Magnetic Nitrogen-Doped Porous Carbon Nanocomposite for Pb(II) Adsorption from Aqueous Solution.

We report in the present study the in situ formation of magnetic nanoparticles (Fe3O4 or Fe) within porous N-doped carbon (Fe3O4/N@C) via simple impregnation, polymerization, and calcination sequentially. The synthesized nanocomposite structural properties were investigated using different techniques showing its good construction. The formed nanocomposite showed a saturation magnetization (Ms) of 23.0 emu g-1 due to the implanted magnetic nanoparticles and high surface area from the porous N-doped carbon. The nanocomposite was formed as graphite-type layers. The well-synthesized nanocomposite showed a high adsorption affinity toward Pb2+ toxic ions. The nanosorbent showed a maximum adsorption capacity of 250.0 mg/g toward the Pb2+ metallic ions at pH of 5.5, initial Pb2+ concentration of 180.0 mg/L, and room temperature. Due to its superparamagnetic characteristics, an external magnet was used for the fast separation of the nanocomposite. This enabled the study of the nanocomposite reusability toward Pb2+ ions, showing good chemical stability even after six cycles. Subsequently, Fe3O4/N@C nanocomposite was shown to have excellent efficiency for the removal of toxic Pb2+ ions from water.

Radiation Shielding efficiency of lead-tungsten-boron glasses with Sb, Al, and Bi against gamma, neutron and charge particles.

We report on newly developed nuclear shielding glass system based on lead-tungsten-boron (PWB) for radiation applications against photon, neutron and charge particles. This newly developed system contains also different additions, in low concentrations, such as Sb, Al and Bi. The gamma/photon shielding performance was tested by using FLUKA Monte Carlo. Moreover, the shielding efficiency of the present system is examined against charged particles (light and heavy ones) and neutrons. The highest gamma/photons attenuation is observed in the lowest incident energy and this is at the region of the photoelectric absorption. We also observe that the values of effective atomic number (Zeff) show a peak at 100 keV incident energy. The reduction of these values is higher for photon energy range 0.1-1 MeV than below 80 keV energies. The lowest half value layer (d1/2), reflecting the best shielding efficiency, is recorded for the PWB-Bi system. The PWB-Bi system demonstrates promising performance better than many of commercial and standard systems and heavy concretes.

Bioinspired engineered nickel nanoparticles with multifunctional attributes for reproductive toxicity.

Nickel nanoparticles (Ni-NPs) have potential applications in high-tech sectors such as battery manufacturing, catalysis, nanotube printing and textile. Apart from their increasing utilisation in daily life, there are concerns about their hazardous nature as they are highly penetrable in biological systems. The carcinogenic and mutagenic ability of Ni-NPs is evident but the research gaps are still there concerning the safety evaluation of Ni-NPs regarding male reproductive ability. This controlled randomized research was planned to assess the male reproductive toxicity of Ni-NPs in Sprague Dawley rats. Ni-NPs of spherical shape and mean particle size of 56 nm were used in the study, characterized by SEM, EDS and XRD. The twenty-five healthy rats (200-220 g) were used for toxicity investigation of Ni-NPs and divided into five groups; negative control (0 Ni-NPs), placebo group (0.9% saline) and three Ni-NPs treated groups (@ 15, 30 and 45 mg/kg BW). The results of 14 days of intraperitoneal exposure to Ni-NPs revealed that a higher dose (45 mg/kg BW) of Ni-NPs caused a significant reduction in body weight, serum testosterone, daily sperm production while the testis index and Ni accumulation and histological changes (necrosis in basement membrane and seminiferous tubules, vacuole formation) in testicular tissues increased with increasing dose of Ni-NPs. It can be concluded from the study that Ni-NPs have potential reproductive toxicity. This study provided the baseline data of Ni-NPs toxicity for the male reproductive system and can be applied for risk assessment in Ni-NPs based products.

Photocatalytic degradation and electrochemical energy storage properties of CuO/SnO2 nanocomposites via the wet-chemical method.

