Energy Dispersive Analysis Research Articles

Mechanical octacalcium phosphate coatings on the plasma electrolytic oxidized pure titanium for bio-implant use

In this study, OCP powder was used for mechanical coating on the plasma electrolytic oxidized (PEO) implant surface to improve bioactivity. PEO treatment was performed on the surface of the implant using a solution mixed with calcium acetate and calcium glycerophosphate, and creates porosity through a pulsed DC power supply. For compositional analysis, energy dispersive X-ray spectrometer analysis was employed to calculate OCP content and X-ray diffractometer analysis was used to confirm the crystal structure. Also, wettability, surface roughness, hardness, elastic modulus, and corrosion resistance testing were performed. Significantly, the reduction in OCP particle size decreased, and pore filling with OCP smaller particles increased as mechanical coating time increased from 0 to 12 h. Surface and cross-sectional morphology showed the presence of OCP on the substrate. Also, surface roughness, contact angles, hardness, and elastic modulus were reduced as mechanical coating time increased. Corrosion resistance was found to be the highest for mechanical OCP coating for 6 h surface treatment on the PEO-treated CW-Ti.

Source Apportionment of PM10 as a Tool for Environmental Sustainability in Three School Districts of Lecce (Apulia)

Air pollution is a great threat to the sustainable development of the world; therefore, the improvement of air quality through the identification and apportionment of emission sources is a significant tool to reach sustainability. Single particle analysis, by means of a scanning electron microscope equipped with X-ray energy dispersive analysis (SEM-EDS), was used to identify the morphological and chemical properties of the PM10 particles in order to identify and quantify the main emission sources in three areas of Lecce, a city in the Apulia region of southern Italy. This type of characterization has not yet been performed for the Lecce site, but it is of particular importance to identify, based on the shape of the particles, the natural sources from the anthropogenic sources that are responsible for the serious health effects of the inhabitants. Three primary schools located in peripheral areas of the city were chosen for the sampling: “School 1” (A site), “School 2” (B site), and “School 3” (C site) to carry out a study of the air quality. The A site is characterized by a greater presence of calcium sulphates probably due both to construction activities present during sampling and to reactions between Ca particles and the sulfur present in the atmosphere. At the C site, there is a relative numerical abundance of different groups of particles that present, in the EDS spectrum, an enrichment in sulfur. At the B site, the number of particle groups is intermediate compared to that of the other two sites. With the source apportionment technique, ten emission sources were identified: combustion, soot, industry, soil, carbonates, sea salt, calcium sulfates, SIA, biological particles, and others. In PM10, the three sites are more affected by the soil source, with an effect greater than 60%.

X-ray diffraction analysis of orthorhombic SnSe nanoparticles by Williamson–Hall, Halder–Wagner and Size–Strain plot methods

SnSe nanoparticles were synthesized using the sonochemical exfoliation technique, employing SnSe single crystals. Various analysis, including Energy Dispersive Analysis of X-rays-Elemental mapping, X-ray Diffraction (XRD), High-Resolution Transmission Electron Microscopy, Ultra-Violet Diffused Reflectance Spectroscopy-Photoluminescence measurements, Raman spectroscopy, and X-ray Photoelectron Spectroscopy, were conducted to determine the chemical composition, crystalline phase, morphological characteristics, optical properties, vibrational modes, and oxidation states of the synthesized nanoparticles. The XRD peak broadening analysis, specifically employing Williamson–Hall (W-H), Size–Strain Plot (SSP), and Halder–Wagner Method (H-W), was employed to examine particle size and intrinsic strain. Additionally, three models within the W-H method, namely the uniform deformation model (UDM), uniform stress deformation model (USDM), and uniform deformation energy density model (UDEDM), were used to investigate physical and microstructural parameters such as strain, stress, and energy density. A comprehensive comparison of the average particle size results obtained from Williamson–Hall, Size–Strain, and Halder–Wagner Methods, along with results from HR-TEM and Particle Size Analysis, was carried out. The comprehensive comparison of results from different techniques adds credibility to the reported findings.

