Electron Microscopy-energy Dispersive X-ray Research Articles

Moringa oleifera Mouthwash Reinforced with Silver Nanoparticles - Preparation, Characterization and its Efficacy Against Oral Aerobic Microorganisms - In Vitro Study

Moringa oleifera (MO) commonly known as drumstick plant, is recognised by modern medicine for its distinctive therapeutic benefits. One of those benefits being its antimicrobial activity. Silver nanoparticles, known for its pharmacological effects as well as synergistic action with various agents have gained popularity in recent years. The aim of this research work was to assess the antibacterial efficacy of 5% Moringa oleifera mouthwash reinforced with silver nanoparticles against oral aerobic organisms. Aqueous extract of 5% Moringa oleifera was used to synthesize silver nanoparticles and prepare the mouthwash. Characterization was done using scanning electron microscopy analysis and energy dispersive x-ray analysis. The antibacterial activity of the mouthwash against Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Candida albicans was investigated using agar well diffusion assay. 5% MO - silver nanoparticles mouthwash had a stronger impact on Staphylococcus aureus and a comparable effect on Streptococcus mutans. The maximum zone of inhibition was 28 mm at 100 µL for Staphylococcus aureus and minimum zone of inhibition was 16mm for Candida albicans. There was a dose dependent effect of MO - silver nanoparticles mouthwash on Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans. Of these, the antimicrobial effect was more appreciable on plaque colonizers like Staphylococcus aureus and Streptococcus mutans. Thus, these characteristics of phytomedicine and nanomedicine prove to be a safer alternative in the management of Plaque associated Gingival diseases.

The Effect of Surface Morphology of Silver Nanoparticles on the Selectivity of Styrene Epoxidation

Catalytic materials at the nanoscale level have an enormous impact on sustainable environmental protection, which is important for the future. Therefore, the researchers will intensively carry out the design of catalytic materials with well-ordered surface structures. In more detail, morphology-controlled nanoparticles have special interactions with the reactants that increase catalytic performance and influence the selectivity for catalytic reactions. For those reasons, obtaining specifically surface structure-tuned nanocrystals having different surface arrangements is a significant priority that promises the best model relationship between well-oriented surface structure and catalytic performance. In this study, silver nanocrystals shaped with cubes, truncated octahedrons, and octahedrons were produced. Their catalytic behaviors were examined as an innovation for epoxidation/oxidation reactions of styrene in mild conditions. The morphological and surface characterizations of nanocrystals were determined by analytical and instrumental methods such as high-resolution transmission electron microscopy energy dispersive X-ray (HR-TEM-EDX), X-ray diffraction (XRD), as well as inductively coupled plasma mass spectroscopy optical emission spectrometry (ICP-OES), and gas chromatography-mass spectrometry (GC-MS). According to the results, nanoparticles having different surface-facets fractions can be employed to increase the selectivity of styrene epoxide.

Structural Correlation of Random Lasing Performance in Plasma-Induced Surface-Modified Gallium Nitride

The surface of GaN has been modified by a simple method that irradiates the substrate with Ar plasma and impurity codeposition, which is termed CoDE (Co-Deposition Etching). Unique structures were formed by the assistance of a small amount of Mo deposition without degradation of the crystal structure. The size of protrusions on the structure is influenced by the amount of deposited Mo particles. The mechanism for the structure formation is discussed based on transmission electron microscopy (TEM) observations and energy dispersive X-ray spectroscopy (EDS) measurements. Based on the GaN surface roughness, we have demonstrated random laser action in the UV region under photoexcitation. The lowest threshold (0.06 J/cm2) for random lasing was observed where the size of the structure is larger than 0.05 μm2, which was formed under conditions with the least amount of deposition. The correlation between the submicro/nanosize structures generated by plasma irradiation and lasing was evaluated in detail. The critical parameter to optimize the random lasing was determined to be the size of structures that can be modified by the Mo deposition rate. The results confirmed that the emission properties can be controlled by the processing conditions. This random laser fabrication technique is expected to be widely applicable to various direct-bandgap compound semiconductors.

Mechanical, Thermal Stability, and Flame Retarding Properties of Phosphorus-Modified PET Blended with DOPO-POSS.

