Dispersive X-ray Elemental Analysis Research Articles

Characterization of functionalized multiwalled carbon nanotubes and comparison of their cellular toxicity between HEK 293 cells and zebra fish in vivo.

Carbon nanotubes (CNTs) hold tremendous potential due to their unique and modifiable properties. Their robust biological applications necessitate minimizing their cytotoxicity and increasing the solubilization. In the present manuscript, we have functionalized multiwalled carbon nanotubes (MWCNTs) using defect functionalization methodology to covalently bind carboxy and amino groups on their walls. This functionalization was reassured through fourier-transform infrared spectroscopy (FTIR), energy dispersive x-ray analysis (EDX), elemental and field emission scanning electron microscopy (FE-SEM) analysis. The observations demonstrated that addition of carboxy as well as amino groups on MWCNTs, besides enabling MWCNTs solubilization also significantly ameliorated the cytotoxicity and the oxidative stress in comparison to pristine MWCNTs. It is envisaged that changes in agglomeration of the functionalized MWCNTs and the acquired surface charge is the reason for the reduction of cytotoxicity. Zebra fish embryo model test system employed for in vivo analysis of the MWCNTs showed no significant toxicity on account of any nanoparticle tested pointing towards intrinsic mechanisms in place for deterring the damage in complex organisms. Overall, the observations besides pointing towards functionalized MWCNTs effectiveness towards weakening the toxicity of pristine MWCNTs also caution for extrapolating in vitro data to in vivo observations. The observations further lend credibility for exploiting the zebra fish as a model system for analyzing the effects of MWCNTs functionalization.

Novel pilot scale photocatalytic treatment of textile & dyeing industry wastewater to achieve process water quality and enabling zero liquid discharge

This paper presents a novel end-to-end pilot scale photocatalytic treatment of real textile & dyeing industry effluent, which involved innovative approach in primary treatment, followed by Heterogenous Photocatalysis (HP) involving nano-TiO2/UV as secondary treatment and suitable filtration leading to treated water meeting process water quality enhancing water re-use efficiency. This enables Zero Liquid Discharge (ZLD); which is the need of the hour in tackling problems of point source pollution and Water Conservation in developing countries like India. Overall treatment led to complete degradation and mineralization of organic pollutants and dye stuff thereby achieving adequate treatment, complete decolourization and deodorization of the effluent and almost hundred times less quantities of sludge residues in comparison to those obtained in conventional treatment methods. The nature and elemental composition of sludge residues, as investigated using Energy Dispersive X-ray (EDX) elemental analysis, confirms complex organic dye components mineralized and nature being non-toxic. The complete treatment took place in 5 h without any kind of bioremediation method, which further highlights highly efficient and fast treatment coupled with small footprint. Overall cost of treatment is estimated to be around 1.55 USD/m3. Such an innovation in wastewater treatment is expected to bring a revolution in developing countries, which are grappled together with problems of rapid industrialization, urbanization, regulatory compliances and environmental challenges.

On the Selective Transport of Nutrients through Polymer Inclusion Membranes Based on Ionic Liquids

In the last few years, the use of ionic liquid-based membranes has gained importance in a wide variety of separation processes due to the unique properties of ionic liquids. The aim of this work is to analyze the transport of nutrients through polymer inclusion membranes based on different concentrations of methyltrioctylammonium chloride, in order to broaden the application range of these kinds of membranes. Calcium chloride (CaCl2) and sodium hydrogen phosphate (Na2HPO4) nutrients were used at the concentration of 1 g·L−1 in the feeding phase. The evolution of the concentration in the receiving phase over time (168 h) was monitored and the experimental data fitted to a diffusion-solution transport model. The results show very low permeation values for CaCl2. By contrast, in the case of Na2HPO4 the permeation values were higher and increase as the amount of ionic liquid in the membrane also increases. The surface of the membranes was characterized before and after being used in the separation process by scanning electron microscopy coupled to energy dispersive X-Ray spectroscopy (SEM–EDX) and elemental mapping analysis. The SEM–EDX images show that the polymer inclusion membranes studied are stable to aqueous solution contacting phases and therefore, they might be used for the selective transport of nutrients in separation processes.

