National Centre for Compositional Characterisation of Materials

The strong correlation between LLZO grain size and the Li–LLZO stability as a function of Li plating rate is demonstrated. The increase in grain size reduces the grain boundary area and hence the number of possible failure points leading to an increased maximum tolerable current density.

A facile and green route for the synthesis of palladium nanoparticles from palladium chloride was developed using non-toxic, renewable plant polymer, gum ghatti (Anogeissus latifolia), as both the reducing and stabilizing agent. The generated nanoparticles were characterized with UV–visible spectroscopy (UV–vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), and X-ray diffraction (XRD) techniques. The formation of palladium nanoparticles was confirmed from the appearance of intense brown colour and broad continuous absorption spectra in the UV–visible region. The produced nanoparticles were found to be spherical in shape, polydisperse and the average particle size was 4.8 ± 1.6 nm. The face centred cubic crystal structure of the fabricated nanoparticles is confirmed from the selected-area electron diffraction and XRD patterns. Compared to earlier reports, the nanoparticles showed superior antioxidant at a much lower nanoparticle dose. Also, the homogenous catalytic activity of palladium nanoparticles was studied by probing the reduction of dyes such as coomassie brilliant blue G-250, methylene blue, methyl orange, and a nitro compound, 4-nitrophenol with sodium borohydride. The nanoparticles exhibited excellent catalytic activity in dye degradation and the results of this study demonstrate the possible application of biogenic palladium nanoparticles as nanocatalyst in environmental remediation. Keywords: Antioxidant, Catalyst, Green synthesis, Gum ghatti, Palladium nanoparticles, Dye degradation

BACKGROUND: Gum ghatti is a proteinaceous edible, exudate tree gum of India and is also used in traditional medicine. A facile and ecofriendly green method has been developed for the synthesis of silver nanoparticles from silver nitrate using gum ghatti (Anogeissus latifolia) as a reducing and stabilizing agent. The influence of concentration of gum and reaction time on the synthesis of nanoparticles was studied. UV-visible spectroscopy, transmission electron microscopy and X-ray diffraction analytical techniques were used to characterize the synthesized nanoparticles. RESULTS: By optimizing the reaction conditions, we could achieve nearly monodispersed and size controlled spherical nanoparticles of around 5.7 ± 0.2 nm. A possible mechanism involved in the reduction and stabilization of nanoparticles has been investigated using Fourier transform infrared spectroscopy and Raman spectroscopy. CONCLUSIONS: The synthesized silver nanoparticles had significant antibacterial action on both the Gram classes of bacteria. As the silver nanoparticles are encapsulated with functional group rich gum, they can be easily integrated for various biological applications.

A simple and ecofriendly procedure have been devised for the green synthesis of silver nanoparticles using the aqueous extract of gum tragacanth ( Astragalus gummifer ), a renewable, nontoxic natural phyto‐exudate. The water soluble components in the gum act as reductants and stabilizers. The generated nanoparticles were analyzed using UV‐visible spectroscopy, transmission electron microscopy, X‐ray diffraction, Fourier transform‐infrared spectroscopy, and Raman spectroscopy. The role of gum concentration and reaction time on the synthesis of nanoparticles was studied. By regulating the reaction conditions, spherical nanoparticles of 13.1 ± 1.0 nm size were produced. Also, the possible functional groups involved in reduction and capping of nanoparticles has been elucidated. The antibacterial activity of the fabricated nanoparticles was tested on model Gram‐negative and Gram‐positive bacterial strains with well‐diffusion method. These nanoparticles exhibited considerable antibacterial activity on both the Gram classes of bacteria, implying their potential biomedical applications.

A strategy was developed to produce quality carbon fibers from industrial waste lignin. The strategy employs an enzyme-mediator system to efficiently fractionate lignin into soluble and insoluble fractions, where the latter serves as a superior carbon fiber precursor. Mechanistic studies revealed that higher MW, less hydroxy groups, and more β-<italic>O</italic>-4 linkages improve the spinnability, crystallization, and mechanical performance of carbon fibers.

