X-ray Diffraction Spectrometer Research Articles

Dispersity and Mechanical Strength Ni-TiO2 Composites Electrodeposited Via Supercritical CO2 Emulsified Electrolyte

Electrodeposition of metal matrix composites (MMCs) is an effective method to enhance physical and chemical properties of materials by allowing dispersion of nanoparticles into the metal matrix. Various kinds of metals including Au, Cu and Ni have been reported as the metal-matrix depending on their target application. In co-electrodeposition with nanoparticles, uneven distribution of the nanoparticles in the metal matrix caused by aggregation of nanoparticles in the electrolyte would lead to an unevenly local enhancement of the desired property. Therefore, in co-electrodeposition of MMCs, controlling the dispersity, such as the size and space distribution, of the particles in the metal matrix is always a research topic of interest. Supercritical carbon dioxide (SC-CO2) is a state of CO2 exists when the temperature and pressure are above its critical point. SC-CO2 has low surface tension and low viscosity, which are advantageous in co-electrodeposition of metal matrix composite. Dispersed phases in the SC-CO2 emulsified electrolyte would improve transfer of materials in the electrolyte and expect to influence incorporation amount and distribution of suspension particles in the electrolyte then eventually affect the dispersity in the electrodeposited metal matrix. In this study, Ni-TiO2 composite coatings are electrodeposited with SC-CO2 emulsified electrolyte. The effects of SC-CO2 emulsion on the amount and distribution of TiO2 particles incorporated in the Ni matrix, and the mechanical property of the Ni-TiO2 composite coatings are evaluated for applications in miniaturized electronics.Ni-TiO2 composite coatings are deposited on cold-worked Cu plates with 3.5 cm2 in surface area through a two-electrode deposition cell. Ni plates are used as counter electrode. Ni Watts bath-based electrolyte, which composed of NiSO4‧6H2O, NiCl2‧6H2O, and H3BO3, with and without addition of 30 g/L TiO2 nanoparticles are used for the electrodeposition process. Since SC-CO2 molecules are non-polar, 0.2 g/L of sodium dodecyl sulfate (SDS) is added to emulsify SC-CO2 with the Ni electrolyte. Pure Ni and Ni-TiO2 composite coatings fabricated from conventional electrodeposition method without addition of SC-CO2 are prepared as comparisons. Pure Ni coatings are named as Ni-S-# (# represents the concentration of SDS in electrolyte) and the Ni-TiO2 composite coatings prepared by conventional method are named as CV-S-#. For the composite coatings prepared from the SC-CO2 emulsified electrolyte, the samples are designated as SC-S-#. For all electrodeposition processes, the temperature is maintained at 50 °C, the deposition time is 40 min, and the applied current density is 30 mA/cm2. Conventional electrodeposition of pure Ni and Ni-TiO2 composite are conducted under ambient pressure, and 15 MPa is used for the electrodeposition with SC-CO2. Volume fraction of SC-CO2 in the reaction cell is 20 vol.%. Surface morphologies of the as-deposited films are observed with a scanning electron microscope. The element composition are characterized by energy dispersive X-ray spectrometry (EDS). The crystalline structure annd grain size are measured by X-ray diffraction spectrometer (XRD). Local density of TiO2 particles in Ni matrix are quantified by a python-based convolution process from Ti EDS mapping datasets. The Ti local density data is revisualized as heatmap and its coefficient of variation is calculated to evaluate the dispersity of TiO2 in composite coatings. Hardness of the films is evaluated by Vickers hardness measurement.TiO2 content and Vickers hardness of Ni-TiO2 composite coatings fabricated with representative electrodeposition conditions are shown in Fig. 1. Benefit from the accelerated mass transfer in SC-CO2 emulsified electrolyte, a significant increase of TiO2 incorporation amount could be found between SC-S-02 and CV-S-02. As a result of grain refinement and high incorporation amount of TiO2 in Ni-TiO2 composite coatings, the Vickers hardness of SC-S-02 is found at about 1150HV, which is threefold of the hardness of CV-S-02. Rest parts of the data, including the influence of SC-CO2 on surface morphology of Ni-TiO2 composite coatings and grain refinement of Ni matrix, and the effect of SC-CO2 on the improvement of dispersity of TiO2 particles incorporated in Ni matrix, will be presented in the ECS meeting. Figure 1