Design guidelines for Al-12%Si latent heat storage encapsulations to optimize performance and mitigate degradation

We provide detailed insight into the growth kinetics of intermetallic layers formed at the interface of molten Al-12%Si with cylindrical encapsulations of 316L stainless steel. This knowledge is relevant for the design and operation of high-temperature latent heat storage and energy harvesting devices at application-relevant conditions. Our continuous experiments on iron-aluminide deposition rates at 600 °C and 700 °C lasted up to 120 days. The layer thickness was determined in metallographic cross sections by light microscopy. We observed deviations from standard growth models, including a delayed layer growth onset at 600 °C and strongly non-parabolic kinetics at 700 °C. We developed a numerical diffusion model that accommodated temperature dependent kinetics and explained the observed deviations by incorporating de-passivation and dissolution phenomena. Numerical fitting of the model to the experiments provided optimized mobility parameters that agree with those reported for the Fe2Al5 compound, whose presence was confirmed by energy dispersive X-ray elemental analysis. Differential scanning calorimetry revealed reductions in heat of fusion and melting temperature, of −10% and −10 K, respectively, after 120 days at 700 °C. Fe concentration in the melt increased from <0.3% to 2.6%, under the same conditions. The validated model was then used to provide design guidance for heat storage applications including degradation. For 8760 h of full-load-charging: a energy density of 370 kJ/kg was conserved, with variable source temperature distribution. For high power density configurations (1430 kW/m3) narrow source temperature distributions were beneficial. Our multi-month experimental campaigns enable more accurate degradation and performance predictions and provide guidelines that result in better long-term performance of the Al-12%Si phase change media.

Synthesis and evaluation of the structural, optical, and antibacterial properties of copper oxide nanoparticles

The nanostructured material, due to their outstanding applications in various fields of science and technology; metal and metal oxide nano are exclusively explored in the progress of nanosized materials. The transition metal oxides including CuO is are used for magnetic storage devices, solar energy applications, sensors, as a catalyst in reactions, as electrode materials in supercapacitors and to tune the semiconducting properties of materials. The current work focuses on the synthesis of CuO nanoparticles (NPs) by combustion technique for various annealing (100°C and 300°C) using ascorbic acid as a capping agent. The XRD pattern confirms that the CuO NPs exhibit the monoclinic structure. The optical properties are investigated using UV–Vis absorption spectra. Further, the refractive index, optical dielectric constant and bulk modulus were investigated using the specific empirical model as a function of temperature. The FTIR spectrum shows that the band in the range 450–500 cm−1 confirms the formation of CuO NPs. The SEM images revealed that the spherical surface morphology of the CuO NPs. The Elemental analysis and the particle size were confirmed by elemental dispersive X-ray analysis (EDX) and particle size analyzer. Moreover, the antibacterial activity of CuO nanoparticles was investigated using E. coli, S. typhi, M. luteus, P. fluorescent, S. flexneri, and V. cholera bacteria.

High-Resolution SEM and EDX Characterization of Deposits Formed by CH₄+Ar DBD Plasma Processing in a Packed Bed Reactor.

The deposits formed during the DBD plasma conversion of CH4 were characterized by high-resolution scanning electron microscopy (HRSEM) and energy dispersive X-ray elemental analysis (EDX) for both cases of a non-packed reactor and a packed reactor. For the non-packed plasma reactor, a layer of deposits was formed on the dielectric surface. HRSEM images in combination with EDX and CHN elemental analysis of this layer revealed that the deposits are made of a polymer-like layer with a high content of hydrogen (60 at%), possessing an amorphous structure. For the packed reactor, γ-alumina, Pd/γ-alumina, BaTiO3, silica-SBA-15, MgO/Al2O3, and α-alumina were used as the packing materials inside the DBD discharges. Carbon-rich agglomerates were formed on the γ-alumina after exposure to plasma. The EDX mapping furthermore indicated the carbon-rich areas in the structure. In contrast, the formation of agglomerates was not observed for Pd-loaded γ-alumina. This was ascribed to the presence of Pd, which enhances the hydrogenation of deposit precursors, and leads to a significantly lower amount of deposits. It was further found that the structure of all other plasma-processed materials, including MgO/Al2O3, silica-SBA-15, BaTiO3, and α-alumina, undergoes morphological changes. These alterations appeared in the forms of the generation of new pores (voids) in the structure, as well as the moderation of the surface roughness towards a smoother surface after the plasma treatment.

