicated the best seamless co-assembly occurs between l-His and l-Phe while in the other cases, different degrees of phase separation could be observed. Indeed, isothermal titration calorimetry (ITC) suggested the highest affinity between l-His and l-Phe where the formation of co-assembled structures was driven by entropy. In accordance, among all the combinations, the co-assembly of l-His and l-Phe produced single crystals. The structure revealed the formation of a 3D network with nanocavities stabilized by hydrogen bonding between -N (l-His) and -NH (l-Phe). Taken together, using the co-assembly approach we expanded the field of amino acid nanomaterials and showed the ability to obtain discrete supramolecular nanostructures containing l-His based on its specific interactions with l-Phe.

Influence of pH on the Properties of Chemically Prepared SnS and CdS Thin Films

The SnS and CdS thin films were chemically prepared from the bath solutions with different pH values of 9.8, 9.9, and10, and 11.3, 11.4, and 11.5 respectively. The X-ray diffraction confirmed the formation of orthorhombic SnS with a preferredorientation along the 013 plane and cubic CdS along the 311 planes. Crystallite size and lattice strain were calculated from theWilliamson-Hall plot, and it was found that the crystallite size increased as pH increased. Raman spectra showed the prominentpeaks of SnS and CdS thin films. Optical studies revealed a decrease in the optical band gap of both samples with increasing pHvalues. SnS films showed needle-like morphology with agglomerates and CdS flake-like interconnected structures. From theEDS analysis, it was noticed that both the SnS and CdS thin films shifted to a metal-rich composition with the increase in thepH of the bath solution. Finally, a solar cell (ITO/SnS/CdS/Ag) was made, and it was found that cell structures formed with SnSand CdS that were deposited with pH values of 10 and 11.3 showed better performance.

Insights into the interaction mechanism of glutelin and rice starch during extrusion processing: The role of specific mechanical energy

Extruded glutelin/rice starch composites were prepared using twin-screw extrusion at various specific mechanical energies (SME), and the interaction mechanism of glutelin and rice starch was investigated at the molecular level. The results indicated that the structure of glutelin was destroyed, hydrophobic interactions and hydrogen bonds between rice starch and glutelin were formed and enhanced as the SME increased, and new hydrogen bonds were formed at the carbonyl (δ- and γ-carbons of glutelin) and C-1 of Tyr. Molecular docking studies confirmed that SME promoted the simultaneous occurrence of the Millard reaction and non-covalent reaction between glutelin and small molecular sugars produced by starch degradation, providing information on binding sites. Additionally, scanning electron microscopy (SEM) revealed dense and uniform flake-like structures induced by these binding interactions. Overall, insights into the interaction mechanism of rice starch and glutelin provide theoretical references for generating reconstituted rice products using extrusion processing.

Electrical conductivity and electrochemical studies of Cr-doped MoO3 nanoflakes for energy storage applications.

The growing demand for electricity has increased the interest of the researchers towards exploration of energy storing devices (ESDs). With the motif for developing electrochemical energy storage devices, this research work is focussed on the study of MoO3 nanoparticles and its doping with chromium as an efficient electrode material for energy storage applications. The nanoparticles were synthesized by hydrothermal method and were examined by powder X-ray diffraction, which determined the thermodynamically stable orthorhombic phase of MoO3, and their morphologies were examined using scanning electron microscopy displaying flake-like structures. The typical vibrational bands of Mo-O were identified from Infra-red and Raman spectral analysis. The ultra violet diffuse reflectance spectra revealed the decrease in optical band gap after doping with chromium. The temperature dependent AC and DC conductivities were enhanced on doping. Electrochemical behaviour of the nanoparticles was probed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) measurements and galvanostatic charge-discharge (GCD) analysis for which specific capacitance (C sp) value of 334 Fg-1 was achieved for Cr-doped MoO3 nanoparticles. The electrochemical performance of the sample was found to be increased after doping with Cr.

Study on the Adsorption Mechanism of Cobalt and Nickel in Manganese Sulfate by δ-MnO2.