Integrating semiconducting functional materials is a way to enlarge the photoexcitation, energy range, and charge separation, greatly elongating the photocatalytic efficiency to enhance the chemical and physical properties of the materials. This work depicts and investigates the impact of cuprous oxide (CuO) and tin dioxide (SnO2)-based catalysts with various CuO concentrations on photocatalytic and supercapacitor applications. Moreover, three distinct composites were made with varied ratios of CuO (5, 10, and 15% wt. Are designated as AT-1, AT-2, and AT-3) with SnO2 to get an optimized performance. The photocatalytic properties indicate that the CuO/SnO2 nanocomposite outperformed its bulk equivalents in photocatalysis using Methyl blue (MB) dye in a photoreactor. The results were monitored using a UV-visible spectrometer. The AT-1 ratio nanocomposite displayed 96% photocatalytic degradation compared to pure SnO2 and CuO. CV analysis reveals a pseudocapacitive charge storage mechanism from 0.0 to 0.7 V in a potential window in an aqueous medium. The capacitive performance was also investigated for all electrodes, and we observed that a high capacitance of 260/155 F/g at 1/10 A/g was attained for the AT-1 electrode compared to others, specifying good rate performance.

Alumina supported copper oxide nanoparticles (CuO/Al2O3) as high-performance electrocatalysts for hydrazine oxidation reaction.

Direct hydrazine liquid fuel cell (DHFC) is perceived as effectual energy generating mean owing to high conversion efficiency and energy density. However, the development of well-designed, cost effective and high performance electrocatalysts is the paramount to establish DHFCs as efficient energy generating technology. Herein, gamma alumina supported copper oxide nanocatalysts (CuO/Al2O3) are synthesized via impregnation method and investigated for their electrocatalytic potential towards hydrazine oxidation reaction. CuO with different weight percentages i.e., 4%, 8%, 12%, 16% and 20% are impregnated on gamma alumina support. X-ray diffraction analysis revealed the cubic crystal structure and nanosized particles of the prepared metal oxides. Transmission electron microscopy also referred to the cubic morphology and nanoparticle formation. Electrochemical oxidation potential of the CuO/Al2O3 nanoparticles is explored via cyclic voltammetry as the analytical tool. Optimization of conditions and electrocatalytic studies shown that 16% CuO/Al2O3 presented the best electronic properties towards N2H2 oxidation reaction. BET analysis ascertained the high surface area (131.2546 m2 g1) and large pore diameter (0.279605 cm³ g-1) for 16% CuO/Al2O3. Nanoparticle formation, high porosity and enlarged surface area of the proposed catalysts resulted in significant oxidation current output (600 µA), high current density (8.2 mA cm-2) and low charge transfer resistance (3.7 kΩ). Electrooxidation of hydrazine on such an affordable and novel electrocatalyst opens a gateway to further explore the metal oxide impregnated alumina materials for different electrochemical applications.

Binder-free cupric-ion containing zinc sulfide nanoplates-like structure for flexible energy storage devices.

Researchers have been enthusiastic about developing high-performance electrode materials based on metal chalcogenides for energy storage applications. Herein, we developed cupric ion-containing zinc sulfide (ZnS:Cu) nanoplates by using a solvothermal approach. The as-synthesized ZnS:Cu nanoplates electrode was characterized and analyzed by using XRD, SEM, TEM, EDS, and XPS. The binder-free flexible ZnS:Cu nanoplates exhibited excellent specific capacitance of 545 F g-1 at a current density of 1 A g-1. The CV and GCD measurements revealed that the specific capacitance was mainly attributed to the Faradaic redox mechanism. Further, the binder-free flexible ZnS:Cu nanoplates electrode retained 87.4% along with excellent Coulombic efficiency (99%) after 5000 cycles. The binder-free flexible ZnS:Cu nanoplates exhibited excellent conductivity, specific capacitance, and stability which are beneficial in energy storage systems. These findings will also open new horizons amongst material scientists toward the new direction of electrode development.

Plasmonic Effects of Au@Ag Nanoparticles in Buffer and Active Layers of Polymer Solar Cells for Efficiency Enhancement.

