FESEM Micrographs Research Articles

Local heterogeneities and order-disorder: An approach to tailor BaTi1-xZrxO3 ceramics properties

Zirconium-doped Barium Titanate with the formula, BaTi1-xZrxO3 (BZT) for 0 ≤ x ≤ 0.08 had been prepared by the modified solid-state reaction route. X-ray diffraction patterns (XRD) and structural refinement showed the formation of single and double phases for pure and Zr-substituted barium titanate, respectively. Pure barium titanate (BT) was found in the tetragonal phase. BZT-3 and BZT-5 had a mixture of tetragonal and orthorhombic phases. A mixture of orthorhombic and rhombohedral phases was present in BZT-8. The Raman analysis confirmed the existence of two oxygen octahedra of Ti and Zr for Zr-doped BT. The FESEM micrograph exhibited an increase in average grain size with Zr content. The temperature-dependent dielectric studies showed single-phase transitions for BT, two-phase transitions for BZT-3 and BZT-5, and three-phase transitions for BZT-8. XPS analysis confirmed the presence of undercoordinated Ti3+ions. The maximum dielectric constant of 5731 was obtained for BZT-3, which decreased linearly afterward. The maximum remanent polarization = 8.287 μC/cm2 was found for BZT-3. The energy storage efficiency ≥ 50.10 % makes all the compositions suitable for high energy density capacitors. Due to the presence of 90.63 % of the orthorhombic phase in BZT-5, the highest d33 = 164 pC/N was obtained. The UV–visible spectroscopy showed the signature of p-d and d-d transitions present in the ceramics due to disordering. The direct optical bandgap increased with the rise in Zr content.

Effect of chromium doping on the band gap tuning of titanium dioxide thin films for solar cell applications

A simple and inexpensive spray pyrolysis deposition (SPD) approach was used to produce TiO2 and Cr (2–8) at.%-doped TiO2 thin films. To explore the morphological features of the films, FE-SEM micrographs were used and found that 6 and 8 at.% TiO2:Cr films had fibrous patterns with diameters of 0.45 and 0.78 μm, respectively, while the remainder of the films were agglomerated particles. From X-ray diffraction investigation, it was found that the TiO2 thin films had an anatase crystal phase (tetragonal) up to 6 at.% Cr doping, while an anatase-rutile mixed crystalline phase was identified for 8 at.% Cr doping. The crystallite size of the pristine TiO2 film was 35 nm, while for TiO2:Cr films, it ranges from 35 to 46 nm. The Fizeau fringes technique was employed to measure the thickness of the TiO2 film and 165 nm was found for pristine TiO2 and 164–180 nm for TiO2:Cr films. UV–visible spectroscopy was used to study optical properties such as absorbance, refractive index, optical band gap, dielectric constant, and optical conductivity. As the Cr concentration increases, the optical band gap decreases from 3.40 eV to 2.70 eV. Using the four-point probe method, it was found that the resistivity changes with temperature and is also affected by the Cr content.

Designing of plasmonic 2D/1D heterostructures for ultrasound assisted photocatalytic removal of tetracycline: Experimental results and modeling

The extensive release of Tetracyclines (TCs) has posed severe environmental challenges. Therefore, there is an urgent need to find greener and more sustainable options for effectively degrading TCs. Here, we will design plasmonic 2D/1D heterostructures that exhibit excellent photocatalytic properties for TC removal. In this research, 2D/1D p-n heterojunctions containing TiO2 nanosheets and NiO nanorods were deposited chemically with various amounts of plasmonic silver nanoparticles (Ag(y)/TNs/NiO(x)). PXRD patterns showed pure anatase and cubic phases for TNs and NiO, respectively, and confirmed that NiO nanorods occupied the (101) facet in TNs. The FESEM and TEM micrographs showed the sheet-like structure and nanorods morphologies for TNs and NiO. The DRS, PL, and Raman studies approved that the NiO nanorods and silver nanoparticles improved the photoresponse of TNs to the visible light region. The Mott–Schottky, EIS and photocurrent analyses indicated that the p-n heterojunction decreased the interfacial resistance, improved the separation of charge carriers, and increased the photocurrent of TNs (from 0.12µA to 3.5µA) in Ag(0.5)/TNs/NiO(0.35) by 30 times. The efficiency of the plasmonic heterojunctions was examined for ultrasound assisted photocatalytic removal of tetracycline (TC). The experimental results were validated using two powerful machine learning techniques (ANN and SGB), and a good accordance between the predicted and experimental values was observed. The reusability tests and electrical energy per order analysis revealed that using plasmonic heterojunctions (Ag(y)/TNs/NiO(0.35)) were more cost-effective and sustainable than using the conventional TiO2 photocatalytic system.

