Mesoporous silica supported adsorbents have been used towards metal ion removal from water due to their thermally stability and good sorption capacity. Thus, mesoporous silica-based methyl acrylate monomer (Silica-APTES-DPNO) was converted into hydroxamic acid (SBHA) by using oximation reaction and all products are analyzed by by FT-IR. The SBHA showed satisfactory binding properties with copper, cobalt, nickel and lead are 242, 206, 195 and 516 mg g-1, respectively, with the batch adsorption system was set to pH 6. The kinetics of metal ions binding obeyed the pseudo-1st-order process up to 60 min. In this study also consider the Langmuir and Freundlich isotherm to find out the sorption behavior. The isotherm study demonstrated the well fit with Freundlich isotherm (R² > 0.99). Thus, adsorption take place as a multilayer system, therefore, SBHA material is useful for the metal ions removal from water.
The fabrication of a network of glucose oxidase-horseradish peroxidase/tin oxide (GOx-HRP/SnO₂), immobilized onto a glassy carbon electrode (GCE) and its utilization as a biosensor for glucose detection is reported. The network established with GOx-HRP/SnO₂ possess high sensitivity and stability by performing the electrocatalytic features in the sensing of glucose. The turbidity of fabrication had been scanned and analyzed using UV-vis spectroscopy. The morphology and composition of the fabricated GOx-HRP/SnO₂ networks were characterized by scanning electron microscopy (SEM). Cyclic voltammetry and amperometry were employed to study the electrochemical properties of the proposed biosensor. The effect of applied electrode potential and pH were systemically investigated. The biosensor responds to glucose at work potential values between -400 mV, and exhibited a lower detection limit (0.025 mM) and long linear range (0.25 to 7.0 mM), and was resistant to common interferences.
A newly synthesized free fatty acids from waste palm oil functionalized magnetic nanoparticles immobilized on the surface of graphene oxide (FFA@MNP-GO) was successfully synthesized and characterized in this research. The combinations of long alkyl chain of free fatty acid with graphene oxide that consists of large delocalized 77-electron systems and abundant of hydrophilic groups with hydroxyl, epoxide and carboxylic groups offer the determination of simultaneous wide range of polarities of organic pollutants in real matrices through hydrogen bonding, hydrophobic and 77-77 interactions. The fabricated adsorbent was successfully applied as a magnetic solid phase extraction (MSPE) adsorbent for the simultaneous separation of selected phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in apple and cabbage extracts prior to their high performance liquid chromatography with diode-array detector (HPLC-DAD) determination. Factors affecting the extraction efficiency such as amount of adsorbent, desorption solvent, volume of desorption solvent, extraction time, desorption time, pH and sample volume were investigated and optimized. The results revealed that under optimal conditions, the detection limit of selected PAEs and PAHs were in the range of 0.56-0.97 ng mL-1 and 0.02-0.93 ng mL-1, respectively. The spiked recoveries of real apple and cabbage extracts for PAEs and PAHs were in the range of 81.5-117.6% with good relative standard deviation (RSD) (n = 5) less than 10% and 86.7-118.2% with acceptable RSDs (n = 5) ranging from 1.5 to 11.0%, respectively. This study reported for the first time the use of MSPE procedure for simultaneous determination of chosen PAHs and PAEs in real samples including apple and cabbage extracts by using new adsorbent, FFA@MNP-GO.
Ga₂O₃/ITO/glass photoelectrodes prepared by the CVD method has rarely been tested in the electrochemical cell for water splitting. In this study, we investigate the photoelectrolytic performance of Ga₂O₃/ITO-glass photocatalysts produced by the high-temperature CVD route. The changing of N₂ carrier gas flow rate from 0 to 1800 seem induces change in the materials properties. XRD signal strength of the produced bi-phase Ga₂O₃ is observed to deteriorate, while diffraction line width broadens with increasing N₂ supply. Films show a combination of nanoclumps and nanostrips morphology. Ga/O ratio decreases, while the optical bandgap gradually increases from 4.37 to 4.42 eV with increasing O content and crystallite size. Photoluminescence measurements show UV, blue, green and red emissions, respectively. Linear sweep voltammetry of the electrodes in 0.1 M KOH electrolyte shows improvement in photocurrent density from 160 to 257 μA/cm² versus Ag/AgCl at 1 V bias, and a maximum photon-to-current conversion efficiency 0.06%.