Petrographic and geochemical characterization of coal from Santa Susana Basin, Portugal

The current and future importance of coal as a geological resource is related with the production of coke, carbon materials, carbon derivatives and other chemical products as well as a promising alternative source of critical trace elements. This study aims the comprehensive characterization of coals from the Santa Susana Basin (SSB), SW of Portugal. The SSB is a Pennsylvanian continental basin located along the Santa Susana Shear Zone that separates two tectonostratigraphic zones of Iberian Massif. Samples of coal and coaly silt-claystone from the main outcrops, Jongeis and Vale de Figueira, were collected for this study. The methodologies used for the petrographic and geochemical characterization included: optical microscopy, scanning electron microscopy with energy dispersive X-ray spectrometry, proximate and elemental analysis and inductively coupled plasma mass spectrometry (ICP-MS). The results demonstrate that the organic matter of coal from SSB is essentially composed of vitrinite and small amounts of inertinite. The mineral matter includes detrital minerals (mainly quartz and clay minerals), iron oxides and oxidized and non-oxidized framboidal pyrite. Epigenetic carbonates (dolomite and ankerite) were only observed in samples from Jongeis outcrop. Vitrinite random reflectance of the samples ranges between 0.90% and 1.25%, indicating a bituminous coal rank. The slightly higher vitrinite reflectance and the occurrence of epigenetic carbonates in samples from Jongeis can be related with differentiated burial history of the basin and post-depositional processes including fluids circulation that may have promoted the enhancement of the thermal maturity. When compared with the geochemical composition of worldwide hard coals, samples from Vale de Figueira are significantly enriched in Cs and In, while samples from Jongeis are significantly enriched in In and Mn. Considering the elements' mode of occurrence, the majority of elements are preferentially associated with mineral matter. The elements S, Cd, Mo, Pb and Se have organic affinity. The strong positive correlation between Ca and Mg, Mn and Te indicates their association with carbonate phases, which is in accordance with the carbonate composition.

Effect of initial concentration of chitosan on the particle size of chitosan nanoparticle

Various applications of chitosan lead to the growing interest of researchers to synthesise chitosan nanoparticles (CNP) which exhibit enhanced properties. However, it is very challenging to synthesise CNP due to the many parameters involved in the synthesis process which can affect the size of CNP. This work aims to synthesise CNP and investigate the effect of initial concentration of chitosan on the particle size of CNP. CNP was produced via ionic gelation process with varying initial concentration of chitosan (0.3, 0.6, 0.9, 1.2, 1.5, 1.8, and 2.1% w/v). Fourier transmission infrared (FTIR) analysis revealed the peak of amide shifted from 1629 cm-1 to 1635 cm-1, which confirmed the formation of CNP. Energy dispersive X-ray (EDX) elemental analysis revealed the presence of phosphorus in CNP. The particle sizes of CNP were measured using dynamic light scattering (DLS) and transmission electron microscopy (TEM). It was found that the average particle size of CNP increased from 46.7 nm to 225.33 nm with the increase in initial concentration of chitosan from 0.3 to 2.1% w/v due to the agglomeration of CNP, as proven from the TEM images.

Structural and spectroscopic studies of bromofullerene

Structural and spectroscopic studies on fullerene and bromofullerene molecules were investigated. The reaction with liquid bromine was used to prepare bromofullerene and it was characterized by using X-ray diffraction, ultraviolet–visible, Fourier transform infrared, Fourier transform Raman, electron paramagnetic resonance, scanning electron microscopy, high resolution transmission electron and energy dispersive X-ray techniques. The XRD pattern of bromofullerene confirms the attachment of bromine to fullerene. FT-IR and FT-Raman characterization reveal the C-Br vibrations in the brominated fullerene which confirms the bromination. UV–Vis spectral analysis endorses shifting of absorption peak. EPR line width, with g-factor values, indicates the magnetic ion sites in the samples. Scanning electron microscope and high resolution transmission electron microscope signify the changes in surface and particle size of the molecule. The particle size was calculated from Debey-Sherrer's formula and corroborated by TEM images. Energy dispersive X-ray elemental micro analysis confirms the presence of bromine element in the molecule. The enhanced reactivity by substitution of bromine paves the way for designing the bioactive molecules which will be useful in the field of carbon nano-medicine and targeted drug delivery applications.