Graft copolymers of collagen and acrylic monomers—Reagents for sizing of cotton yarn

AbstractA new highly effective sizing reagent based on grafted collagen copolymers has been proposed for cotton yarn. The copolymers were synthesized by reacting an aqueous solution of collagen with acrylic monomers—acrylic, matacrylic acids, and their amides in the presence of potassium persulfate. Based on Scanning electron microscopy ‐ Energy dispersive (SEM‐EDS) analysis data, the composition of the copolymers was determined. Unsaturated acids are more actively grafted onto collagen than their amides. When a polymer film is formed from a solution of a collagen copolymer with (meth)acrylic acid, microcracks appear on the surface of the sample; microcracks are absent in films of copolymers with (meth)acrylamide. Films of copolymers, especially methacrylamide, are quite flexible and contribute to a significant improvement in the properties of the yarn. The tensile strength of yarn sized with copolymers increases by 20%–65% compared to unsized yarn, and by 13%–38% compared to yarn sized with a starch solution. At the same time, the relative tensile elongation of the experimental yarn improves by 14%–58%, while this property of starch‐size yarn deteriorates by 14%–22% compared to unsized yarn. The complete removal of graft copolymers from the surface of the yarn in the process of biochemical desizing using the enzyme protease is shown.Highlights Graft copolymerization of (meth)acrylamide with collagen was carried out. Grafting is initiated by the interaction of collagen with potassium persulfate. The synthesized copolymers are effective sizing reagents for cotton yarn. The copolymer with poly(meth)acrylamide forms a flexible and stable film. The protease enzyme completely removes the size from the surface of the yarn.

Influence of Hf doping on structural, morphological, optical and electrochemical properties of NiO thin films: Electrochromic application

In this study, the authors investigated the influence of hafnium doping on the properties of NiO thin films using the spray pyrolysis (SP) method. A comprehensive analysis was conducted to evaluate the structural, morphological, optical, and electrochemical characteristics of the deposited films. Techniques such as X-ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (FESEM), energy dispersive analysis by X-ray (EDS), UV–Vis–NIR spectrophotometry, cyclic voltammetry (CV), and chronoamperometry (CA) were employed. XRD examination revealed that the NiO thin films exhibit a polycrystalline cubic phase, with a preferred orientation along the (111) plane. The successful integration of Hf ions into the NiO matrix was confirmed by the Raman spectrum. SEM images depicted the formation of dense and uniform nanograins on all film surfaces, free from any cracks. EDS analysis and elemental mapping indicated uniform and homogeneous distribution of Ni, O, and Hf elements across the films. The optical analysis suggested a decrease in the optical band gap energy from 3.54 eV to 3.49 eV with an increase in hafnium doping concentration. Electrochemical results revealed a continuous improvement in specific capacitance with Hf doping. The NHf6 sample reached 65 F. g−1 at 5 mV s−1, compared to 46 F. g−1 at 5 mV s−1 for the NHf0 sample. However, the NHf4 film exhibited the highest optical density variation (49%), shortest response times (tb = 3.58 s, tc = 4.67 s), and the largest coloration efficiency (63.39 cm2/C), indicating enhanced electrochromic performance at this Hf doping rate. These findings suggest that Hf-doped NiO holds promise as a candidate for use as a counter-electrode in electrochromic devices.

Ultrasound Pretreatment for Enhancing Fine and Ultrafine Flake Graphite Flotation Beneficiation.