Improved electrochemical performance of bio-derived plasticized starch/ reduced graphene oxide/ molybdenum disulfide ternary nanocomposite for flexible energy storage applications

A ternary nanocomposite of plasticized starch (PS), reduced graphene oxide (rGO), and molybdenum disulfide (MoS2) was prepared via a solution casting process, with MoS2 concentrations ranging from 0.25 to 1.00 wt%. The structural, surface morphological, optical, and electrochemical properties of the nanocomposites were studied. FTIR analysis reveals the formation of new chemical bonds between PS, rGO, and MoS2, indicating strong interactions among them. The XRD analysis showed a reduction in the crystallinity of the nanocomposite from 40 to 21% due to the incorporation of nanofiller. FESEM micrograph showed an increment of the surface roughness due to the incorporation of rGO-MoS2 layers. UV–vis spectroscopy demonstrated a reduction of optical bandgap from 4.71 to 2.90 eV, resulting from enhanced charge transfer between the layers and defect states due to the addition of nanofillers. The incorporation of MoS2 increase the specific capacitance of the PS from 2.78 to 124.98 F g−1 at a current density of 0.10 mA g−1. The EIS analysis revealed that the nanofiller significantly reduces the charge transfer resistance from 4574 to 0 Ω, facilitating the ion transportation between the layers. The PS/rGO/MoS2 nanocomposite also exhibited excellent stability, retaining about 85% of its capacitance up to 10,000 charging-discharging cycles. These biocompatible polymer-based nanocomposites with improved electrochemical performance synthesized from an easy and economical route may offer a promising direction to fabricate a nature-friendly electrode material for energy storage applications.

MICROSTRUCTURAL EVOLUTION AND ANTI-CORROSION CHARACTERISTICS OF AS-CAST AND LPBF PRINTED INCONEL PLATES IN SEAWATER ENVIRONMENT

Inconel 718 (IN 718) belongs to the category of nickel-based superalloys with outstanding mechanical characteristics such as high strength, better corrosion resistance, greater hardness, fatigue and wear resistance. This alloy is mostly implemented in manufacturing the components of aeroengines, nuclear reactors, space shuttles, pressurized boilers and so on. In most cases, the parts made from this alloy work in severe aggressive environments. A prolonged exposure of this alloy in such environments will pave the way for corrosion phenomenon which will minimize the service life of the components. It is reported that the parts made via additive manufacturing will exhibit better mechanical characteristics than the casted and forged parts. This work is aimed to investigate the anti-corrosion characteristics of both as-cast and LPBF printed IN 718 samples at various time intervals in the seawater environment. By means of FESEM micrographs, the microstructural evolution in both as-cast and LPBF printed IN 718 samples was analyzed. The anti-corrosion characteristics of both samples were investigated in the environment containing 3.5 wt.% NaCl (seawater) in terms of EIS and potentiodynamic polarization curves along with the corroded morphology. The results showed that the LPBF printed IN 718 samples exhibit fine cellular and columnar grains decorated with the NbC precipitates along their boundaries, whereas the casted samples have larger and coarser grains with uneven segregation of NbC precipitates. From the Tafel and EIS (Nyquist and Bode) plots, the LPBF IN 718 sample showed greater corrosion resistance in terms of current density and polarization resistance values. In particular, the 15 h LPBF sample has a strong, compact passive film formed on it. This compact passive film paved the way for this sample to exhibit lower current density (3.03 × 10[Formula: see text] A/cm2) and higher polarization resistance (3678 Ω · cm2) when compared with the LPBF and cast samples at other intervals.