Facile synthesis of graphene oxide–silver nanocomposite for decontamination of water from multiple pollutants by adsorption, catalysis and antibacterial activity

Here in, we presented a facile one-step method for the synthesis of Graphene oxide–silver (GO–Ag) nanocomposite and its applications as a sorbent for the elimination of some toxic pollutants from aqueous medium, as an efficient catalyst in the individual as well as simultaneous reduction reactions of multiple compounds, and as an antibacterial agent for the destruction of some harmful microorganisms existent in wastewater. GO was prepared using a modified Hummers method and Ag nanoparticles were integrated on GO sheets by chemical reduction of Ag+ ions on the surfaces of GO sheets. The composition and morphology of the nanocomposite was extensively characterized with elemental dispersive X-ray analysis (EDX), Fourier transform infra-red (FT-IR) spectroscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The GO–Ag nanocomposite demonstrated remarkable adsorption capacities and recyclability for malachite green (MG) and ethyl violet (EV) dyes. Various experimental parameters affecting adsorptive behavior of nanocomposite like temperature, pH, time of contact between dye and adsorbent, and adsorbent dose were evaluated thoroughly. Experimental data was simulated with different adsorption isotherms and kinetic models to evaluate adsorption behavior of both dyes and results confirmed the adsorption of both the dyes to be followed by pseudo 2nd order kinetic model and Langmuir adsorption model. Moreover, adsorbent was regenerated in suitable media for both dyes without any loss in removal efficiency. The catalytic performance for the 2-nitroaniline (2-NA) reduction was investigated in detail. Most importantly, the prepared nanocomposite was found to have potential to adsorb multiple pollutants all together as well as to catalyze the simultaneous reduction of a mixture of dyes (MG, MO, and EV) and 2-NA. An additional advantage of the GO-Ag nanocomposite was its antibacterial activity acquired to the presence of Ag nanoparticles. Two bacterial strains (Gram-negative bacterium, E. coli and the Gram-positive bacterium, S. aureus) were used to test antibacterial activity of composite and the results confirmed the remarkable performance of the nanocomposite in destroying harmful pathogens.

Purification of textile wastewater by using coated Sr/S/N doped TiO2 nanolayers on glass orbs

Simultaneous doping of TiO2 nanoparticles with three elements including Sr, S, and N is reported. The resulting material shows superior photocatalytic performance toward degradation of textile waste under visible and sunlight. The pure and doped TiO2 nanolayers were prepared by sol-gel method and were fixed on a bed of glass orbs. The immobilized TiO2 were characterized by a variety of techniques: X-ray diffraction (XRD), scanning electron microscopy (SEM), spectroscopy diffusion reflection (DRS), energy dispersive X-ray spectrometry (EDS) and elemental analysis (CHNS). The photocatalytic activity of the prepared fixed-bed materials toward degradation of the textile wastes was determined by using ultraviolet-visible spectroscopy (UV-Vis) and measurement of the chemical oxygen demand testing (COD). The best photocatalytic activity was observed with the use of Sr/S/N-TiO2 nano-layers. Afterwards, the experimental conditions were optimized by tuning reaction parameters, including amount of doped metal ion on photocatalyst structure, sample solution pH and photoreactor output flow rate. The results confirmed that at natural pH 5.9 of sample solution, maximum decomposition of 91-99% of azo dyes was obtained in 8 h under visible irradiation. Finally, the experiments were repeated under 1.5 AM sunlight with high volume of reactants in order to confirm the cost-effectiveness of the designed photocatalyst.