With the severe depletion of coarse flake graphite (a critical raw material) resources, developing and utilizing fine and ultrafine graphite resources have recently attracted attention. Froth flotation is a widely used technique for the initial enrichment of graphite; however, the flotation selectivity decreases significantly along with particle size reduction. Ultrasound pretreatment would be a promising method to improve the flotation of fine particles. As an innovative approach to understand better the flotation response of different flake graphite sizes, this study conducted a comparative analysis based on flotation concentrate yield and ash as well as ash removal rate between the flake graphite with various particle sizes after ultrasound pretreatment. Particle size, X-ray powder diffraction, and scanning electron microscopy and energy dispersive X-ray spectroscopy analyses were used to investigate the effect of ultrasound treatment on mineralogical properties of the flake graphite with varied particle sizes. Process outcomes indicated that the flotation performance of fine flake graphite (mean chord length: 62.63 μm) was significantly enhanced after ultrasound pretreatment. However, flotation of the ultrafine flake graphite (mean chord length: 24.97 μm) after ultrasound treatment was limited due to the difficulty of generating sufficient fragmentation and dissociation by microjets and shock waves formed by the cavitation effect. Compared with conventional flotation, the concentrate yield of ultrasound flotation increased from 88.95 to 94.98%, ash content decreased from 5.72 to 4.87%, and ash removal rate enhanced from 36.94 to 42.61%. Particle size and mineral property analyses confirmed that further crushing and dissociation of the larger flake graphite after ultrasound pretreatment would be the main factors contributing to improved flotation performance. Additionally, the formation of air flocs in the coarse flake graphite during the ultrasound pretreatment process facilitated the flotation recovery of the crushed graphite particles.

Effect of silver diamine fluoride on the longevity of the bonding properties to caries-affected dentine

ObjectivesThis study aimed to evaluate the adhesive properties in dentine after the application of silver diamine fluoride (SDF) on carious dentine lesions immediately and after 2 years of water storage. Methods96 human molars used were subjected to artificial dentine caries production, and then randomly divided into 12 experimental groups according to 1. application of an SDF solution (carious dentine lesion without SDF treatment [control], with 12 % silver diamine fluoride [SDF 12 %] or 38 % silver diamine fluoride [SDF 38 %]); 2. Universal adhesives (Clearfil Universal Bond Quick [CUQ] and Single Bond Universal [SBU]); 3. adhesive strategy (etch-and-rinse [ER] and self-etch [SE]). After restoration, the specimens were sectioned and submitted to the microtensile bond strength test (μTBS) and energy-dispersive X-ray spectrometry analysis (SEM/EDX). All tests were performed immediately and after 2 years of water storage. Data from the μTBS were analyzed using four-way ANOVA and Tukey's test (α = 0.05). ResultsOnly the interaction of factors 'SDF' vs 'time' was significant (p = 0.03). After 2 years of storage, the groups where SDF was applied showed higher μTBS values compared to the control group. No significant decrease in μTBS values was observed for SBU when comparing immediate and 2-year results, but a significant reduction in μTBS values was observed after 2 years for CUQ. ConclusionIndependent of the adhesive strategy, the use of SDF may be a promising alternative to maintain the bonding of universal adhesives to carious dentinal lesions. Clinical significanceThis study may clarify and support clinicians regarding the longevity of resin-based restoration in caries-affected dentine treated with silver diamine fluoride.

Investigation on barium zirconate nanocomposites for optical and dielectric properties

There are numerous applications for the barium zirconate (BaZrO3) perovskite. Regarding the molten phases created during the fabrication of copper-oxide-based superconducting single crystals, it exhibits high corrosion resistance. ZrO2 and BaZrO3 were created by the co-precipitation method in the current experiment. Powder X-ray diffraction, Fourier-transform infrared spectra, and energy dispersive analysis by X-ray, which displays the elemental analysis of the specimens, were used to analyze the samples. The majority of the particles were grouped together in this way. It must be useful in many catalytic processes due to its high ion exchange ability and redox moment and ferroelectric applications because of its high dielectric constant value.