Fabrication and Testing of Crop Waste Ceiba pentandra Shell Powder Reinforced Biodegradable Composite Films.

Ceiba pentandra shell powder (CPSP) biowaste is chosen as a biofiller combined with poly(vinyl alcohol) (PVA) as a matrix to make biofilms to increase the exploitation of biowaste materials and reduce the use of plastic materials. FTIR plots indicated no significant chemical reaction or formation of new functional groups during interaction between PVA and CPSP. XRD diffractograms showed that the crystallinity index (35.3, 38.6, 42.3, 46.4, and 48.5%) and crystalline size (18.14, 20.89, 23.23, 24.87, and 26.34 nm) of biofilms increased with CPSP loading (5-25 wt %). The PVA/CPSP films are thermally stable up to 322 °C. The peak highs of AFM images showed that the films' surface roughness gradually increased from 94.75 nm (5 wt % CPSP) to 320.17 nm (25 wt % CPSP). The FESEM micrographs clarify the homogeneous distribution of CPSP in the PVA matrix. Tensile strength and tensile modulus are noticeably increased by 26.32 and 37.92%, respectively, as a result of the loading of CPSP from 5 to 20 wt % in the PVA matrix. The PVA/CPSP films outperform pure PVA films in UV shielding (350-450 nm). The 59% weight loss of films was estimated during 60 days of burial. The fabricated biofilms maintained their suitable structural, thermal, morphological, and mechanical properties. Additionally, they exhibited consistent performance in ultraviolet (UV) barrier, opacity, water absorption, water vapor permeability, soil burial, and antimicrobial characteristics over time. Overall, PVA/CPSP (5-25 wt %) films are biodegradable and have promising applications as good packaging materials.

Novel synthesis of stabilized Bi1–x–yGdxDyyO1.5 solid electrolytes with enhanced conductivity for intermediate temperature solid oxide fuel cells (SOFCs)

Herein, we report the synthesis of a Dy–Gd co-doped cubic phase-stabilized Bi2O3 solid electrolyte system via solid-state processing under atmospheric conditions. Doping with Dy3+ and Gd3+ has been observed to significantly enhance the densification process during sintering for stabilization purposes, thereby improving the electrical properties of δ-Bi2O3-type polymorphs. The synthesized ceramics were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy-energy dispersive X-ray spectroscopy (FESEM-EDX), thermal gravimetry/differential thermal analysis (TG/DTA), and the four-point probe technique (4PPT). XRD analysis reveals that the samples Bi1–x–yGdxDyyO1.5 (y = 0.05/x = 0.05, 0.10, 0.15, and 0.20, and x = 0.05/y = 0.10, 0.15, and 0.20) exhibit a stable face-centered cubic δ-phase and a mixed-phase crystallographic structure. The XRD analysis of the stabilized δ-phase suggests that the prepared oxides show a face-centered cubic (FCC) structure with a space group of Fm-3m. FESEM micrographs reveal that the composition Bi0.90Gd0.05Dy0.05O1.5 has no significant holes. Nevertheless, an evident increase in the pore formation is observed as the amount of Gd2O3 increases until it reaches 20%. This finding suggests that dense pellets are formed during the sintering process at 900–1000 °C. The DTA analyses were performed to verify the phase stability, which agrees with the XRD results. The electrochemical performance of the synthesized Dy–Gd co-doped Bi2O3 solid electrolyte system was evaluated and analyzed in detail by using the electrochemical impedance spectroscopy (EIS) technique. Based on EIS and conductivity measurements, Bi0.75Gd0.20Dy0.05O1.5 exhibits the lowest activation energy of 0.519 eV and the highest conductivity value of 0.398 S/cm at 627 °C compared to the other samples; this composition can be used as a solid electrolyte for intermediate-temperature solid oxide fuel cells (SOFCs).