Mesoporous activated carbon produced from coconut shell using a single-step physical activation process

In this work, the pore properties and textural characterization of resulting activated carbons (ACs) derived from dried coconut shell (DCS) were investigated in duplicate using a single-step physical activation process. Based on the thermochemical properties of DCS analyzed, the process features its carbonization temperature of 500 °C at a constant heating rate of 10 °C/min under nitrogen flow, subsequently switched to the gasification with CO2 gas in the ranges of 700–900 °C (activation temperature) and 0–60 min (holding time) in the same reactor. The results showed that the pore properties (including mesoporosity) of resulting AC products, obtained from nitrogen adsorption-desorption isotherm and true density measurements, were on an increasing trend as activation temperature and holding time increased. These findings were attributable to the severe reactions of the lignocellulose-based char with CO2. According to the maximal Brunauer-Emmet-Teller (BET) surface area (˃ 1100 m2/g) and mesoporosity percentage (˃ 40%), the optimal activation conditions should be performed at 850 °C for a holding time of 60 min, but will result in relatively low yield. Furthermore, the textural structures and elemental compositions of DCS-based ACs were viewed using the scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM-EDS) and elemental analysis, showing consistent results as described above.

SEM (EDX) is an indispensable tool for the characterization of subcutaneous, preperitoneal and visceral adipose tissue of obese patients

In this work the scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) elemental analysis were used for the characterization of adipose tissue samples taken from volunteer obese patients. The adipose tissue was taken from subcutaneous, preperitoneal and visceral layers of the adipose tissue. The obtained results provided information about the structural composition of adipose tissue layers in the human body, as well as the main microstructural features. It was demonstrated for the first time, to the best of our knowledge, that SEM and EDX are indispensable tools in order to investigate some special morphological features and the elemental composition of different layers of the human adipose tissue, identifying the surface microstructure and its qualitative composition. From the obtained results we concluded that such characterization of the adipose tissue is an essential step for the possible prediction of symptoms of different diseases.

The potential role of spherocrystals in the detoxification of essential trace metals following exposure to Cu and Zn in the fighting conch Strombus (Lobatus) pugilis.

Crypt cells-one of the three cell types composing Strombidae digestive tubules-are characterized by the presence of numerous metal-containing phosphate granules termed spherocrystals. We explored the bioaccumulation and detoxification of metals in Strombidae by exposing wild fighting conch Strombus pugilis for 9days to waterborne CuSO4 and ZnSO4. The total amount of Cu and Zn was determined in the digestive gland and in the rest of the body by Inductively Coupled Plasma (ICP) analyses. The digestive gland spherocrystal metal content was investigated based on the semi-quantitative energy dispersive X-ray (EDX) elemental analysis. ICP analyses of unexposed individuals revealed that 87.0 ± 5.9% of the Zn is contained in the digestive gland, where its concentration is 36 times higher than in the rest of the body. Regarding Cu, 25.8 ± 16.4% of the metal was located in the digestive gland of the control individuals, increasing to 61.5 ± 16.4% in exposed individuals. Both Cu and Zn concentrations in the digestive gland increased after exposures, pointing to a potential role of this organ in the detoxification of these metals. EDX analysis of spherocrystals revealed the presence of Ca, Cl, Fe, K, Mg, P, and Zn in unexposed individuals. No difference was found in the relative proportion of Zn in spherocrystals of exposed versus control individuals. Contrastingly, copper was never detected in the spherocrystals from controls and Zn-exposed individuals, but the relative proportion of Cu in spherocrystals of Cu-exposed individuals varied from 0.3 to 5.7%. Our results show the direct role of spherocrystals in Cu detoxification.

Animal manure-derived biochars produced via fast pyrolysis for the removal of divalent copper from aqueous media

Here, we report a pyrolyzed guinea fowl manure-derived biochar (GFM-BC) and cattle manure-derived biochar (CTM-BC) and their use as adsorbent for the removal of divalent copper from aqueous media was evaluated. The BCs physical and chemical properties were characterized by Scanning electron microscopy (SEM), Elemental dispersive x-ray analysis (EDX), Fourier transform infrared microscopy (FTIR) and thermo gravimetric analysis (TGA). The results presented that the BCs obtained higher content were quite effective for Cu (II) removal with maximum capacities of 43.60 and 44.50 mg g−1 for GFM-BC and CTM-BC, respectively. From simulation of experimental data with different adsorption isotherms and kinetics models it was found that the adsorption of both BCs was adequately fitted by Freundlich adsorption model and pseudo-second order kinetic model, respectively. Thermodynamic parameters suggested that the adsorption of Cu (II) onto both BCs was feasible, spontaneous and exothermic under evaluated parameters. Thus, the biomass used in this study proved to be effective adsorbents for the removal of Cu (II) from aqueous media.