Study of Non-Transformable t’-YSZ by Addition of Niobia for TBC Application

The high toughness of zirconia is paving the way for the development of new materials for application in TBC for gas turbine blades. The main aim of this work was the obtainment of tetragonal zirconia polycrystalline (TZP) with high density, from mixtures of high-purity powder of zirconia, yttria, and niobia with different compositions (14.5 to 21 mol%), through the processes of cold pressing by uniaxial pressing and by isostatic pressing, followed by air sintering processes at 1550 °C for 1 h. The samples were characterized for phase composition by X-ray diffraction, Rietveld analysis, and morphology by transmission electron microscopy and energy dispersive spectroscopy analyses. Mechanical and tribological resistance was evaluated by fracture toughness and nanoindentation tests as well as Weibull statistics. The incorporation of yttria and niobia resulted in relatively denser ceramics with stabilization of the tetragonal phase which was confirmed by detailed X-ray diffraction analysis. Modified ceramics for TBC with 17.5 mol% of yttria and niobia showed higher hardness and fracture toughness, 16.16 GPa and 173.38 GPa, respectively. Through nano hardness measurements, it was possible to verify the effect of the samples’ ferroelasticity. Thus, the addition of niobia and yttria to zirconia represents an opportunity for the development of new materials with increasing mechanical and tribological resistance for TBC application.

Biogenic Synthesis of Copper Nanoparticles from flower extract and their Cell Cytotoxic Potential

In order to overcome the negative potential risks of conventional nanoparticles and achieve the goal of human therapeutic uses, sustainable nanoparticles must be synthesized. In this paper, we have created a simple method for producing copper nanoparticles using green chemistry. With the use of Cassia auriculata's floral aqueous extract, copper nanoparticles (CuNPs) were effectively produced. In a UV-Visible Spectrophotometer, sythesized CuNPs detect absorbance at 276 nm, a hallmark of copper nanoparticles. The relevant functional groups involved in lowering and stabilizing CuNPs were found using Fourier Transform Infrared Spectroscopy. CuNPs shape, crystalline phase, and elemental composition were seen using scanning and transmission electron microscopy, energy dispersive analysis spectroscopy, and other techniques. Moreover, CuNPs' antibacterial and antifungal properties produced good inhibitory action against the pathogens that were put to the test. Furthermore, at low doses, CuNPs had no effect on the cytotoxicity of the cell lines MDCK and Caco-2. CuNPs may thus be turned into nano-drugs for the treatment of infectious diseases and tumour research.

Contributions of Chinese hamster ovary cell derived extracellular vesicles and other cellular materials to hollow fiber filter fouling during perfusion manufacturing of monoclonal antibodies.

Hollow fiber filter fouling is a common issue plaguing perfusion production process for biologics therapeutics, but the nature of filter foulant has been elusive. Here we studied cell culture materials especially Chinese hamster ovary (CHO) cell-derived extracellular vesicles in perfusion process to determine their role in filter fouling. We found that the decrease of CHO-derived small extracellular vesicles (sEVs) with 50-200 nm in diameter in perfusion permeates always preceded the increase in transmembrane pressure (TMP) and subsequent decrease in product sieving, suggesting that sEVs might have been retained inside filters and contributed to filter fouling. Using scanning electron microscopy and helium ion microscopy, we found sEV-like structures in pores and on foulant patches of hollow fiber tangential flow filtration filter (HF-TFF) membranes. We also observed that the Day 28 TMP of perfusion culture correlated positively with the percentage of foulant patch areas. In addition, energy dispersive X-ray spectroscopy-based elemental mapping microscopy and spectroscopy analysis suggests that foulant patches had enriched cellular materials but not antifoam. Fluorescent staining results further indicate that these cellular materials could be DNA, proteins, and even adherent CHO cells. Lastly, in a small-scale HF-TFF model, addition of CHO-specific sEVs in CHO culture simulated filter fouling behaviors in a concentration-dependent manner. Based on these results, we proposed a mechanism of HF-TFF fouling, in which filter pore constriction by CHO sEVs is followed by cake formation of cellular materials on filter membrane.

Calcium absorption by Alaska pollock surimi protein hydrolysate promotes osteoblast differentiation.