Functionalization of fullerene soot through oxidative decarboxylative coupling with silver dinitrobenzoate

In this research, we extend the functionalization of fullerene soot with nitroaryl substituents through oxidative decarboxylative coupling with silver 3,5-dinitrobenzoate. For this purpose, silver 3,5-dinitrobenzoate is first prepared in two-steps from 3,5-dinitrobenzoic acid. Then, this compound as a substrate together with potassium persulfate as an oxidant is used in acetonitrile as a solvent to functionalize fullerene soot. The reactions with different equivalent ratios of substrate and oxidant are conducted by both thermal and microwave conditions. This strategy is able to induce about 88.03 wt.% O and 5.79 wt.% N to the composition of fullerene soot. The advantage of this strategy is that the reaction can happen without the need for a catalyst, because silver(I) present in the substrate can catalyze the reaction progress. To prove the functionalization, several characterization techniques are used, i.e. XRD patterns, EDX spectra and SEM elemental distribution images, FE-SEM and TEM micrographs, particle size distribution histograms, FT-IR and Raman spectra, as well as TGA and DSC curves, which demonstrate the changes on fullerene soot. The novelty of this research is that it provides a new strategy for oxidative decarboxylative coupling of silver(I) carboxylates with the carbon surface.

Synthesis and tailoring the structural and magnetic characteristics of Zn–Zr substituted Sr-hexaferrite targeting diverse applications

SrZnxZrxFe12-2xO19 (x varying within 0.1–0.4) samples were prepared successfully via solid state route. Their structural characteristics (along with microstructural and magnetic) have been discussed. Rietveld refinement established the phase purity for the samples x ≤ 0.3 (goodness-of-fit <1.15) whereas the presence of ZnFe2O4 and SrZrO3 impure phases was observed in x = 0.4 sample. The three-phase model resulted in decreasing χ2 values from 1.21 to 1.05 for x = 0.4 sample. The XRD findings also reveal an increasing cell volume from 690.675 Å3 (x = 0.1) to 693.096 Å3 (x = 0.3) and a decreasing porosity from 33% to 30% on increasing ˋx’. The average grain size increases from 0.83 μm to 1.04 μm according to FESEM micrographs with increasing ˋx’. The TEM measurements reveal the presence of rod like particles (in addition to random shaped particles) in x = 0.1–0.3 samples. M v/s H studies reveal, and increase in Ms from 90.26 emu/g (for x = 0.0) to 91.41 emu/g (for x = 0.1) and a decreasing trend afterwards to 87.90 emu/g (at x = 0.3). Hc value continuously decreases from 5032 Oe (for x = 0.0) to 1903 Oe (for x = 0.4). Low temperature M − H and M-T measurements coupled with room temperature M − H measurements reveal the absence of superparamagnetic behaviour. The magnetic data suggest that all the samples possess hard ferrite characteristics and could be useful for microwave absorbers, permanent magnets as well as high-density recording media applications.

Aloe vera extract mediated hydrothermal synthesis of rose-like copper iron sulfide for efficient oxygen evolution reaction

BackgroundFabricating electrocatalysts with high surface area is salient to attain water splitting reaction with high efficiency. Conventionally, complexing agent assisted hydrothermal synthesis is often used to synthesize electrocatalyst with unique morphologies that could improve the electrocatalytic surface area. MethodIn this work, a novel approach of adopting aloe vera extract as green complexing agent was used to fabricate copper iron sulfide (CuFeSx)-based nanostructure on nickel foam. Different ratios of aloe vera extract and water were used to identify the effect of complexing agent on morphology of the material. Significantfindings FESEM micrographs verified the role of aloe vera extract as green complexing agent that formed nanorose-like morphology when 75% aloe vera was used. The optimized composition showed that only 234 mV overpotential was required upon iR-compensation to attain 100 mA cm−2 with a corresponding Tafel slope of 81 mV dec−1. Electrochemical surface area analysis (ECSA) revealed that high surface area exposure aided in lowering the overpotential to achieve high current density. The electrocatalyst exhibited good stability upon sustained exposure to alkaline medium for 48 h, retaining up to 84% of its initial current density. This study highlights the potential of using phytochemical-mediated synthesis to fabricate electrocatalysts for generation of sustainable hydrogen fuel via water splitting.