The nanoparticles used in this study were prepared from AgNO3 using NaBH4 in the presence of capping agents such as citrate, sodium dodecyl sulfate, and polyvinylpyrrolidone. The formed nanoparticles were characterized with UV-Vis, TEM, and XRD. The generation of silver nanoparticles was confirmed from the appearance of yellow colour and an absorption maximum between 399 and 404 nm. The produced nanoparticles were found to be spherical in shape and polydisperse. For citrate, SDS, and PVP capped nanoparticles, the average particle sizes were 38.3 ± 13.5, 19.3 ± 6.0, and 16.0 ± 4.8 nm, respectively. The crystallinity of the nanoparticles in FCC structure is confirmed from the SAED and XRD patterns. Also, the combined antibacterial activity of these differently capped nanoparticles with selected antibiotics (streptomycin, ampicillin, and tetracycline) was evaluated on model Gram-negative and Gram-positive bacteria, employing disc diffusion assay. The activity of the tested antibiotics was enhanced in combination with all the stabilized nanoparticles, against both the Gram classes of bacteria. The combined effects of silver nanoparticles and antibiotics were more prominent with PVP capped nanoparticles as compared to citrate and SDS capped ones. The results of this study demonstrate potential therapeutic applications of silver nanoparticles in combination with antibiotics.

Silver nanoparticles synthesized from gum kondagogu (5 nm) were used to evaluate the antibacterial activity against Gram-positive and Gram-negative bacteria. To decipher the mode of antibacterial action of nanoparticles, a comprehensive study was carried out employing a variety of susceptibility assays: micro-broth dilution, antibiofilm activity, growth kinetics, cytoplasmic content leakage, membrane permeabilization, etc. The production of reactive oxygen species (ROS) and cell surface damage during bacterial nanoparticle interaction were also demonstrated using dichlorodihydrofluorescein diacetate, N-acetylcysteine; and scanning electron microscopy and energy dispersive X-ray spectra. Further, the biocompatibility with HeLa cell line was also evaluated. Compared to earlier reports, the minimum inhibitory concentration values were lower by 3.2- and 16-folds for Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli strains, respectively. The minimum bactericidal concentration values were lower by 4 and 50-folds. Thus, the biogenic silver nanoparticles were found to be more potent bactericidal agents in terms of concentration. The nanoparticles exhibited significant antibiofilm activity against test strains at 2 μg mL−1, which can have implications in the treatment of drug resistant bacterial infections caused by biofilms. Growth curve in nanoparticle supplemented indicated a faster inhibition in Gram-negative bacteria as compared to Gram-positive. Treatment with nanoparticles caused cytoplasmic content leakage and membrane permeabilization in a dose dependent manner, an evidence for membrane damage. The observations noted in our study substantiated the association of ROS and membrane damage in the antibacterial action of silver nanoparticles. The promising antibacterial activity enables these nanoparticles as potential bactericidal material for various environmental and biomedical applications.

Quality lignin-based carbon fiber with high mechanical performance has been made from enzyme–mediator and dialysis fractionated lignin. In particular, the elastic modulus of lignin-based carbon fiber showed good correlations with PDI.

MgO nanostructures with controllable morphology and tunable textural properties synthesized <italic>via</italic> aqueous based route in the absence of organic templates were found to be excellent adsorbent for the removal of Pb(<sc>ii</sc>) and Cd(<sc>ii</sc>) ions from water.