In this study, an antidroplet flame retardant system based on FRPET (phosphorus-containing copolyester) is constructed with DOPO-POSS (polyhedral oligomeric silsesquioxane containing DOPO) as an additive flame retardant. It is demonstrated that DOPO-POSS has good dispersibility at a lower amount. When the amount of DOPO-POSS is 9 wt %, the residual char of DOPO-POSS/FRPET at 700 °C increases to 23.56 from 18.16% of FRPET, and the maximum thermal weight loss rate also reduces. What is more is that the limiting oxygen index increases to 33 from 26% of FRPET. The flame burning time is shortened to 4.95 from 20.8 s, the phenomenon of self-extinguishing of the fire occurs, and the vertical combustion level is increased from V-2 to V-0. Compared with FRPET, the peak of the heat release rate decreases by 66.0%, the total heat release decreases by 32.4%, the flame retardancy index (FRI) reaches an excellent value, and the condensed-phase products significantly improve. The Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX), thermogravimetric-FTIR (TG-FTIR), and pyrolysis-gas chromatograph/mass spectrometry (Py-GC/MS) results indicate that DOPO-POSS contributes to the formation of char layers and decomposes to generate free radicals with a quenching effect. In a word, DOPO-POSS is an effective radical trapper and charring agent for PET and exerts a flame retardancy effect in gaseous and condensed phases simultaneously.

Mn2O3 nanoparticle impregnated glycine max husks for the optimization of oil remediation in contaminated water

The sorption of crude oil using raw (unmodified) and Mn2O3 nanoparticle-modified glycine max husks was investigated for treatment of oil-spilled water surfaces by batch sorption technique. Box-Behnken design was employed for optimization of the sorption process by response surface methodology using design expert software. The sorbents’ characterization was by Fourier-transform infrared spectroscopy, scanning electron microscope–energy dispersive X-ray spectroscopy, Brunauer-Emmett-Teller surface area analysis, X-ray diffraction analysis, and Thermogravimetric analysis. Equilibrium isotherm data were evaluated using Langmuir, Freundlich, Temkin, and Scatchard models. The Langmuir gave the best fit to the experimental data and maximum monolayer uptake capacities of 3.47 and 5.29 gg−1 were obtained for the raw and nanoparticle-modified glycine max husks (RGMH and NGMH), respectively. Kinetics showed that their sorption will be satisfactorily described using pseudo-second-order, based on their large R2 values and at equilibrium uptake time of 70 and 50 min for oil onto the RGMH and NGMH, respectively. Thermodynamic parameters revealed a process that is non-spontaneous for RGMH, and spontaneous and feasible for NGMH. Regeneration and reusability after three sets of sorption-desorption were better with NGMH. Thus, Mn2O3 NGMH has greater potential as a sorbent for the management of oil-spilled water surfaces than RGMH.

Alleviation of Cr(VI) Toxicity and Improve Phytostabilization Potential of Vigna radiata Using a Novel Cr(VI) Reducing Multi-Stress-Tolerant Plant Growth Promoting Rhizobacterial Strain Bacillus flexus M2

Chromium (Cr) is a toxic heavy metal discharged into the environment through various anthropogenic sources, which affects soil properties and fertility. Hence, an effective soil restoration strategy is the need of the hour. In this study, a potent Cr(VI)-reducing strain M2 was isolated from the rhizosphere of Zea mays L. grown in leather industrial effluent contaminated sites and identified as Bacillus flexus through 16S rDNA sequencing. Strain M2 exhibited strong tolerance to multi-stresses such as temperature (up to 45 °C), pH (up to 9.0), Sodium chloride (NaCl) (up to 7%) and PEG 6000 (up to 50%) and showed strong Cr(VI) reduction with the presence of multi-stresses. The interaction of Cr(VI) with strain M2 was elucidated through various instrumentation analyses. Fourier Transform Infra-red (FTIR) Spectroscopy analysis confirmed that Cr(VI) exposures induce significant changes in the cell-surface functional groups. Raman spectrum and Transmission Electron Microscopy–Energy Dispersive X-ray spectroscopy (TEM-EDX) analysis confirmed the bio-reduction of Cr(VI) to Cr(III) and their intracellular localization as Cr(III). Further, strain M2 produced a significant quantity of Indole acetic acid (IAA), ammonia, and exopolysaccharide (EPS) and showed positive results for various plant-growth-promoting activities with the presence of Cr(VI). In greenhouse experiments, the strain M2 inoculation progressively increased the plant growth parameters and stabilized the antioxidant system of Vigna radiata under Cr stress. However, Cr(VI) exposure decreased the growth parameters and increased the level of proline content, Hydrogen peroxide (H2O2) accumulation, and antioxidant enzymes expression in V. radiata. Interestingly, strain M2 inoculation significantly reduced the accumulation of Cr in root and shoot of V. radiata when compared to the uninoculated Cr(VI) treatment. Hence, this study confirms that rhizobacterial inoculation markedly reduced the negative impact of Cr toxicity and improved V. radiata growth even in harsh environments by stabilizing the mobility of Cr in the rhizosphere.