Effect of multi-walled carbon nanotube/Porous Carbon/SiO2 on reinforcing of cement mortar matrix: Modeling studies of effective parameters

The enhancement of the mechanical properties of cement composites by various nanomaterials is now a trendy subject. This study assessed the impact of three nanomaterials on the compressive and tensile strength of Portland cement mortar: biomass-derived porous carbon, MWCNT, and SiO2. These nanoparticles were developed using environmentally friendly, inexpensive technologies, and they underwent material characterization analyses using FESEM, N2 adsorption-desorption, contact angle, FTIR, XRD, and TEM. After 7 and 28 days, the compressive and tensile strength was assessed. According to the findings, among the samples, cement-SiO2 had the maximum compressive strength (19.32 MPa). The FESEM micrographs amply support the creation of the C-H-S gel and the presence of the bridge. The outcomes further showed that the nanoparticle's presence in the matrix does not significantly impact the tensile strength. SiO2-cement had the highest tensile strength, 1.45 MPa, matching the conclusions drawn from the compressive strength. Moreover, the compressive strength of cement was unaffected by the total pore volume of nanomaterials or the pore-filling mechanism of cement. Modeling (Linear regression-least square method) made it possible to predict the compressive strength for a period of 92 days and examine the influence of effective ingredients on it. Ultimately, the results indicate that porous carbon and silica can be viable alternatives for MWCNT.

Impact of Crystallite Size on Structural, Optical and Magnetic Characteristics of La0.7Sr0.15Ca0.15MnO3 Nanocrystalline

Nanocrystalline La0.7Sr0.15Ca0.15MnO3 (LSCMO) manganites were prepared by the combustion process and heated to various annealing temperatures (TA) to get various sized crystallites. The X-ray diffraction (XRD) patterns provided evidence that a Rhombohedral structure with space group was formed. Additionally, an increase in the size of the crystallites was observed, from 15.64 to 36.78nm, as the temperature (TA) increased from 700℃ to 1300℃. The FESEM micrographs revealed that homogeneous with porosity. The FTIR spectra showed five absorption peaks. The Optical energy gap of LSCMO nanocrystalline is decreased from 3.51 to 3.28 eV as annealed temperature raised, reveals that the LSCMO nanoparticles are semiconductor in nature. Room temperature Raman spectra of LSCMO nanoparticles demonstrate a notable reliance on annealing temperature. When the Raman modes were analysed with respect to TA, it was observed that the Raman vibrational phonon mode below 200cm-1 (A1g) and four modes (Eg) in the range 200-800cm-1 displayed significant displacements and widening, which were associated with oxygen sublattice distortion. Considerable changes were observed in both the intensity and full width half maximum (FWHM) of the five Raman modes as the annealing temperature increased. Magnetic behaviour using M-H loop at room temperature were measured by the Vibrating sample magnetometer revealed that gradation of saturation magnetization as the function of annealing temperature. Hence there is a remarkable crystallite size effect on optical and magnetic properties of LSCMO nanocrystallites.