The calcium-binding capacity and osteoblast proliferation and differentiation were studied in Alaska pollock surimi hydrolysate (APSH) using a system that mimics the gastrointestinal digestive system. Evaluation of the calcium absorption-promoting ability of APSH revealed that the best calcium-binding ability was achieved after hydrolysis with a combination of pepsin, α-chymotrypsin, and trypsin, and separation into <3kDa (APSH-I), 3-5kDa (APSH-II), 5-10kDa (APSH-III), and <10kDa (APSH-IV) fractions. Scanning electron microscopy with energy-dispersive X-ray spectroscopy analysis confirmed that the hydrolysate and calcium ions formed a complex. Comparison of the calcium absorption capacity using Caco-2 cells showed that calcium absorption was promoted by these hydrolysates. Measurement of the osteoblast activation revealed higher alkaline phosphatase activity, collagen synthesis, and mineralization effect for the low-molecular-weight hydrolysate (LMH) than for the other hydrolysates. In addition, LMH promoted the expression of osteocalcin, osteopontin, and bone morphogenetic protein-2 and -4, which are hormones related to bone formation. Expression of the Runx2 transcription factor, which regulates the expression of these hormones, also increased. These results suggest that Alaska pollock surimi protein hydrolysates prepared using a system that mimics gastrointestinal hydrolysis may result in better osteoblast proliferation and bone health than those prepared using other proteases.

Obtaining Polyvinylpyrrolidone Fibers Using the Electroforming Method with the Inclusion of Microcrystalline High-Temperature Phosphates.

The results of the synthesis of microcrystalline calcium phosphates such as hydroxoapatite, pyrophosphate, and tricalcium phosphate are presented herein. The influence of the addition of polyvinylpyrrolidone (PVP) on the phase characteristics of the resulting high-temperature ceramic sample is considered. The X-ray results show that hydroxyapatite (HAp) consists of a Ca5(PO4)3(OH) phase, while the sample with the addition of polyvinylpyrrolidone contains β-Ca3(PO4)2 (65.5%) and β-Ca2P2O7 (34.5%) phases calcium phosphates (CPs). IR spectroscopy was used to characterize the compositions of the samples. An important characteristic of the obtained samples is the elemental Ca/P ratio, which was determined via energy-dispersive analysis. The data obtained are consistent with the composition of dental enamel apatites, namely, in the CPs (1.27) and HAp (1.40). SEM was used to study the morphology of the surfaces of hydroxyapatite particles. Polyvinylpyrrolidone polymer fibers were obtained using the electroforming method with the inclusion of CPs in the composition. The fibers were oriented randomly, and nanoscale hydroxyapatite particles were incorporated into the fiber structure. Solubility data of the HAp, CPs, and Fibers in a physiological solution at room temperature and human body temperature were obtained. The solubility of the resulting HAp turned out to be higher than the solubility of the CPs. In turn, the concentration of Ca2+ in a physiological solution of PVP composite fibers with the inclusion of CPs was lower than that in powdered CPs.

Synthesis and characterization of prebiotic composite struvite/kappa-carrageenan

A struvite / kappa-carrageenan composite was synthesized from an aqueous solution of a polysaccharide and inorganic precursors. The phase, elemental composition and sizes of composite particles in an aqueous colloidal solution have been studied by X-ray phase analysis, X-ray energy dispersive analysis, and dynamic light scattering. It has been shown that this promising prebiotic composite is capable of producing diffusion-mobile aqueous colloidal solutions with varying degrees of association of structural elements, which is convenient for use in biomedicine.