Elemental Characterization of Leaded and Lead-Free Inorganic Primer Gunshot Residue Standards Using Single Particle Inductively Coupled Plasma Time-of-Flight Mass Spectrometry.

This study describes the use of single particle inductively coupled plasma time-of-flight mass spectrometry (spICP-TOFMS) for the detection and classification of inorganic gunshot residue (IGSR) particles. To establish reliable multi-element criteria to classify IGSR particles, leaded and lead-free IGSR reference materials were analyzed, and the elemental compositions of the individual particles were quantified. The results suggest that expanded element compositions may be used to classify IGSR particles via spICP-TOFMS compared to those used in conventional IGSR analysis using scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS). For spICP-TOFMS analysis of leaded IGSR particles, classification may be based on the presence of lead (Pb), antimony (Sb), and barium (Ba) just as in SEM-EDS; however, additional particle types, such as lead-copper (Pb-Cu) particles, contribute significantly (∼30%) to the leaded IGSR particle population. In lead-free IGSR particles, the dominate multi-metal particle composition found is titanium-zinc (Ti-Zn) with a conserved Zn:Ti ratio of 1.4:1, but other elements, such as copper (Cu), are also characteristic. In mixtures of the two IGSR reference materials, we were able to classify over 80% of the multi-metal particles detected with no false-positive particle-type assignments. With spICP-TOFMS, particles smaller than those typically measured by SEM-EDS are detected, with estimated median diameters for leaded and lead-free IGSR of 180 and 320 nm, respectively. Through measuring these smaller particles, up to ∼two times more particles per mL are recorded by spICP-TOFMS compared to that found by SEM-EDS. Overall, high-sensitivity and high-throughput analysis using spICP-TOFMS enables quantitative, rapid multi-elemental characterization, and classification of individual IGSR particles.

Optimization Effect of Metakaolin on Macro- and Micro-Mechanical Properties of Composite Cementitious Materials under Different Curing Conditions

To provide the theoretical basis for the engineering application of metakaolin as aluminum-rich pozzolanic ash materials, the promoting effect of metakaolin on the macro- and micro-mechanical properties of composite cement-based composite materials was explored under high-temperature steam and standard curing conditions. Analysis techniques, which involved thermogravimetric and nanoindentation coupled with scanning electron microscopy-energy dispersive X-ray spectroscopy, were used. To analyze the experimental data, the ACI empirical formula and the copula function were used. The correlation among the hydration degree of the MK-cement cementation system, the Al/Si of the C-(A)-S-H phase, and the nanomechanical properties of the C-(A)-S-H gel phase was investigated. According to prior research, the macroscopic mechanical properties and the substitution rate of the MK-cement composite cementitious system can be improved under high-temperature curing conditions in a short period, in which the optimum substitution rate of metakaolin is 20%. The ACI empirical formula was used to demonstrate the functional relationship between the metakaolin replacement rate, curing time, and compressive strength. The MK-cement cementation system can eliminate the defect phase, reduce the CH phase content, and then increase the C-(A)-S-H gel phase content and bulk density. The micro-mechanical properties of the C-(A)-S-H gel phase rises due to its phase content and Al/Si ratio. Furthermore, the copula function verifies the dependence of the nanomechanical properties of C-(A)-S-H gel and Al/Si.