This article discusses aspects of biofouling and corrosion in the thermo-fluid heat exchanger (TFHX) and in the cooling water system of a nuclear test reactor. During inspection, it was observed that >90% of the TFHX tube bundle was clogged with thick fouling deposits. Both X-ray diffraction and Mossbauer analyses of the fouling deposit demonstrated iron corrosion products. The exterior of the tubercle showed the presence of a calcium and magnesium carbonate mixture along with iron oxides. Raman spectroscopy analysis confirmed the presence of calcium carbonate scale in the calcite phase. The interior of the tubercle contained significant iron sulphide, magnetite and iron-oxy-hydroxide. A microbiological assay showed a considerable population of iron oxidizing bacteria and sulphate reducing bacteria (10(5) to 10(6) cfu g(-1) of deposit). As the temperature of the TFHX is in the range of 45-50 degrees C, the microbiota isolated/assayed from the fouling deposit are designated as thermo-tolerant bacteria. The mean corrosion rate of the CS coupons exposed online was approximately 2.0 mpy and the microbial counts of various corrosion causing bacteria were in the range 10(3) to 10(5) cfu ml(-1) in the cooling water and 10(6) to 10(8) cfu ml(-1) in the biofilm.

We report the preparation of two anomeric cyclic carbonate monomers from CO₂ and natural sugar 2-deoxy-<sc>d</sc>-ribose, their ring-opening polymerisation and copolymerisation with trimethylene carbonate to produce aliphatic polycarbonates with tunable properties.

A dispersive liquid–liquid microextraction (DLLME) method was developed for the determination of uranium(VI) in groundwater/seawater by inductively coupled plasma–optical emission spectrometry (ICP–OES) and flow injection–inductively coupled plasma mass spectrometry (FI–ICPMS). This is the first report on the extraction of uranium(VI) by a DLLME method. In this method, uranium(VI) was complexed with ammonium pyrrolidine dithiocarbamate (APDC) in the presence of cetyltrimethyl ammonium bromide (CTAB), which enhanced the hydrophobicity of the ion–association complex resulting in improved extraction into chloroform. The extraction was carried out after adjusting the pH of the water sample to 1. The uranyl ion was back extracted from chloroform layer with nitric acid for determination by ICP–OES/FI–ICPMS. Some effective parameters for complex formation and extraction, such as volume of extraction and disperser solvent, extraction time, pH and concentration of the chelating agent and surfactant have been optimized using ICP–OES. Under optimum conditions, enrichment factors of 11 and 25 were obtained from 10 mL of water sample for determinations by ICP–OES and FI–ICPMS respectively. The calibration graphs were linear in the range of 5–200 μg L−1 and 50–5000 ng L−1 with limits of detection of 2.0 μg L−1 and 30 ng L−1 respectively for ICP–OES and FI–ICPMS. The method has been applied to a few groundwater and seawater samples. The recoveries obtained for uranium(VI) in groundwater and seawater samples spiked to levels of 10 and 5 μg L−1 were 90–105% respectively. The results obtained by the proposed method have been cross validated by laser fluorimetry.

An attempt was made to isolate selenite-reducing bacteria from a contaminated lake that receives industrial effluents and domestic sewage. The isolated dominant bacterial strain AJK3 was identified as Bacillus cereus, based on biochemical characterization and 16S rDNA sequencing. The time dependent selenium removal at different selenite concentrations monitored with ICP-AES indicates the substantial selenite reduction capability of the isolated strain. The selenium nanoparticles produced during the bacterial reduction of selenite were analyzed with UV–visible spectroscopy, X-ray diffraction, transmission electron microscopy, zeta potential measurement, Fourier transform infrared spectroscopy and Raman spectroscopy. The nanoparticle synthesis was confirmed from the red colour emergence in culture broth and wide UV–vis peaks. The produced nanoparticles were polydisperse, spherical, size varied from 50 to 150 nm and the mean particle size was about 93 nm. The amorphous nature of the generated nanoparticles was confirmed from the Raman spectroscopy, XRD and SAED patterns. The IR data and zeta potential values substantiated the protein capping of the produced nanoparticles. Thus, the present study suggests that the isolated bacterial strain can be exploited as a prospective, renewable, natural, nanofactory for the bacteriogenic synthesis of nanoparticles. Also, the study has application in bioremediation of selenite from the contaminated environment.