Charge Storage and Magnetic Properties Nitrogen-Containing Nanoporous Bio-Carbon

This article presents the technology for the preparation of a nitrogen-containing nanoporous bio-carbon and investigates its properties. It has been shown that the synthesised bio-carbon is characterised by a high degree of homogeneity, which has been confirmed by energy dispersive spectroscopy. The obtained bio-carbon has a micromesoporous structure, which has been confirmed by the results of studies using the method of low-temperature nitrogen adsorption and desorption. It was found that the specific surface area of biochar is 1247 m2/g. The data on nitrogen adsorption and desorption were compared with the data on small-angle X-ray scattering, and it was found that the micropores in the synthesised bio-carbon are open pores, while mesopores remain closed. The energy dispersion analysis showed that the structure of the bio-carbon does not contain ferromagnetic atoms, but due to the addition of nitrogen, the synthesised bio-carbon in a magnetic field has the properties of a ferromagnet with a characteristic hysteresis of the specific magnetisation. It was found that this material has a saturation magnetisation σs of 1.4 A∙m2∙kg−1 and a coercive force Hc of 10 kA/m. Symmetric supercapacitors were fabricated from the synthesised bio-carbon material with 30% aqueous KOH and 1 M Na2SO4 as electrolytes. It was found that for bio-carbon synthesised at 800 °C, the specific capacitance in a 30% aqueous solution of KOH is 180 F/g, and in a 1 M aqueous solution of Na2SO4, it is 124 F/g. The cyclic voltammetry of the fabricated supercapacitors at different rates of potential expansion was investigated and analysed. Impedance studies on these supercapacitors were carried out. The equivalent electrical circuits describing the electrochemical processes in the studied supercapacitors were constructed and characterised.

Structural and physical properties of Ni 1−x V x alloys around and away from quantum critical point

We investigate the room temperature structure (global and local), temperature dependent magnetic and transport behaviour of Ni 1−x V x ( 0⩽x⩽0.13 ) alloys. Our Energy Dispersive Analysis of x-rays results show that the prepared compositions are stoichiometric. With increase in V doping, the compounds exhibit a quantum phase transition around x c = 0.12, where the ferromagnetic phase is suppressed. Our results show that all the compounds stabilize in face centred cubic structure at RT and the lattice parameter shows unusual behaviour close to x c . The magnetic and heat capacity studies show signature of Griffiths phase on either side of x c . From 25 K to the lowest collected temperature, we observe a linear T dependence of resistivity at x = 0.1 and around x c , which is separated by a Fermi-liquid region around x = 0.106. This suggests that the origin of the transport behaviour is different around the quantum critical point and away from it. Our Ni K-edge x-ray Absorption Spectroscopy results show that there is a significant reduction in the first coordination number around Ni central atom on doping. Further, with doping, there is distortion in the first coordination shell around Ni. This suggests, with V doping, the local structure around Ni is different from the global structure as obtained from the x-ray Diffraction results. Interestingly, with doping, we observe a direct connection between the extent of distortion at RT and the magnetic disorder obtained at 2 K. We believe our results will motivate the scientific community to further study the interplay between the structural disorder and quantum fluctuations with temperature at the local level.

An investigation on hot corrosion behavior of Al0.4MnCrCoFeNi high entropy alloy in different molten salts at 750 °C

The hot corrosion behavior of Al0.4MnCrCoFeNi high entropy alloy in different molten salts at 750 °C was investigated. The high entropy alloy was synthesized by vacuum melting and casting. The hot corrosion tests were performed in 75%Na2SO4 + 25%NaCl, 75%Na2SO4 + 20%NaCl + 5%V2O5, 75%Na2SO4 + 5%NaCl + 10%V2O5, and 60%Na2SO4 + 40%V2O5 mixture salts. Microstructural characterizations were carried out using a field emission scanning electron microscope equipped with an X-ray energy dispersive (EDS) analyzer. X-ray diffraction method with CuKα radiation was also used for phase analysis of corrosion products. The results indicated that Al0.4MnCrCoFeNi alloy had relatively good resistance to hot corrosion in 75%Na2SO4 + 25%NaCl molten salt compared to the other salts due to the formation of a protective layer consisting of Mn, Cr, and Al oxides. The addition of V2O5 to the mixture salt promoted the dissolution of the oxide layer in the molten salt and hence decreased the resistance of the alloy to hot corrosion. The mechanisms of hot corrosion were oxidation-sulfidation and fluxing. The least resistance to hot corrosion was observed in 60%Na2SO4 + 40%V2O5 mixture salt because the oxide scale was destroyed seriously, resulting in accelerated propagation of hot corrosion.