Crack Propagation for Glass Fiber Reinforced Laminates Containing Flame Retardant: Based on Single-Edge Tensile Loading

Research on crack propagation for fiber reinforced composites containing flame retardant is rare. The micro-cracks propagation is a reason for delamination and debonding failure of fiber reinforced composites. To study the crack propagation of continuous glass fiber reinforced epoxy resin laminates that contained ammonium polyphosphate flame retardant (GFRP-APP), the quasi-static single-edge tensile loading (SETL) experiments for the end-notched GFRP-APP specimens were carried out by MTS universal electronic testing machine. The crack propagation of the end-notched 90� GFRP-APP specimen includes two types, both of which belong to opening type (mode I). Namely, one type is mode I multi-cracks propagation without preexisting crack, and the other is mode I fiber bridge propagation with preexisting crack. The intralaminar fracture toughness along fiber direction of GFRP-APP is approximately 8.4 N/mm, which is calculated by area method. The opening displacement-tensile force curves can be divided into three stages for 90� GFRP-APP specimen without crack, i.e., crack gestation, crack birth and crack propagation. However, the 90� GFRP-APP specimen with crack not contains the crack birth stage. Additionally, the microscopic morphology for the fracture face of pure epoxy resin and GFRP-APP, and the phase analysis for GFRP-APP were performed by scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). As a conclusion, the pores and interfaces in materials were the guiding factors of micro-crack propagation, and the ammonium polyphosphate flame retardant particle contributed extra interfaces.

Synthesis and Characterizations of Novel Spinel Ferrites Nanocomposites Al0.5Cr0.5Zn0Fe2O4 and Zn0.5Cr0.5Al0Fe2O4

In this study, novel spinel ferrites nanocomposites containing aluminum chromium zinc nanoferrites, Al0.5Cr0.5Zn0Fe2O4 and Zn0.5Cr0.5Al0Fe2O4 have been fabricated and characterized to determine the properties of highly stable conduction materials. The nanocomposites have been synthesized through the sol–gel method. Zinc and aluminum-doped chromium ferrites were prepared with the stoichiometric composition ZnxAlx-0.5Cr0.5Fe2O4 with ammonium hydroxide solution (NH4OH) and polyethylene glycol (PEG) at different temperatures with consecutive steps. After sintering the final nanoferrites, characterizations for morphological, spectral properties, and crystallinity have been determined through scanning electron microscope (SEM), Fourier transformation infrared spectroscopy, and X-ray diffraction spectrometer, respectively. SEM micrographs presented that higher sample density and agglomeration of the nanocomposite outer surface with temperature increase. The investigation of the dielectric and conduction properties presented with varying sintering temperature and Al–Zn doping greatly influenced the dielectric properties of spinel nanoferrites dielectric properties: dielectric loss tangent and dielectric constant. The effects of various sintering temperatures provide synergistic effects on the morphology and dielectric conductivity features. The characterizations presented that the dopants (Al, Zn) enhanced the magnetic and electrical properties of both chromium nanoferrites which can be implemented in high frequency single-layered electromagnetic waves absorbing devices in electrical and medical appliances in future.

Microstructure Evolution of Inertia Friction Welded Joints of TC21 Titanium Alloy

In this paper, TC21 titanium alloy welded joints were successfully formed through inertial friction welding (IFW) processes. Microstructure evolution of IFW joints was investigated by way of different analysis methods including optical microscope (OM), scanning electron microscope(SEM), Electron Back-Scattered Diffraction(EBSD), X-Ray Diffraction(XRD), and Energy Dispersive Spectrometer(EDS). The results indicate that large-sized equiaxial β grains, original α phases, and basketweave structure existing in the BM have completely disappeared in the WZ. Instead, fine equiaxial grains sized at 20–30 μm and very fine α + β lamellar microstructure are formed in the WZ. However, as transition zones, the microstructures of the TMAZ and HAZ are also in transition state while the microstructures existing in the BM partially remain in the TMAZ and completely remain in the HAZ. In addition, second α phases are precipitated and fine α + β lamellar microstructure are formed on the original β base in the TMAZ and HAZ. XRD and EBSD results reveal that the proportion of β phase in the WZ zone decreases greatly. EDS results show that there are aggregations of stabilizing elements of β phase in the BM, but no element aggregation in the WZ. Dynamic recrystallization during the IFW process and element distribution under the rapid cooling condition after the welding process are believed to be responsible for formation of the microstructure in the weld zone of IFW joints.