Evaluation of the suitability of Pleurotus as a fluid loss control agent using the chemical structural properties approach

One of the main functions of the drilling fluid is to prevent filtrate from entering the formation by exhibiting good fluid loss properties during oil and gas drilling operations by sealing off the walls of the wellbore. Pleurotus is a type of edible mushroom that has been discovered by researchers to play the role of fluid loss additives in the mud system. The Pleurotus sample was processed as per the API standard and measured accordingly using laboratory measurements such as Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy (SEM-EDS) for characterization, the X-Ray diffraction (XRD) methods used by scanning the sample to determine the chemical structure, name, and physicochemical properties by matching the results obtained with a different library, such as the NIST and PubChem. The Fourier Transform Infrared Spectrometer-FTIR 8600S helped to discover some of the functional groups which then confirmed the results and the matching of the XRD. The key chemical composition of Pleurotus are Chitin, glucans, and glycoproteins and their functional groups are amine (NH) and hydroxyl (R-OH), its high fiber and cellulose contents from chitin and glucans are the main constituents in the fluid loss control characteristics for its effectiveness. The position of the carbon-carbon, nitrogen-hydrogen, and hydrogen-oxygen indicating the point of the double bond was confirmed from the FTIR. The result of the sample was matched and found to be Psilocin which gave the structures to be more amorphous since they are more organic materials.

One-Step Microcrystalline Glass Preparation Using Smelting Slag from Waste Automobile Three-Way Catalysts through Iron Collection

The smelting slag obtained through iron collection from waste automobile three-way catalysts was used as a raw material to prepare microcrystalline glass through a one-step crystallization heat treatment. The phase composition and microstructure of the prepared glass were analyzed through X-ray diffraction and scanning electron microscopy–energy dispersive X-ray spectroscopy, respectively. Single-factor experiments were conducted to investigate the effects of crystallization temperature from 900 to 950 °C and crystallization time from 0.5 to 4 h on the physical and chemical properties of the microcrystalline glass. The results indicated that the optimum crystallization temperature and time for preparing microcrystalline glass with glass smelting slag through the proposed one-step crystallization heat treatment process were 950 °C and 3 h, respectively. Under these experimental conditions, the number of crystalline phases of the microcrystalline glass was high, the grains were mainly spherical and columnar particles, the sample structure was dense, and the best results were obtained: the density was 2.72 g/cm3, the water absorption was 1.55%, the porosity was 4.2%, the Vickers hardness was 618 HV, the acid resistance was 2.6%, and the alkali resistance was 0.04%. In addition, the results of the toxicity characteristic leaching procedure indicated that the leaching concentrations of heavy metals such as Zn, Cr, and Pb in the microcrystalline glass were lower than those in the base glass and were considerably lower than the acceptable limits. The microcrystalline glass obtained from final smelting slag through heat treatment can enhance the stabilization of harmful elements. The findings of this study can be applied to the treatment of bulk solid waste.

Synthesis and characterization of SbSI modified g-C3N4 composite for photocatalytic and energy storage applications

Two dimensional carbon related materials with superior charge separation and excellent transport properties have been highly used in the field of photocatalytic and electrochemical applications. The hydrothermally synthesized antimony sulfoiodide (SbSI) doped g-C3N4 composite (CSI) has excellent charge storage and charge transport properties. The physio-chemical properties of the synthesized SbSI doped g-C3N4 materials are examined by X-ray diffraction (XRD), transmission electron microscopy (TEM) energy dispersive x-ray spectroscopy (EDS), Fourier transform-infra red spectroscopy (FT-IR), Ultraviolet-diffuse reflectance spectroscopy (UV-DRS), X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PL) techniques. The photocatalytic examination of the synthesized catalyst materials is carried out in presence of visible light irradiation using Rhodamine B (RhB), Bromophenol blue (BPB) and mixed dye effluents. The synthesized photocatalyst material CSI shows excellent photocatalytic activity of 94%, 80% and 92% against BPB, RhB and mixed dye effluent and the stability of the prepared material was 95% even after four consecutive photocatalytic performances. In addition, the electrochemical properties of the synthesized CSI composite is examined by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) analysis and electrochemical impedance spectroscopy (EIS) investigations. The synthesized composite material depicts good specific capacitance of 212 F/g at 0.5 A/g current density and retains 96% of the stability after 1000 consecutive GCD performance. The experimental finding confirms that the CSI composites have enhanced photocatalytic and electrochemical performance than the synthesized SbSI and g-C3N4 materials.