In this work, a simple, co-precipitation technique was used to prepare un-doped, pure tin oxide (SnO₂). As synthesized SnO₂ nanoparticles were doped with Cu2+ ions. Detailed characterization was carried out to observe the crystalline phase, morphological features and chemical constituents with opto-electrical and magnetic properties of the synthesized nanoparticles (NPs). X-ray diffraction analysis showed the existence of crystalline, tetragonal structure of SnO₂. Both the sample synthesized here showed different crystalline morphology. The band gap energy (Eg) of the synthesized sample was estimated and it was found to decrease from 3.60 to 3.26 eV. The band gap energy reduced due to increase in Cu2+ dopant amount inside the SnO₂ lattice. Optical properties were analyzed using absorption spectra and Photoluminescence (PL) spectra. It was observed that Cu2+ ions incorporated SnO₂ NPs exhibited more degradation efficiencies for Rhodamine B (RhB) dye compared to un-doped sample under UV-Visible irradiation. The dielectric characteristics of un-doped, pure and Cu2+ incorporated SnO₂ nanoparticles were studied at different frequency region under different temperatures. The ac conductivity and impedance analysis of pure and Cu2+ incorporated SnO₂ nanoparticles was also studied. The magnetic properties of the synthesized samples were analysed. Both the sample showed ferromagnetic properties. The research indicated that the Cu2+ ions doping can make the sample a promising candidate for using in the field of optoelectronics, magneto electronics, and microwave devices.
Silver-reduced graphene oxide (Ag-rGO) nanohybrid was synthesized by applying a slight modification to the Turkevich method using trisodium citrate as a reducing and stabilizing agent to catalyze the non-enzymatic electrochemical detection of hydrogen peroxide (H₂O₂). Spherical silver nanoparticles (AgNPs) with an average particle size of 2.2 nm surfaced on reduced graphene oxide (rGO) sheets. Cyclic voltammograms (CV) obtained from glassy carbon (GC) electrode coated with Ag-rGO nanohybrid (4 mM) exhibited a peak at an overpotential of -0.52 V, with a larger faradaic current for the reduction of H₂O₂. Using the modified electrode for the linear sweep voltammetry (LSV) detection of H₂O₂, the detection limit and sensitivity were determined to be 4.8 μM (S/N ═ 3) and 0.0262 μA μM-1, respectively. The sensor appeared selective and stable towards H₂O₂ in the presence of possible interference, and it also demonstrated good recoveries of H₂O₂ concentration in real water samples.
A simple spin-coating process for fabricating vertical organic light-emitting transistors (VOLETs) is realized by utilizing silver nanowire (AgNW) as a source electrode. The optical, electrical and morphological properties of the AgNW formation was initially optimized, prior VOFET fabrication. A high molecular weight of poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] MEH-PPV was used as an organic semiconductor layer in the VOFET in forming a multilayer structure by solution process. It was found that current density and luminance intensity of the VOLET can be modulated by a small magnitude of gate voltage. The modulation process was induced by changing an injection barrier via gate voltage bias. A space-charge-limited current (SCLC) approach in determining transistor mobility has been introduced. This preliminary and fundamental work is beneficial towards all-solution processing display devices.
Using solar-powered water electrolysis systems for hydrogen generation is a key decision for the development of a sustainable hydrogen economy. A facile approach is presented in the present investigation to improve the solar-powered photoelectrochemical performance of water electrolysis systems by synthesising well-aligned and highly ordered TiO₂ nanotube films without bundling through the electrochemical anodisation technique. Herein, geometrical calculations were conducted for all synthesised TiO₂ nanotubes, and determination of the aspect ratio (AR) and geometric surface area factor (G) was achieved. On the basis of the collected data, well-aligned TiO₂ nanotubes with an AR of approximately 60 and G of approximately 400 m² ·g-1 were successfully formed in an electrolyte mixture of ethylene glycol with 0.3 wt% NH4F and 5 wt% H₂O₂ at 40 V for 60 min. The nanotubes were subsequently annealed at 400 °C to form anatase-phase TiO₂ nanotube films. The resultant well-aligned and highly ordered TiO₂ nanotube films exhibited a photocurrent density of 1.5 mA · cm-2 due to a large number of photo-induced electrons moving along the tube axis and perpendicular to the Ti substrate, which greatly reduces interfacial recombination losses.