2-Aminothiazole-functionalized triazine-modified polystyrene decorated with gold nanoparticles as composite catalyst for the reduction of 4-nitrophenol

Herein, polystyrene (PS) bearing di(2-aminothiazole)-substituted triazine as chelation unit for both Au(III) ions and Au(0) nanoclusters was prepared through successive chemical modification of native polystyrene including nitration (treatment with HNO3/H2SO4), reductive amination (treatment with SnCl2/HCl), and successive grafting of 2,4,6-trichloro-1,3,5-triazine and 2-aminothiazole. The derived gold nanoparticles- (AuNPs-) containing composite material was obtained through chelation of the nanogold precursor, namely hydrogen tetrachloroaurate, and subsequent in situ hydride-assisted reduction providing gold nanoparticles with low size (about 14nm) and spherical shape. It is shown that the presence of 2-aminothiazole-grafted triazine units on the phenyl side groups of PS enables the stable anchoring of the AuNPs while preventing agglomeration. Chemical structure of the PS derivatives was confirmed after each synthesis step by a combination of experimental methods such as infrared and energy dispersive X-ray spectroscopies, elemental analysis, X-ray diffraction and scanning electron microscopy. To highlight the catalytic potential of the so-designed nanostructured catalyst, the reduction of 4-nitrophenol was considered in the presence of a large excess of sodium borohydride as reductant specie. UV–visible spectroscopic monitoring of the progress of the reaction confirmed the pseudo-first order kinetic profile associated with a rate constant as high as 3.07×10−2s−1.

Natural biowaste of Groundnut shell derived nano carbons: Synthesis, characterization and itsin vitro antibacterial activity

In this work, we aimed to develop a facile and cost-effective method for the green synthesis of nano carbons (NCs) from Groundnut shell, a natural biowaste and renewable resource. The synthetic process involves a single step pyrolysis technique in a nitrogen atmosphere at different temperatures (550, 750 and 950 °C). The as synthesized NCs were characterized by powder X-ray diffraction pattern (XRD), scanning electron microscopy (SEM), elemental dispersive X-ray (EDX) analysis, Fourier transform infrared (FTIR) spectroscopy and thermogravimetric (TG) analysis. The synthesized NCs possess stable fluorescent properties and shows good bio-compatibility. XRD pattern indicates that the synthesized NCs exhibit crystalline in nature. SEM analysis revealed the formation of disordered pores over the carbon particle surface and the average size was found to be ∼50 nm. The EDX analysis confirmed that carbon is the major element, i.e., 87%, 91% and 93% for 550 °C, 750 °C, 950 °C respectively, present. FTIR spectra show the functional molecules (cellulose, hemicelluloses, lignin and pectin) which are responsible for formation of NCs. Furthermore, the synthesized NCs were checked for antibacterial activity on Escherichia coli, Chromobacterium violaceum and Bacillus cereus. Growth of all the organisms tested was inhibited indicating that these NCs have good biocide activity. Thus, these results suggest that the proposed green synthesized NCs could be utilized for microbial growth inhibitor, bio-imaging and drug delivery applications.