A novel strategy to synthesize bioactive glass based on the eutectic reaction of B2O3–K2O

Melt-derived route was used to prepare modified bioactive glass-ceramic based on the 45S5 composition with the same network connectivity. Their phase composition, sinterability, and bioactivity were studied. A modified composition was proposed using potassium tetraborate (K2B4O7) to reduce the melting temperature during manufacture. The phase composition and the bioactivity was determined by X-ray diffraction and Fourier transform infrared spectroscopy. Furthermore, the antibacterial properties were evaluated against Enterococcus faecalis. The result shows that glass-ceramics already had P–O and C–O bond functional groups on day 2. These bonds are responsible for the creation of the HCA layer. Scanning electron microscopy (SEM) pictures and Energy Dispersive X-ray Spectroscopy (EDX) investigations showed that, after being immersed in SBF solution, a layer of hydroxyapatite (HA) formed on both BG surfaces on day 2 and that by day 21, HCA cluster crystals had developed. Inductively coupled plasma-optical emission spectroscopy metrics of ionic release from the prepared glass-ceramic, mainly calcium and phosphorus ions in SBF solution, revealed that HCA formation occurred on both BG surfaces, which correlated to the increasing pH within 2 days of incubation; furthermore, it exhibited good antibacterial behavior against the Enterococcus faecalis.

The Victoria and Albert Museum Plaster Casts by the Nineteenth-Century Workshops of the Notre-Dame Cathedral: Scientific Analysis and Conservation

Four nineteenth-century casts of the decoration on the north side of the exterior of the apse of the Notre-Dame Cathedral in Paris are held in the plaster casts collection at the Victoria and Albert Museum in London. The casts were manufactured by two different nineteenth-century workshops, one run by Jean Pouzadoux and the other by Auguste Malzieux. After an assessment of the condition of the casts, a scientific analysis allowed the characterization of the manufacturing materials and subsequent conservation treatments aimed at ensuring the stability of the casts and removing dirt and grime from the casts’ surfaces. Optical microscopy of the samples taken from the casts allowed the stratigraphy to be studied, which largely consisted of gypsum plaster and a coating layer (oxidized diterpenic resin or shellac) containing silicon and aluminium partially diffused in the porous substrate. These materials were identified by a range of techniques, including X-ray diffraction, scanning electron microscope–energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and gas chromatography/mass spectrometry. The conservation works returned stability to the panels for redisplay in the galleries and achieved a closer comparative study between the two workshops. The two sets of panels showed numerous differences in manufacturing processes that corresponded to their observed deterioration.

EPR Analysis of Cu2+ ion Doped Potassium borodicitrate Single Crystal

In our present investigation single crystals of Potassium borodicitrate (KBDC) (for a fixed content- host lattice) with Cu2+, a guest species, as a dopant (at four 0.2, 0.5, 1 and 2 g) in weight ratio have been synthesized at room temperature by using slow evaporation method. These as-synthesized 4 crystals have been subjected to Electron Paramagnetic Resonance (EPR) studies. The EPR spectrum shows that 0.5 g dopant KBDC give a 4 equidistant hyperfine lines with the perfect symmetry confirms that the localization of Cu2+, a paramagnetic impurity, within it reveals that the maximum absorption of EPR signals happens at 0.5 g Cu2+ than any other concentrations with reference to 20° in horizontal plane than the normal and vertical recording in the same angular projection. The Spin Hamiltonian calculations are used to obtain spectroscopic field splitting factor g-tensor values, gxx = 2.0421, gyy = 2.1962, gzz = 2.2827 and hyperfine splitting factor A-tensor values Axx = 150, Ayy = 112 and Azz = 134. The K–O bond length associated with directional cosines of gzz tensor reveal that the Cu2+ is located interstitially. This optimized single crystal has furtherance been subjected to Single cystal X-ray diffraction (SXRD), Fourier transform infrared Spectrascopy (FTIR). Scanning electron microscope (SEM) Energy dispersive X-ray analysis (EDAX) and compared with pure KBDC single crystal. The XRD unit cell crystalline parameter variations reveal that there is doping effect of Cu2+ into the host lattice brings forth structural coordination of Cu2+ with KBDC. The FTIR confirms that complexation of host and guest through molecular interactions in the finger print region. The EDAX mapping shows Cu2+ presence in the crystal. HIGHLIGHTS SXRD are taken to confirm that structure of pure KBDC and Cu2+ doped KBDC are same The spin Hamiltonian parameters of KBDC-Cu2+ single crystal are calculated through EPR spectra On analyzing the spectra, it is found that the doped ion site location symmetry is identified as interstitial and experience orthorhombic local field symmetry In addition to the above studies FTIR and EDX confirms the presence of Cu2+ ion GRAPHICAL ABSTRACT

