A simple microwave-assisted (MWI) wet chemical route to synthesize pure anatase phase titanium dioxide (TiO2) nanoparticles (NPs) is reported here using titanium tetrachloride (TiCl4) as starting material. The as-prepared TiO2 NPs were characterized by electron microscopy, X-ray diffraction, UV/visible absorption spectroscopy, and infrared and Raman spectroscopic techniques. Further modification of the anatase TiO2 NPs was carried out by incorporating plasmonic silver (Ag) NPs and graphene oxide (GO) in order to enhance the visible light absorption. The photocatalytic activities of the anatase TiO2, Ag/TiO2, and Ag/TiO2/GO nanocomposites were evaluated under both ultraviolet (UV) and visible light irradiation using phenol as a model contaminant. The presence of Ag NPs was found to play a significant role to define the photocatalytic activity of the Ag/TiO2/GO nanocomposite. It was found that the Ag performed like a sink under UV excitation and stored photo-generated electrons from TiO2, whereas, under visible light excitation, the Ag acted as a photosensitizer enhancing the photocatalytic activity of the nanocomposite. The detailed mechanism was studied based on photocatalytic activities of Ag/TiO2/GO nanocomposites. Therefore, the as-prepared Ag/TiO2/GO nanocomposite was used as photocatalytic materials under both UV and visible light irradiation toward degradation of organic molecules.

Separation of rare earth ions (RE3+) from aqueous solution is a tricky problem due to their physico-chemical similarities of properties. In this study, we investigate the influence of the functionalized ligands on the adsorption efficiency and selective adsorption of La3+, Nd3+, Gd3+ and Y3+ from aqueous solution using Magnetite (Fe3O4) nanoparticles (NPs) functionalized with citric acid (CA@Fe3O4 NPs) or L-cysteine (Cys@Fe3O4 NPs). The microstructure, thermal behavior and surface functionalization of the synthesized nanoparticles were studied. The general adsorption capacity of Cys@Fe3O4 NPs was found to be high (98 mg g−1) in comparison to CA@Fe3O4 NPs (52 mg g−1) at neutral pH 7.0. The adsorption kinetic studies revealed that the adsorption of RE3+ ions follows a pseudo second-order model and the adsorption equilibrium data fits well to the Langmuir isotherm. Thermodynamic studies imply that the adsorption process was endothermic and spontaneous in nature. Controlled desorption within 30 min of the adsorbed RE3+ ions from both Cys@Fe3O4 NPs and CA@Fe3O4 NPs was achieved with 0.5 M HNO3. Furthermore, Cys@Fe3O4 NPs exhibited a higher separation factor (SF) in the separation of Gd3+/La3+, Gd3+/Nd3+, Gd3+/Y3+ ions compared to CA@Fe3O4 NPs.

Polymer-based nanocomposites (PNCs) display fascinating functionalities to be useful in electrical switching applications like circuit breakers, switch gears, etc. These PNCs are fabricated by incorporating nanoparticles (NPs) into a polymer by in-situ polymerization. When the PNCs interrupt the high energetic fault currents generate between the two contacts in a circuit breaker, they outgas (ablation) chemical species and cooling gases, which change the thermodynamic properties of the arcing environment leading to quench the electrical arcs quickly. Two PNCs are fabricated with different wt% of oleic acid modified CuO NPs and a polymer matrix i.e. poly methyl methacrylate (PMMA). These PNCs are tested with the electrical arcs of a prospective current of 1.6 kA generated in the test-setup. The electrical signals (arc current and voltage) and computed dissipated enegy i.e., ∫𝑖(𝑡)𝑉(𝑡)𝑑𝑡 help to understand the effect of PNCs on the electrical arcs. In addition to that, the computed joule integral and mass loss of the PNCs due to outgassing is reported. The re-depositions of the chemical species are analyzed by using Fourier transform infrared spectroscopy (FTIR) and the morphological changes on the surface of outgassed PNCs are analyzed by using scanning electron microscopy (SEM). These results help to understand the effect of PNCs on the arc interruption process in circuit breakers.

We report the studies on origin of peroxidase-like activity for gold nanoparticles, as well as the impact from morphology and surface charge of nanoparticles. For this purpose, we have synthesized hollow gold nanospheres (HAuNS) and gold nanorods (AuNR) with different morphology and surface chemistry to investigate their influence on the catalytic activity. We found that citrate-capped HAuNS show catalyzing efficiency in oxidation reaction of 3,3′,5,5′-tetramethylbenzidine (TMB) by hydrogen peroxide (H2O2) and it is superior to that of cetyltrimethylammonium bromide (CTAB)-capped AuNR. The kinetics of catalytic activities from HAuNS and AuNR were respectively studied under varied temperatures. The results indicated that surface chemistry rather than morphology of nanoparticles plays an important role in the catalytic reaction of substrate. Furthermore, influencing factors such as pH, amount of nanoparticle and H2O2 concentration were also investigated on HAuNS-catalyzed system. The great impact of nanoparticle surface properties on catalytic reactions makes a paradigm in constructing nanozymes as peroxidase mimic for sensing application.