Manganese has excellent performance in removing metal ions from aqueous solutions, but there are few studies on the adsorption and removal of heavy metal impurities in metal salt solutions. In this paper, the adsorption of cobalt and nickel ions in MnSO4 solution by δ-MnO2 prepared from two different manganese sources was studied. The optimum adsorption conditions were as follows: When the concentration of Mn2+ was 20 g/L, δ-MnO2 addition was 10 g/L, Co2+ concentration was 80 mg/L, Ni2+ concentration was 80 mg/L, reaction time was 60 min, reaction temperature was 80 °C, and pH value was 7, the adsorption rate of Co2+ and Ni2+ reached more than 80%. The manganese dioxide adsorbed by heavy metals was analyzed and detected. The results showed that MnOOH appeared in the phases of both kinds of δ-MnO2, and their morphologies were dense rod-like structures with different lengths and flake-like structures of fine particles. Co and Ni were distributed on the surface and gap of MnO2 particles, and the atomic percentage of Co was slightly higher than that of Ni. The new vibration peaks appeared near wave numbers of 2668.32, 1401.00, and 2052.19 cm–1, which were caused by the complexation of cations such as Co2 + and Ni2 + with hydroxyl groups. Some cobalt and nickel appeared on the surface of δ-MnO2, and the surface oxygen increased after adsorption. The above characterization revealed that the adsorption of cobalt and nickel in manganese sulfate by δ-MnO2 was realized by the reaction of its surface hydroxyl with metal ions (M) to form ≡SOMOH.

Functionalising insoluble pea protein aggregates using high-pressure homogenisation: Effects on physicochemical, microstructural and functional properties

Commercial plant protein isolates contain a large fraction of non-functional proteins due to the harsh processing conditions used. Therefore, greater value can be unlocked by functionalising these “inert” plant proteins. Using commercial insoluble pea protein isolate (I-PPI) as an example, this study demonstrates the application of high-pressure homogenisation (HPH) as a physical method to improve the techno-functionality of I-PPI. The dispersions were HPH-treated at 60, 120, or 180 MPa for one, three, and five pressure cycles. HPH treatments resulted in decreased particle size (from 16.7 ± 1.3–9.4 ± 0.2 µm at 60 MPa) and increased zeta-potential. Microstructural observations revealed the formation of smaller aggregate clusters and flake-like structures after HPH treatments. The protein solubility of I-PPI (15.9 ± 2.0 %) under acidic conditions (pH 2) significantly increased at all HPH treatment levels, with the greatest increase at 120 MPa for 5 passes (27.2 ± 2.0 %). Remarkably, the non-gelling I-PPI was able to form self-standing gels (15 % w/w) after HPH treatments, with the greatest gel strength observed at 180 MPa. The emulsifying and foaming stability of HPH-treated I-PPI increased from 60 to 120 MPa but decreased at 180 MPa. Overall, our results demonstrate a key paradigm in protein modification: transforming insoluble plant proteins into functional protein ingredients.

Efficient luminescence of doped bismuth oxychloride nanophosphors and its surfaces prompted applications

The materials which cater to excellent sensitivity, superior contrast, inexpensive and eco-friendly are in urgent need for law enforcement applications. To overcome these barriers, red-emitting BiOCl:Eu3+ (1–9 ​mol %) nanophosphors were prepared by the self-ignited combustion method. The powdered x-ray diffraction profiles were well indexed to a tetragonal phase of BiOCl without any traces of impurities. The 2-dimensional agglomerated irregular flake-like structures without any clear boundaries were clearly revealed. The photoluminescence emission spectra consist of distinct sharp peaks at ∼ 536, 555, 594, 621, 652 and 698 ​nm, which were owing to 5D1→7F1, 5D1→7F2, 5D0→7F1, 5D0→7F2, 5D0→7F3 and 5D0→7F4 transitions of Eu3+ ions, respectively. A noticeable increment in the photoluminescence emission intensity with an increase of activator Eu3+ concentration up to 5 ​mol % and later it diminished. The dipole-dipole interaction was mainly responsible for observed concentration quenching. The estimated commission international de l'eclairage coordinates are found in orange-red as well as a red region in the diagram, indicating that the emission color can be tuned by varying activator Eu3+ ions concentration. The fingerprints developed using optimized nanophosphor showed distinctive papillary ridge particulars and hence specifies the higher sensitivity without any background hindrance. The aged fingerprints developed on the glass surface retained their ridge characteristics up to level 2 even after being stored for 180 days. The developed anti-counterfeiting labels can only be decoded under ultra-violet 365 ​nm light with clear intense red color. The obtained results clearly demonstrated the effectiveness of the fluorescence nanophosphor for latent fingerprint visualization and data encryption applications.