Application of artificial neural network for prediction of fluoride removal efficiency using neutralized activated red mud from aqueous medium in a continuous fixed bed column.

The present research work approaches the removal of fluoride from aqueous medium using neutralized activated red mud (NARM) in a continuous fixed bed column. Artificial neural network (ANN) technique was applied effectively for optimization of the model for the practicability of the removal process. The consequences of various experimental variables, like bed length, adsorbate concentration, experimental time, and adsorbate solution flow rate are studied to know the breakthrough point and saturation times. The highest removal potentiality of NARM was considered to be 3.815mgg-1 of F- in the bed height of 15cm, starting concentration 1ppm, susceptible time 120min, adsorbate solution flow rate 0.5mLmin-1, and constant room temperature, respectively. Bohart-Adams and Thomas models were considered to describe the fixed bed column effect to the bed height and adsorbate concentrations. The experimental data were applied to a back propagation (BP) learning algorithm programme with a four-seven-one architecture model. The artificial neural network model was considered to be functioning correctly as absolute relative percentage error throughout the learning period. Differentiation between the predicted outcomes from ANN model and actual results from experimental analysis affords a high degree of correlation (R2 = 0.998) stipulating that the model was able to predict the adsorption efficiency. Experimented adsorbent materials were characterized using different instrumental analysis that is scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD).

Enhanced durability of round bamboo treated with copper naphthenate under heat-cold impregnation.

Round bamboo has aroused much interest in construction for its mechanical properties, but poor biological durability seriously restricts its application. In order to develop a suitable and effective preservative treatment method for round bamboo, copper naphthenate (CuN) was adopted and impregnated into round bamboo using heat-cold procedure. The distribution and retention of copper naphthenate in round bamboo were studied, and the biological durability represented by the mould and decay resistance were investigated. The results showed that the retention and fixation of copper reached 0.39 kg⋅m-3 and 85.3%, respectively. Scanning electron microscopy-energy dispersive X-ray spectrometry further disclosed an increasing trend in the composition of CuN from the end inward. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses later revealed that CuN could be fixed on bamboo in the form of hydrogen bond or complex reaction. Statistical analysis showed that the increasing concentration of CuN from 0.3% to 0.5% and 0.8% (calculated as Cu2+ content) has significant contribution against Trametes versicolor and Gloeophyllum trabeum in comparison with the untreated bamboo. Meanwhile, when the concentration of treating solution increased to 0.8 wt%, the resisting efficacy for Aspergillus niger, Penicillium citrinum and Trichoderma viride soared as high as 85.9%, 94.8% and 70.3%, respectively.

Using zeolite and Fe3O4@zeolite composites in removal of Reactive Red 120 from wastewater: Isotherm, kinetic, thermodynamic and adsorption behaviors

It is a well-known fact that the release and dispersion of complex organic dyestuffs into the environment adversely affect human health and other living organisms. Due to industrial activities, pollution of water resources, which are vital for living organisms, is one of the most critical environmental problems nowadays. It is essential to remove the pollutants before they are discharged into the environment to eliminate environmental damage. In this study for the removal of Reactive Red 120 (RR120) dyestuff from an aqueous solution, we employed natural zeolite and iron oxide-zeolite (Fe3O4@Z) as adsorbents. The adsorbents were characterized by Fourier transform infrared spectroscopy, X-ray diffractometry, X-ray fluorescence spectrometry, Scanning electron microscopy energy dispersive X-ray spectroscopy, and Brunauer–Emmett–Teller analysis. The effects of parameters such as pH, contact time, and temperature on RR120 adsorption were also investigated. In addition, the adsorption equilibrium was analyzed with kinetic, isotherm, and thermodynamic parameters. It was found that the adsorption of RR120 on natural zeolite and Fe3O4@Z followed the Langmuir and Freundlich isotherm, respectively, and the adsorption process for both adsorbents proceeded spontaneously (ΔG∘ <0) and exothermic (ΔH∘ <0) with a pseudo-second-order kinetic model. Zeolite and Fe3O4@Z adsorption capacities for RR120 were 145.9 and 154.3 mg/g at 20 °C, respectively. It was determined that no significant matrix effect occurs in adsorption with synthetic wastewater prepared to evaluate the potential performance of adsorbents. According to the results obtained, Fe3O4@Z composite was found more effective adsorbent than natural zeolite for RR120 removal.