Ru-dye grafted CdS and reduced graphene oxide Ru/CdS/rGO composite: An efficient and photo tuneable electrode material for solid state dye sensitized polymer solar cells

This article provides a facile one step synthesis of CdS (cadmium sulphide) and CdS/rGO (reduced graphene oxide CdS nanocomposites) using DMF (N, N-Dimethyl formamide) both as a solvent and a reducing agent for the reduction of grapheme oxide. XRD (X-ray diffraction), FESEM (Field emission scanning electron microscopy), EDX (Elemental dispersive X-ray analysis), TEM (Transmission electron microscopy), UV–Vis (UV–visible) and Raman spectroscopy have been employed for the characterization of prepared samples. The prepared nano-composite was photosensitized with three well known Ru (Ruthenium) dyes i.e. N3 [cis-Bis(isothiocyanato) bis(2,2′-bipyridyl-4,4′-dicarboxylato ruthenium(II))], N719 [Di-tetrabutylammoniumcis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium (II)] and Z907 [cis-Bis(isothiocyanato)(2,2′-bipyridyl-4,4′-dicarboxylato)(4,4′-di-nonyl-2′-bipyridyl)ruthenium(II)]. The effect of concentration and number of anchoring groups on the grafting was extensively studied in order to explore structure-activity relationship. Photosensitization of CdS/rGO nanocomposite was evidenced by UV–Visible, PL (Photoluminiscence), FT-IR (Fourier transform infra-red) spectroscopy and I-V (current-voltage measurements). The prepared samples were found as effective electrode materials for application in SSDSSCs (solid state dye sensitized solar cells) with a maximum output efficiency of 1.01% which is two times higher than the reference device under the same experimental conditions. The components of the synthesized nanohybrid material were found to be capable of providing a uni-directional and cascade path for the flow of electrons and holes in the desired directions.

Estimation of Energy Levels of Self-assembled Ferrocenyls and Investigation of Charge-driven Electro-crystallization of Ferricenyl Materials

Three tetra-ferrocenylethynylpyridinyl copper complexes, L4(CuI)4 (1), L4(CuBr)2 (2), L4(CuCl)2 (3) and one ferrocenylethynylpyridinyl Ligand (L) have been investigated for their HOMO and LUMO energy levels. The band gap energy for each material has been calculated using optical absorption spectrum. Cyclic Voltammetry was used to estimate the oxidation potential and energy band diagram consequently. Cyclic voltammetry in dichloroethane showed chemically reversible multiferrocenyl oxidation signals with evidence for product electro-crystallization. We isolated the semi-oxidized products by electrodeposition onto a Pt disc electrode and investigated by scanning electron microscopy (SEM). SEM confirmed the spontaneous formation of crystalline oxidation products with distinctive morphologies for complex 1 &3. Energy dispersive X-ray elemental analysis shows presence of hexaflurophosphate (counter-ion) with the Fe:P ratio of 2:1, and 2:1 for the electrocrystallized products of 1 and 3, respectively proposing the formulae [1]2+(PF6−)4 and [3]2+(PF6−)2 for the electro-crystallized products.

Characterization of Some Real Mixed Plastics from WEEE: A Focus on Chlorine and Bromine Determination by Different Analytical Methods

Bromine and chlorine are almost ubiquitous in waste of electrical and electronic equipment (WEEE) and the knowledge of their content in the plastic fraction is an essential step for proper end of life management. The aim of this study is to compare the following analytical methods: energy dispersive X-ray fluorescence spectroscopy (ED-XRF), ion chromatography (IC), ion-selective electrodes (ISEs), and elemental analysis for the quantitative determination of chlorine and bromine in four real samples taken from different WEEE treatment plants, identifying the best analytical technique for waste management workers. Home-made plastic standard materials with known concentrations of chlorine or bromine have been used for calibration of ED-XRF and to test the techniques before the sample analysis. Results showed that IC and ISEs, based upon dissolution of the products of the sample combustion, have not always achieved a quantitative absorption of the analytes in the basic solutions and that bromine could be underestimated since several oxidation states occur after combustion. Elemental analysis designed for chlorine determination is subjected to strong interference from bromine and required frequent regeneration and recalibration of the measurement cell. The most reliable method seemed to be the non-destructive ED-XRF. Calibration with home-made standards, having a similar plastic matrix of the samples, enabled us to carry out quantitative determinations, which have been revealed to be satisfactorily accurate and precise. In all the analyzed samples a total concentration of chlorine and/or bromine between 0.6 and 4 w/w% was detected, compromising the feasibility of a mechanical recycling and suggesting the exploration of an alternative route for managing these plastic wastes.