Novel decoration of high aspect ratio zinc oxide nanowires (ZnO NWs) with noble metals such as Ag and Au nanoparticles (NPs) was demonstrated in this work. A facile method of chemical deposition with good controllability, as well as good homogeneity would be a huge advantage towards large scale fabrication. The highlight of this work is the feasibility of multiple component decoration such as a hybrid (co-exist) Ag-Au NPs decorated ZnO NWs formation that could be beneficial towards the development of nanoarchitectured materials with the most desired properties. The local surface plasmon effect (LSPR) of Ag and Au NPs were confirmed using extinction spectra and significant photoelectrochemical conversion efficiency (PCE) enhancement of dye-sensitized solar cells (DSSCs) was achieved. The Ag-NPs and hybrid Ag-Au NPs decorated ZnO NWs marked an impressive 125 and 240% efficiency improvement against pure ZnO NWs. The improved dye light extinction resulted from the LSPR effect that had enabled greater electron generation leading to improved PCE. As the complex design of oxides' nanoarchitectures have reached a point of saturation, this novel method would enable further enhancement in their photoelectrochemical properties through decoration with noble metals via a simple chemical deposition route.
In this study, a series of copper-ion-doped titanium dioxide (Cu-ion-doped TiO₂) nanotubes (NTs) were synthesized via a hydrothermal method by the concentration variation of doped Cu ions (0.00, 0.50, 1.00, 2.50, and 5.00 mmol). In addition, the samples were characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), nitrogen gas adsorption measurements, and ultraviolet-visible (UV-Vis) diffuse-reflectance spectroscopy. The photocatalytic activity of the Cu-iondoped TiO₂ NTs was investigated for the degradation of methyl orange (MO) under sunlight. The results obtained from the structural and morphological studies revealed that, at low concentrations of Cu-doped TiO₂ NTs, Cu is incorporated into the interstitial positions of the TiO₂ lattice, affording a new phase of TiO₂ (hexagonal) instead of the anatase TiO₂ (tetragonal) observed for undoped TiO₂ NTs. EDX analysis confirmed the presence of Cu in the TiO₂-based photocatalyst. All of the investigated samples exhibited a hollow fibrous-like structure, indicative of an NT morphology. The inner and outer diameters of the NTs were 4 nm and 10 nm, respectively. The photocatalysts exhibited a large surface area due to the NT morphology and a type IV isotherm and H3 hysteresis, corresponding to the mesopores and slit-shaped pores. The Cu-ion-doped TiO₂ NTs were excited by sunlight because of their low bandgap energy; and after the incorporation of Cu ions into the interstitial positions of the TiO₂ lattice, the NTs exhibited high visible-light activity owing to the low bandgap.
Herein, we report the facile synthesis of Iron oxide@Pt core-shell nanoparticles (NPs) by facile two step synthesis process. The first step follows the growth of iron oxide nanoparticle by thermal decomposition process while the second step deals with the formation of iron oxide@Pt core-shell nanoparticles by the chemical reduction method. The synthesized core-shell nanoparticles were characterized by several techniques and used for the catalytic reductive translation of Cr(VI) to Cr(III) in the presence of formic acid by a UV-vis spectrophotometer. The UV photo-spectrometer analysis confirmed the conversion efficiency from 12% to as high as 98.8% at the end of 30 minutes. Thus, the presence of Iron oxide @Pt core-shell nanoparticles (NPs) can be effectively used as a catalyst for the reducion of Cr(VI) to Cr(III) ions. Additionally, antibacterial studies were performed for the prepared core-shell nanoparticles against two bacterial strains, i.e., gram (+ve) Staphylococcus Aureus (S. Aureus) and gram (-ve) Escherichia Coli (E. Coli).
The vanadium (V) and nitrogen (N) dopants on TiO₂ demonstrated superior photocatalytic performance for the degradation of methylene blue (MB) dye under visible light. The vanadium, V, N-co-doped TiO₂ was synthesized by a modified sol-gel method. It revealed that V and N codoping had a significant effect on the band gap (Eg) of TiO₂, where the pristine TiO₂ possessed a wide band gap (3.18 eV) compared to V-doped TiO₂ (2.89 eV) and N-doped TiO₂ (2.87 eV) while the V, N-co-doped TiO₂ depicted the narrowest band gap (2.65 eV). The greatly increased specific surface area for the V, N-co-doped TiO₂ (103.87 m²/g) as compared to P25 TiO₂ (51.68 m²/g) also contributed to the major improvement in the MB dye degradation efficiency (0.055 min-1). The V, N-co-doped TiO₂ exhibit rapid photocatalytic activity for the degradation of MB with almost 99% of degradation in 120 minutes.