Structural, Morphological, and Dielectric Properties of Gd3+ modified LaPO4 Ceramics

Gd3+ modified LaPO4 (Gd x La1-x PO4, where x = 0.02, 0.04 & 0.06) ceramics have been prepared using Auto Combustion. X-Ray diffractograms analysis shows that samples exhibits pure monoclinic structural phase upto x = 0.04 without presence of any other secondary phases whereas in x = 0.6, some secondary phases appears. The FESEM micrographs show grain growth, densification along with compactness of grains whereas EDS micrographs confirm the presence of elements according to stoichiometric proportion. Elemental mapping gives information about uniform distribution of elements. The dielectric relaxation behavior of prepared ceramics confirms from Cole-Cole model whereas dielectric loss gives information about conductivity of samples which has also be confirmed from conductivity profile.

Reuse of end—of—life membranes through accelerated polyamide degradation

End—of—life (EoL) thin—film composite (TFC) reverse osmosis membranes were converted into ultrafiltration—like (UF) membranes in an accelerated degradation process of the polyamide (PA) using an oxidant (NaOCl) in the presence of either MgCl2 or CaCl2. The PA degradation was evaluated by measuring pure water permeability (PWP), MgSO4 passage and molecular weight cut—off; the more PWP increased, and the less MgSO4 was retained after treatment, the more the PA was degraded. By adding 10 mM of metal ions, PWP increased 2.1 (MgCl2) and 3.1 (CaCl2) times compared to the increase achieved with hypochlorite alone (2560 ppm∙h of free chlorine). Changes in the membranes after treatment were analyzed by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE—SEM), and by measuring their surface charge and contact angle. FTIR and FE—SEM confirmed the PA layer degradation. FE—SEM micrographs showed that full removal of the PA layer can be achieved by using an oxidation dose of 12,700 ppm∙h when Ca2+ is used but doses as high as 300,000 ppm*h are needed without catalyst. The results proved that by controlling the oxidation process it was possible to control the cut—off (MWCO) value of the membrane from 16,100 g∙mol—1 to 27,100 g∙mol—1. Before treatment, EoL membranes showed a MWCO of approximately 1200 g∙mol—1, meaning that molecules with that size could be retained in a 90%. In summary, the presented method enables reducing waste by the conversion EoL membranes into tailored UF—like membranes and by decreasing the amount of oxidant used in the conversion process.

The comparative study on microstructure and magnetic properties of cobalt ferrite/MWCNTs nanocomposite prepared using mechanical mixing and hydrothermal routs

The mechanical mixing (MM) and hydrothermal are known as prevalent and facile synthesis methods of the nanocomposite. In this research, the cobalt ferrite/ multi-wall carbon nanotubes (CF/MWCNTs) nanocomposites synthesized by these methods and microstructure and magnetic properties were investigated. The nanocomposites were characterized using X-ray diffraction (XRD), Field emission electron microscope (FESEM), Raman spectroscopy, thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and vibration sample magnetometer (VSM). Furthermore, the specific surface area of prepared nanocomposite was measured by the Brunauer-Emmett-Teller (BET) method. The single-phase cobalt ferrite without any impurities was observed in XRD patterns. The samples’ mean crystallite size was calculated by the Williamson –Hall and Rietveld methods which show that samples prepared by hydrothermal procedure has a larger crystallite size. Also, the obtained nanocomposites by both methods have a suitable phase distribution of CF nanoparticles and MWCNTs according to the FE-SEM micrographs. Moreover, the maximum magnetization (Mmax) for samples prepared by MM and hydrothermal methods were 35.6 and 49.5 emu/g, respectively. It is noteworthy that the Mmax values increase by 13.5 emu/g for sample synthesized by hydrothermal method compare to MM preparation. The results revealed that the presence of MWCNTs in the synthesis medium leads to cobalt ferrite nanoparticle growth and thus improves the magnetic properties.

Investigating the Mechanical, Thermal, and Crystalline Properties of Raw and Potassium Hydroxide Treated Butea Parviflora Fibers for Green Polymer Composites.