Kinetics-driven design of 3D VN/MXene composite structure for superior zinc storage and charge transfer

Aqueous zinc-ion batteries (ZIBs) employing zinc as the anode have recently inspired widespread attention. However, crackly cathode and inefficient transfer kinetics upon the Zn2+ shuttle make the storage capacity and service life far from satisfactory to meet the practical demand. Herein, a 3D VN/MXene composite structure is elaborately designed as the electrode by uniformly encapsulating VN microspheres in MXene nanosheets, which prevents the microsphere over aggregation to ensure full exposure of reactive sites, and serves as a conductive buffer for inhibiting the structure damage to realize fast transfer kinetics. VN/MXene anode exhibits high reversible capacity (521 mAh g−1vs. 324 mAh g−1) at 0.5 A g−1 and superior rate performance, remarkably higher than that of pure VN electrode. The capacity still maintains 146.3 mAh g−1 at 5 A g−1 coupled with high stability up to 2200 cycles. Moreover, the energy storage mechanism of highly reversible phase transition of VN upon Zn2+/H+ co-insertion/extraction is elucidated by in-situ X-ray diffraction and ex-situ X-ray photoelectron spectrometer. The structural merits of 3D VN/MXene composite work with fast and reversible Zn2+ (de)intercalation toward superior zinc storage and charge transfer. Such design strategy lights up a brilliant insight into the development of cathode materials for ZIBs.

Study on immobilization of nitrogen and phosphorus in sediments using modified fly ash composite material

Abstract In this paper, a new type of particle-modified fly ash composite material was prepared using fly ash as the main raw material, which could immobilize nitrogen and phosphorus pollutants in sediment and control its release into water. Preliminary modification of fly ash was achieved by soaking in NaOH and calcining at high temperature of CaO. The modified fly ash was mixed with four auxiliary materials, namely cement, slag, water glass and quartz sand, and was formed after 14 days of curing. X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) were used to examine the material microstructure, element composition, crystal mineral changes, and also to further examine the physical indicators and mechanical properties of the material. In the end, we chose to use modified fly ash composite 10% cement to make granular modified fly ash composite materials. Taking the actual polluted river sediment as the research object, a 22-day coverage effect experiment was carried out, and it was finally found that the 2 cm-thick modified fly ash composite material cover layer inhibited the ammonia nitrogen (NH4+-N)、total nitrogen (TN) and total phosphorus (TP) of the sediments at 90.91%, 75.06% and 90.63%, respectively. This confirms that it is a material with good performance and practical application value.

A new strategy to integrate silver nanowires with waterborne coating to improve their antimicrobial and antiviral properties

PurposeThis study aims to focus on the preparation and characterization of the silver nanowire (AgNWs), as well as their application as antimicrobial and antivirus activities either with incorporation on the waterborne coating formulation or on their own.Design/methodology/approachPrepared AgNWs are characterized by different analytical instruments, such as ultraviolet-visible spectroscope, scanning electron microscope and X-ray diffraction spectrometer. All the paint formulation's physical and mechanical qualities were tested using American Society for Testing and Materials, a worldwide standard test procedure. The biological activities of the prepared AgNWs and the waterborne coating based on AgNWs were investigated. And, their effects on pathogenic bacteria, antioxidants, antiviral activity and cytotoxicity were also investigated.FindingsThe obtained results of the physical and mechanical characteristics of the paint formulation demonstrated the formulations' greatest performance, as well as giving good scrub resistance and film durability. In the antimicrobial activity, the paint did not have any activity against bacterial pathogen, whereas the AgNWs and AgNWs with paint have similar activity against bacterial pathogen with inhibition zone range from 10 to 14 mm. The development of antioxidant and cytotoxicity activity of the paint incorporated with AgNWs were also observed. The cytopathic effects of herpes simplex virus type 1 (HSV-1) were reduced in all three investigated modes of action when compared to the positive control group (HSV-1-infected cells), suggesting that these compounds have promising antiviral activity against a wide range of viruses, including DNA and RNA viruses.Originality/valueThe new waterborne coating based on nanoparticles has the potential to be promising in the manufacturing and development of paints, allowing them to function to prevent the spread of microbial infection, which is exactly what the world requires at this time.