The present study focuses on the microstructural and bioactive properties evolution in selective laser melting (SLM) β titanium alloys. We have applied cross-scan strategy for improving mechanical properties and lower elastic modulus of SLMed Ti-20Mg-5Ta alloys which has been shown to be altering the microstructure and refining the grain size. The cross-scan strategy can refine the microstructure and induce various deformation textures in contrast to the conventional scan strategy. The microstructures of Ti-20Mg-5Ta alloys indicate that the cross-scan strategy will yield the best mechanical properties and lower elastic modulus. The corrosion behavior of the Ti-20Mg-5Ta alloys was studied during immersion in an acellular simulated body fluid (SBF) at 37±0.50 °C for 28 days. Both the mechanical and bioactive properties showed that the novel Ti-20Mg-5Ta alloys should be ideal for bone implants.
This research has been accomplished using the advanced selective laser melting (SLM) technique as well as HIP post-treatment in order to improve mechanical properties and biocompatibility of Mg- Ca-Sr alloy. Through this research it becomes clearly noticeable that the Mg-1.5Ca-xSr (x = 0.6, 2.1, 2.5) alloys with Sr exhibited better mechanical properties and corrosion potentials. This is more particular with the Mg-1.5Ca-2.5Sr alloy after HIP post-treatment allowing it to provide a desired combination of degradation and mechanical behavior for orthopedic fracture fixation during a desired treatment period. In vivo trials, there was a clear indication and exhibition that this Mg-1.5Ca-2.5Sr alloy screw can completely dissolve in miniature pig's body which leads to an acceleration in growth of bone tissues. Mg-Ca-Sr alloy proved potential candidate for use in orthopedic fixation devices through Our results concluded that Mg-Ca-Sr alloy are potential candidate for use in orthopedic fixation devices through mechanical strength and biocompatibility evaluations (in vitro or In vivo).
Herein, we report the effect of synthesis temperature on the morphologies, optical and electronic properties of magnesium oxide (MgO) nanostructures. The MgO nanostructures were synthesized at different temperatures, i.e., 100 °C, 300 °C, and 600 °C by simple chemical reaction process and their morphology, particle size, optical, and electrical properties were examined by different techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and UV-Vis. spectroscopy. The morphological investigations revealed that various morphologies of MgO nanostructures, i.e., nanoparticles, nanosheet networks, and nanoneedles were synthesized at 100 °C, 300 °C, and 600 °C. The XRD results confirmed that with increasing the synthesis temperature, the crystallinity of the synthesized nanostructures increases. Further, the dielectric properties and AC conductivity at various frequencies for MgO nanostructures were studied which revealed that the dielectric losses decrease with increase in frequency and temperature. In addition, the observed band gap decreases from 4.89 eV to 4.438 eV (100 °C to 600 °C) representing its increase in the conductivity.
Solid polymer electrolytes (SPEs) were prepared using rice starch as the polymer, sodium iodide (NaI) as the salt and 1-hexyl-3-methylimidazolium iodide (HMII) as the ionic liquid (IL). The solution casting technique was used for preparation of the PEs. The ionic conductivity and temperaturedependent properties of the PEs were measured and all the SPEs were found to follow the Arrhenius thermal activated model. Ionic conductivity increased as the percentage of ILs increased. The SPE containing 20% (wt) of HMII IL showed the highest ionic conductivity of 1.83×10-3 S/cm. Spectral and structural characterization of the PEs were performed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), respectively. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicate that the decomposition temperature (Tdc), glass transition temperatures (Tg) and melting points (Tm) shifted when complexation with HMII occurred. The PEs were used to fabricate dye-sensitized solar cells (DSSCs) and the DSSCs were analyzed under a 1-sun simulator. The SPE with the highest ionic conductivity displayed a short circuit current density (Jsc) of 9.07 (mA cm-2), open circuit voltage (Voc) of 0.58 (V), a fill factor (FF) of 0.65 and had the highest energy conversion efficiency of 3.42%.