Analysis of Phase and Energy Band Gap Width of Corncob Carbon-PEG 4000

This study aims to identify and analyze the band gap width of the carbon phase produced from corncobs mixed with PEG-4000 to see the surface area of the corncob carbon phase. First, the characterization test was carried out using Scanning Electron Microscope Energy-Dispersive X-ray (SEM-EDX) spectroscopy to determine the morphology and Ultraviolet–Visible (UV-Vis) spectroscopy to determine the band gap width of corncob carbon. Then, adding Polyethylene Glycol (PEG) 4000 at a specific concentration to develop the potential of corncob carbon. Finally, the corncob-PEG 4000 carbon reduction process was sifted through and tested by UV-Vis spectroscopy, and the energy gap value was 0.954 eV. DOI: 10.17977/um024v7i22022p142

Laser cleaning on severely corroded steel members: Engineering attempt and cleanliness assessment

A highly effective, environmentally friendly, high-power continuous-wave laser (CWL) transmitter was newly developed to remove corrosion products from severely corroded steel structures. In this regard, treatment conditions of dry laser cleaning (DLC) and wet laser cleaning (WLC) of the drench, soak, and rinse methods are adopted, and the cleanliness effect is compared with that of conventional abrasive blasting treatment. The morphologies and chemical compositions of untreated and treated surfaces are analyzed using three-dimensional digital microscopy, laser confocal microscopy, and scanning electron microscopy–energy dispersive X-ray spectrometry. The results show that laser cleaning can efficiently remove corrosion products and salts that severely corrode steel members, as well as prolong the re-corrosion time of the cleaned surfaces. WLC can achieve excellent microscopic cleaning and reduce the effect of high-temperature inputs on the surface via laser irradiation. Further mechanistic analysis indicates that ablation, melting, and evaporation during laser cleaning primarily contribute to the removal of corrosion products and salts. As a result, the WLC drench method yields the best surface cleanliness and is suitable for practical engineering applications. This study provides a basis for maintaining severely corroded structures via laser-cleaning techniques.

Enamel biomineralization under the effects of indomethacin and celecoxib non-steroidal anti-inflammatory drugs

The aim of this study was to explore the effects of nonsteroidal anti-inflammatory drugs on biomineralization of enamel. Sixty C57Bl6 male mice were used, which were assigned into three groups: celecoxib (n = 20) or indomethacin (n = 20) treatment for a period of 28 days or received no medication (control group, n = 20). Visual inspection and microcomputed tomography were used to analyze enamel morphology. Scanning electron microscopy–Energy dispersive X-ray and Knoop microhardness test were used to quantify chemical element content (Ca, P, C, O) and enamel microhardness, respectively. Tissues were collected to investigate the synthesis, activity or nuclear translocation of metalloproteinase-20, transcription factor Runx2, dentin sialoprotein and cyclooxygenase-2 enzyme by means of immunohistochemistry, in situ zymography and indirect immunofluorescence. Treatment with indomethacin and celecoxib reduced the Ca and P content, microhardness and mineral density in enamel. Treatment with nonsteroidal anti-inflammatory drugs caused an accumulation of metalloproteinase-20 and overall increased enzymatic activity in enamel matrix, while the synthesis of the transcription factor Runx2 was inhibited by these drugs. Interestingly, indomethacin inhibited Runx2 translocation to the nucleus whereas celecoxib did not. Those findings show that non-steroidal anti-inflammatory drugs impact the enamel biomineralization and could be involved in the etiology tooth enamel defects if used during the period of tooth formation and mineralization.