Determination of Gel Products in Alkali-Activated Fly Ash-Based Composites Incorporating Inorganic Calcium Additives

The introduction of soluble calcium additives contributes to forming calcium-containing geopolymer (N,C)-A-S-H and/or calcium (alumino)silicate hydration C-(A)-S-H in alkali-activated fly ash-based composites (AAFCs). However, the quantitative determination of the final gel product has yet been unclear due to the different chemical components, which influences the prediction of mechanical strength and microstructure. This study aims to propose a method to clarify the gel products in AAFCs by the critical elemental compositions in gel products. Furthermore, the AAFCs were prepared (by casting method) using soda residue (SR) as the calcium additive, fly ash as the aluminosilicate precursor, and sodium silicate solution as the alkaline activator. The compressive strengths of the AAFCs with different SR contents were recorded. The microstructures and gel products of AAFCs were detected through scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and 29Si nuclear magnetic resonance spectrometer (29Si NMR). Finally, the proposed determination method was verified with the experimental results. The new proposed quantitative method refers to a limit value of 2Ca/Al = 1.00 about the critical chemical elements in gel products, which helps to determine the calcium-containing geopolymer (N,C)-A-S-H or/and calcium (alumino)silicate hydration C-(A)-S-H in stable AAFCs. Results show that the gel products are determined as single (N,C)-A-S-H gels when 2Ca/Al is lower than 1.00; meanwhile, (N,C)-A-S-H and C-(A)-S-H gels coexist when 2Ca/Al is higher than 1.00 by the above proposed quantitative determination method. Furthermore, it works that the industrial solid waste SRs regarded as calcium additive are applied in the AAFCs to verify the gel products by 2Ca/Al = 1.00 as the limit value. The results provide the theoretical and experimental basis for the performance prediction and microstructural determination.

Electrosynthesis of perchlorate using neodymium-doped PbO 2 electrode: application of experimental design methodology for optimization of the effective parameters

In recent decades, extensive research has been done on substrates (i.e., titanium and carbon) with lead dioxide coating to design a cheap anode in electrochemical systems instead of a platinized (Pt) electrode. Various factors can affect the structure and catalytic activity of lead dioxide coating. The most important of them are the type of substrate, how to prepare the substrate for the coating process and the types of lead dioxide additives. In this work, the effective factors in the preparation of the substrate were first investigated. Subsequently, the effect of neodymium as an additive on the catalytic activity of the electrode was studied. We prepared these electrodes and they were first evaluated by scanning electron microscopy (SEM), X-ray diffraction (XRD) spectrometer, voltammetry and electrochemical impedance spectrometer (EIS). The results showed that the potential of water oxidation on the modified electrodes by neodymium was 2 V. Here, we used an electrochemical method to prepare perchlorate. Since the anode potential for perchlorate oxidation is near that for water oxidation, conventional electrodes can’t be used in the perchlorate electrosynthesis. To achieve high production yield in the preparation of perchlorate from chlorate, various parameters including pH, time, and current density were optimized by the Box-Behnken design of the experiment method. The optimal values for this process were obtained at pH = 11, temperature 40 °C and current density of 0.5 mA cm−2. The results at the optimal condition showed that the perchlorate production yield by modified electrodes was 80% in the 300 min. This value was only 60% for the unmodified electrode.

Extraction of Thorium Oxide (ThO<sub>2</sub>) from Malaysian Monazite through Alkali Digestion: Physical and Chemical Characterization Using X-Ray Analysis

Extraction of thorium oxide (ThO2) from monazite mineral specifically from Perak, Malaysia become a bright opportunity for the new income generation in Malaysia eventhough it is involved complex processing routes and require variety of chemicals. Monazite that is known as monazite-(Ce)-PO4 minerals, not just contain thorium, but it also consist rare earth elements (REE) such as cerium (Ce), neodymium (Nd), lanthanum (La) and gadolinium (Gd) and also associated with thorium (Th) and uranium (U) at about 7 wt% and 0.2 wt% respectively. One of the challenges in this R&D work is to determine the presence of thorium, uranium and REE at each processing step due to its similarities of chemical composition and physical properties. Therefore, the aim of this paper is to use several x-ray characterization techniques to identify elemental composition obtained at each processing route to show the evidence of the presence of ThO2 extracted from Malaysia monazite. This paper focused on the use of wavelength dispersive x-ray fluorescence (WDXRF), field emission scanning electron microscope (FESEM) with energy dispersive x-ray (EDX) and x-ray diffraction (XRD) spectrometer to show evidence of ThO2 formation. Result shows that the final product contain of 85 wt% of ThO2 and it is thorianite with nanorod morphology. Thus, conforming that the feasibility of the current processing route to produce ThO2 from Malaysia monazite.