Indium antimonide nanowires were synthesized by electrochemical deposition using anodic aluminum oxide template in the presence of gold film as conductive layers. Field emission scanning electron microscopy and energy dispersive X-ray spectrometry measurements were carried out to investigate the effect of adhesive insulated tape covered below the conductive layer. Results showed that the anodic aluminum oxide template covered with insulating tapes had better morphology with less presence of overgrown rough film on the topside of the anodic aluminum oxide template and it exhibited a smoother nanowire sidewall as compared to the uncovered ones. Additionally, the unique properties of anodic aluminum oxide were controllable pore diameter with a narrow size distribution at some intervals. It was evident from the energy dispersive X-ray spectrum that the nanowires synthesized from the covered template condition exhibited better InSb composition and stoichiometric ratio compared to the uncovered template condition.
Inorganic nanoparticles are commonly employed as vectors for delivering drugs into cancer cells while decreasing undesired cytotoxicity in healthy tissues. Carbonate apatite is an attractive nonviral vector that releases drugs at acidic environment inside the cells following endocytosis. However, maintaining the smaller particle size is crucial for enhancing cellular uptake of drugs as well as prolonging their systemic circulation time. We aimed to modify carbonate apatite with citrate for reducing the growth kinetics of carbonate apatite particles and enhancing the cellular uptake of cyclophosphamide via endocytosis. Several concentrations of sodium citrate were used to fabricate citrate-modified carbonate apatite (CMCA) particle complexes in absence or presence of cyclophosphamide. The binding affinity of the drug towards the particles and its cellular uptake were measured by high-performance liquid chromatography (HPLC). The nanoparticles' average size and zeta potential were determined by Malvern Zetasizer. Fourier-transform infrared spectroscopy (FTIR) was performed to justify association of citrate with carbonate apatite. MTT assay was performed to evaluate the cell viability. CMCA exhibited 6% more binding efficiency for cyclophosphamide and promoted fast cellular uptake of cyclophosphamide with enhanced cytotoxicity in MCF-7 cells, compared to unmodified carbonate apatite. Therefore, CMCA nanoparticles have a high potential for intracellular delivery of anti-cancer drugs and demand for further investigated in animal models of cancer.
Shaped-controlled ZnO architectures including spherical, rod, rice-like and flower-like were fabricated via a reflux method in which the morphology, crystallinity, functional group and optical properties were tailored under different pH values in the precursor solution. The photoactivities of the prepared ZnO were evaluated under UV irradiation and the findings implied that the flower-like ZnO synthesized at pH 12 displayed superior activities on palm oil mil effluent degradation than those of other structures. The photocatalytic enhancement of flower-like ZnO was ascribed to its unique architecture, good crystallinity and superior optical properties. The flower-like ZnO with excellent photocatalytic performance have been confirmed by formation of hydroxyl radicals using a terephthalic acid-photoluminescence test. There was an optimal photocatalyst amount of 1.0 g/L, at which a maximum chemical oxygen demand removal of palm oil mill effluent was achieved under exposure of UV light. The phytotoxicity experiment via mung beans demonstrated a decrease in phytotoxicity.
Glycerol electro-oxidation offers a green route to produce the high value added chemicals. Here in, we report the glycerol electro-oxidation over a series of multi walled carbon nano tubes supported monometallic (Pt/CNT and Pd/CNT) and bimetallic (Pt-Pd/CNT) catalysts in alkaline medium. The cyclic voltammetry, linear sweep voltammetry and chronoamperometry measurements were used to evaluate the activity and stability of the catalysts. The Pt-Pd/CNT electrocatalyst exhibited the highest activity in terms of higher current density (129.25 A/m²) and electrochemical surface area (382 m²/g). The glycerol electro-oxidation products formed at a potential of 0.013 V were analyzed systematically by high performance liquid chromatography. Overall, six compounds were found including mesoxalic acid, 1,3-dihydroxyacetone, glyceraldehyde, glyceric acid, tartronic acid and oxalic acid. A highest mesoxalic acid selectivity of 86.42% was obtained for Pt-Pd/CNT catalyst while a maximum tartronic acid selectivity of 50.17% and 46.02% was achieved for Pd/CNT and Pt/CNT respectively. It was found that the introduction of Pd into Pt/CNT lattice facilitated the formation of C3 products in terms of maximum selectivity achieved (86.42%) while the monometallic catalysts (Pd/CNT and Pt/CNT) showed a poor performance in comparison to their counterpart.