Diagnosis of osteomyelitis presents a formidable challenge. Lack of pathognomonic clinical sign (s) and diagnostic tests that can diagnose osteomyelitis at an early stage contribute to this difficulty. If the diagnosis is not made early, the disease becomes very difficult to eradicate and can lead to limb threatening and potentially life-threatening complications. Staphylococcus aureus is the most common organism causing osteomyelitis. Raman Spectroscopy provides information about molecular vibration that could potentially be considered as a spectral signature for cellular changes in specific pathologic conditions. In this study we describe a technique using Raman spectroscopy that could potentially be used to diagnose staphylococcal osteomyelitis. Human bone samples were co-cultured with Staphylococcus aureus (S. aureus) and the effects of bacterial growth on bone quality were monitored using Raman spectroscopy. A major drop in the bone mineral quality and crystallinity was observed in the infected bones compared to the controls. S. infection was also found to be cross-linking to the collagen. Our study shows that specific spectral signatures are present for the cause as well as the effect of staphylococcal osteomyelitis, opening the possibility of developing a useful diagnostic modality for early and rapid diagnosis of this condition.

The exchange role of gold (Au) and silver (Ag) in bimetallic films co-evaporated onto soda-lime glass substrates with Au-Ag volume ratios of 1:2, 1:1 and 2:1 have been demonstrated. Annealing of the films above the glass transition temperature in air led to non-alloying nature of the films, silver neutrals (Ag-0) and gold nanoparticles (AuNPs) on the surface, along with silver nanoparticles (AgNPs) inside the glass matrix. Moreover, the size distribution and interparticle spacing of the AuNPs on the surface were governed by the Ag content in the deposited film. In contrast, the content of Au in the film played an opposite role leading to the migration of Ag ions (i.e. Ag-0 being transformed to Ag ions after annealing in oxygen ambient) to form AgNPs inside the glass matrix. The higher the Au content in the film is, the more likely Ag-0 to stay on the surface and impacts on the size distribution of AuNPs and consequently on the refractive index sensitivity measurements. Experimental realisation of this fact was reflected from the best performance for localized surface plasmon resonance (LSPR) sensitivity test achieved with Au-Ag ratio of 1:2. The Au/Ag/glass bimetallic dynamic results of this study can be pertinent to sensor applications integrated with optical devices.

The performance of a capacitive deionization (CDI) device is governed by complex relations between the electrode material properties, fluid velocity and fluid distribution within the device. In order to maximize fluid (water) interaction with the electrodes, the relationships between fluid flow and electrode material properties are explored here to develop novel CDI architectures which reduce the pressure drop, improve surface utilization factor and improve the electrode salt adsorption capacity. Using activated carbon cloth (ACC) as the electrode material, the pressure drop across the CDI device is quantified with respect to flow scheme (flow-between and flow-through CDI modes) used. Computational fluid dynamic (CFD) models are developed to study and optimize the fluid velocity and distribution in order to minimize the device fluid pressure losses. The model predictions are verified by constructing the conceptualized CDI devices and correlating the theoretical and experimentally obtained pressure drops, salt adsorption capacities and fluid flow parameters. The results indicate that up to 60% reduction in pressure drop and similar to 35% increase in specific salt adsorption capacity can be achieved by simple changes to the input-output port architecture of the CDI units. The results describe a method to considerably lower energy consumption in commercial CDI devices.

Aquaculture is a billion dollar industry and biofouling of aquaculture installations has heavy economic penalties. The natural antifouling (AF) defence mechanism of some seaweed that inhibits biofouling by production of reactive oxygen species (ROS) inspired us to mimic this process by fabricating ZnO photocatalytic nanocoating. AF activity of fishing nets modified with ZnO nanocoating was compared with uncoated nets (control) and nets painted with copper-based AF paint. One month experiment in tropical waters showed that nanocoatings reduce abundances of microfouling organisms by 3-fold compared to the control and had higher antifouling performance over AF paint. Metagenomic analysis of prokaryotic and eukaryotic fouling organisms using next generation sequencing platform proved that nanocoatings compared to AF paint were not selectively enriching communities with the resistant and pathogenic species. The proposed bio-inspired nanocoating is an important contribution towards environmentally friendly AF technologies for aquaculture.

Multifunctional core-shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into one entity, which is composed of a single Fe3O4 NP as the magnetic core, mesoporous silica (mSiO2) with cavities as the sandwiched layer, and thermosensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) copolymer as the outer shell. The mSiO2-coated Fe3O4 NPs (Fe3O4@mSiO2) are monodisperse and the particle sizes were varied from 25 to 95 nm by precisely controlling the thickness of mSiO2-coating layer. The P(NIPAAm-co-AAm) were then grown onto surface-initiator-modified Fe3O4@mSiO2 NPs through free radical polymerization. These core-shell composite NPs (designated as Fe3O4@mSiO2@P(NIPAAm-co-AAm)) were found to be superparamagnetic with high r2 relaxivity. To manipulate the phase transition behavior of these thermosensitive polymer-coated NPs for future in vivo applications, the characteristic lower critical solution temperature (LCST) was subtly tuned by adjusting the composition of the monomers to be around the human body temperature (i.e. 37 °C), from ca. 34 to ca. 42 °C. The thermal response of the core-shell composite NPs to the external magnetic field was also demonstrated. Owing to their multiple functionality characteristics, these porous superparamagnetic and thermosensitive NPs may prove valuable for simultaneous magnetic resonance imaging (MRI), temperature-controlled drug release, and temperature-programed magnetic targeting and separation applications.