Application of Ni-doped ZnO nanorods in surface acoustic wave ultraviolet photodetectors

A surface acoustic wave ultraviolet photodetector was fabricated on a ZnO thin film with pure and Ni-doped ZnO nanorods deposited on a Si substrate. Piezoelectric ZnO thin films were grown on Si through radio-frequency magnetron sputtering, and ZnO nanorods were synthesized on ZnO thin films by using the hydrothermal method. The crystalline structure, surface morphology, and luminescent characteristics of ZnO films and nanorods were examined using X-ray diffraction and photoluminescence spectrometers and scanning electron microscope. The performance of the surface acoustic wave photodetector was evaluated using the variations in surface capacitance, insertion loss, and phase shift. ZnO nanorods became shorter and thicker with an increase in the concentration of Ni doping; however, the variations in surface capacitance of Ni-doped ZnO nanorods were greater than those of pure ZnO nanorods obtained under ultraviolet irradiation. Devices with Ni-doped ZnO nanorods exhibited larger shifts in insertion loss and phase than those with pure ZnO nanorods did.

Synthesis and study on optical properties of CeO2-Mg(OH)2 and inverted Mg(OH)2-CeO2 nanocomposites

Well-crystalline CeO2-Mg(OH)2 and inverted Mg(OH)2-CeO2 nanocomposites were successfully synthesized by a facile ‘one-pot’ chemical precipitation method at low temperature. The crystal structure, morphology and optical properties of the CeO2- Mg(OH)2 and inverted Mg(OH)2-CeO2 nanocomposites were investigated using X-ray diffraction, TEM, FTIR, UV-vis absorption and PL spectrometer. The photoluminescence study revealed visible light emission for the nanocomposite. Interestingly, significant red shift observed for Mg(OH)2-CeO2 nanocomposites. The optical tuning nanocomposites can be used for the optoelectronic applications.

Preparation of (111)c-oriented Cu2Se films by pulsed laser deposition method

In this study, the low-temperature phase α-Cu2Se target with nearly ideal chemical stoichiometric ratio was synthesized through solid reaction process. After that, a series of pure and oriented α-Cu2Se films on single crystal Si (111) was prepared using pulsed laser deposition method, by carefully choosing the appropriate experimental parameters. Despite the increase of deposition time, the chemical composition, the crystal microstructure and the orientation of α-Cu2Se films keep the same. X-ray diffraction (XRD) and energy dispersive X-ray spectrometer show that all the α-Cu2Se films have the uniformity of chemical composition, without any other impurities. Scanning electron spectroscopy and high resolution transmission electron microscopy reveal that α-Cu2Se are stacked nanosheets with exposed crystal planes (111)c. Particularly, the (111)c planes are parallel to Si substrate surface proved by the results of XRD φ-scan and pole figure. This report is a further step to realize the adjustment of anisotropy of Cu2Se properties.

Re-utilization of Chinese medicinal herbal residue: waste wormwood rod-derived porous carbon as a low-cost adsorbent for methyl orange removal.

A cost-effective approach was applied to prepare porous carbon samples by the simple carbonization of wormwood rod followed by salt activator (NaCl) activation. The effect of preparation parameters on the characteristics of the wormwood rod-based porous carbons (WWRs) were studied. The properties of these samples were investigated by SEM, BET surface area, X-ray diffraction, FT-IR spectra and X-ray photoelectron spectrometer. The prepared WWRs were applied as new adsorbent materials to remove methyl orange (MO). The experimental results indicated that WWR-800 activated at 800 °C possesses the best adsorption performance. Several factors that affected the adsorption property of the system such as the solution pH, dosing of adsorbent, initial dye concentration and ionic strength were examined. In addition, the thermodynamic parameters and kinetic parameters of MO with WWR-800 were studied. The results indicated that the adsorption of MO on WWR-800 was an endothermic process and non-spontaneous under standard conditions. The maximum equilibrium adsorption capacity of MO on WWR-800 was 454.55 mg/g. After five adsorption/desorption cycles, the adsorption capacity of MO on WWR-800 remained at 94%, which indicated that wormwood rod-based porous carbon possessed good reusability.