Embedding nanoparticles (NPs) in the buffer layer of bulk heterojunction polymer solar cells (BHJ PSCs) excites the surface plasmonic polaritons and enhances the pathlength of the light in the solar cells. On the other hand, embedding NPs in the active layer significantly improves absorption and increases the production of electron-hole (e-h) pairs in BHJ PSCs. Increasing the volume ratio of NPs embedded in BHJ PSCs enables the direct interfacing of the NPs with the active layer, which then serves as a charge recombination center. Therefore, this study integrates the aforementioned phenomena by exploiting the effects of embedding plasmonic Au@Ag NPs in the buffer and active layers of PSC and then determining the optimum volume ratio of Au@Ag NPs. The results show the absorption is increased across the 350-750 nm wavelength region, and the PCE of the device with embedded Au@Ag in two locations is enhanced from 2.50 to 4.24%, which implies a 69.6% improvement in the PCE in comparison to the reference cell. This improvement is contributed by the combined localized surface plasmon resonance (LSPR) effects of multi-positional Au@Ag NPs, spiky durian-shaped morphology of Au@Ag NPs, and optimized volume ratio of Au@Ag NPs embedded in the PEDOT: PSS and PTB7:PC71BM layers.

Electrochemical corrosion resistance of aluminum alloy 6101 with cerium-based coatings in an alkaline environment.

Chromium-free materials as eco-friendly coatings with higher corrosion resistance are crucial in various industrial processes. Herein, we report the deposition of cerium-based conversion, a chromium-free, eco-friendly chemical conversion coating for aluminum alloy 6101, by the dip coating method. Immersion in cerium salt precursors assisted with hydrogen peroxide was performed for the deposition of cerium-based conversion coatings on aluminum alloy 6101 at different bathing temperatures. The electrochemical corrosion behavior was assessed in an alkaline solution of sodium hydroxide (pH 11), including mass loss measurements, free corrosion risk, polarization, and electrochemical impedance spectroscopy. X-ray diffraction and photoelectron spectroscopy analysis showed that the coatings were composed of Ce (III) and Ce (IV) oxides. Surface modifications and surface degradation of the coating and substrate after immersion in corrosive media were analyzed by scanning electron microscopy. Additionally, energy dispersive scanning analysis demonstrated the elemental composition before and after corrosion of the cerium salt conversion-based coating. The results demonstrated that selectively deposited cerium-based conversion coatings improved the corrosion resistance by up to 96% in a strong corrosive alkaline media.

Spiky Durian-Shaped Au@Ag Nanoparticles in PEDOT:PSS for Improved Efficiency of Organic Solar Cells.

The localized surface plasmon resonance (LSPR) effects of nanoparticles (NPs) are effective for enhancing the power conversion efficiency (PCE) of organic solar cells (OSCs). In this study, spiky durian-shaped Au@Ag core-shell NPs were synthesized and embedded in the hole transport layer (HTL) (poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS)) of PTB7:PC71BM bulk-heterojunction OSCs. Different volume ratios of PEDOT:PSS-to-Au@Ag NPs (8%, 10%, 12%, 14%, and 16%) were prepared to optimize synthesis conditions for increased efficiency. The size properties and surface morphology of the NPs and HTL were analyzed using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). UV-Vis spectroscopy and current density-voltage (J-V) analysis were used to investigate the electrical performance of the fabricated OSCs. From the results, we observed that the OSC with a volume ratio of 14% (PEDOT:PSS-to-Au@Ag NPs) performed better than others, where the PCE was improved from 2.50% to 4.15%, which is a 66% increase compared to the device without NPs.

Design and synthesis of amine grafted graphene oxide encapsulated chitosan hybrid beads for defluoridation of water.

The promising adsorbent like graphene oxide (GO), chitosan (CS) and amine functionalized graphene oxide (AGO) decorated chitosan (CS) namely AGO@CS composite beads was efficiently prepared for defluoridation studies. The prepared AGO@CS composite beads possess enriched defluoridation capacity (DC) of 4650 mgF- kg-1. Batch method was used to optimize the maximum DC of AGO@CS composite beads. The physicochemical properties of AGO@CS composite beads were explored by numerous instrumental techniques viz., FTIR, Raman, XPS, SEM and TGA investigation. The experimental values of AGO@CS composite beads for fluoride removal at various temperature conditions were assessed with adsorption isotherms, kinetic and thermodynamic studies. The possible defluoridation mechanism of AGO@CS beads was mostly proposed that electrostatic attraction. The reusability and field investigation results of AGO@CS beads shows they are regenerable and applicable at field circumstances.