Abstract Background The disposable plates made up of plastics such as polythene, polypropylene, polystyrene, polycarbonate, polyvinyl chloride, etc. pose health risks due to the release of toxic chemicals; bisphenol A, melamine, vinyl chloride, and phthalates. The usage of disposable plasticware not only depletes fossil fuels but also causes microplastics pollution. Thus, thrust has been shifted to utilization of disposable plates made from plant leaves, which are renewable, biodegradable, and enriched with antioxidants and medicinal values. Results In India, serving food on leaf dining plates is a long-standing tradition with its own cultural, religious, medicinal, and socioeconomic significance. The leaf plate stitching is a livelihood activity for tribal people in Odisha, Madhya Pradesh, Chhattisgarh, Andhra Pradesh, and Telangana states of India. The leaves and leaf plates are used for offering naivedyam to god during worship and distribution of prasadam to devotees. They are extensively used for serving food during marriages, religious festivals, community feasts, etc. The leaves from a vast variety of plants are used as dining plates, food wraps during steam cooking, grilling and frying of various dishes, and food packing material in India. Conclusions The biodegradable leaf plates have vast potential in international market, which should meet in terms of quality and design. To sustain the practice of using leaf plates and discourage plastic plates; necessary regulations should be imposed by the government and monitored through local governing bodies. In addition, school children and college students should be educated and motivated to realize the importance.

Abstract The presence of microplastic (MP) in the aquatic environment is recognized as a global-scale pollution issue. Secondary MP particles result from an ongoing fragmentation process governed by various biotic and abiotic factors. For a reliable risk assessment of these MP particles, knowledge about interactions with biota is needed. However, extensive testing with standard organisms under reproducible laboratory conditions with well-characterized MP suspensions is not available yet. As MP in the environment represents a mixture of particles differing in properties (e.g., size, color, polymer type, surface characteristics), it is likely that only specific particle fractions pose a threat towards organisms. In order to assign hazardous effects to specific particle properties, these characteristics need to be analyzed. As shown by the testing of particles (e.g. nanoparticles), characteristics other than chemical properties are important for the emergence of toxicity in organisms, and parameters such as surface area or size distribution need consideration. Therefore, the use of “well-defined” particles for ecotoxicological testing (i.e., standard particles) facilitates the establishment of causal links between physical-chemical properties of MP particles and toxic effects in organisms. However, the benefits of well-defined particles under laboratory conditions are offset by the disadvantage of the unknown comparability with MP in the environment. Therefore, weathering effects caused by biological, chemical, physical or mechanical processes have to be considered. To date, the characterization of the progression of MP weathering based on powder and suspension characterization methods is in its infancy. The aim of this commentary is to illustrate the prerequisites for testing MP in the laboratory from 3 perspectives: (i) knowledge of particle properties; (ii) behavior of MP in test setups involving ecotoxicological test organisms; and (iii) accordingly, test conditions that may need adjustment. Only under those prerequisites will reliable hazard assessment of MP be feasible. Integr Environ Assess Manag 2017;13:500–504. © 2017 SETAC Key Points Understanding the environmental behavior of microplastic (MP) requires extensive knowledge about its physical–chemical characteristics; the relevance and implementation of an improved particle characterization for meaningful ecotoxicological testing is elaborated in this commentary. Microplastic in water bodies must be perceived as a mixture of particles with diverse characteristics, and the importance of single parameters for assessing the environmental hazard of MP will be prospected. Because MP in the environment is subject to changes due to weathering processes, the investigation of both pristine and weathered MP under controlled laboratory conditions is recommended, and challenges regarding the characteristics of weathered particles are discussed. An improved particle characterization of MP is the basis for understanding the relevant differences between well-defined and weathered as well as environmental MP and the key to interpreting ecotoxicological data and finally improving hazard assessment.

Through magnetic field-assisted hydrothermal synthesis, high thermoelectric performance of SnSe is obtained due to Se quantum dots and smaller nano grains, leading to enhanced density of states and energy filtering effect.