Tribological assessment of additive doped B30 biodiesel-diesel blend by using high frequency reciprocating rig test

Biodiesel is auto-oxidative in nature. It can change its composition due to auto-oxidation. Therefore, it causes fluctuation in its lubrication property during application. The present study aims to assess the effect of Pyrogallol (PY), Propyl gallate (PG) and Butylated hydroxy toluene (BHT) additives on the sustainability and lubrication behaviour of B30 (30% biodiesel in diesel) blend on mild steel (MS) flat surface by using high frequency reciprocating rig (HFRR). The tests are conducted under a constant load of 75 N and frequency of 33 Hz at room temperature for 1 h with B30 (30% biodiesel in diesel) blend in the absence and presence of 600 ppm additives. The MS metal surfaces obtained after conducting HFRR tests are analysed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and atomic force spectrometer (AFM). Tested fuels are characterized by Fourier transform infrared spectroscopy (FTIR). The tribological results indicate that PG doped B30 performs better lubricating performance than other tested additives for steel/steel contacts. Presence of PG causes the least weight loss (0.0003 g) with the least wear scar width (1.13 mm). The average coefficient of friction (CoF) is also observed to be minimal for PG doped B30 blend. The compounds formed on MS surface when tested with PG doped B30 show relatively less oxygen and high carbon content. The possible mechanism in enhancing lubricity of PG doped B30 blend could be attributed to the formation of relatively more stable and effective ester-based tribo-films at the contact surfaces.

In-situ synthesis and purification of high grade titanium carbonitride powder via carbonitrothermic reduction of low grade titanium ore

This study reports the production of pure titanium carbonitride powder via carbonitrothermic reduction of low grade titanium ore. High temperature reduction of the as-milled samples in a nitrogen-containing atmosphere at 1400 °C for 20 min was maintained for the synthesis of the Fe – TiCN composite. An acid solution of 10% concentration, which contains HCl acid, was used to purify the Fe – TiCN composite, for the purpose of obtaining a high purity TiCN powder. The obtained TiCN powder was characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction spectrometer (XRD), particle size analyser (PSA), LECO non – metal analyser, Raman spectroscopy, and high resolution transmission electron microscope (HRTEM) was used to study the powder lattice orientation and particle distribution. The overall results of these analyses confirm the formation of high grade TiCN powder, as the synthesized powder was free of iron and other impurities, and its mean particle size was found to be 4.687 μm.

Preparation of 2D Graphene/MXene nanocomposite for the electrochemical determination of hazardous bisphenol A in plastic products

Bisphenol A (BPA) is one of the major contaminants with significant health hazards, which could also affect the endocrine system or induce cancer. It is essential to develop a highly sensitive and selective BPA sensor for environmental and food safety. Herein, 2D hybrid graphene/Ti3C2Tx nanocomposite (Gr/MXene) was prepared via a top-down method and then used to fabricate an electrochemical BPA sensor. The X-ray diffraction spectrometer (XRD) and Raman spectroscopy analysis were carried out to verify the successful formation of Gr sheets with MXene. The high resolution scanning electron microscopy (HR-SEM) was revealed the formation of MXene, and Gr/MXene nanocomposite. Furthermore, the 2D hybrid Gr/MXene nanocomposite modified glassy carbon electrode (GCE) was prepared for BPA oxidation in 100 mM phosphate buffer solution (PBS). Under the optimized condition, the Gr/MXene/GCE was displayed a linear range of detection from 10 to 180 nM and 1 to 10 μM BPA with the detection limits of 4.08 nM and 0.35 μM by amperometry and differential pulse voltammetry (DPV), respectively. Moreover, the proposed Gr/MXene modified electrode exhibited excellent stability, selectivity, repeatability and reproducibility towards the BPA detection. As a proof of concept, Gr/MXene modified sensor was effectively used to detect BPA in modern plastic products with the recovery ranging from 99.2 to 104.5%.

Effective Antiplasmodial and Cytotoxic Activities of Synthesized Zinc Oxide Nanoparticles Using Rhazya stricta Leaf Extract.