Synthesis of Polymer-Based Magnetic Nanocomposite for Multi-Pollutants Removal from Water.

A magnetic polymer-based nanocomposite was fabricated by the modification of an Fe3O4/SiO2 magnetic composite with polypyrrole (PPy) via co-precipitation polymerization to form PPy/Fe3O4/SiO2 for the removal of Congo red dye (CR) and hexavalent chromium Cr(VI) ions from water. The nanocomposite was characterized using various techniques including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), vibration sample magnetometer, and thermogravimetric analysis (TGA). The results confirm the successful fabrication of the nanocomposite in the size of nanometers. The effect of different conditions such as the contact time, adsorbent dosage, solution pH, and initial concentration on the adsorption process was investigated. The adsorption isotherm suggested monolayer adsorption of both contaminants over the PPy/Fe3O4/SiO2 nanocomposite following a Langmuir isotherm, with maximum adsorption of 361 and 298 mg.g-1 for CR dye and Cr(VI), respectively. Furthermore, the effect of water type on the adsorption process was examined, indicating the applicability of the PPy/Fe3O4/SiO2 nanocomposite for real sample treatment. Interestingly, the reusability of the nanocomposite for the removal of the studied contaminants was investigated with good results even after six successive cycles. All results make this nanocomposite a promising material for water treatment.

The Application of Nanomaterials for the Electrochemical Detection of Antibiotics: A Review.

Antibiotics can accumulate through food metabolism in the human body which may have a significant effect on human safety and health. It is therefore highly beneficial to establish easy and sensitive approaches for rapid assessment of antibiotic amounts. In the development of next-generation biosensors, nanomaterials (NMs) with outstanding thermal, mechanical, optical, and electrical properties have been identified as one of the most hopeful materials for opening new gates. This study discusses the latest developments in the identification of antibiotics by nanomaterial-constructed biosensors. The construction of biosensors for electrochemical signal-transducing mechanisms has been utilized in various types of nanomaterials, including quantum dots (QDs), metal-organic frameworks (MOFs), magnetic nanoparticles (NPs), metal nanomaterials, and carbon nanomaterials. To provide an outline for future study directions, the existing problems and future opportunities in this area are also included. The current review, therefore, summarizes an in-depth assessment of the nanostructured electrochemical sensing method for residues of antibiotics in different systems.

Synthesis, Characterization and Application of Polypyrrole Functionalized Nanocellulose for the Removal of Cr(VI) from Aqueous Solution.

Heavy metals are toxic substances that pose a real danger to humans and organisms, even at low concentration. Therefore, there is an urgent need to remove heavy metals. Herein, the nanocellulose (NC) was synthesized by the hydrolysis of cellulose using sulfuric acid, and then functionalized using polypyrrole (ppy) through a polymerization reaction to produce polypyrrole/nanocellulose (ppy/NC) nanocomposite. The synthesized nanocomposite was characterized using familiar techniques including XRD, FT-IR, SEM, TEM, and TGA. The obtained results showed a well-constructed nanocomposite with excellent thermal stability in the nano-sized scale. The adsorption experiments showed that the ppy/NC nanocomposite was able to adsorb hexavalent chromium (Cr(VI)). The optimum pH for the removal of the heavy metal was pH 2. The interfering ions showed minor effect on the adsorption of Cr(VI) resulted from the competition between ions for the adsorption sites. The adsorption kinetics were studied using pseudo 1st order and pseudo 2nd order models indicating that the pseudo second order model showed the best fit to the experimental data, signifying that the adsorption process is controlled by the chemisorption mechanism. Additionally, the nanocomposite showed a maximum adsorption capacity of 560 mg/g according to Langmuir isotherm. The study of the removal mechanism showed that Cr(VI) ions were removed via the reduction of high toxic Cr(VI) to lower toxic Cr(III) and the electrostatic attraction between protonated ppy and Cr(VI). Interestingly, the ppy/NC nanocomposite was reused for Cr(VI) uptake up to six cycles showing excellent regeneration results. Subsequently, Cr(VI) ions can be effectively removed from aqueous solution using the synthesized nanocomposite as reusable and cost-effective adsorbent.