A simple and novel sequential mixed-micelle cloud point extraction procedure has been developed for ultra-trace speciation analysis of thallium in environmental water samples by inductively coupled plasma mass spectrometry (ICP-MS). A mixed micelle consisting of sodium dodecyl sulfate (SDS) and Triton X-114 is used as a chelating as well as an extracting agent. Tl(III)–DTPA (diethylenetriaminepentaacetic acid) complex in an HCl medium is extracted into a surfactant-rich phase in the presence of Tl(I). The Tl(I) in the supernatant is subjected to a similar extraction procedure after bromine oxidation. Ultrasonically assisted back-extraction is used to extract the Tl(III) species from the surfactant-rich phase into a small volume of aqueous L-cysteine. The pre-concentration factor and detection limit are 125 and 0.02 pg mL−1, respectively. The recoveries are in the range 98–103% at 10–20 pg mL−1Tl(III) with relative standard deviation (RSD) of 1–3%. The procedure is validated by comparing the sum of the concentrations of individual Tl species with total thallium concentration in certified reference materials such as Trace elements in water NIST SRM 1643c and Open ocean seawater NASS-4 and NASS-5, and also by applying it to various samples collected locally.

A ‘water in oil’ emulsification procedure has been applied to a transverse heated electrothermal atomic absorption spectrometer (TH-ETAAS) for direct determination of Ni and V in petroleum products such as naphtha, NIST SRM 1618 Residual Oil and NIST SRM 1634c Residual Fuel Oil. The utility of permanent chemical modifiers such as W, W–Rh and W–Ir, has been examined in determining these elements. The furnace with an integrated platform coated with W and Ir was found to provide 25–30% improved sensitivity than other coatings for Ni. In the case of V, a pyrocoated tube with an integrated platform was found to give the best results. The W–Ir coated tube could be used for nearly 400 firings. The limit of detection for naphtha emulsion was 0.002 and 0.006 µg g−1 for Ni and V, respectively, indicating that the method is well suited for matrices containing very low concentration of trace elements. The method can also be applied to dense matrices such as SRMs Residual Oil and Residual Fuel Oil. In this case, the limit of detection was 0.1 µg g−1 for Ni and 0.5 µg g−1 for V with a precision of less than 5%.

ATCC 35218. Bacteriogenic nanoparticles were methodologically characterized employing UV-vis, XRD, Raman spectroscopy, SEM, TEM, DLS and FTIR techniques. Generation of nanoparticles was visualized from the appearance of red colour in the selenite supplemented culture medium and broad absorption bands in the UV-vis. Biofabricated nanoparticles were spherical, polydisperse, ranged from 100-183 nm and the average particle size was about 155 nm. Based on selected-area electron diffraction, XRD patterns; and Raman spectroscopy the nanospheres were found to be amorphous. IR spectrum revealed the involvement of bacterial proteins in the reduction of selenite and stabilization of nanoparticles. Used bacterial strain demonstrated efficient selenite reduction capability which was evident from 89.2% of selenium removal within 72 h at a concentration of 1 mM. Observation noted in the current study highlight the importance of bacterial reduction in selenium nanoparticle generation which can be scaled up for commercial production. Also, the bacteriogenic, amorphous nanoparticles can also be used as nutritional supplements for humans since selenium nanoparticles of 5-200 nm are bioavailable and known to induce seleno enzymes involved in antioxidant defence.

We present an approximate theoretical treatment of pressure and viscous heating effects on the flow of a power law fluid through a slit die. It is assumed that the flow remains one dimensional, and the accuracy of this approximation is checked via finite element simulations of the complete momentum and energy equations. For pressures typically achieved in the laboratory it is seen that the one dimensional approximation compares well with the simulations. The model therefore offers a method of including pressure and viscous heating effects in the analysis of experiments and is used to rationalize experimentally obtained pressure profiles for the flow of polymer melts through a slit die. Data for the flow of a linear low density polyethylene and a polystyrene melt in a slit die show these two effects are significant under normal laboratory conditions. Thus, the shear stress–shear rate curves will be affected to the point of being inaccurate at high shear rates. In addition, it is found that the typical technique to correct for a pressure dependent viscosity is also inaccurate being affected by the viscous heating and heat transfer from the melt to the die.