In the present study, zinc oxide (ZnO) nanoparticles were prepared using ZnCl2.2H2O as a precursor, via green route using leaf extract of Rhazya stricta as capping and reducing agent. The prepared ZnO nanoparticles were examined using UV-visible spectrophotometer (UV-Vis), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction spectrometer (XRD), and scanning electron microscope (SEM). The UV-Vis absorption spectrum at 355 nm showed an absorption peak, which indicates the formation of ZnO NPs. The FT-IR spectra analysis was performed to identify the potential biomolecule of the as-prepared ZnO NPs. The FT-IR spectra showed peaks at 3455, 1438, 883, and 671 cm−1 in the region of 4000–500 cm−1, which indicates –OH, NH, C-H, and M-O groups, respectively. The SEM images showed aggregation of ZnO nanoparticles with an average size of 70–90 nm. The XRD study indicated that the ZnO NPs were crystalline in nature with hexagonal wurtzite structure and broad peaks were observed at 2 theta positions 31.8°, 34.44°, 36.29°, 47.57°, 56.61°, 67.96°, and 69.07°. The synthesized ZnO NPs were found to be good antiplasmodial with a 50% inhibitory concentration (IC50) value of 3.41 μg/mL. It is concluded from the current study that the ZnO NPs exhibited noble antiplasmodial activity, and for the improvement of antiplasmodial medications, it might be used after further in vivo studies.

Potential of a novel facultative anaerobic denitrifying Cupriavidus sp. W12 to remove fluoride and calcium through calcium bioprecipitation

This study focused on a novel denitrifying Cupriavidus sp. W12, which can perform microbial induced calcium precipitation (MICP) to remove fluoride (F-) under aerobic and anaerobic conditions. Under anaerobic condition, the removal ratios of F-, calcium (Ca2+), and nitrate (NO3-–N) reached 87.52%, 65.03%, and 96.06%, respectively, which were higher than that under aerobic condition (50.17%, 88.21%, and 67.33%, respectively). Higher pH of 8.26 was obtained after 120 h of the strain W12 growth under anaerobic condition than that under aerobic condition (7.77). The F- removal ratio of 98.20% was predicted by the response surface methodology (RSM). Scanning electron microscopy (SEM) images of anaerobic precipitation were dense and porous. CaCO3, Ca5(PO4)3OH, Ca5(PO4)3F, and CaF2 were determined by X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). Self-aggregation of bacteria and adsorption of biological crystal seeds were the determinant of the precipitates formation. The results of infrared spectrometer (FTIR) and excitation-emission matrix (EEM) showed that anaerobic extracellular polymeric substances (EPS) expression led the proportion of hydroxylapatite in the precipitates increased. As the first report on the anaerobic MICP to remove F-, it provides a theoretical basis for the remediation of F-, Ca2+, and NO3-–N in groundwater.

Efficient reclaiming phosphate from aqueous solution using waste limestone modified sludge biochar: Mechanism and application as soil amendments

A novel limestone-modified biochar derived from sewage sludge was prepared to reclaim phosphorus (P) from aqueous solution, and the potential application of P-laden biochar as soil amendments was also investigated. The limestone-modified biochar demonstrated excellent performance on phosphate recovery from aqueous solution in a wide range of pH (2.0–11.0), with maximum adsorption capacity of the biochar (Limestone/sludge mass ratio of 3:1) up to 231.28 mg P/g, which was 10.7 times that of the original sludge biochar. The adsorption was well described by the pseudo second-order model and Langmuir isotherm model. According to the adsorption thermodynamic parameters, the phosphate adsorption was spontaneous (ΔG0 < 0) and endothermic (ΔH0 > 0) so that increasing the temperature was beneficial to adsorption. Characterization analysis by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscope-energy dispersive spectrometer (SEM-EDS) proved that electrostatic attraction, surface complexation and brushite (CaHPO4.2H2O) precipitation were the dominant mechanism. The P-laden biochar exhibited an excellent ability to be reused as a new slow-release P fertilizer for soil. Pot experiment results showed that the treatment of P-laden LB 3:1 (P content of 22.8%) addition (1 wt%) significantly promoted Indian Lettuce germination (increasing by 14.4%), plant height (increasing by 18.6%), and dry biomass (53.0%) compared with the control, though it underperformed compared to commercial fertilizer.