Effect of Individual Alloying Addition on the Microstructure and Creep Behavior of Squeeze Cast AZ91 Magnesium Alloy

The microstructure of AZ91 (Mg-Al) alloy is comprised of α-Mg and β-Mg17Al12 massive phase. The lower melting point associated with the β-Mg17Al12 phase results in poor creep resistance of the alloy. In the present study, the AZ91 alloy with the addition of calcium (Ca, 1wt%) and cerium (Ce, 1wt%) is cast, and their effect on the microstructure and creep behavior of AZ91 alloy have been investigated. Thermally stable phases such as Al2Ca and Al11Ce3 are introduced in the AZ91 alloy through the addition of Ca and Ce elements. Energy dispersive spectroscopy (EDS) and x-ray diffraction analysis confirmed the presence of these intermetallic phases in the microstructure. Tensile creep tests on the as-cast samples were performed at 175°C temperature under 50 MPa stress. The study shows that the creep resistance of AZ91 alloy is greatly improved with the presence of Al2Ca and Al11Ce3 intermetallic phases because of their better thermal stability than β-Mg17Al12.

Thermal and mechanical properties of a sustainable bio-flax fibre-based lightweight aggregate concrete

A novel lightweight aggregate concrete (LWAC) or lightweight concrete (LWC) is developed using expanded perlite powder and lightweight expanded clay aggregate as a replacement for conventional fine and coarse aggregates, respectively. Furthermore, the natural plant-based flax fibre in treated form was added to the LWC mix at three different volume fractions. The mechanical and thermal characterisation of LWC was carried out using the compressive strength test, split tensile test, modulus of rupture, thermal conductivity and thermal resistance test. Moreover, the microstructural and durability properties were obtained using scanning electron microscopy/energy dispersive X-ray spectrum analysis, rapid chloride penetration test, sorptivity test and water absorption test. Test results reveal that the addition of 2.0% flax fibre resulted in improved mechanical, thermal and durability properties when compared to LWC with no fibres. Moreover, the microstructural analysis using SEM revealed the formation of ettringite which is responsible for the strength development in the LWAC mix.

Synthesis of carbon quantum dots from waste Phaseolus vulgaris for the development of a fluorescence sensing probe to detect plasticizer in cookies

Dibutyl phthalate (DBP) is a commonly used plasticizer in the fabrication of various packaging materials, however upon exposure, it poses significant health and environmental hazards. These plasticizers consist of low-molecular-weight components, which permeate easily into the food matrix. Hence, the development of a cost-effective detection technique is necessary for the detection and monitoring of DBP. Therefore, this research focuses on the utilization of broken Phaseolus vulgaris-derived carbon quantum dots (PV-CQDs) as a fluorescent probe for the detection of DBP in cookies. Herein, PV-CQDs were synthesized through a hydrothermal reaction, which exhibited a blue color under UV-luminescence and localized surface plasmon resonance spectrum at 238 and 270 nm. The highest fluorescence emission intensity was recorded at 428 nm. The resulting PV-CQDs exhibited an average particle size of 1.22 ± 0.05 nm and prominent peaks obtained during infrared spectroscopy were found to be of carboxylic and hydroxyl functional groups, respectively. Transmission electron microscopy and energy dispersive spectroscopy analyses confirmed the spherical morphology and elemental composition, which include C (58.05% by weight) and O (41.92% by weight), respectively. The topographical height profile of the PV-CQDs was observed by atomic force microscopy and it was found to be approximately 100 µm with a thickness of 2.9 µm . The inherent fluorescence of CQDs demonstrated notable quenching efficiency when exposed to varying concentrations of 0.1, 0.2, 0.3, 0.4, 0.5, 1, 5, and 10 µM of DBP residue, resulting in a linear relationship with a high detection sensitivity of 3.19634 µM. Furthermore, the developed method was successfully implemented to determine DBP in cookies, achieving recovery rates within the range of 97–99%. Thus, the rapid sensing capabilities of CQDs could be highlighted as their promising potential for the detection of DBP in food products.