The only biotic factor that can satisfy the needs of human species are plants. In order to minimize plastic usage and spread an immediate require of environmental awareness, the globe urges for the development of green composite materials. Natural fibers show good renewability and sustainability and are hence utilized as reinforcements in polymer matrix composites. The present work concerns on the usage of Butea parviflora fiber (BP), a green material, for high end applications. The study throws light upon the characterization of raw and potassium hydroxide (KOH)-treated Butea Parviflora plant, where its physical, structural, morphological, mechanical, and thermal properties are analyzed using the powder XRD, FTIR spectroscopy, FESEM micrographs, tensile testing, Tg-DTA, Thermal conductivity, Chemical composition, and CHNS analysis. The density values of untreated and KOH-treated fibers are 1.238 g/cc and 1.340 g/cc, respectively. The crystallinity index of the treated fiber has significantly increased from 83.63% to 86.03%. The cellulose content of the treated fiber also experienced a substantial increase from 58.50% to 60.72%. Treated fibers exhibited a reduction in both hemicelluloses and wax content. Spectroscopic studies registered varying vibrations of functional groups residing on the fibers. SEM images distinguished specific changes on the raw and treated fiber surfaces. The Availability of elements Carbon, Nitrogen, and Hydrogen were analyzed using the CHNS studies. The tensile strength and modulus of treated fibers has risen to 192.97 MPa and 3.46 Gpa, respectively. Thermal conductivity (K) using Lee's disc showed a decrement in the K values of alkalized BP. The activation energy Ea lies between 55.95 and 73.15 kJ/mol. The fibers can withstand a good temperature of up to 240 °C, presenting that it can be tuned in for making sustainable composites.

Preparation and characterization of plywood panels using recycled HDPE as a formaldehyde-free adhesive: A comparative study

Formaldehyde-based resins such as urea-formaldehyde (UF) are the most widely used adhesives in the plywood industry. However, due to the concerns about formaldehyde toxicity, there is a need to develop formaldehyde-free adhesive materials. Therefore, the present study aimed to minimize or eliminate the harmful effects of UF resin by using recycled high-density polyethylene (HDPE) from post-consumed fruit packing boxes as a nontoxic adhesive. Three-layer plywood panels using poplar veneers and recycled HDPE films were prepared. UF was used as a control adhesive for the comparison. The influence of three variable parameters in terms of HDPE content (from 80 to 320 g/m2), hot-pressing temperature (from 140 to 180 °C), and pressing duration (from 3 to 8 min) on the properties of plywood panels were evaluated. For evaluation, physical properties, namely water absorption (WA), thickness swelling (TS), and mechanical properties, namely modulus of elasticity (MOE), modulus of rupture (MOR), and glue-line shear strength of the samples, were studied. The findings of this work confirmed that HDPE films gave the values of mechanical properties of plywood panels comparable to those obtained with UF adhesive, even though the adhesive content and pressing time were lower than when the UF adhesive was used. The obtained bonding strength values of HDPE-bonded plywood panels ranged from 0.82 to 1.60 MPa and met the requirement for the European Standard EN 314-2. According to FE-SEM micrographs, the fractured surface of plywood panels with 240 g/m2 of HDPE displayed a homogeneous cross-section area, and a large amount of HDPE was attached to the veneer surfaces. It was found that the average mechanical properties tended to increase with an increase in the pressing temperature and time. The type of adhesive had a significant effect on WA and TS. The smallest values of WA and TS were observed in plywood samples using high contents of HDPE films (240 and 320 g/m2). The optimum conditions were an HDPE loading of 240 g/m2, a hot-pressing temperature of 160 °C, and a hot-pressing time of 5 min. The overall results showed that recycled HDPE had enough potential to reuse as a promising adhesive for the environmentally-friendly plywood manufacturing.

Study of ZnO nanoparticle-supported clay minerals for electrochemical sensors, photocatalysis, and antioxidant applications

In view of the current study's demonstration of the synthesis of clay-doped ZnO composites, we present a low-cost method for producing clay-metal oxide (clay/ZnO). Utilizing the solution combustion technique, a composite of clay/ZnO was produced utilizing citric acid as both a fuel and a complexing agent. The hexagonal unit cell structure of the created clay/ZnO may be seen using XRD patterns. The ZnO-infused clay was visible in FE-SEM micrographs as homogenous, sphere-shaped ZnO. The possible involvement of clay/ZnO photocatalytic activity in the UV-induced photodegradation of malachite green dye was investigated. The 90% degradation rate shows the composite's outstanding photocatalytic degradation capacity. The resulting substance was electrochemically analyzed using a constructed electrode in 0.1 M KOH electrolyte. It increased its sensor capabilities, which now include chemical and biomolecule sensors, and it excelled in cyclic voltammetry-based redox potential studies. To efficiently evaluate chemically synthesized NPs for electrochemical, sensing, and photocatalytic applications, this study intends to create a solution combustion procedure for the synthesis of clay/ZnO nanocomposite using urea as fuel.

Long term durability assessment of self-compacting concrete made with crushed recycled glass and metakaolin

Sustainable production in construction industry can only be possible through a proper management and conservation of limited natural resources such as fine aggregates. This challenge can be tackled by efficient utilization of discarded waste material such as glass in production of sustainable concrete. This paper investigates the use of crushed recycled glass (CRG) and metakaolin (MK) in development of durable self-compacting concrete (SCC). Four groups of SCC mixtures were prepared using different proportions of CRG (0–50%), while keeping MK concentration equal to 0%, 4%, 8% and 12%. Durability performance of SCC was accessed using water absorption, sorptivity, chloride ion permeability, drying shrinkage, water penetrability under pressure and alkali-silica reaction (ASR) tests. As the CRG content increased, group 4 (having 12 % MK) was most efficient in improving drying shrinkage and pressurized water penetration results; whereas Group 1 (0% MK mixtures) exhibited a minimal change. Raising CRG content in the mix resulted in decrease of water absorption and chloride ion penetration for all groups with group 4 exhibiting maximum reduction. ASR testing revealed that incorporating glass at a higher concentration (40% and 50%) resulted in excessive expansion (more than prescribed limit of 0.1%), which can be suppressed by partially substituting cement with MK. FE-SEM and TGA analysis were carried out to understand the mechanism behind these changes, which revealed that the secondary hydration products formed by addition of MK in concrete can densify the pore structure and refine CRG particle-cement paste interfacial micro-crack width (was evident from FE-SEM micrographs), thus improving the durability of concrete. Indeed, simultaneous incorporation of CRG and MK proved to be advantageous for development of green SCC.

Activation of functionalized graphene oxide incorporated poly acrylonitrile nanofibers for producing highly porous carbon nanostructures

Porous carbon materials, including activated carbon nanofibers (ACNFs), have wide applications in the fields of recycling, separation, storage, drug delivery, etc. due to their high surface area and high porosity. On the other hand, the combination of these materials with graphene structures may have a synergistic effect on the properties of the product for the target application. In the present research, polyacrylonitrile nanofibers containing different percentages of synthesized graphene oxide, functionalized by chlorosulfonic acid were produced by the electrospinning method. Then, carbonization and activation were carried out to produce a porous activated carbon nanofibrous web. The investigation proved that the average diameter of the functionalized graphene oxide (FGO) incorporated PAN nanofibers increases as the amount of the incorporated FGO is increased. FESEM micrographs showed that the FGO incorporated nanofibers disfigure to some extent after activation, whereas the neat PAN nanofibers keep their original fiber form. XRD analysis showed that after activation, the D spacing in FGO-incorporated nanofibers decreases to some extent, but generally the effect of FGO on the microstructure of PAN nanofibers is not overwhelming. FTIR spectrum confirmed the presence of FGO in ACNFs. BET results showed that the specific surface area of the ACNF decreases with increasing amounts of the incorporated FGO. The maximum specific surface area recorded was 941.37 m2/g. This was lower than that of the neat ACNF (988.5 m2/g). Total pore volume showed the same trend. The presence of FGO in ACNFs leads to an increase in mesopores content and in other words, the share of micropores decreases.